Fundamentals of veterinary clinical pathology 2nd Edition

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s, ....... L S'ockham, DVM. MS. Diplo"",,,,. American Cou.g. ofV."'rinary Pathologist. (Oinical P:othol· ogy): Prokssor in tho o.partmCeS :and in""'. ISBN.]3: 978-0-S138·0076-9 (:d.k. p"per) ISBN·IO: O-S138·0076-5 (:d.k. p"per) I. V... rirury clinical p"thology. I. Soott. Mid.. el A. (Michoel Abn). 1957- II. Title. [DNu.t: l. Animal Dis....... p"thology. 2. Cliniul LIDo"'OOY Tr
e. Pwm.

I. Pl..,m. is the fluid component of blood th . t is ru.rv<Slffl .fw ctntrifug.tion of an amicwguJ.t.d blood sampl... PjasJrul will contain the .ntj~Jant th.t can illt.rf.t. with some :uu)"l. 2. Anticoagulants ust {2} M.jor disadvantages (a) Alters morphologic fe.tures :md staining of lrnkocyt.. {b} Allows dotting:as efh:t. are slowly o""rridd~n by the coagulation system {c} Allows platd" dump' to form

1/ INTRODUCTORY CONCEPTS

7

3. PI.. ma h.. two IIUjor compon~nts. a. Water: .bout 92- 95 % of plasma volume; 100 ml of pl ..1IU contains 92- 95 ml of H,O. b. Solid" about 5-8 % of plasma volume. Most ",lid. ar~ prot~in' on a _ight per volume (w~ightlvolume) basis. Other ",lids are glucose, ure., electrolyte., and other chemicals. 4. G..nerally, the chemicol compo.ition of plasma is very ,imilar to interstitial fluid in moll tissues. Plasma and interstitial fluid are the a tracdlular fluid. , one intraVll5Cll_ lar and one atravascu.lar. D. Serum I. s"rum is the fluid component of blood that i. harvrned after centrifug>tion of. coagulued (clotted) blood sample. As deKribed in Cru.pter 5, the clotting involves platelets .nd coagulation protein,. To 1:"1: the ffillimal .mount of ""rum from the clotted sample, centrifugation should not be ,uned prior to the retraction of the clot (which typically uke. at I.... st 30 min if. clot actiVOltor is not pr=nt in the tube). If samples are centrifuged prior to clot retraction, some ""rum will be tr~pped in a ",ft fibrin clot. 2. s"rum ha. essentiaUy the 1mle romposition .. pl"'ma except ""rum does not contain most of the coagulation proteim. Th~ Imjor prot~in {on. weight/volume b",is} that is .bsent in ""rum but present in plasma is fibrinogen. 3. During the clotting process, substance. rel=ed from "d is .her the analyte roncen_ trations in ""rum. For aample. platdets rel......, K+, and thu. ",rum [K+] is greater than pl .. m. [K+] (..,. Chapter 9). [I.

Urine Sampl~s A. Other than blood, urine is the most common sample .nalyzed by laboratory """'ys. AI with blood, urine must be collected and processed properly", that the =y reruh, reflect the true composition of the product of the urinary system. B. To prevent .nifactual changes in urine, it ,hould be processed soon .fter collection. Gen~ral guidelines for the collection and processing of urine for routine .nal)"'e5 are d=ribed in Cru.pter 8.

Ill.

Other Body Fluid £amples A. Pleural fluid. peritoneal fluid, synovia, and cerdJrospinai fluid samples are collected to characterize body cavity effusiom, joint di"".,e., and central nervou, system dilOrder.'l, respectivdy. B. The processing and ru.ndling of covitary fluid. are deKrib.d in Cru.pter 19.

MAJOR lYPES OF lABORATORY ASSAYS I.

M.ny laboratory tests or assay. involvt the an.lyli. of body fluid. (blood, ""rum, plasma, urine, peritonral fluid, pl~ural fluid, cerebrospinal fluid, and .ynovia), tissue 1mlples, or feces. Most clinicall. boratory procedure, fall into one of thrtt large groups (aamples follow .ubdivi,iom); IIUny procedures rould be cl.... ified into more than one group. A. Clinical hematology assays: Most assaY' are completed on whole blood sample •. I. Quantitation of cell concentrations in blood: total leukocyte concentration {count}, erythrocyte concentration, and platelet concentration

B

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY 2 s"miqlLOmitation of cdl con~mrations: ",lculata! abwJuu J.ukocyu coIIrtal as 3.0. C. Wh~n tq>Oning "'mlu from additions or mbtractioll! that use two or more numbt" with appropriate signifialm figu",". th~ final calmlatal r~.ult should havr no more significant figures than th~ numbtr{s} with th~ f.west signifialm figures. For 1.23 + 2.4 = 3.63. the sum should bt ",]>Onal as 3.6.

II.

[t is f"' 1.2 X 10' 3. 1145 --> 1.1 x 10'

Ill.

How many significam figures.", in a numbtr? s." T.bl. 1.2.

[v.

U.rIing 'yn~m' will r mol.

mol

millimole, 10-' mol micromol., I mol nanomole, 10-' mol picomoJ., 10- 11 mol femtomole, 10-" mol anomol., 10-" mol

mmol

cr

,mol nruol

pmoJ fmol amol

L

liter

dL

decilitor, lO- 1 L millait"', 10-' L microlit .., [crL nanol;,«, I ()' L piroliw, 10-" L femtoliter, 10-" L anolit", 10- 10 L

mL ,L oL pL fl.

.L

,"

kilogram, 10' g

m,

milligram,lo-'g

"0,

micrognm, 10-' g nanogr:ml,lo-' g pirogram, 10-" g femtogn m, 10- " g

pg

""

w· m

aooll·m, lo-IOG

omer £lYle" NIST style

Non_NIST

Symbol, un:dtc=i in the plural

20 PC

20 pg.

Symbols not follow . - ••

T ..... '.6. C-........ ol .....sI-n. .. S1 .....

A.odyl" Aa . . .

,cr"

,>t.

..".'""'-, .-'.'-

.-' .,,-, -, • --,-, ..-. -, "'-, -, .-' -, " -.' .'" ........

~-

AIOO . ......

l\-HydoOI)l>'",...' ocire .. nt the refer~n"" population 4. Rifrrmu !!dlur. • value {result} obtainM by oburvalion or m~asurem~nt of. panicular ,ubstan"", in a ref~rencr individual 5. Rifrrmu dhtriburion: Ih. distribution of r~f~ren"'" value>, which i. not n=sarily Gaussian {a kll.,haprd curve} 6. Rifrrmu limitr: the lowes{ value {Iowa ,ifnmu limit} and the highest value {upp" "fi,au:r limit} of the rrftren"'" interval, a. derivM from a ref.rencr dinribution 7. Rifrrmu inurVdl: an int.rval be-iw..:n and including th~ two ref~ren". limi" 8. Qb"""d !!du.r. a value ob,.inM by observation or m.asurement thaI i. to k comp.red to the r~ftren"'" interval C. Use of th~ term "fi,ma mngr i, discouragnl for two r"'Kln,. l. Sutistically, a 'lint' i. th~ differen"" be-iWttn high'" and lowest observations: for example, the r:mge i. 40 if th~ high'" observation wa.< 50 and Ihe lowest wa.< 10.


17

2. Some comid" a ranu to indude all m.-amr the values betw..,n two "f."ncr limit .. D. Using the t"m. nCrmIll and "bnDrmIll to de",rib. laboratory test result, am b. mi,le"". ifll: and i, discouragffi. I. A l.boratory ..suit con b. WRI but niH rdlttl a pathologic proct:M. For aample, • strum sodium concrntration that i. WRJ in a ddtydratc< dinribution .

• la tho left graph. tho rm"''''''' ....1ues oonformtraumatic ""nipunctu.. to minimize: h~molysis ~nd activation of clotting pror.ins ~nd platd.,.,.) c. PfOJ"'r coll=ion contain~r (.,.g.. st~ril~ v~r.",s nonn~ril~ or clot rub.: vc:rsus an EDTA tu~) d. Pro~r .ntico>gulants wh~n n~M {•. g., EDTA vusu. h~parin, or wdium heparin vorsus lithium h~parin} •. AdaJuat~ volum., for ous;oys (•. g., to obuin I mL of .. rum, • volum., of at l=t 3 mL of blood is usuaUy n~MM) 2. S;,mpl~ handling a. Pro~r lobding of all specimens (".g., .nimal id~ntificotion by nam~ or number, dat~, and tim~ of collection) b. Samples kq>t at appropriat., t~m~mur., prior to and .ft~r proc=ing, during shipm~nt. or during stong. {•. g., 25 'C, 4 'C, or - 25°C} c. Prompt proctlsing {•. g., for a labil~ analyt~, proct.. immMiatdy so th., .nalyt., does not d~t~riorat.,} B. Analytical n-roys should be minimi=:! by att~ntion to th., following: l. M~thod appropriat~ for species {•. g., an instrument designed to m...."'.. th., rdativdy brg.. human ~rythrocytes may not provid~ """unt~ m~..... r~m~nt of small~r ~rythrocyt.,. from the domestic mammal.} 2. Quality of innruments and aJuipment (i.~., g~n ..ally 'you g~t what you pay for," but • qu. lity ifi!trum~nt remain. a quality instrum.,nt only if it is properly maintainM) 3. Quality of rragI

cv (expr~ssaI as a ~re;.,nt"l:~) =

23 standard drn..tion

X

100

{LL}

m~~n

a. A

m~thod·,

CV i, deurminal from rq>li"'t. analytis within an .....y run and run, of th. sam. assay. A wimin-resenu aruolytiml ~rror. An """y' _ CV wiU typically vary with the analyte·, con"'ntration. High~r CV valu.. may be found at the lower and up~r limiu of the .....y', IDalytiml range. Within th. analytical range, CV values are typimlly higher at th. lower analyte ron",mration, kause CV values are exp=W .., ~rcentag ... (a) If ID assay has a CV of to % ~t all rone;.,ntrations, then the .... y', nandard d~iation would be 0.1 mgldL at an analyt~ cone;.,ntration of I mgldL, I mgldL at an analyte concentration of 10 mgldL, 10 mgldL at an analyte cone;.,ntration of 100 mgldL, etc. Depending on the analyt. and th~ amount of biologic variation, a CV of 10 % am be completdy unaccq>tabl~ aruolyticaJ variation or be very a.c 13,txXl/j.IL to bt rdi.bly

oonsid,,«1 a biologic changlory (est .. mh, a Jarg, The ..fore, for th~ strum gluco ... a .... y to ~ clinically valuable, its '=pcabl. random onor can ~ largtr thall tho ralldom .nor of the .. rum Na+ :way, B, Westgard rules. James 0, Wmgard, Ph,D" is • leader in tho fidd of quality :wurance progr.ms for clinical laboratories, H e has d.vdop«l a system that i. desigll.d to da::ide whether an =y'. run .ite npt.im th~ k." concepts {http://www,wostgard, rom}, L A quality as.mrance program should ~ d •• ignffl '" that it detects analytical erron that llliIy ~ of clinical significallce, All measuremellts colltain erron, and tho two IlliIjor types are random error and S)"tematic «ror, Random error i, cu m by facton that randomly affect tho meamrements, such as vari ations ill disptnsffl ""lum. of rea!:"m or umpl~, SysullliItic ~rror is a rq>roduciblo inaccuracy that will ronsistently muh in value, that are too high or too low, Th~ Westgard system is d .. igllffl to detect both types of erron, 2, W'..gard ",k, a", a stries of rules that are appliffl systematically, oith~r sillgly or ill combinatiom," This >ystem i, appliffl to tho results ob[ained for control ... mples that a", analyzed roncurremly with pati~m samples, In his abbreviation >yn~m, "s" , cands for ,candard devi ation, a, I,. rule: A rull is rrjecud when a .ingle control m~asurem~m nettds the m~at1 plu, ls or the m ....11 minus ls of pr.vious control sample values, or it .. rves :as a warning system [0 illitiat~ additiollal inspection of control data. b, I" rule: A rull is .. jectffl when a .ingle control m~asurem~m nettds the m~at1 plus 3s or the m ....11 minus 3, of pr.vious rontrol ,ample values, This rul~ is primarily ... nsitivt to random ~rror,


3.

4.

5.

6.

27

e. 2,. rul~ A rull is ..j=a! wh~1I two colI!«mive comrol m~asur~ments nettr.ble random .nalytica.l error. The less impr«ise the ''''''y is, the mo .. likdy it is that. high or low control ... mple v:due will truly indicate a problem with [he assay and the I.... stringtable). If, b.saI on knowl~ of biologic variations, wr imerpret two v:du .. that ..e within to mgldL of ...ch other a[ a d",ision threshold to be the same. then we will colI!id.. such error as acceptable or .Jlov,able. Thu., the allowable total error (fEJ for .n assay is 10 mgldL a[ a d«i.ion [hreshold. Erron of [hat magnitud~ or less will not .ff"'t interpretation of the results. TE,. must be d~termillM at dinica.l d",isioll thresholds, the values a[ which d",isiolls about the p....llce or ab",n"" of diseaR are made.

2B

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY

'" '00 ,,-

t< uulyzM with .,m .., of p.tient umpLes, .00 ,esults of .:och control . oluno ... ar< pLotted in .. par ... u..y-Jrnnings oontrol cbar"'. For other ....Y'. rontrol solutions might b. rnalyud with eadt shift (•. g., iV R&.uIIs of sa"", method 00 diffemol instruments (n • 19-111) _ R&.utts of sarno method 00 oa"", instrumool(n. 12- 15) Fig. 1.5. Resul", from umilar:and differ.nt .. soy m ... in agrttm~nt when thq product ess.ntially th~ same .. mit from the ",me ..mple. A. Importantly, results may"" mongly corrdatM but not in agr.,.m~nt. Line~r rq: ..... ion con "" used to establi.h • relationship ""tw..,n independent .nd d~ndent v.riables. If two ....."..re m~mpting to me~JUre th~ sam. an.lyt., thry should ha"" a relationship, but neith.. measur~d value i. a d~ndent v",iable. B. The mC< is 2 mmollL (bia., - 2 JIUDOUL). li.... "'pr
25

1 (ImIOflJ

~

,l'--_-_-~

:J\

Fig. 1.7. D.ming .00 Passing 6< Bablok method comp.mons. Th. remJ", ""'.. tobubtprn. Th. analy>i, of th. two gnp!.. , " " , I r a mikl proportional bi.., tbat ill. th. . !>solu« differrnc< be""""" th.
rang. more bro:odly. d. Figu... 1.6 .nd 1.7 show excdlent oorrd.tion (f = 0.98) ~tw""n d.na ~5, but th. bi", plots illustrate th ... js a bias ~tw,""n the ''''''Y'. 3. [n Ih. Deming method, imp=:ision is allowed in both method, .nd the variance" must ~ normally dinributed {i .•.• it is. p>':mle'lric aruolrsi. method}. Th.
rum

Comparison of Urine Heme Reactions: Reneclance Photometric versus Visual Grading

H > " 0

-,,,

""G"~v"

I ""!Jat.....

R.m"'ctanC8

, ",

,~

"" 0 0 0

, , ",

, ,, ,

ic Grltdinll

0

0 0

0 0

0

Wetghted kappa value. 0.78 Interpretation guidelines

0.20 ~ 0.39

F";r

0.OO ~ 0.19

Poor

, I , • 0 0 0

,

Fig. 1.8. K.pp •..,.groement d ... for urin< he"", ,u"tion. Aft .. dipping the ruction pad in tOO u,in< ''''''ple.. the color cltrn~ in a horne-,e:ote 2 Di:ognostic mppon =1 b. .vail.bl. &om nteri",,'Y clinical pamoJogim in the laboratory. 3. Ref.ren"" illt.rv:.!, should b. .ppropriat. for the .~j ... 4. Mon laboratori., have a qu:dity m~m.nt .yn.m in pi""", to hdp enSUf. qu:dity results. Th •• yn.m oli.n includ.. proficiency testing by an at.rnal group such that pftrs. 5. Many more di.gnonic assays ... typically available than "r .vailabl. in .n in_hou .. laboratory. 6. Th. eost for sample analysi. i, more clnrly determined and thll'l can b. chargffi to th. e1i.m on ...mpl~by_sampl. basi,. B. Di..dvantago' l. Not .Jl.n:olyt..." st.bl•• nd thus ",m. dff.riorat. during shipm.nt. Som•• n:olytes requi .. sp«ial shipping. 2. Turnaround time, V:lf}' with location: wme ... av.ilable the .. me day, .nd most a.. a..... il.bl. th. next day ucept for .peci:ol um. Somelaboratorie. off.. couri....",ice and n:JUlu "ported via fax ma.chin.. or e_mail.

,,,,,,,It•.

[v.

Laboratory in loc:ol human hospit:ol A. An adv.mage i, that turnaround times am be within hours. B. Di..dvantago' l. Quality ..f..ence interval, fur veterinary .ampl.. may not be establiohed by the laboratory. 2. )"say mffhod, may not be appropriate for veterinary sampl ... 3. Technician, .nd technologist, may not be trained to rorreccly idemity .peci.. variation, or di,..,..." that are unique to veterinary sampl... 4. Pathologists who specialize: in human pati.nts frequ.ntly a" very int.... t.d in hdping, but lack the training in th. di"'.... of domncic animal, .nd variation! lttn in veterinary sampl... 5. Th. f= charged by laboratories may be "latively high. C. Testing in local laboratori.. that .peci:oliu in human m.dicin. should gen.rally be avoided.

EVAlUATING AND VALIDATING U.BORATORY METHODS" I.

Re"",ns for tients th .r do not have the di",... of interest (Eq. 1.2b) 2. A test tmot has high diagnostic .prcificity COlI k a good one for confimling tmot an .nimal has • dis..,... kcau .. the ten has vtry few FP results. If the result is positivt , thert is the prevalence of the dis..,... in the studi«i population? The effect of prev._ lence i. illustrated in F~. 1.10. Basically, when the di ..... prevalence is very low, it i. more likely that there will k FP resulu. Conversely, wh.n the di ..~ .. pr:mu •• a positive reru.lt from a neg .. ive result? Extentivo evaluation of.n atS1)' i. somst btc.ust 27 % of ""limn with th. di ..= h;,,,,, valu .. of 40 mgldL or I. ... c. This example emphasizes that for many diagnostic tests •• nimah with and without the di"'''''' of inte..st may have the .. me .....y result. 2. Anoth" key concept rdated to this illustration is th . t e.ch ROC curve .. prestnts the resulu obtained from one sampling of the defined popubtions by using on. assay:u it compares to one gold nandard. Anoth" sampling ming the same sdection criteria, the same assay, and the same gold nandard probably will not produ"", the ... me ROC curv• . F. F.cton oth" th.n the probability of correctly classifYing .n aninul .. having or not having a di"'''''' can influ. n"", where decision th ... holds "'" ost . blished: I. If the monality rate is very high for a dis ...... that is not treated promptly, the decision thr..mold may be changed 50 that th"e ... few.:r fal .. negative>. 2. If the dist ... is known to cause I"'in or unreasonable discomfon, the decision th ... hold may be ch . nged so that there are few" f. lst negati=. 3. If the tr .... tm. nt i. known to ha"" "",ere .ide effects, the deci.ion thr..mold may be ch anged so that the", are few" f.l", positives. 4. If the fin:mciN on exp"ri~n~ and r...euch. Giv~n th~ int~rloboratory ",rittn ~valuata! in ~~ral ways. I. M.,n h~rd v:.!ue; truly b. comp.ral to mean ",lue; of ",f~ren"" h~rds. When metabolic profiling was first describal. th~ ..f..~n~ int~rval for an a""lyre was defina! as th~ m.... n of its me' n! for r~f.."n~ h~rds. ± 2 sd. How~""r. th~ .. h~rd ",f..en~ inte",:.!, .re not re.dily .",il abl~ beau", of the ex~n .. of te;ting and diffirulti~, id~ntifying ,uitabl~ ref~ren"" h~rd,.

2.

M~.n h~rd

v:.!ue; truly b. comp..ed to an e;tabli,hed expecra! m....n result for the and group of int.... t. For exampl~. it has !>ttn 'ug~ned th .r m.... n urin~ pH ,hould b. 6.0-7.0 in prefre,h row, fa! anions to hdp prevent milk f~~r. A m~.n pH of 6.0-7.0 mpports appropriat~ acidification of th~ group. When the herd·, m.... n ± an un~rtainty int~rval doe. not includ~ 6.0-7.0. a h~rd·. urine pH i, cons.ideral inappropriate. When th~ herd·, me.n valu~ is not 6.0-7.0. but the mean ± un~nainty int~rval o""rlaps thi, tatg"t. the results are cons.id",al bord..line. A 75 % confiden"" int~rval ha, !>ttn mggesta! as a u",ful guid~ for metabolic profiling and a reasonabl~ compromi'" becw",n 95 % confid~n"" and practicality. 3. The !",/"Centage of individual results abo"" or b.low an establi,hed d«i,ion threshold may b. calculata! and compara! to what i. con.sid~ral an a=ptable !",/"Centage of high or low ",lue;. A p"rctntag~ (± un""rtainty int~rval) gr~at .. than th~ a.cctpted p"rctntage 'ignal, a problem. A p"rctntagt and confid~n"" int~rval overlapping with the accq>ted !",/"Centagt is a bord~rline r~.uh. D«ision thresholds may "" "'m~h at artificial in that the ri stimulnr diff... nt;",ion .nd prolif".{ion of B.lymphocyt.. and T .lymphocyt... 2 lymphocyt~, Jeav. lymph nod.. vi dr.rent lymphatic v....d, and .ntt~ to lymph nod~ corti= via .p dT~ .. nt lymph atic """ds. and ",rurn to blood. 2. About 25 % of blood lymphocyt.. ~nt~r lymph nod .. ~ach d"Y through postcapil. lary v~nul... which han uniqu~ tall ~ndothdial edl. and r~tor>. D. Lymphocytes ill oth~r tissu .. I. lymphocyt.. ~migr:lt~ to ti ....... to ""rform functions. Th~r~ thry moy und~rgo blmogtn..i., ~nt~r lymph atic v....d. to mum to blood. or di~ . 2. Lik~ n~utrophih. migr:ltion to tissu .. invol"". lymphocyt~ ch~motaxis .nd bindillg to ~ndothdial cdl ~tors. E. M.jor processel that influ~n'" m~asurw blood lymphocyt~ con"'ntratiollJ I. Production a. Sum cdl prolif~ .. tion and diff~ .. ntiatioll b. BI.. tog~lI ..is 2. Distribution of lymphocyt.. k!w""n th~ CLP and th~ MLP a. Migmioll from blood to lymph nod...nd oth~r tissu~. b. Migmioll from lymph nod .. via ~ff..~nt lymphatic v....d, to blood F. Lymphocyt~ lif. .pall varies from hours to )""'Irs. Monocyt~

IV.

pooh and kinetia A. Monocyt~. and naltrophil. sha.. a common bipot~ntial st~m cdl {CFU.GM} that i• • timul>lw to diff~r~miat~ by inflommatory cytokill". B. Monocyte. dn-dop from mOllobwts and promollocyt... Wh~1I rd~ased from morrow. monocytes distribut~ ~n m..ginatw .nd circulating poot.. C. Lik~ oth~r leukocyt... monocyt .. ~migrat~ to ti ..!U~. aft~r binding to .ndothdial edt.. 011'" in tissu ... monocytes may diff~r~miat. into cdl. of th~ mOllollucl~.r phagocyt~ .ynem: macrophages {including Kupffer edl ••• lvrol.. mocrophagcs. and type A .ynoviocyte.l. microglial edls, or d~lIdritic ",H•. I. Th~ rming ma.croph~ is sometimes callw a histiocyt~ or fin-d macroph~ 2. Delldritic cdls ar~ .ntigen.pr=nting ",lis. Examples includ. the ung~rhans ceUs of the .kin and im..digiming ",lis in lymph nodes.

V.

Eminophil pools .nd kinetics A. Eosinopoi..is is stimulatw by 'J"'Cific medi ator>. illcluding IL-5 {msinophil differ~nti •• tioll f.ctor} and GM·CSF from ma.tion is increased. the di",.,e is causing at l.ast on. of the following: a. Inc",.,ffi production of that ",ll type b. A shift of that ",II t)'~ from a no~ or noncirculating pool to circulating blood c. An incr.....d circulating li£. span of the cdl typkocytes for morphologic abnormalities and record the findings. 2. Microscopic enmination of a nain.d blood film is especially imponant in sick patients .nd Ihose with .bnormal concenlr.tions ofleukocytes. erythrocytes. or plaldeu. o.,fecu found in th. blood cells.", described in Chapters 2-4. F. Staining of blood ceUs I. iWmanoWiky 'taim. which .re the best for staining blood cells. were described by Romanow..ky (1891) as. rombination of eo.in and methylene blue to produce. spectrum of colon from blue to raldi.h orangt'o depending on Ih. pH of the cell·s rontent. a. Wright IMin i. a combination of "".in and oxidized methylene blu •. The oxidized methylene blue nains are call.d /Wi" dytl. b. Other Romanow..ky stains include Giemsa. W,igh,_Gi.msa. and Wright_ Leishman. which are ... rious combinatioru of a7.llrr dyes and "".in. c. Generally when staled or w,itten. "Wright" nain ..f.rs to • Romanow.ky_type stain and not the otiginal W,ighl stain.

mapes.•

62

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY 2. Wh at."" th~ oont~lIIs of sin dye and ,c.in Slructures from ral or pink 10 orang•. 3. T.rms usa! to doscrik colon or staining proptrties a. Nrumphilje: n(urro (n.ilhor alkaline nor acidic) pJu.s phiuc {"loving"j b. E~linqphilk: loves «>sin {.cidic} dre; will'" rw to orang. c. &',ophilic: Joves b.. ic (:dkalin. :md nur.) dy.. ; will k blue to purple d. Azurophilic: Ions ..ure dye; will h.ve a blue to purple to reddish purple to pink oolor dq>. Bts.id.. tho .. ch.nges associatffl with pathologic nau" in vitro changes amsffl by poor s;omple handling con mah accur:ll< identificotion of leukocyte, n... rly imJ""Sible. B. [WBC] l. [WBC} i, the number of leukocytes ~r unit volume of blood {in clinical jargon, commonly r.ferted to as WBC rount}. The [WBC] by it..,lf is of limitffl value without asses.!ing the con""ntrations of e. ch ty~ ofleukocyte. 2. By wme method" the [WBC] actlllly i, ~ total nucle.tal cdl con""mr:ltion. If it i. , the [WBC] must be correctffl when nRBCs.", pr...,nt (0« correctffl [WBC] in Eq.2.l). 3. Unit conversion: "'J.IL X 10' J.IUL _ " X IO"L (SI unit) C. Differential leukocyte count l. A diffirmtial ltuktlcyu count is ~ method of determining the rda ti"" numbers (or the ~r""nt:lge.) of the l""kocyt .. in blood. 2 Raw data :He reportal ., ~r""ntage. (e.g., 80 % neutrophil,). These ~r""ntage. plus the [WBC] :He USffl to calCllJ.te th~ con""ntrations of each ty~ of leukocyte in a blood ..mple.

Ill.

Principl.. of determining l""kocyte concentr:ltion. A. Hemocytometer method l. A hemocytometer (Fig. 2.4) is u..,d to determine [WBC] by diluting the blood {mually with the Unopette system} .nd then dispensing the dilutffl blood into the hemocytometer chambers formffl bene . th • cover glass. The leukocyte diluent contain, a lysing agent that rupture. the erythrocyte. 50 they do not interf~re with the nucleatffl cell enume.. tion. 2. The chamber is examinffl with a microscope:, .nd leukocyte, at< countffl within the 0.9 J.Il volume of Huid dem:Hcotffl by the nine large ""Ilres. To obtain. leukocyte concentntion, the number of leukocyte. countffl is lim muhipliffl by l.l to

2/ LEUKOCYTES

63 Hemocytometer

~ Elf

1- ------ - --- -- ---

r' , ~

~

l mm peCioJ Ilowi"ll fluid, The Iluid dynamics in thr 'J"t<m ",eat< a ,I>< dil""'t to form a umplr ",.. m, eeUs in tl>< .....pLe st,. .m pass througb a w., br:un, monly 0 . . . . . . timr, Each erJl "'....... tho light in dilf< I.... brant,

"",ud

'p""

{I}

Th~

[WBC] .nd th~ blood [h~moglobinl are d~rrminffl in dilutffl blood

aftrr cdl, (l~ukocyu" ~rythrocytes, :md platd~u) .'" Iy=' but nucl~i r~main as !""tides, {2} In da .. ic impffiancr m~ho{h, th~ [WBC] i, r~ally. total nucJ..at~d alJ ron<Jrmr>tion b«au.. the nucl~i from leukocytes .nd nud~~tal ~rythrocyt~, a,e not diffe",miatffl, C. Optical or la,., How cdl cytometer> {e,g" CELL-DYN innrument', ADVIA, .nd IDFXX LaserCyte Hematology Analyzer} L Basic principl. {Fig, 2,5}

2/ LEUKOCYTES

65

a. Lastr light i, satt~rM when it hits. cdl. Th~ tyP' of scatt~r d~pends on cdl .iu. inr.mal structu... gr:mularity. and mm."" structu... and th= f.... tures ar~ USM to diffe .. ntiar. cdls. b. Instruments may ~ abl~ to diff... ntiar. the major l.ukocytes. but computstic ""lls}. basophils (in human sampl..). and polymorphonucl.... r cdls {neutrophils .nd eosinophils}. Conine and fdine b"",phib a.. not delectM by th" basophil ch:mnel. c. If th~ .. are erythrocytes that are wi",:mt to lrsi •• the [WBC] of the peroxidase channel will ~ falsely incr~• ..d. but th" basophil channel [WBC] should ~ .ccurat~. The pr=n"" of nucl~atM ~rythrocytes is suggested if the "polymorpho. nucl~.r ""II" ron""ntration from the basophil channd i. greater th.n the mm of th~ neutrophils .nd eo.inophil con""ntratiom from th" peroxidase rnannd (u""pt in cau. because th"ir eosinophilt lack peroxidase activity). d In cont .... t to th" microlOOpic differ~ntialleukocyt" count. this el~ctronic diff"rential count differentiates thous;ond, of I.... kocytes. and thus sampling "rror is typically not a problem. How"ve:r. th~ el"'tronic methods mun ~ species specific and may not ~ a.ccu .. te when atypical ""lis {•. g.• toxic neutrophils. and r...ctive lymphocytes} a.. pr=nt. Automated differential counts may ~ con· sidered reliable wh"n ""II populatiom are d ... rly >qlaraud as indicated by ""ruin d"finM crit~ri .. D. Quantitative buffy CO>l {QBC} an.lpi,'· {QBC V.tAutor ...d}

""U,

66


Butry coat

EryIhrocyt...

Fig. 2.6. Scbem. tic "'p,ostion of ...hoI. blood. G.ntrifug..l forces "'I',..t< II.. compo"""'" of blood into fiv< 1.J"'J'lI (pWIIU, pl.",,,, .. , agr=ulocytes, grrnulocym,:md rryth.rocyt"') b....d on 'Mil r.uti ... densin... Tn. buJJy coat (coml"""'d of pb"Le. 4. Th~ . ccuracy of th~ p"nial leukocyt~ diff,,~mial coulll d.".,nd. on the .milling "':lCIiOIll of the leukocyt.. and their d~",iti ... Atypicol stainillg or d~",itie> will /"<SuIt ill ~rronl" in most CBC remh., alld thus diff~tug< _
Low oonfid~n"" limit ""lu.. Neutrophil, Neutrophil, Em.inophil, Eo1ino~hil,

""

X

10'Ij.lL

70

14.0'

30

6.0

4 0

0.' O.~

Actual v..!u..

,,'

X

1001j.lL

"40

16.0'

"

'.if

0

'.0

O.~

High oonfid~n"" limit valu ..

"" "" " 4

X

1001j.lL

17.6 F. Corr«tion of [WBC] for th~ pr~ .. ncr of nUcln!M.rythrocyt.. (nROC,) if th. [WBC] i. r~..!ly. total nud'>!M cdl oon""ntntion 1. Microsropic and som~ d«tronic mrtho,j, drt~rmin. [WBC] by counting nud.atM ""US or nucl~i {.ith~r ofleukocyt.. or nRBCs}. By thosr m",hod. , a mnsurM [WBC] rrprosrncs th. sum of nud"'!M crlJ concrntration, (leukocytrs + nRBCs),

2/ LEUKOCYTES

69

ob",,,,ffi during th~ n:lmination of th~ blood film. thr~

oorrected [WBC) = m=ured [WBC) X Exampl~:

"',.,-:;:c"""':;;;;""'" "" 100 + ffnRBCIIOOWBC

(2·1.1

mltd

ABNOR.,\1AL LEUKOCYTE CONCENTRATIONS IN BLOOD

I.

Abnormal neutrophil con~mrations

A. ufl shift l. A "fi shift {shili: to Ih. HI} is .n inc""....,j cono:mmion of non"'gm~med n..... tro_ phil. (usually baud,) in blood. When th~ .. i, """at d~maud for n..... trophil. in ti"u~,. younger stages {m"':mlydocytes. mydocyu •• and rarely progranulocytes} Im}' b. pr=m iu th~ ldi ,hift. a. u,ft mift, occur when rei..,. .. of u..... trophil, from marrow diminishes the SNP . • nd younger cdl, a.. then rei..,....! from th~ MatNP. The capability of ueutro_ phil, to respond to stimuli .nd migrate iner....' .. they m.,ur~, thu •• ..gmented n..... trophil, respoud fi"t .ud immature forms respond J.t~r. b. Becau.. it usually occur> in ... ponse to rd.,ivdy intense, often acute inft.mma_ tory stimuli, • left shift i. fr"'lu~ndy con,idered the hallmark of ""ute inflamm._ tion. Such infl:mlmation i, rypiGlUy cau...! by inf'n:tiou, "Cenu (~.g., pyo~nic b.icwia, or fungi) but can b. caused by noninf..aioUl ditord~" (e.g., u,""rosis, immuue_medi.oted di ..=, or ueopla'ia). Glucoconicoid hormon .. and eudo_ toxins alto ,timulat~ rd..,. .. of n..... trophil, .ud thu, m.y GlU,. a mild l~ft shift. 2. uft_shift classificatiou. a. Severity, Two diff~""nt f~.tur~s might b. consid~red wh~u d=ribing the !lNerity of a left shift. Siuce th~ t~rm' can describ. differ~nt fiudings, one must b. car~ful iu imerp..,.,ing or using the term •. {I} Immaturity of noutrophils in th~ l~ft .hi&' bands {I+ or slight}; baud and metamydocyt~, (2+ or mod~r.ue), and b.nd, metamydocyt .., and mydo_ cytes (3+ or marked)' {2} Magnitud~ of nonsq:memed neutrophil oono:mmion" mild « 1.0 X lo-'lJ.ll), mod~rat~ (1.0-1O.0 X Io-'Ij.ll), and marked (> 10.0 X Io-'Ij.ll). R,mg.. are provided as examples .ud mch guiddines vary with species.

2/ LEUKOCYTES

71

venu.s degt'lluati"" l~ft_shift d""ilications lim d~=ikd by Dr. O.W. Scru.lm (fath~r of vet~rinary h~matology). spmlic criteria for dassiJYillg ld't .hifts w~ .. not providnl.' (a) A rrg~lI~mive l~ft .hift is "cru... ct~riznl by a leukocytmis du~ to neutrophilia alld with th~ apptann"" of immatu'" lI~utrophils in ~riph ...l blood" lp. 272). (b) In. d~!:"nemive ld't shift. "toulleukocyu count ",mins within th~ normal rallC" or is ollly slightly d~ud. whil~ th~ occumn"" of young gunulocytes in th~ circul>lioll is promin~nt ' (p. 272). {2} In th~ 1986 rdition of St:lu.lm·, Vnninmy Hr""''''~, th= nates .'" de=ikd as follows:' (a) ' ~n~rative l~ft shift i. char.ct~riud by a leukocytosis due to naltro_ phili •• nd with th~ .p~aran"" of immatu .. neutrophil. in p from multiple days will ben.. characwiu th~ llrutrophil response:. If th~ ..!:""e.. ti"" l~ft .hift p (endogenous or exog~nom) deer",,, emigration of nrutrophils to tissue by down_ ..gulatillg adhesioll molecules and thu.s can cou,. • right .hift. b.

R..g~lI~ntive

(I)

Wh~1I

72

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY Table 2.5. Di..,a..,. and conditions thai ca u.c neutrophilia Inft.mmatory neutrophilia '[nf=ions: bacterial, fungal, vir'!, protozoal 'Immune hemolytic :onemi. 'N«rosil: hemolysis, hcmorrh3J:c, inf:lJ'Cl', bums, neoplasia, ,{incphrinr Chronic ncutrophili" [cuhmi. rarallNpiani, neutrophilia Oth.", or unknown m~nism' Neutrophilia of leukocyte adh ...ion ddicicncy G_CSF administration Emoge" {oxicmis (carly) • R.btivoly common dis. ... or condition

2. Ocher causn ofa right ,hift: PoodJ~ marrow dyscr:asia,' F~LV_associated mydodyscr:asia; '"'Iuin~ idiopathic hYP"r"'gm~ntation,'''" vitamin B" d~ficiency in giant sdlllauu", with an inherited nulabwrption .yndrome," folate deficiency in a cot," occasionally chronic inflammatory di..,a~, and in vitro :oging due to ddayed analysi., C. Neutrophilia (incr~a..d mrasurrd blood naltrophil ron""'ntmion) (fable 2,51 L ACllte inHamm.rory naltrophilia a, This naltrophilia resulu from changes in neutrophil kinetics cru.t ar~ cousrd by 'CIIt~ inflammatory mrdiators. Th~ net re",1t i. an increa.M CNP that may contain a ld't mift {Fig, 2,7B}, {I} Rdea .. from SNP OCC\Irs within hou", after on.. t of inflammation and muse. initial neutrophilia if reins. U""'MS neutrophil emigration to inflamed tissue, {2} Rdease from MatNP cau... a left shift and OCC\I'" aft .. rrduction or depletion of SNP, {3} Increased production from th~ myelocyte u,,*, It takes 2--4 d before effect. are ... n in periph~ral blood, {4} Increased production via stem cdls: Thi. will lead to granulocytic hyper_ plasia. It takes about 5 d before effect. ar~ =n in peripheral blood, b, Acutr refer.; to th~ rype: of inflamnutory reaction and not the duration of the di ......, 1be acute inflammatory pattern con be = in an anim.! with a prolongrd infum_ matory state if th~", rmuins an acti"" need for IleUtrophils in th~ inflamal tiSSlle, c, Infl.mmatory mediators must enter systemic blood and uimulate marrow a:lls for a naltrophilia to devc:lop,

A Normi:ll 118ulrophil

• B. Arute innammatory neutrophilia

•

"""'

MalNP

iii

•

"""'

MalNP

--

D. Steroid neutrophilia

•

"""'

, - , MII1NP

,

,:@~:, ,

E. Physiologic (shift) neutrophilia

•

"""'

MII1NP

F. Chronic myeloid leukemia

,

"""'

MII1NP

~I

I, :

Fig. 2.7. N ... trophilia kinetic>. A. Neutropbil kinNtrophi~a: N ... trophilia occurs ~ oftb • •bift of neutropbils from tl>< MNP to th. CNP. F. Chronic m)""Loid leukemia: Neutrophili. 0Clory mrdi>lors. When th~

75

2/ LEUKOCYTES

rat~ of namophil rd~~", from marrow is grrat~r than th~ rat< of neutrophil margin.rion and ~migr>!ion to tissu .., • neutrophilia develops. b, Chronic indirectly rd'",. to the duration of the di"", .. ; the infLommatory process has ~r:sistM long enough to r.sult in granulocytic hYP"rplasia, c, Wh~n.n animal has a chronic inflammatory neutrophilia, oth" lrukocyt~ abnormaliti.. may include lymphocyto.i. (with or without reactive lymphocyt..), monocytosi., ..,sinophil"" I>=>philia, a I.ft shift, ~ right shift, and toxic nrutrophils, 3, Steroid {mess} neutrophili a a, This n.... trophilia r.. uhs from changes crratM by th~ effeet. of endogenou. or nogenom gluroconicoids on n.... trophil kin..riu {Fig, 2,7D}, Although this nrutrophil", is frequently callM a itrN n(urrophi/ill, it mould not be confusM with th~ """iologic (lhifi) nrotroph;{id COUsM by the me,,_indu=l rd.~ .. of catecholamin.., {I} Neutrophil. shift from th~ MNP to the CNP b.cou"" the production of oodh..ion mol<cul.. is down_regulatM, {a} This proc= con potentially doubl~ th~ mrasurM neutrophil concentra_ tion! in canine, equin~, and bovine blood G ..... t~r incr..... in m~ .. urM neutrophil concentration! may occur in fdin~ blood b.coUst of th. larger fdin~ MNP, {b} 8«;ou"" of thi, mift, few~r n.... trophil! ~migra" to tissues, .nd thm neutrophils have an incrrastd circulating Ii£. .pan, Th. old~r neutro_ phih may becom. hypr;~ty of inflamm.tory Sl ales in caltk mastitis, pnalmon;" P~riph~ra1 dmruction Immun~.ma!iata! n~utro~nia

H~mophagocytic .yndrom.. Granulocytic hypoplasia ·Inf.crious: parvovirm (dogs .nd calS), F~LY, T"""pfil=, EhrfkhiA Nwpl astic: primary or metastatic Toxic ·P.. di=bl~: emog~n, ch~moth..apeutic drug., chloramph~nirol (cats) Idiosyncntic: ph~nylbuurone, brack~n fern, grioa>fuIvin Murow n=ruis Mydofibrosi. In~ff.crin production Immun.... ma!iated n~utro~nia Diphenylhydantoin and phcnylbut37.0n. toxiro.is (su.pected in .nimal,) Chronic idiopathic naltropen;" {G.CSF deficiency} Cyclic h~matopoi .. is Cyclic hellliltopoiesi. of grey oolli.. Cyclic hematopoiesis :wociala! with F.LY • A ,.tll;vtw an.mi • . c. In~f&ctive nrutropoi ..is i. m.ract"ized by a persin~nt neutropenia {with little or no l~ft shift} concurr~nt with marrow hyperpl",ia prior to th~ d~f'""tive ,ue 30,0 X 100IJlL in dogs), d Concurrent lrukogram abnormalities commonly include a neutrophilia (mature, perruops with right shift or left mifr) and/or a monocytosi. and =LSionally.n eosinophilia andlor basophil;", 2, Physiologic (shift) lymphocytosis {Fig, 2,9Cj a, This lymphocytosis is co.....! by shifring of lymphocytes from the M LP to the CLP (especially from the .plrc:n) that i. promoted by nogtnous or endogenous cotecholamines, Thr lymphocyte shift i. probably mediated through both increased blood flow rate .nd d,""rea.=i lymphocyte adherence to endothriium," b, The m"l:nitudr of lymphocyto.is may be up to 2 X URL, and the lymphocytosi. usually lasts minutes to hours, c, Morphologic chan~ in lymphocytes :lie not expeered, bUlthe.. arc data to indicotr that the cotecholamine effect is mosdy on natural killer ceUs, which may appc. r as granul ar lymphocytes (also called large: gr:mular lymphocytes),"

B2


,I ,'

, I

,C!'

Fig. 2.9. Lymphocytosis ki""Ocs. A. lymphogmt. n •• lymphocytosis it • port of lymphoid hyp<rpwia. C. Physiologic (.bift) lymphocytooi~ Lymphocytooi. oeru" b.a.... of the .hili of lympho:x:yks from tho MLP to the Cll'. D. LymphoproJifontiw «>pmi>: A lymphoid J.ukomi., .... lu from:on unoontrolled pro~fm of hypoad .. nororticism consists of a low_normal to decr..... d neutrophil concentr>tion, high_normal to increased lymphocyte concentration, • normal monocyte concentntion, .nd a high_norJrulI to inc",ased alsinophil concentration. 5. "lymphocytosis" of young animals a. Puppies, kin~ns, calves, .nd foals have great.. blood lymphocyte concentrations than do adult animals. lymphocyte concentrations in canle increase until about I yr of~, and then graduaUy dec",... owr the yt"3-rs in adult • .' b. Compared to adult refe .. nce inter""],, the app ... nt lymphocytosis may "" up to 2x URL B. lymphopenia (dec",ased mearured blood lymphocyte concentration) (Table 2.10) l. Acute inflammatory lymphopenia {Fig. 2. lOA} a. This lymphopenia is caused by changes in lymphocyte kin~ics nimul>led by .cut~ inflamJrultory medi.tors that reduce the ClP.'"

Table 2. 10. Di""UC5 and condition. that cau"" lymphopenia Acute inflammation 'Acute bacterial infection> 'Acute viral infectiom Endotoxemia Steroids 's.-. the list for neroid nrutrophilia in Table 2.5 Depletion lymphoid e/fusion; chylothorax, .nd fdine cardiomyo!",thy loss of lymph; alim~ntary lymphoJrul, enteric neopl",m., granulomatous em..itis, puatu""rculosis, protein_losiIli: ~mero!"'thy, lymphangi«tasia, ulceratiw enteritis lymphoid hypopl .. ia or aplasia lmmunosuppr=iw drug, or whole body irradi.tion Destruction of lymphoid tissues; multicentric lymphoJrul. gSse"l hound, Cudig.n Wdsh corgi, and Jack Russell terri..) Thymic aplasia of black_piro D. ni,h cattle • A rel. ti",ly oommon dioe .... 01 a",dition Not
~ll,

{3} Reducing the m . oflymphocym lnving lymph nod .. via ~ffe""m lym_ phatic nssth b. Most .cut~ inHamJrultory leukogr;oms with neulrophil", or n~ulro~nia also hav~ lympho~nia. Dis;;op~mm"" of lymph0l"'nia is gener;olly ronsid~ral a good prognostic .ign. c. Historically. lympho~nia w;o, oonsid~=' to ~ causal by th~ .1....' associalal with acut~ inflammation nth" th:m causal by th~ inH.mJrullory process itsdf.

2/ LEUKOCYTES

2,

3.

4.

5.

III.

85

Th~ stress of an illn .... m.y indu,,~ th. Iympho~nia, but documentation of ruch • pathog..n ...is w;o. not fOund, Stuoid {mess} lymphopeni. {Fig, 2,IOB} a, This lymphopenia is ",msn! by th~ "hangOm indicat~ the Iymphopeni. is caus.d by d=....s.d .fflux of lymphocytes from lymph nod ..," wh.,.... oth., d. u indicat. a ralimibu_ tion to bon. marrow,"'" {2} Ln.r: Lymphotoxic .ff.cts caustory function> or to the .ttraction of eosinophils to ti ... u.. after mast celJ or basophil degranulation. 2 An eosinophil", sugge;ts the po .. ibility of m>ny di..,,,,,, nates (Table 2.12). a. In the hyper",nsitiviry disorders, typically there are clinical .igns associ.red with the involved tissues: for nample, pruritus with II .... bite or naphyloroccal dermatiti •. b. Both internal and extern.l parasit.. are frequently blamed for .n eosinophil"" but many .nim>l. with similar p.rasitic infections do not have an eosinophilia. Per..inent mild eosinophil", is oeinophilic pnrumonili., eosinophilic granuloma complu in Sibtrian huski .. 'UI: eo.inophilic granuloma romplu, =inophilic ~nurili" hyp<mninophilic syndrom. Paranwplastic =inophilia (including mast ctll neoplasm.) Eosinophilic leuk~mia • A lel1t;vely common di..... 01 condition Note: Lins of spr, but animals cbuifiM .. having hyp«:au.. neopJ:.stic ~lls often han similar light_samet propC'ntine_inducM inflammation." .nd in dy=ia. inducM by ""fonicid or cdaudon . ... How~... r. it ,hould be noted tru.t ju,t th~ p..",nu of. l~ft mift i, not a toxic chang
II.

t.n.kocyte. that conuin miscellaneous indusiom A. Sideroleukocyte (Plate IJ) l. A iidmJ/i"lwcyu is • neutrophil or monocyt~ containing hemo,id .. in. On Wright_ stainffi blood films. h~mo.id~rin is a blu~_grttn or ydlow_brown pigment. Its p..,..n~ can bt confirmed with .n iron nain {Prussian blue}. 2 Sideroleukocyte. a.. rarely found but c;on bt =n with hemolytic an~mias (e.g.. equin~ inf=ioU1 an~mia or immune_medi.tffi hemolytic .nemia) and aft~r transfu_ sion. Th~ h~m",id..in in blood l~ukocytes may r~pr=nt hemosid~rin ~ngulfed by tho,. cells while they we .. in a splttn or other tissues." B. Erythrophage (Plm IK) l. An rrytltrophdgr is typically. monocyu or n~utrophil that has ~ngulfffi an erythrocyt~.

2. It is occasionally =n in immun~ h~molytic anemias such as idiopathic immune hemolytic anemia in dogs. equine infectious anemia. and neon.tal is""'rythrolpi'. C. LUpU1 eryth~matosus (LE) ~JJ I. ALE ull is • neutrophil that engulfffi nucl~ar amigtn-amibody complexes. With. Wright st.in. thi, mat~rial 'pf><ars ., pink or pale blue homog~nroU1 inclusiom of variable sizes. N~ m~hylen~ blu~ suining produces mo .. prominem LE indusions with homog~neou. staining.

2/ LEUKOCYTES

95

2. Rardy s,""n in dommic mamm:ds even in th~ LE cdl t~st d~sign«i to produ"", th~ cdl in vitro. D. N~utrophils rontaining rill.. t cdl granules: Rardy. blood and maJIOW neutrophih ronuin JIUS{ "",J] gram,] ... In on~ describnl a1Scuoliution ill lymphocytes. D. Hrrfflitary anomaly of n~utrophil granulation in Birrruon ats'· ' l. This .nomaly is .n auto",mal recessi"" trait in pur. brffl Birman aU. 2. Diagnostic f... tures indud. promin~nt fine eo'inophilic granul.tion ill the cyto_ pl"'ms of neutrophils that mull be, diff.rrntiatffl from toxic granul...nd inclusions of MPS type VI. Uhr:astructural morphologic f...tures of granules ... normal. E. MPS type P""'·J l. This is • hrrfflitory dirord.. in domestic cats. dog•• and peopl~ that i, caused by. d.ficiency of u_L-iduronidase. 2. [n som~ studi... leukocytic cytoplasmic inclusions were...,n via tran.mission da:troll microscopy but not in routin~ light microscopy. Oth." hove found that fdill. n~utrophils have .bllormal cytoplasmic granulation {.rruoll pink granules}. F. MPS type IllB'" l. This is a hrrfflitary di",rd.. in schipperk.. that is au...i by a defici.ncy oflyso_ ""mal glycosidase N_a""tyl-a- D_g! ucosaminidase {u_N """""trlgl urosamillidase}.

100

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY 2 Blood lymphocyt.. :md marrow m3oCrophag~', lymphocyte., and plasm. cd], we", d.""ikd as having abnormal dork_,taining gr:mulation. G. MPS typt VI'" l. Thi, is • hgllonic f""tu ... of the .yndrome l. Hypersegmemtd or gint n~utrophils 2. Macrocytic normochromic erythrocyu. without an.mia or rrticulocyto.is. Their m•• n cdl volumes usually at< 80-110 fl (in most unaffrcttd dog" 60- 77 IL), their m.. n cdl h~moglobin ron",mration,.t< usually WRI, and th.ir m""n cdl hemo_ globin valu .. a.. iner"",..! (compartd to tho .. of most unaffrct"! dog,).

2/ LEUKOCYTES

101

Ill.

[diop. thic hyptrsq:ment«i neutrophil, of hor...'"'' A. The di"l:nostic feam", of this syndrome is hypmegmented neutrophils and has bttn d=ribed in two hor... of the qu .. ter ho= brttd. In one rq>rt. neutrophil nuclei h.d 3-11 ddinitin lob., "p,... trd by filoments, and .bout 70 % of nuclei had 7- 10 lobes. Oth.. cas.. han b.en .imil... B. Hypt=gmemation i. not :woci. trd with the common COUIe; of hyptnq;menution; that i., hy~rad .. noconici,m (Cmhing', di ..... ) and aogenous gluroconicoids. The co.,.., of the .yndrome has not bttn det .. min.d. The po"ibility that hy~rsOi. in ",;"iatu".ncytk.....,.;. '«r interstitial cells product Epo in =pon .. to r.nal hypoxia. Renal hypoxia moy ~

Fig. j.l. &ythrocyte lWmia in h..Jth: Tho erythron con";", .!uN m. jo, pools: erythrocyte prerurso" (mosdy in marrow), blood erythrocytes, md .p!.nic .J}'throcyt.. , Afrer .timubtion by Epo, colony_fonning uni.--"rythroid ""Us (CFU_E) differ. ntia.. into rub,ibb.", (Rb) md th. ptKUl5Ol'S prolife .... (vi:. mit"'is) and .... tu'" until erythrocytes (E) ... fo,mod, An ord.rly maturation P'DCe.U produces a pynmidd distribution of .rythroid ",U pol"'lations (only th.e top half is .mown), rele ... to th. blood, erythrocytes circuh .. in tbe v=u~ system.o ttmsport 0, to tiss ...., A resen'< pool of erytbrocytes is ""'I"",..nd in th.e ,£,leen of mOlt mom"",h, So .... ",nt erythrocytes"", d.stroyed by macropboge', M1 for caul.

n.

Erythrocyu kin involving GR and catalase. B. Hgb function (Fig. 10.3) l. Hgb (with F~") tr>nsports 0, from lungs to tissues. In health, Hgb i. ]00 % satur>tro with a, in an ..ial blood. Hgb .. F~ does not tran>pon 0,. 2 Hgb plays two major rol .. in the tr>nsport of CO, from ti<su.. to lungs. a. When CO, diffu ... into erythrocytes, corbonic anhyd .... cotalyzes in reoction with H,O to form H+ and HCO,- . Hgb xts as a buffer (H + + Hgb- --> HHgb) to r~mo"" the H+, and HCO,- diffuses from the "",Il to the pl:uma. The buffer .. ing of H+ by Hgb f.cilitat .. the additional conversion of CO, to HCO,-. When erythrocytes return to lungs, ,,""tions .re "",ned .nd CO, i. rdeased for expiration. About 70 % of the CO, formed in tissu .. i. tr>nsportro to lungs vi;, this system. b. When CO, diffu ... into erythrocytes, ",me binds with Hgb to form carbamino .. hemoglobin. About 20 % of ch~ CO, formro in ti ....... is tr>nsportal to lungs vi;, this system. C. Hgb synth..is l. This occurs in erythrocyte pr<cursors (rubriblasts through reticulocyt .. ) in a .. ri.. of "'action> (Fig. 3.2).

.am

3/ ERYTHROCYTES

113 Hemoglobin Synthesis in Erythrocyte Precursors

lhci>o • succinyl GoA

5.ALA synIhilse & Be

protopoJUum.. two molK:uLes of ATP rnd produ= fow mokcuLes of ATP. PFK j, tb. me-limiting mzymr~ detmnina! by gtnetia. and ...ch sprcies has diff~r~nt .ntig~ns. In ptopl~. blood.group f:octors Im}' function •• m~mbr:m~ transpon~rs. r"""ptors. lig.nds. or structural prot~ins. 2. A v..i.-.:y of nom~ndatu'" .ystem. han bttn UIM for som~ blood types. Th .. ~ .'" th~ mor~ common syst~m' u,a! B. In dogs. at 1~:lS{ a d"",n blood groups h.ve b«n d~scrikd. and nin~ are currently nIDla! using th~ tioru . .. bigh in dogs rnd ho""" but very low in c.. dr rnd co ... '" 1.3·DPG. 1.3..dipbosphoglyc for all ~rythro. cytes in th .... mpl~. 3. Rd.lionship of indiu. a. Brau", th. MCH "'Pr=ms how much Hgb is in .n av,,"Clll"hroma,;a. F. nRBC. I. Th~ nRBCs o,bstrv.d during the examin.tio,n of. blood film are enumerat"! by counting the number of nRBCs seen while 100 (or mo",) leukocytes a" differenti.t"! and rounted. Th~ conventional method of recordiIll: the number of nud... t"! ~rythrocytes is number of nRBCsJlOO WBCs (e.g., 10 nRBCsJ 100 WBCs). 2. M.nual and some electronic method. det~rmine the [WBC] by rounting nud... t"! cdl, o,r nudei (either of leukocytes or nRBC.). By these methods, • _a,urd [WBC] "present' the sum of nud...t"! cdl cone< (V) rnd Hgb cODcen,mion {I-Iq of ..ch. ~rythrocyt< (RBC) is gr>phicolly di,£>lay«! in rn RBC VHC (vo"'"", hemogLobin oonCffitr:otion) grid (riCou.,._ displ.y). In , ..... cytogramO

129

3/ ERYTHROCYTES

Table 3.3. Potential efFc.:ts of ..,lccled . ample and palienl conditions on hemalocril (H eI) and values u....! 10 calculale H CI Condition

S~un

[noo:l«\"",r mixing Exces.s EDTA shrink. RBCs in blood Clots in sampl~ [n vitro h.molY'is [noo:l«\"",r "",mrifugation Agglutiruotion V rry IDull ~rythrocyt~. Hyponatrrmia Hyp",natremia Leukocytosis Thrombocytosis (marked) HYP"rprouin~mia (m ..kedJ

U

U

U

"" " ";

Hypoprol.in~mia

" " ;

Hcr"

Calc. HeI'

NN

U

;

MCV' •

;'

[RBC]

Cond Hc!"

U

U

"" "" " " NA

NA

; ; ;

;

"" "

NA NA

;

" ; ; ;

"

• Spun Het i.s the Het d,".rmincd by =trifug..ion, .ithrr the microh ......ocri. metbod 0' tl>< QBC _<W. • Cook, Het i.s .... Het c:dcuhtrd by imprd....., «Jl counter> after "",.mring MCV and IRBC], < MCV mges may ~ :of&cta! by agglutination. 4. Basics of pro=:lures a. Manual (nticroJropic) procedute {I} Equal volumes of blood and NMB , rain are mixa! . nd krpt at room tempeon. dec",ased production of .rythrocyt'" m.y b. 0 ... re...,n for the anemi •. Or. it could be too •.,ly (< 3-A d) fo, • ,eticulocyt. ""po ...... • c..t I: n..: .. is .viden"" of increased erythrocyte production. Tb. aggt"ll"'" ,.tirul'" that tbe", is no longer." in"",...d rete...: of aggtegat. r.. irulocytes. • Cat 4: Evidmc< of inc", ... d erytbrocyte prodoction is not pre>
A....essm.lII: Morphologic f..tures of uythrocytes ar~ ....atuat..:! .. P"fi of a routill' CBC or as a "p"rat. prO«dur~. For .bnormalities ill siR, shal"', .nd color, rdatin quantities of •• ch abllorm. lity p.fol< maturing to rrticulocytes. {2} Disorden or conditiom that cau"" inappropriate rubricytosis (a) Marrow dunagffl by n«:tosis. infLommation. endotonmia. hemic or nonhemic nroplasi •• or hypoxia; Nucle.trd erythrocytes gain entranc:r imo m:arrow .inu.., through damagrd sinu""idal endothdium. {b} Extramrdullory hematopoi..i, {esJ>"Cially splenic}; Thi. may :dlow rd.... of ctlls b.fore nuclear extrusion. {c} Splenic contraction; Splenic blood ronuins nude.trd erythrocytes that are oompleting maturation. {d} Splenrctomy; The few nRBCs that are normally rd.....d from marrow at< not· rought" by the spl..,n. (e) In.d poiwning in dogs. ""rhap' the result of damage to marrow "nus.. (/) Bone marrow dpcrasi. in poodles with macrocytmi. (..., Oth.. Nonnropl ..nic Leukocyte Diwrdm. Ket. II. in Chapt" 21"

=""

III.

Erythrocyte oolor A. emlr"{ pallor refers to the pale ""ntr:d region of an erythrocyte that is due to the rdati"" thinness of the area cr ... trd by the cd]", bironcave ,ha"". l. Inc"""",d ""ntral p:dlor is us,",lly indicative ofhypochrom.. ia. 2. Drc""asal ""ntral p:dlor m,",lly indicat.. abnormally .m.ped erythrocyt.. {poikilocytes. including spherocytes}. It is:d"" commonly =n near a blood film·, feath"rd rdge b.ao.us.- of anifact,",l distortion of erythrocyte .ha"". B. A ~if all i, an extremdy pate_staining erythrocyte consining primarily of cdl mem_ brane with only a .mall amount of r.. id,",l ""ripheral cytoplasmic Hgb (Plate 3D). l. Ghost cdls . 1< usually formrd during complement_mrdiatrd intrava5Cular hemolysis. Membrane acrack complexes form membrane por.. through which Hgb leaks out. 2. Ghost cdls may form in vitro as a result of smearing trauma. Thest artifactual ghon cdl. arr often distoned. C. A hypcchromk ")'t/n-gryti i. a poikilocyte with incr ...srd central paUor and more faintly stainrd Hgb than u,,",l {Plate 3E}.

138

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY l. HYJ!«"""",,i/J j. an inc,..,....:! numbtr of hypochromic uythrocytes, which ffi"}' bt

",f\«1ed by a d«r=d MCHC and CHCM if the hypochromic population is luge enough. 2. Hypochromic erythrocytes remit from a da:, raonj intncdJuJ:.r Hgb ronumration. When visually rvid.nt, th~ usually are ..,5Oci ated with F. deficiency. How~.r. hypochrom"'", b>=l on th. MCHC or CHCM alone (without microscopically ,pp",nt hypochromic erythrocyt..) is usu. 3. & rirulocytolu {increased blood Re). like increased polychromasia. i. an imponant indicator of acederat"'" erythropoiesi •. [yo

Erythrocyte organisms A. IdentiJYing features are list"'" in Tabl. 3.5. B. Major .. peets of th. anemias or disord.rs caused by organisms.", includ"'" in the Nonr'l:"n ... tive An.mia and the Hemolytic An.mias KCtions.

v.

Inclusions other than organisms crable 3.6) A. BalOphilic stippling {puncute basophili.} {Pl ate 4GJ l. Basophilir ftippling is the presen"", of fine to roar... blue to dark purple don of aggregat"'" ribosome! (RNA) dispersed within the erythrocyte cytoplasm. Basophilic

'1

,11 1

t t

II

L

II

'1

J l{11

11!1 jf,!· ,!!jl

j

~ Ii

Iillh!

dtlt i i j j"]} j' j' ]'1 1!,,"'1l I!, l'ljc Jii l1 l" l l, l'l'lj 1',l l, " " .~

£1 1

.• 1 I ~-:c! ... ~I

1 · ~"···'I"IJ" ~~~ '! !u ; ,,1~~ -i! ;~i!"~~_~~! ;. ii.~gj • ,

,f

.g

!

t,

~

,

~ ;It~l i1~i:i~1~r ~ 1~~1j! ~ r 'I ,£, "1,""-·' "J! :f· 1 '!..!;~m ~~ "lR.·.Pi ~.P 1 1 ~Il r ~;~ia "IF", ~ .gjll! ~;:: II: ,• ",J~8 ; . f~"I ~~ "t"~1i . ~~. ~! R a_ lt~"e lyl- ;• 1

r

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1l5~~.i: !r-~ i~~1i"'-li"-!3

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~6

11

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• 1

i

•

,~

.t

•t J

:t

.

f

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1, I ']. 'tJ:;p l'! §:

]jjlH

1I ~ ~ ~

1'/

l

1 1

1

I

J

1!

1

mli

.. . , .

,.

Ij IE:

11 .

t

l.

.

., il , p.

!

jI,

t

i!!

h J ,',

t'"

i!l

§.i j

Hli Ji lJ!~'" ~tl

~g~

g

r iJ

-I'

llt5-ti

z.t

j 11 ,

i ,.

J 1 ,.

i~}~

,I , •.

I

! .t

i 1t

Ji~

li~

. .

!. ,

H

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1

1.lh t'' ,.

i;

~

,

!

t .1,.l H

'

1q Ii ,j '

1't I

'j'

j

. -

I

,.1 'f"

j

.

11

11

l!l~ 1 11i, 11l {l - "-1 " •• 'J,t ' " I 'j ljiiP lli~ ~lijl!j!hHt }l . . ." . . . l~t -.'"'j·.'l . . 1·j _j~.i,~ttit • 'Jolt!l' i~ iljH! l.l1tglj~rJl~i~ I ' j' I f -i I• , ! ;!i fj i f 1 ' II j:." .. flJi

;

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.

n

3/ ERYTHROCYTES

B,

C.

D,

E,

141

stippling must b. difftr~ntiatw from sid~rotic gr:mul.., which a.. mu:dly located in duners. 2, ~philic lIippling is 5«n with r~nemi"" an~mias, esp«iIlly in canl~, but :dso in dogs .nd en" 3, When seen without corresponding polycluom:lSia or reticulocytosis, or in nonane_ mic .nim:d" plumbism is a common cause, eo;pecially in dogs, Lead inhibits the pyrimidine S'_nud..,tid.... cru.t hel", degrade nud..,tid .. in RNA Heinz bodi.. (Plate 4H :md I) ], Hrinz bodin a.. ~regates of d~n.tured Hgb cau...! by oxidatin dam:.ge, 2, H~inz bodi.. are visu:diud with NMB min :lS pal~ blu~, protruding, rounded structu.., associ.tw with ~rythrocyu membran.. , In Wright_stained films, H~inz bodi.. han nearly th~ s;om~ suining featur.. as norm:d Hgb but appear as slightly p:de structures th. t c",at~ membr:me defects or protrud~, Heinz bodi.. nuy deuch from erythrocytes .nd OCCut as free bodi.. in • blood film, 3, Exc;.,pt in cal>, the preseno: of H~inz bodi.. in :m :mim:d with. hemolytic anemia indicates Heinz body hemolysis, Sm:dl single Heinz bodies {diam~t .. .. 0,5 ).lm; ..e the srruollen forms in Pl. te 41} can b. found in the erythrocytes of cats without dinical anemia or h~molysis, Hgb """,Ii (Plate 4J) L The.. are seen occasioruolly in domestic mamm:d erythrocyt.. (induding dogs and cats), but their significano: i, unknown, Some may form in vitro becau .. of s;omple storage ronditions, 2, Hgb electrophoresis has failed to demonstrate abnorm:d Hgb molecul.. in domestic numJrulh that have ru.d Hgb cryllals, Howell-Jolly bodi.. {Pt.", 4K . nd L} L A H~UKll-J~11y IMdy i, a nucl .. r remnant th . t h •• remained free in the cytoplasm after mitmis of.n erythrocyte precursor, The Howell-Jolly body is nuclear materi:d tru.t W:lS not incorporated into. new nudeus, 2, Howell-Jolly bodies can b. found in healthy Jrulmm:d., frequently in cal> and occasion:dly in dogs :md hor ... , The numb.r of Howell-Jolly bodies in blood incr..... during .cederated erythropoiesis .nd also m.y incr.... in Jrulmm:d, with decr .....! splenic function {including aft .. splenectomy}, Refr.ctile anifacts {Pute SA} L Erythrocyte ..fractile anifacts .'" frequently found in stained blood film" Objects are rrfoutik when they chang. from dark to shiny as the focal plane is ch:mgffi; refractile anif.ctl a.. recognized by fomsing up:md down :md :use:ssing for this pro!",ny, They may appear as cre=nts or as sm:dl to brge, irregular sh'pes within the erythrocyt.. , Erythrocyte refractile structu... in blood films suined with Romanow.ky_type stains .re :dways .nif.ct" The d.fect that creat.. the refractile structure devel.o", during the drying or suining of the erythrocytes. 2, When refraclile .nifacts .'" in a pl. ne of focm that Jrulke. Ihem r..emble bl. ck structure!, Ihey can b. contu...! wilh erythrocyte indu.ions or """,,ites, 3, Refractil. arlifacts are different from erythrocyte refractile bodi.. :lS described by Sch:dm!' Erythrocyte refractile bodies are Heinz bodies seen on air-dried blood films by using. weI NMB sl. in under a cover glass, In thest prq>.ralions, Heinz bodi.. appear :lS erythrocyte refraclile bodies in erythrocytes; the bodies are dark foci in one focal plane but become ..fraclile when slightly out of focus,

142

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY H~inz

bodi..... not .. fracta~ in films suinffl with. Rom:mowsky_typ< stain

Wrij:ht,

(~.g..

Wright_Gi~msa,

or Wrij:ht_uishmon). F. Siderotic I:r.;mul•• (p. pp
';

It

"f"

,

14

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,

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lUl iHllHl!

'i1 dl

111. >'"

In

]I' ! I J~" 131 ~i'i13 .H -;.t t:

,j:" I

mup.

",... _., ..... ............. """'""'"""'ow "'-..., ,!"'_, _Kulu

..."

p.j«> .... (h. ... ); b.. ,." bo ...
FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY 2 Echinocyus ... thought to form wh~n th. surfa"" area of Ih. ouUr lipid Jay'" of Ih. ""U memb"m. incre>ses relal;"" to cru.t of Ih. inn., lipid loyer b«:au.. of in .. rtion of lipid. or amphipathic drugs. Th.y Im}' ""0 form KCOndary to inc,,,,,..,. in pH. nythrocyt. ATP dq.l.tion, dam~ by phospholipases, and thologic minocyto,j, h", bttn :rnCilal with erythrocyte trauma and PK deficiency in a Cairn terrier (unpublish..:! case report) but i, rarely report":!. 2. In people. pincered edls h.vt bttn associat":! with erythrocyte fragmentation. h"alitaty spherocytosis." .nd erythroleukemia" Pyknocyte {irrq;ularly cont"'ct..:! cdl} {Pl.te 6E .nd F} I. Pyknocytosis is lttn concurrently with =ntrocyto.is in dogs and horses :md probably will be ...,n in other animal,. Pyknocytes likely form from =ntrocytes. but oxid atin damage might cause: both directly. 2. Pyknocytes suin more intensdy with NMB nain than do di=x:yt.. or spherocytes. at I..." in ho ..... 3. Vi. light microocopy. !Orne pyknocyt.. look like sph"ocytes. However. the.., spheroid pyknocytes a.. usu.lly .crompanial bye=ntrocytes :md pyknocyt.. with memb",ne tags. so the pathologic mange:. can be recognized. Via dectron microscopy. pylmocytes had memb",ne irregularities or t"i:s :md w"e not pc:rfrct sph"es.''' Smizocyte (.rni!locyte or RBC fngment) (Pl.te 6G) l. Schiwcytosis occurs when rigid structu.., or rheologic forces traumatize erythrocytes. 2. Pathologic sum associat":! with ,mizocyto,i. indude int"'VlIOCUl" ooagulation. va",utiti, induding glomerulonq.hritis and hemolytic uremic syndrome. hem' fIl:iosarooma. caval .yndrome of dirofil.ri..,i,. endocarditis. liv" di ....... heart failure.

".


Q

h~mophagocytjc hisliocytic dj""rd~n, a.cquir prOCus .nd m.y cau.. ~ systolic h...rt murmur, [I.

Classific;;otions of anemi., Th"e are three common dassific;;otion syst.ms, e~ch with its .dvanug.. and limitations in certain clinical situations, A, Classific;;otion by IIUrrow ... ponsiveness L This dnsification syst.m is primarily b=
c. Becaust MCV .nd MCHC or CHCM are a""rag.', erythrocyt~ cytogums or blood film exoomiruo,ion. are typically more .. n,i,ive m.. hods of d....cring manocytic, microcytic, or hypochromic cdls. With .ith~r m.. hod, it i, possible to have a normocytic normochromic an~mia with detectable macrocytic, microcytic, or hypochromic popul.cions. 3. Normocytic normochromic .nemia, a. Blood film findings: Erythrocytes are typically uniform but =yoccasion.lly hav~ morphologic abnorm.li,i ... b. Most .nemia, btgin as normocytic normochromic anemias. Wh~n marrow rd~..... many larger or smaller ~rythrocyte. wi,h normal or d,""reaonl Hgb conce"'rn.tions, ,hen MCV or MCHC (and CHCM) will chan~. MCV or MCHC {and CHCM} mu", be ou"id~ of refe .. nce int~rval, btfore th. morphologic dassifico'ion changes.

155

3/ ERYTHROCYTES c.

P~rsin~nt

normocytic normochromic

an~mias ar~ n~«i

to b.

noru~generative.

d. Most ~nemias in horse. at< normocytic normochromic because their trulrrows rde ... few r~ticulocyt ... [f sufficient macrocyt.. a.. rdused. th~ anemia will b.com~ macrocytic. 4. Macrocytic hypochromic .nemias a. Blood film findings: One tocytosis may have macrocytic hypochromic cell •. " d. [n autotrulted h~matologic instrum~nts, th~ MCHC is cakulat«i from the measur«i blood [Hgb] ~nd a Hct that i, calculat«i nom. measu=' MCV.nd [RBC]. [f the [RBC] is .ccurate .nd the MCV i, fal!dy inc..ased (see the foUowing sect:. S.c), th~n the cakulat«i MCHC will b. falsely da:reastd. 5. Macrocytic normochromic an.mw a. Blood film findings: On. « the following sect, 12), Compne to the CHCM, if .vailabl., Normocytic hyperchromic an.mi:as: Typically, the MCHC is falsdy increased {see the following sect, 12}, Compne to the CHCM if it is av.ilable, Microcytic hyperchromic anemias a, Falsdy low Mev and high MCHC (CHCM) may be produced when erythro_ cyt.. are in hypoosmolal plasma,"" Erythrocytes adjust in vivo to the hypo_ osmoW.nvironment mu.ed by hypon . tremia and hypochloremia by h. vi"i: decreased cytoplasmic osmolality, When placed in • diluent prior to counting, osmo,is results in H,O leoving the erythrocyt.. and thus decreasing volume of .rythrocytes, b, If the MCHC {or CHCM} is falsdy increased for other reasono, then potenti.l mu"", of a pathologic microcytosi. mould be considered, Inc..ased MCHC or CHCM a, In theory, it is not physiologimlly possible to produce hyperchromic erythro_ cyt.. beame Hgb synthesis stops in . n erythrocyte precursor when an optimal [Hgb] is reached within its cytopl:asm, b, Most increased MCHCs n. falsdy incr....ed, and the blood "'mpl.,.' MCH value> also are falsely incrrased CHCM. are more reliable but mn .lso be falsdy increased, c.u..s of falsdy inc ..... ed MCHC, CHCM, and MCH include the fOllowi"i:: {I} P.thologic hemoglobinemia: Blood [!-1gb] is used to calculate MCHC and MCH, and it would indude Hgb from .rythrocytes and the Hgb in pia. rna, The CHCM would not be . ffected A more acrurat. MCHC amId be calculated by correcti"i: the blood [Hgb] by usi"i: • value for Hgb....., {2} Oxyglobin: Th. free Hgb &om theraJ>
""U,

3/ ERYTHROCYTES

159 j He!, j [H gb[, or j [RBG[

I

Raticulocylosis or

incroased poIychmmao.ia

I P.......nl

,

...

, -"'

RogooescuJ.r damage: poor nutritioruol st;;otus 3. uboratory finding. a. Normocyti, normochromic, nonrege"."'tiv. anemia b. Evid.nct of mronic renal dise;;o.., or dy.function, such as not.mi., utine .~ific gravity in the isonhenuric range .• nd d.ctrolyt. disturb:mces C. Dj ....... , causing marrow hypoplasia or .plasia of multipl. cd] lineage. l. Major con~pts a. Dam"l:' can ~ to one or more of the rompon.nts of the marrow', micr""nvi· rooment: blood vessels and/or ,inusoids, r~ticular adventitial cell" marrow stroma (fat cells or fibrocyt~.) , or h~matopoiHic n~m cell.. Th~ r~"Ilting marrow will bt hypoplastic or aplastic, b, Dam"i:~ may bt irrrversibl~ or reversibl~ and may cause: aplastic an~mia (hypo_ planic pancytopenia), 2, Disorder> a, Marrow hypoplasia or aplasia in domestic animals ofi~n has an unprov~n disord~r (idiopathic), [n peopl~, aplastic an~mia is usually immun~ m"!iatM. b, Inf,""tiollS agd • demonstrable ",rum SIlbsun~ (probably .ntibody) that inhibits ~rythropoi ...i, in vitro. but oth~r dogs do not."' c. The disord~r may b. ... ponsi"" to immun~_SlIppr... i"" dosage> of glucoconicoid compounds or oth.. immunosupp=sive th~rapy. but the",py may tak~ 2 wk or longer bofo.. .vidence of respon'" (~.g .• reticulocytosi,). Some dogs =Iuire long_ t~rm th~rapy to pr~nt r~cur .. nce of an .nemia. d. Loboratory findings (I) Typieolly. thry indud~ normocytic normochromic anemia and sometimes spherocytic an~mia.

164

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY {2} Nonregtn~ra{in .n~mia {3} A Coombs' un might yidd • positin mult. (4) Mmow aoomintion ~n.J, markffi hypopluia or aplasia (.b",nct ) of the erythroid a:l.lliorag {I } Typically. thry include normocytic normochromic anemia and ",melimo. spherocytic anemia. {2} Nonregrneratin anemia, ofte" SNore {3} A Coombs' ten might yidd • positi'" mult. (4) Mmow ex;;omintion "'''",lions from erythroid hypoplas;" with an inromplm l.ft_shiftal stries (m. turation ar=t) to erythroid h)'P"rpl.. i. , oft~n with subtle but d~.a .bl~ phagocytosi, of intact erythroid pr«:llrsors at Ihe latesl stage of ordtrly d""dopment (plat~ 9G). Th~ production of oth~r cdllines i, effecti"". 3. F~LV_ induc:ffi ~rythroid hypopl .. i. a. F.LV nuy sd.aivdy damage .rythroid ""II, to QlU,. erythroid hypopla'ia or lransform a cdl into a neopla'lic cdllin•. b. PalhogII~mia resolv.d .nd th~ erythrocyt~ indices improvtd when th~ th~ .. py for copper nO"'1:e dis ...... "",...d. [m~rpreution of th~ = dar. WlI.! compliatal by ~id~nce of hq.. tic dysfunction. {4} Microcytic hypochromic anemi", do d~lop in copper-ddicient pigs. c. Folat~ or oobalamin (vitamin B,~ d~fici~ncy {I} Folate . nd cobalamin . .. requir.d for DNA synthesis, .nd thus d~ficiencies might au.., .bnormal ~rythrocyt~ d~dopm~m. Folat~ and cobal.min deficienci •• may cause a macrocytic .n~mia in people but .. rdy a.. such disord~rs found in domestic mammals. {2} Cau with aperimental folate deficiency hood m~oblastic marrow erythroid cdls but n~ith~r macrocyto1is nor an~mia." A at with a congenital coJ..la_ min defici~ncy b.d normocytic erythrocytes." {3} Giant .mnauurs with .n inherit.d malabsorption of cobalamin had a robalamin deficiency and . normocytic nonr~gene ..tiv. anemi • . M. rrow sampl.. cont:nn.d megalobl.,tic erythroid cells, .nd macrocytes and ovalocytes we .. found in blood films. Rq>ort.dly, an increasffl MCV WlI.! not p..",m btau.. of roncurrem microcytosis; an aplanation of th~ microcytosis v..as not provid.d.'" Dy.plastic ch anges in the mydoid cells indudal hYP"~ent.d n.... trophil. and giant neutrophil .. M",hylmalonic a.ciduria WlI.! also present. {4} A Bord~r coUie with inh..it.d malabsorption of cobalamin had a normo_ cytic normochromic anemi .. " {S} Cattle that d~dop a oobo.lamin deficiency &om gm.ing on cobalt-deficiem soil may d~dop a normocytic normochromic anemia." d. Pyridoxine {viumin BJ d~fici~ncy: A di=ry pyridoxine deficiency in growing kitt~m ..",h.d in .nemia, but th~ features and pathogen.. i. of the anemia w~'" not deseribtd." {2}

Wh~n

165


'" 5.

Endocrin~ di""rd~rs

a. Hypothyroidism {I} Sttn primarily in docs, chi, causes a mild normocytic normochromic an~m

{2}

....

P.thogtn~sis

ofch. anemi., D""""asffi [toul thyroxine] and [total triiodo_ in a d=eaIM metabolic "Ie and thus • d""r~ n~ for thyronine] 0, in "",iph.",] {;ssu... Th. decr.,.,ffi lI,""d for 0, leads to decreasal Epo production and thll'l I... ''Yduocyre production. A II wh.n blood is lost from th~ body {includifii: into the gastrointestinal tract or urinary tract} over several w..,h to months, Anemia results from. combination of f.ctors but is primarily the r~SlI1t of Fe ddici.ncy (Fig, 3,9),

3/ ERYTHROCYTES

169

T...... .

Spleen

8. A.

'0

'''' c.

When No

t,

erythropoie'" mk:rocytic hypoclw'omic srythrocyto •.

Fig. .}.9. Erythrocyte kinotia of duonic blood loss tlut tion with intrav:ascular h~molysis tru.t was not m~ntion.d. b. Di ..~ may cau.. an~mia by both intnvascul.. and extravascular h~moly.is. Extravascular hemoly.is typiC;;O[ly .crompanies intr:ln.ICular h~molysis. c. Disord.rs may switch from on~ to .noth~r (i .•. , .n intnn.ICular h~molytic crisis can d~dop in .n anima! tru.t has a mild extravascular hemolytic disord~r). 4. M.jor f~aturr:s of th. h~molytic di!Ord~rs ... listal in T .bl~ 3. II. C. Thoro~h u amination of ~rythrocyt .. in • blood film i. an e=mial diagnostic proc.du.. for suspa;t.d or oonfirm.d h~molytic .n~mias. A well_mad~ and wdl_nain.d blood UIl... r and a good microscop" with a IOOx oil obj.cri"" a.. nttd.d for such examinations. On. may ..e organisms or ddinite dues of a hemolytic pro",,,•. I. Organisnu; MyrDplimnll, A""plimnll, Bab";.,, .nd Thtikria 2. Clues of a h~molytic proe<ss; sphmxytes, H.inz Ixx!ies, =ntrocyt<s. pykn.ocyt~s, .chirocytes, ~rato(yu" and .canthocytes D. Hemolytic ict~rU! ijaundi""} {Fig. 3.10} I. Pathologic hemoly.is l~.ds to incr~as.d Hgb d.gr. dation, thus inc..as.d bilirubin formation, and p"rh ap" drvdopm~nt of ict~rus. Jct~rus may d~velop in .nimah with eith~r imravascu.l .. or utraVll.'lCular h~molytic diKlrd~rs. [n both forms, Hgb degradation incr~~, but the ,;tes of ~rythrocyt~ destruction diff~r. Jct~rus may drvdop in animals with intnva!Cular h~molysis beau.. of concurr.nt utravascular h~molysis.

2. H.molytic hy!",rbilirubin.mia occurs when Bu travels through th~ blood from tissue /lUCrophages to th~ linr. Excq>t for uncommon situations, th~ capacity for Bu uplah gHatly ucttds that of bilirubin uc..-tion, so upuh is not rat~ limiting. If Bu formation ucttds an .nima]"s .bility to acret~ it imo the bile ., Be, hyperbiliru_ bin~mia will d~dop. If th~ capacity of th. linr for Bu upuh, conjug.tion, .nd acretion {the rat._limiting st~p} ... not excttd.d, .. rum [bilirubin] moy .. moin WRI ~.n though pathologic h~molysis is pr~.. m. 3. Th~ rat~_limiting nep in bilirubin acretion is the transport of Bc to th. biliary s)"lum. On"" the transport maximum is r.-.chal, Be is "regurgitat.d" out of hepatocytes .nd imo plasma. 4. Bu and Be com!"'t. for the same =< (C/",rrid;um pnj'rinx"", ITI'" A) Clostridial infection, in horses EIAY" F~LV' H~molY'i, a"""iatt
Site of hemolysis

Wilhin blood ve.sd. or hean

Degrtt of RBC damage dir«dyall1srd by Ihe hemolytic agem or process Sev.rity of anemi. On!el of illness Reliculocyto.i.

Marked

Hemoglobinemia

Yes. but may nol be. Crossly yj,ible

Hemoglobinuria H yperbil irub inemia

y"

Bilirubinuria

Marked or rapidly falling Hours 10 daY" U",ally :mer inilial presentalion

No or yeif

Prrdomin.ndy exlravaocul. r hemolysi.· M.aoph.gt. near blood sinl1Se'l of spleen. liver. or marrow Mild 10 markrd

Mild 10 m.rkrd Day:; 10 weeks Usually at initial presentation No No Usually at pre.ent.lion; Bu;> Be Usually at pre.enmion

NoorE • OinicaJ intr.v1K'Uw, homolysis is =ogniu< diso«kn. intw.=ubr bemoly>is rruy be occwring but not =«",ly enough to cwsr homoglobi ...mi. ot homoglobinuria. < Soon after the 0 ..... of intr>vucuW hrmol}"is. hY!"'rbilirubinrmi. and boilirubinuri • ..iU probably not be p, ... nt. Witb timr. incrrasris could contribu.. to tbe .. =s boi~rubin formation and thUll byprrbi~rubinrmi. or bi~rubinuria. HY!"'rbilirubinrmia and bi~rubi· nuri. would be mot. upectrd .. ben tI",rr is concurrent _ransrul .. hrmolysis of mf!icient du .. tion and _rrity.

2. Bu is H,O in.olubl. and i. bound wilh albumin in plasm>. so ""I}' little Bu p also ha"" a mild albuminuria. and thus Ihe bilirubin det«IN may be. Bu bound 10 albumin. 4. Bilirubinuria umally occur> be.fo.. clinical hyp d .......

T\

--- ---

~

HPI~

Hgb

I

r

Hgb dime< Hgb dime< '

HI*

,

Me~

HpIIHgb dmoors

. "- -. \.

--- -- ------

,

,

Glomerular

capill

HptlHgb dimers

I

'"\.

, ,

/'-..

""'!hem..

d.......

Hgb dimer

Proximal tubu epHhelial cell Hgb dime.

I ..,. I

"

'"I

Hepatocyte

"

---!---Hgbdn-

I

Hgbdimer

in uri....

--------' . _ .. _ .--

Fis. j. 11.

Padtog ...... is of ... moglobi .... mia and h<mogIobinuri. duri", imnY2&CUlar h<mlyoH. f;e ~Ia>«l du.in, intnyaxular hemolysis an be divided into primary IUld ...:onduy 'l""' ..... Thor 1)"''''''''' ar~ no< .. rurat«i durin, .... ltk , and th", be"'ocIobi....rn. .. nor _n in heoIth. In pathologic tion of the prirnory and S«JOndary O)"temoglobinuria (1001 ofH~ and Fe). • The primary . J"k1D aFe ~tion (the "'_ UnportlUlt, which mor boco"", ....... «< c:onoc ......

_..........,

.tat.., .......

• In' ........ b. nythrocyw dam.V o. darh au ... .. Ie ... ofH~ to pI ....... n.. ul"dtoblt: Hgb mnnw:. 'I'~tJ in' o di....... and il1lIDOd.i. tdy binds H,r, (if ....,.jlabl~). n.. HptfHgb d ...... Ian ore de>=l from plas ..... pnmarily by hepatocyte" 'which ckgnde Hgb dimrn t o Bu, F...., and omino acidJ. I:IUII n..~ .. tyidmoo tho, m""roph'ga have . rKIOpwr for the H p
'0

F.....~' • In pooplt: ond nonhuman prima_. m..beme:alto binds to :albumin. and the tocthemei:albumin complt:. ..,"'n hepOtoptoclobin; and Hp .. htmopeUn.

175

116


T able 3. 12. D ifferential feature. of hematuria, hemoglobinuria, and myoglobinuria Ho P[",ma color Urine oolor

H~maturi.

H~mo~obinuri.

Mro~obinuri.

WRI" Not pink to r~d' Pink to rcd'

D,""",,,,,,,d Pink to fffl Pink to =t' Posit;""

WRI

Urine heme .. "",ion'" Positi"" RBC. in urine wimcnt Yo" No' Information to su~~r{ mUld. d . mW No No • UnLess ,b.", is :on :woci. « wi ... >«Ii""", ",,:urUn>.tion. 'The« could b. concu,,,,nt bmutu,i. bee ..... of anotb.r pathologic P'''''''' or to '""'pJ. colJ.ction. 'Infornutioa auy incJud. hiltorical or phyo;c:d ffid.nc< of muscJ. d:omoge (~.g .• "jJJ..... 0' tnwna) 0'

incre;>st of the n~rn)

(a) [n NI, ingesta! m aternal colostral alJoantibo
d.rived erythrocyte surf~e. .nti!:"ns. The ~ntibody-ro.ted erythrocyt.. a.. then ly>ed by macroph.!:", or romplement. {b} In cau , NI occurs when. qu.. n with typ< B blood passes h.. anti_A alloantibodi.. to h.. ty~ A or tJ'P" AB kitten! via colostrum. TJ'P" B eryduocyt.. are uncommon in American domestic shonhair cats (< S %), and the high .. t incidene. i. found in British shonhair {41 %}, ~on rex {40 %}, .nd Corni,h rex (34 %) cots.'" Anti_B allo· {4} P~rasitemi. is usuaUy pr... nt during h.molysis. but it may sudd.nly disappear (within hours). Abo. organisms will falloff erythrocytes in vitro and thus it is advisable to =omin. blood films made &om fresh blood. b. Conin. hemic Myroplanna .pp. {I} M}rop/a""a ha(mot"llnis {n.,,,,nym. HIl(mobllrtondJa ranis} (a) P....it.mia i. usually...,n in .plen«tomized and in immunologically compromised dogs. {b} Like the fdine hemotropic mycoplasmas. M. ha(molilnil Jruly d=rn from .rythrocytes '" the umple ages and it i, difficult to identify the organisms in pl.. JruI. {2} "umdidaru, Mycopl"'ma haeJrultop.rvum" {a} This small org.ni,m was found in a spl.necromized dog.'" {b} Genetic a""lysi. indicates the organism is more do..,ly rdated to "umdidllruJ Mycoplasma h •• mominutum" than to M}rop/a'ma ha(moranis. u , c. Oth.. hemic Myropliuma .pp. {all previously called EptryffnW;Mn} {I} M}rop/a""a ha(mo.ui, . nd M. paroum in pigs {2} M}roplmma W('9'onii in catde {3} "umdidAtul M. h .. molamae" in llam", and .lpacas d. P. thogc:n .... of the.. hemolytic anemia.! a.. thought to involve immune_ mediated mechanisms. Antibodies bind to the p.rasitized .rythrocytes eith.. beam.. of bound parasite ~nti~ns or anti~ns exposed on . lter.d m.mbranes.

182


•. Major l.boratory findings

{l} Thest include Myrop/a'mll 'pp. on uythrocytes in films of fresh blood. P"..,it.. are most numuous when He! is falling. Organism. =y detach from erythrocyte, in vitro, so th. kn crun". to det'"'" and id.mity organ_ isms is in blood films mad. imm«iiatdy aft" blood colb:{ion. {2} Loboratory finding> also include moderate to ~r. :memi., reticulocytosis and polycluom.'"" mild to mod". te hyphrmorrhagira .. rotype., PCR positivity for Lrp""pi,a spp" .nd Lrprorpira not found in blood film., 4, Cwtridium 'pp, a, Clwridium harmo/yricum and C novyii type D {I} Disease: bacillary hemoglobinuria in cartle and sh"'P {red warer disease and Nevw ra! water} {2} Cu,rtridium harmo/yricum .nd C novyii type D a.. normal inhabitants of soil .nd may remain dormant in cattle until an ... rohic conditio", promote their growth, In th~ United States, bacillary hemoglobinuria is ...,n prillUr_

3/ ERYTHROCYTES

183

ily in poorly dnining ."".. of GulfCoasl and Wm~rn states, :md th«~ is • rq>On«l >SSOciation with liver flukes, {3} Pathogenesis of anemia: Erythrocyu damage is caus«! primarily by a p_toxin {produced by either C h,,,,,"oryricum or C /Wry;; type D} that has phmpho_ lip... C or lecithinase activity, The p_toxin thus degrades membrane lecithin :md cau..s lysis of erythrocytes, Oth~r rdativdy minor hemolysillS {lipa.., proteinase, and .noth~r lecithinase} h.ve .lso bttn .. ported as products of C hannolyticum,IJO {4} M.jor labomory findings: acut. seve...n~mia, h.moglobinemia, and h~moglobinuria

{5} Confirmatory diagnostic finding.: postmon~m l.,ion., Gram_positive baciUi in tissues (liver :md 'Plttn) or fluids {blood .nd peritoneal fluid}, C hannolyticum cultur«l from liver, and phspholip= C activity (p_toxin) detected in tissues b, Ch>rtridium pnftingrm type A (C _khit) in rumin:mts {I} Di... ",: yeUow lamb di",= in cal""" and lamb. (also know as emerotox_ emi" jaundi"", or the ydlows) {2} CIo>tri4ium pnftingnu type A i. part of normal im in lambs :md calv." of oth« region. (e,g" Canada, Australia, N= ualand, and South Africa), {3} Pathogenesis of anemia: An a_toxin th.t ill.. phospholip... C .ctivity .nd i. produced by C pnftingnu type A came. hydrolysis of membrane phospho_ lipid. and thus lysis of .rythrocytes, leukocytes, plotdm, endothelial cdls, :md myocyt ..,'" {4} Major labomory findings (a) Acut ........ cases: anemia, hemoglobinemia, hemoglobinuria, and icterus {b} Le ......... form.: an.mi., polychromasia, basophilic stippling. rubricy_ tosis, .nd leukocytosi, c, Ch>stridium pnftingrn, type A {C uxkhil1 in hor... {I} A horse with a clostridial aoo.. had. Coombs' _positive . nemia with sphero«hinocytII acute imravascuJ., hemolytic .nemia in :lCIIte '["l:'" Mor< commonly. it is • chronic extra ..... "'ula' hemolytic anemia or .. chronic normocytic normochromic anemia. {2} Ocher finding" hemoglobin.m;" {acute}, peth.!", anisocytosis and Dl. e. Major laboratory findings (I) Chronic form: few to rare organisms in blood, mild an~mi, mild lympho_ cytosis {due to chronic .ntig~nic nimulwJ, seropo.itivity to &b,,;.. spp., and PCR positivity for &b,,;.. 'pp. (2) [n .rute or subacute forms: many piropl.,,,,, in blood, mod~rate to =er~ an~mia, retirulocytOlis, increased polychrom .. i, macrocytosis. hJ'P'rbilirubinemia, bilirubinuria, possibly h~moglobinuria, ,ometimes sphrrocytosis, and occasionally =ntrocytosi,

3/ ERYTHROCYTES

185

8. "Iki/ma spp. a. Erythrocyt~ piroplasms .'" intr.ocdlulor and highly pleomorphic, d~~nding on spa;ie! and Slag~ of par.olitemia. Many form. resembl~ CJlaUXZJIQ'" but oth~" r..~mbl. "nan b.be.ia[ piropwms. b. "Ikikr;a rqui (ba""nym, Bab"ia ~qul)''' infects horses and is ~ndemic in many tropical and subtropical ar .... Th~ infectod ho"" may han a subclinical di",,,,,, or may han pathologic SUt .. , including intr.ovascular h~molytic anemia, ict~rus. hepatom~y, and splenom~y."· c. In th~ United States {Mi1SOuri, Texas, North C.rolina, and Michigan}, bovin~ case:s of theil~riosis hav~ i>ttn caused by T. bujfiu.' ....'" Num..ou. piroplasm' w~re pr=nt in clinically ill row,; piroplasm. we", . .", in subclinicol cases. P.thogenesis of the an~mia is not esublished and may includ~ both d=eased erythrocyte production and decreased ~rythrocyt~ lif~ span (becau.. of .ith~r iDUIlunologic or oxid atin da~). Ntojor laboratory finding. ar. piroplasms in erythrocytes. macrocytosis, polychromasia, basophilic stippling, lymphocytlis, and hyperbilirubinemia and bilirubinuria. d. In other oountri.. , many lbritnu. spp.•'" ra:ogniud .. causing h~molytic .n~mi .. in canl~ and oth~r ungulates. Erythrocytic piroplasms are th~ major pathogtnic forms in T. mutant, T. orirnta!iJ. and T. "rgmti. Th~ m.jor patho. genic s~ of T. parva i, in th~ intralymphocytic schizont, wh~r..... ~rythrocytic .nd lymphocytic form. are romiderod imporunt for T. an" ufllta.''''·''' A Thn~. ria sp. wa. found in SwiM cotd~ that w~re roncut",ndy infectod with la~ &Imid .p., ANJplmmll m'''-giNJ!'. Myoplmma wm}unii, .nd A. phagoryrQphiu.m.'" •. In Spain, 21 dog. wer. "'ported to be infected with B. mi""ti.liu organisms, but .nalysis of ribo""mal RNA from organi.ms in thIN dogs indicoted that the org.nism. w~r. T. anna~. t. . The dogs wer~ anemic .nd had ""id~nce of a prot.in. losing glomerulop.thy. f. PCR testing can be used to diffe .. ntiat~ .imilar org.nisms. 9. TrypalUlwma spp. (Pl.te 8K and L) a. The.. are Hag~U atal protozoa th.t occur as fIN.living Hagdlated trypomanigot.. in blood and .. amanigot .. in J>S"udoc)",,, or macroph"l:es in oth~r tis.!ues. The p.thogenicity of th~ par..itic spa;i.. varies, and th~ host .pa;ificity is minimal. t" b. In th~ United Stat~s, T. ~i/m (b ..onym, T. amnkanum) is found in cotd~ .nd typically i. not rollSid~rod a pathogen. Th~r. are repom of finding it in Kansu, Wyoming, Oklahoma, Louisiana, Mis.iOuri, llJinoi" P~nnsylvania, and N= York. It is .1"" found in oth~r rountrie!. c. TrypanD"""a cruz; infects dog. and cou in South .nd Central Am~rico and in the south~rn Unit~d States of America. Trypomastigotes.", found in blood in the acute stagts, but mon lesiollJ involve amastigote! in nonhemic tissue! (h~art, brain, .nd lymph node), .nd h~molytic anemia is not a f",cur. of th~ disorder"" TrypanD"'''''' cruzi caus.. Chag.. di .."", in people. d. Major Mricon trypanosom .. of v"'~rinary significonce are T. crmgu!mu, T. vivax, T. brucri, and T. ,imilU. A sub.pa;ie! of T. b,uc,; caus.. African slerping sickness in people. {I} In the .cute nages of T. vivax infections in canl~, the .nimah may have an ""ute hemolytic an. mia, l.uko!",nia, .nd thrombocyto~nia. Phagocytmis of

' 0;

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY h~mic pr«ursors ~nd pJatd~ts is • promjn~nt finding in IIUrrow, :md Ihm indfa:t;", h~matopoie;j, comributes to ch~ p"lIcytopn~l1' conformational chang .. to form

hemicl"om.. (Hgb_F .... with unique binding of Fe to nitrogenous bases of g1obins) or to form a h~me-dqJl~t..d Hgb. {cl H.michrom~s or h.mMqJl.t..d Hgb mol«ul .. pr«ipitat~ .nd aggrtia). onion, {Allium 'pp.}. ph.nazopyridin•. proporol. and propyl.n~ glycol'" {cl Horses: onions. ph~nothiazin•. wilt..d or dry r..d mapl~ (Aur ,.,.b,.,.m) and red ""'pl. hybrid l~aves {gallic .cid and oth~r oxidanu).'" possibly other ""'pIe leaves. and g.rlic (Allium Ultivumj'" (d) Ruminants: Bra"k" spp. (kal •• nd rape). cop!",r. hydrogen !",roxid~ (intrav.nous). onions •• nd ryegrass (red mapl~ leaves in alpaeu) {3} Can are ""ry sUKeptible to acetaminoph.n bea.... they lack a glururonyl transferast that is usn! by most .nimals to conjugat~ .ceuminoph~n. Without th. conjugation •• ceuminoph.n is connrted to """'tin m.tabo_ lites that dqJlet~ gluu thione concentrations and th~refore d«re... prot«_ tion from oxidatin injury. {4} Pathogenesis of the anemia may inml"" multiple mechanisms'" (a) Erythrocyt.. oontaini"l: Heinz bodies are less d.formable and ar~ trapped and lysn! in the spl..,n. {b} Structural dam"i:" em=' by oxidation of membrane prot~ins or binding of Heinz body to erythrocyte m.mbrane le.ds to fr:li:il. cells that ""'Y Irs«! in cattle. P4:" and cats; how",,, .• nemia Wll.I not rq>Oned as • fe.tu .. of these form •. ''''''··''' Lead poisoning creat...n acquired porphyria becau.. lead inhibits enzym.. in the h.me synthetic pathway. An.mi. =y be pr..ent in plumbism but is not con!id"ed a hemolytic anemia caused by the porphyrin accumulation. 4. Hypo05mol .. h.molysis a. Rapid infusion of hypotonic Huid int..""nou.Jy {such as st..ile H,O} or the inge;tion of large quantiti .. of wat .. by calves {v.at" intoxication} can cause rapid intravaocular hemoly!is. b. Pathogenesis of th. anemia: Infusion of a hypotonic solution or .bsorption of l..~ quantiti .. of wat" c",at.. hypoosmol .. plasma. Rapid mo""ment of H,O into erythrocyt.. vi. o.m05i, causes .rythrocyte swdling and l,.-..i •. c. The major laboratory findings are an.mia. h.moglobinemia, .nd hemoglobinuria. the ...."iti.. of which d.pend on the ,,,,..ity of the hypoosmolar ,Urr. D. Erythrocyte fragmentation in blood c"'ating .roiwcyt... keratocyt ... or acanthocym l. Erythrocyte damage is thought to be due to trauma caused by rdatively rigid structu... (fibrin) or by rheologic forces {= T.bl. 3.10 for disorders}. but oth" f.cto .. =y be involved. 2. P.. hog.n.... of an.mia: Becau.. the .rythrocyte trauma i. a oon"'lu.na: of oth.. pathologic starr,. proa:.... that cause: the .nemia may be multifaa:ted. a. Erythrocyte trauma .ith" directly causes ly.is or creat.. poikilocyte> that have • ,hort.ned life .p.n. Acanthocyt.. =y form in the circulation became of memb",n. lipid chang.. rath" than mech.nical or rheologic for=. but th... for= may contribut. to the .ced.rated fragmentation of .canthocyt.. (budding fragmentation). b. Primary di ....... arMl'},fu. OfY'Nocy.OIIU h.. IMen

neopI~5m!I

d.oooa~

o.

confiaoed, m. .rumal is ",omiD«i ro....id.moo of tho "'".. COm""'" co""",: I>nnoconcrntnrion '" ",Ionic contr>ioIopc: erytbrocytOlis): The ¥t-o
Megaloblastic anemia A. A m~fqb/a;tic anrmiIJ has th~ concurrent findings of .nemia and mq;aloblastic erythroid precursors in bone marrow or blood. B. Megalobla.nic ~rythroid precursors form became of asynchronou, maturation of nudeus and cytoplasm (Plate 9l). N uclear maturation i, arrested. 10 nuclei.", largr. with exagg with erythro_ cyte diameters I Yr 2 times those of healthy cats 3. Bon~ marrow finding. in cats a. Erythroid cell numb.rs: vari able. inc......d to d=raK are dysplastic but are not neoplastic.

202


2 Erythroid na>pl..ia a. Acut. mydoid leuhmi.: erythroleuhmi. or erythrolruk.mia with erythroid prfflominan"" b. Prim:ory mydody'pla,{ic syndromn: mydodyspl:ostic syndrome or mydody'pJ.,· tic syndrome with erythroid prMominanu

X.

Sid.robJ""tic anem;" in dog,"

A. A di"l:nos;, of ,id.robJast;c anemia was basal on th. concu,,,,,nc p,ese""" of> IS % .id.roblast, in marrow :md of ring
• inc,,",=d F~ loss: chronic external blood [0 .. Dec",,= 25 %, Only the most severdy

3/ ERYTHROCYTES

""

.n~mic coIf (Hcr = 9 %) had clinical sigll! of an~mia . Th~ co"", of tho appar~nt cong..nit>l hypof~rremia and F.-ddicient staU WlI.I not dot~rmin~d." c. Rolatin to .dult MCV values, fo.h han. po-ak microcytosis becw,""n 3 mo and 5 mo of age." Ho~r, th~ir strum F~ concrntratiom wer~ oqu:d to or gr ... t~r than concr ntratiom found in h~:dthy .dult ho", •." Stabl.d Dutch w;umblood fo:d. ( 1- 3 mo of age) that w~ro fa! freshly cut grass had low~r blood [Hgb], Hct, blood [F.], .nd ""rcrnt>~ transf~rrin saturation than ,imilar fo.h raisod on p"nur•. Th~ d.t> providod t~.ll Fe-bindifll: sites, .nd then tho bound_ F~ and f=-F. fr.ction. are "p"rat.d by ch~micol methods. Tho F." in th~ ,aturat.d transf~rrin molecules r...crs with a d~ to detormin. the bound [F.], which .. pmonts the TlBC. {2} Th. UlBC i. calrulmd: UIBC = nBC - .. rum [Fe]. c. In som~ clinical assays, plasma Hgb (hemoglobinc:mia) may co"", spoctral inter_ !n.ncr in :assay> that [nc:amre [Fe] {.... Laboratory Methods for Assessing Iron Status, socr. 1.B.4} and thus amId result in .rtonmut nBC and UlBC ,",ults. B. Incr••...! .. rum TlBC (Tabl~ 3.( 7) l. Fe ddici~ncy a. Pmpl~ with F. deficiency may Ita"" an incr"""! nBC b=me of the incr....d production of transf~rrin to corry available F~ ro crlls. b. Fe-ddicient dogs rypico.lly do not have increasod nBc.'


'0;

Table 3.17. Di..,rdc" and condition. thai cau"" increased TIBC inc,",asM apotr.mfcrrin production

F" deficiency: sp«i .. vari.obl. Other or unknown m.dunisms Young animals (fO. ls)

Table 3. 18. Di.."dcn and condition. thai au "" decreased TIBC D~.. ~

apotr.mfcrrin production • inHammalion Hepatic insufficiency lnn"asal transferrin lou (protein.lo,ing nephropathies, potentially other protein_Iming sUtc.)

• A ,.t1tiv
3/ ERYTHROCYTES

""

IV.

Stainable F. in macropha.ges of marrow. srl"'n. or liver A. In microscopic aamination, of form.lin_fix.d tissue or air_dri..:! cytologic p.. paration,. h.mo,id ..in i, ,,,,n .,. ydlow to brown granular or globular pigm.nt in maeroph"*,,. B. Wh.n att.mpting to quantity the amount of F. in 'to~ (esp«:ially for F. deficien')'}. the UM of.n F....,J"Cific nain (such ., Prussian blue) enables a more definitive ass=_ ment than does the US< of routine naim. HOWN... the p=" i, ,ubi"'tive and rpl .. ia: histiocytic ... rroma (malignant hiniocyto,i, ) Shift of ferritin from tissue to plasma Liver di ..... Hemoly.i. herci", in horses • A "1";,,,,ly oommon di..... or condition

208


2 Inn,,=t cool during tnmpon. EIythrocytes are washal al I.... ,{ Ih,tt times with salin. or phosphate_buff.rM saliM prior to • dilute .rythrocyu su.p<nsion ~ing mad •. 2. W.,hgainst IgG, IgM. or rompl.m.nt. 3. If the patient's erythrocyu. arr coat«i with antibodies lor complement}, the fluore=in_lobd«i .ntibodie. win bind to them to make tho.., erythrocytes fluore=nt, 08. Smith IE.. Mohand .. N. SboI.tt SB. 1982. Inttnctio~ of amphipad.ic d"". ,..;t!. ~. from vuio ••• ptci1odo, Eid>' c .... (l98S- 1992). J Am Yrt Mod A.oc

tot"

"""""'ocyto....

,,,,,itt.

n..:

2OS,tSS-460. 81 . Mtinkoti. J. Kocan M . Whitwrtb L Mwph., G. F~% JC. W.,."J, JP. 2000. c." N"';";"'; na"'''] inf",tlon ... t!. C_ _ foiir. IS co o,;:;0

. ~

";~ ·~rJ;;;-

o . --J.o-";:;

::o..!.-;. .s~

~

3

E.

] ! ~ i l j I }' ,f~ !d I' ,j' , I , 1 ,1 "" I l"ii .. t , . ,~ j , , I 1 J, .ti~, , 1 , ••~..,'f l * , rI ~, f f J!,!j ,,~, ~ ~~. ; . ilt ~ , ' ~., ~I l .1~5 I j , ! ! < cat (hi;, ,.-j, P,diminuy i~ on inhorit"." paturn. Am J V... R... 29d6H- 1657. 199. Wttb TK. 19SO. Pobin. ..,,[_« d,fid."'J" and mrth~",ia in. doc&I Am Ani.. Hoop Aaooc 17,329-832218. Bak", OC. Gaunt SD. 19I1S. Niootin.",id.o-.admino din..dooti.k-mrth'moclbin ...Iucta" activity in od on .~",.... tk uoalyr. .. Rt •..Jt. f '" ;ntne
..,"'r

226

4/ PLATELETS

227

B. Platd"" production is .fI«t~d mostly by th~ degr.., of cytokin~ stimulation and th~ numbtion l. s..mple a. EDTA antioo>gulation of venous blood is routine for eBc. {= Analytical Principles and Methods, ,,",,I. I.D, in Chap,.r 2}, but cit""..! venous blood {I pM! citm. to 9 parts blood} can be, usN (e.g., when EDTA.indu=l plaut", dumping is .n.ptctal). Citme dilution requires {rull th. mea.urM [plotdet] be, oorr«tM (corr«1al plalde! OOllctlltrat;on = measural platd", collctntration xl.I ).

b. HqJarini=:l .ampJ.. should not b. n=!, kcaust plotd.! clumping frequemly ~".

u,ay

c. Pt.td.u can b. xtivatffl during blood colb:tion • • nd activ. tion cauoes dumping. Pl. td"u can dump b.cau,e th.y are hyperactive. b.cau", of slow or poor v"nipunctu .. tMniqu". or ba::;,,,,,, of dd"ynl or inadequate mixing of blood and "nticoagulmt. Plotdets of em and cattle are very pron" to dumping. d. Blood coll«tion tub.. containing citrat". theophylline. dipyridamole. and . d"no,in" (CTAD tubts) provid" platd~ inhibitory factors that hdp rfflu"", in vitro pt.tdet .ctivation." Th... ""'y b. p"niculorly u..,ful in cats. e. The.. are v.riou... ported ,tatemenU regarding the stability of platdet (X",,,,,n_ tration,.".>.! On average . con""mratiom . ppear rea,onably stabl" for 8 h.t room temperature . nd fOr 48 h .t 4 'c. Ho~er. con""ntr>lion. ""'y incr....., or d« ..... comiderably in individU1W pbttpt]Wphilum, &bnl4 amu, &bniA pb»"I, bovine viral diarrhea virus, c:mi ne di.um!"', viru .. coni"" parvovirus. CytAUXZOt11I fty.. EhrlifhiA spp.. equine infccliow anemia virus, feline leukemia virus. fdine immunodeficiency viru •• HiJNpt.u",., cAp,"IANml, LriJhmllniA spp., L~purpiM >pp., 7Mi!nw spp, Endoroumia "Nn>plasia: carcinomas, hmungin=ma and. olh~ .. rromas. lymphoma, l. ukemias Drugs Hypophosphatemia wociattd with hyperalimcnration Anaphy\axis " A rclui.-dy o:>mrnon diooue Of condition Nooe: Usa of >peciIic disotdo .. ot condilio .... . te no< complete bu< ale peet. II.F. I} und .. idiopathic conditions until bemr characteriud. 3. Acquir..d .m~gahl}"O1 have bttn associ atal with bone marrow hypoplasia and bicytopeni. or p:mcytopen", in dogs :md prob.obly in hors .. {only phenylbuu7.0ne}, .,....... {3} Trim...:hoprim_mlfadiaz.ine and trim.rhoprim_sulfonamide ha"" bttn assoti""mia and/or

~ndotonmi.

:lSSOCiatffi with

=~

..

~nt~ritis.

d. Production failu .. IlliIy rontribut~ to thrombocytoptni"nia has oon reportal in dogs. but the

{I}

[n

patho~n • ..,'

have not oon establishal. III h. Systemic immuII. tic di..,=, infN:tion', massi"" nrcro,i" panc""atiti" nroplasia, o""rh~.ting. or sopti~mi .. {3} Drug, and fOf.rin, con indu,,", ""'~" thrombocytopenia in h~parini=:l and nonh.pariniud dogs, appar~ndy through. di=t proaggrq;. tory dfrcr,'''' {b} Foreign m>trrial, ustd within th. VlI1Cular .yst~m {e,g" tubing and coth.urs} ."" t.. ted and chosen to minimiu platd~t activation, but accd~rated ronsumption may occur, {4} En""nomation (without DICj: Th~ num~rom type. of ""noms from num.rou. aninul sprcies diffi:r in th~ir .ffrcrs. V~nom from "'m~ m.h. nuy contain pl atd.t_activ.ting factors th at indu~ thrombocytopenia in th~ abMn~ of DIC,'" Oth .. v~noms indue. Dlc" JO {5} Vasct1liti, or ~ndocorditis: InHammation of blood """"I, or endocordium con ah~r ~ndothdial cdl, or l~.d to expolUrttn incriminat«i in dogs with errtain types of n""pl .. ia {e.g., lymphoma} by u.. of indir= platdet and megmryocyte assays." {d} Oth.. contributors may include hemorrh . g>tomeg:dy inducffl by n""plastic infiltration {e.g., hemangiosarcom.} or ,econd..ry organ conges_ tion may be associat«i with plaldel Kquestration. 4. Drugs: Ai; :dr....dy nOl«i (Thrombocyto~nia, ...as. II.CA. D.2.c, IDd D.3.b), the thrombocyto~nia """",iat«i with drugs may be
[I.

Dis"""" and conditions (T.bl. 4.3) A. Hemic neopla,", (dona/thrombocytosis) l. Primary (.... mial) thrombocythemia: • ra .. chronic mydoproliftmi"" distasr that has bttn "'portffl in a few dogs and em {Stt Plat~ 7I}.'" ->''' a. pJ.tdet ronc;.,ntmions have bttn mark~dly inc==! (1<XXl-5000 X IO'Ij.lL).

b. Lorge. pleomorphic. or hypogranular pJ.tdets Im}' ~ p ...ent and .tients with iron deficiency. Th. specific cause is not known. but blood coneentmions of measured thrombopoietic cytokinu (e.g .• Tpo and IL-6) ha"" not bttn incr• ...d in hUJruln pati.ms with iron d.fici.ncy and thrombocy_ tosis.'" Cross-reactivity of Epo with Tpo rea:pton i, also apparently not the cau ... ' " d. Vinca alkaloids: Vincristin•• nd vinblastine "imula,. thrombopoiesis that can l",d to thrombocytosis without increased MPV.'''.l '' ln patients with IMT. these drug, Jruly l",d to inc .......:! platdet concentrations by o[h" mechanism •• including inhibition of the M PS and th".fore decreased platdet destruction. e. Recovery from thrombocytopenia (rebound thrombocytosi'l : Thrombocytopenia may srimulal< enough thrombopoi..i, that produpJ..,i. may au"" or contribute to thrombocytoois in many of th... ca, ... Thrombocyto_ ,is omociatrd with blood 10.. moy =luire th. pr=nc;., of. spl..,,,; it occurr«i with repeat«i phld>otomy (chronic blood lou) in nonsplenectomized r.obbits that we .. supplementM with iron. but did not occur in iron.supplemented, .plen«_ {omiud nbbi( •. '" h. HypuconisoJemi.: Hypu,,".and ..d&ct ,.lotion. ,hip is not drat. Thrombocyto.is may rdate to underlying or concurrent

conditions. prffinisone administration to hnlthy dogs r~SIllted in no inCJu..,"· or • qu~tionabl~ incru",'" in pl.rd"" oonetntr>tiofll.

PU-TELET VOLUME I.

[ntupretation of MPV ... Iu.. is limited by inaccunci.. and inronsisunci.. of routin~ MPV nteasurem~nt and limited knowl~ of f.cton influencing platdet ,ize,""" e.~ially in dontestic s~i ... A. Valu .. should b., interpreted rdati"" to rd'",enet intervals t
III.

Imrrpretation A. [n ma>ry. increaM' in miculatal pbldets suggtg" han bttn pr~ .. nt. wh~n evaluat..!. in

mon dog, .nd hor... with thrombocytoptni:u em=' by deer",,=' platdet .urvival.··"' .... 2. Erythropoietin .dmillinration to dog, wa, "-""'Ciat~d with incr~"'..! numbrrs of reticulat"! platdets .nd platd" hypls th.t abnormal reticulatw platd" r.. ults may han ",me sptcificity for platd" diwrd.",. However. samples with incr",,=' reticulat"! platelets w.'" 1I0t report"! in this nudy to confirm that .n incre... in reticulat"! platd", could br d"ectai C. Reticulat"! pl atd" v:du .. h.ve usually b.~11 .. port"! alld int"pm..! '" pt=nt>g~s rath" thall .t concentrations. I. Analogout to int~rpr~tatioll of immatur~ ~rythrocytes {miculocyt~,}. on~ must con,id~r the possibility that reticulat"! platd", I"'=m>g~ illo"", may br r~lati"" and not truly indicative of incr.. =' platd" production. 2. How"",,. ,,"~II with ages may br iner",,=' in ~~ .. thrombocytoptnw without inc",.,.. in reticulat~d platd", concentrations beau.. ther~ may .imply br too f~ platdets for ..... n a high reticulat"! platelet pt=nt>g~ to yidd an illc.....w micul at.-d [platdet].'"'a. Reticulat"! platdet roncentration. m.y al50 br ,uppr~=d by th~ mark.-dly reduced platelet Ii£. SpallS in.."... thrombocytoptnw. Th~ rdativdy few platd",. must br collsum.-d at an .ccd~rat.-d rat~ to maintain normal vascular intq:rity. "~ll

4/ PLATELETS

249

b. Also. th~ pathologic proct:S! consuming or d.. troying pl.cdeu rruoy target young and old platdeu alih. D. Th. clinical utility of «ticul.ta! platdet ...... m~nt in dommic rruommals is uncl~ar and :!W.its fimh~r nudy in a vari~ty of disord.rs. TESTS FOR IMMUNE_MEDIATED THROMBOCYTOPENIA (IMn I.

A ... riel)' of speci..tiz< 17S,.(97- SOI. 61 . McCandli,k IA. Mworo CD, B...u RG. N . ... AS. 1979. Honnooo-prod..ci"li: ...ian _ . n in tho . J Y.. In"", Med h75-M. 154. O·O"....dJ MR. Slidrt .. SJ. W,j,d", PL S-t. R. 1981. PI .. d .. ond fibo.j""V" kin
HE..\lOSTAS[S HmwifasU it th •• mst of bl • .ding or th. illl.rruption of blood flow through ~ v.... J. Th. t.. m is ..lto us.d mor. g. n....JJy to ref.. to th. illlricat• • nd bal. nc.d physiologic proc,,,... th .. t m.inuin blood in. &.ely flowing " .. t. but .. Uow th. rapid form ..tion of localizal solid plugs to .....J injured v...ds. Normal h.mo" .. sis d'p'nds on th. complex illl.ractions of its mojor romponelllS: pl ..,dets. OOtriction redu"",,, blood los~ :and actin",d ..,dotb.lial ",,[Js ""press both produombotic functions to limit b~ng md :ontithrombotic functiom to ~mit dotting. • Pt.",lett adhere to apo...d mb.ndotb.lium, 'I',.. d to patch the ton for platdet membnne glycopro_ tein Clo.~" plotdm ~r"Cialiud USIS ... u..d to assess platdet respon= in vitro.' The.. [<m are av:nubl~ in labs with 'J>"Cialiud aJ>"rtist and aJuipm~nt induding flow cytom~t~f1, ~rrgom~tef1, and th~ PFA· ]()() analyur {Dad~ Ikhring, Miami, FL}.ln addition to d"',""ting and chara.ct~riI.ing d,""r~ platd", function, thu e tests em also d"''"''t hyJ>"r:lctin p!'tdm as may occur with inf=ions {~.g., fc:lin~ inf=ioUJ J>"ritonitis or heartworm di",ase} , malignanci~" th~ nephrotic syndrom~, .nd oth.. dioord~f1.''''''' A sll'lJ>"Ctffi sJ>"Cific thrombopathia m.y b.: d~monstr:lbl. by sJ>"Cific [tion and «<mion nudies or by mol"Opl~}, but conin. platdets rontain v. ry littl . ....,., C. S,""r",al vWF forms noncoval.nt compln.. with cwgulation factor VIII and seN.. as a nabilizing and prot'""ti"" carrier mol«:tJ.J~ for factor VII!.'"'

II.

von WilJebrand di",= (vWD) A. vWD, which i. a disord~r of primary hemonasi, cousa! by. d~fici~n but i, r:lr~ in cattl~," cots," and horst • .'l-" B. vWD is usually an inh~rital disord~r, but acquirffi vWD occurs rardy in peopl • ."''' Acquirffi vWD has not bttn d ...ly do Th. finding of vWF: Ag v:du .. that w"". WRl for hypothyroid doc' I>tocytes, meg:obryocyus, lymphocytes, and v:ascular ,mooth mu..d~ crlJ.. 71 It h.. a half_lift of about 0.5- 1.5 d and is consumal by Arc during co~lation. (2) Factor V][[ may bt producrd in muhipl~ cdl typt" but h~patocyt .. apprar to bt most imporunt. (a) It i, sex linkal. It. g.ne i, on the X rnromooome." (b) It circulatrs in a nonroval~nt complex with vWF but i, distinct from

,WF. (c) Th. half_lif~ of human factor Villi, .bout 0.5 d, but it is Ie .. in the abs.ncr of vWF, its carrier prot.in. (d) It i, consumal by APC during coagulation. (.) It i, a "",itive acute-ph ... protein, iner...ing in pi"""" with eRrci.. and inflammation."''' (3) Factors V .nd VIII ..., ronsumal during clotting and at. not prestnt in .. rum. d. EDTA, oxal.t~, and citrate function:as in vitro anticoagulanu by binding fCa""' and pr...",nting it from interacting with coagulation proteins. In vim, ther. i, alwaY" .nough fCa""' for roagulation "".n with hypocalcrmia. F. PhY"iologic inhibitors of coagulation hdp pr""~nt acessi"" co~lation. Deficiencies of these anticoagulanu are associ.tal with thrombotmbolic di ...... Som~ of th~ inhibiton con bt m~alUrai

Fig. So2. ~ti~~"

• Common path..-.y: This is th. COJIUDOn rontinu .. ion of the TF and mrfioco-indu=! path......}". beginning with > ~ lt~! l1t~

lil~11 ~Jt~ ~ >
. tocytes, .nd megakaryocyt ... • . Additional anticwgulation occur> by this pathway b.au"", thrombin bound to thrombomodulin cannot d •• "" fibrinogen. and th. romplex is int>tocytes. It also circulates in pJ.tdm and in pl.!ffiO, mostly bound to lipopro"ins. In the pr=nce of ft:.", TFPI inhibit. TF_Vlh by forming •• ta bl. quater_ nary complex: TF_VIl ..... f. ctor Xa- TFPI." Thi. inhibits furth .. g.n ... tion of f:>tic.Uy. AT activity i, mo.rloodly ~nItanood in rhr preontrolled coagula.ion an prnfunnationol dtangn in AT th ... nalW i, to bind to and inbibi. f""to< Xx, bu. ".,. .brombin. • o..c.eued pLum. AT activity and _ntrotion O«W" via ...... ru"'f";"" "'''''0 intraYuculu coagubrion .. inctaOed 0' af... injecOon of."ogmow hepa.rin. Deanoed COllcaluaOono may aIaoOCCW" from dea.-.t It.epWc production at from ""CUI;"'" lou d ... to poott. mlum. rrquir":! fot ~nticoagulating a volum~ of blood with a ginn Hct:>55 %: C = 0.002 X {IOO - Hct} X V C: cicr.t. mlum. (mL) Hct: blood h~matocrit (%) V: coll= ..:! blood mlum. {mL}

(5 .!.)

E. Sampl~ processing and subility" l. Tim. and t~m~ratur. ~for. p""", .. ing" a. Excq>t for whole blood clotting =Y', studies of human blood indict. that whole blood .amples may ~ rdJig~rat..:! or hpt at room t~m~ratur. for up to 8-12 h (PIT a.!S>y for nonhqmini=:l pati~nu, IT a~, and coagulation f.ctor ~ruolY'.. ) or up to 24 h {PT =y} ~for. processing.""" b. Ho~r, a good g. Fibrin fo,m"ion;' th. ond point fo,udt "' ... PTr rnd ACT .-nlu"o =..,.,I"ion f.oClon in th. mrfac (Itt Coagulation, =t, IV), B, Activatal COus (di.tollUceous) ~.nh, which acrivau. the mrf=_inducffl {intrinsic) pathway. b. The blood is mix..! by five in""",;o"" and the ru~ is inrub. tal (37°C) for 60 •. Th. IU~ is th.n ch~kal {visually while tipping it} ....'1 5 or 10 s for th. first

ddinite

~id.n""

of a clOi.

c. The tim. from contact of blood with s.ilaca>m ..,mh to the initial ddinite signs of a clot is the ACT. d. Units: ,,",,,lid, (nrarm 5 or to., d~nding on the f=iu.ney of inspffiion) 4. Interpreti"" colISid .."'tiom a. lnt.rpr..ution is similar to that for PIT (Stt Coagulotion, =1. IV), but th .. 1m has Jess diagnonic stns.itivity .nd may requi .. :> 90--95 % deficiency of a single fxtor for a proJong«i result. b. ~""r.. thrombocyto~nia « 10 X 10' pludm/J.lL) is commonly stat"'" to prolong ACT, b=ou.. of dee""as.,d phospholipid availobility. HoW. analyzers. r"'i:,ms. and protocol.. 3. As ~uine data indicat~. values in healthy n=borns {< 24 h old} may k great~r than .. fcr~nce interval. est.blished for .dult.. """" 4. Th, test is rdatively inscmitivc. bur. for optimized • .,ays. rcmlu ,hould k prolonged when there is .bout • 70 % decr..... in the a.ctivity of a .ingle

282

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY co"l:"luioll f:OCior (30 % of ap«t~d activity). [n on~ srudy of various PT reagents

and m.tho,h. th. f.ctor VII activity n=:l«i to kttp PT WRI v.n,"", from 16 % to 39 %.'" 5. Mild" rffluctions in individ,",J f.ctor .ctivities may k d.uctal when multipl. f.ctors are .if«taj. 6. PTT ..sayod at 37'C may ovtrestimat. in vivo coagul>tion in muk.dly hypoth". mic !"Ili.lI1S 1>«:..= enzyme activiti", "" temptntur. depys B. Principle and method l. Test plasJIU .nd a C."_thromboplastin reagy. Activ.tion should proceed along the common pathw>y so '" to form fibrin monom.... which polym~riu to form an insoluble fibrin dot that em be deteetro optirnlly or electromech:mirnlly. de~nding on th~ inarin ina.ctiv. tors ill m""r thromboplanin r< Shortrn.d PT is not rdiable for detecting hypc:rroagul.biliry but may occur wirh increased [fibrillogen] or f. ctor V.'" PT i, usc:d to moniror w.rfarin therapy (rargc:r PT .. 1.5- 2.0 rimes balelillc). INR i. a unid... ratio {Eq. 5.2} used widdy ill hUJruln m.dicine to hdp nalldardizc: the r~porrillg of PT v. lues to hdp correcr for diffe .. na:. in rhromboplastin r,,,!:,,nts .mong laboratories."" [n Eq. 5.2, refe"'na: PT is the mean of a valid ",fe",na: im.rvaI for the speci.. in question, nor a random control .. mple value. The lSI {lmemational Sensiriv· iry Index} is a lIumb.r determined and provid.d by rhe rhromboplastill reagtm Jrulnufactu .. r for rach lor of re.~nt by ming • particular PT method. The lSI, which reH and diff"ent thromboplastin 'liem I. [SI = 1.5: PT = 12.0.; n"" mean = 8.0 • {Eq. 5.}:!} {2} P.tient 2. [SI = 23: PT = 12.0.; n"" mean = 8.0, (Eq. 5.3b) {3} Patients I and 2 had the same PT (12.0.) when patient 2 was teJlM with. I... ..,nsitive thromboplastin rtd production :lSSOCit.d with inHamJrultion or pr ~uine data indicate. value; in he;o/thy newborn, { 5/ HEMOSTASIS

"'7

B. F.ctor ddicienci .. a.. indial.!..:! if. I: 1 dilution of test pl:lSm. with normal plasma oorrne:u prolong..:! PT or PTT (provides the missing f.ctor or factors). wh ......, failute to ruff<et ~ulation time, support' the prose:n"", of.n inhibitor (on: =t •. XJI and XIII). C. Clotting . Udys for ,~ific factors ...... the .bility of the p>ti.nt pla,1IU to rorrect the PT or PTT of .~ific faaor_d.ficient pla,ma,. ,., l. PIT is used for anticoagulant statu. I. Plasma AT is usually m, 3, Units a, Units

ar~ %

.ctivity compared to ~ith" • 'pa:i~'-'P'""ific or human plasma pool to have: ] 00 % activity, 8«;oUsOnM in UlmL or UldL, whu~ I UlmL or ]00 UldL, "'I"""tive:ly, i, arbit"'rily assignM a, th~ me;on value of th~ ref~r~n"" ""'pl~ pool. 4, Subility: AT .ppe.n to ~ st.ble in citmM pluma for 6 010 at - 70'C and for 6 wk in whol~ blood storM at 4 'C"" 5, Int~rpr~tive: con,id~ .. tiom a, Foal. and human neonar .. have bttn mown to have plasm. AT activiti~, that ar~ substantially lower than aduh v:due!,llo,,,· This must ~ consid"M wh~n im"prcring AT value! in young pati~nts, e'l"""iaily in [h~ ab .. nce of "1:"_ matchM r~f~ .. nce im~rv:d .. b, AT activity llUy ~ ove:rcnillUtM when mcarurM by !lOme thrombin chromo_ genic ....ys bccau.. heparin cofactor II .ctivity llUy ~ dffcctM in .ddition to AT activity.'""'''" 6. D,""",asal AT activity''','"''· ..• (Fig. 5.4 and Tabl~ 5.8) a. Dccr""M AT activity may ~ eith~r. cause or an ~ffcct ofhypercoaguJ.bl~ (prothrombotic) nat~'. Oth~r clinicl .nd labo""o'1 finding, should ~ U'M to help dcrermin~ irs pathogene,is. b. Dccr""M production {I} InhuitM d~fici~ncies hav~ not bttn reporrM in animal, but occur in pcopl~ as type I {d,""",asal amigtn .nd activity, a qu amitative: disorduJ and type II {d.cr.....,J activity but norm.1 amoun" of .mig~n, • qualitative: di,ord,,).''' {2} live:r di ..... (including ponosY"'.mic ,hun,,}'" may cu .. or contribute to AT d~fici~ncy in """,,,,I ways. including dccr..... d AT production relatM to d'""r .....d hepatocellular IlUlS.

""

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY {3} InHamm. t;on may d,""""as. AT production in >om •• ~j ... AT w:lS shown to be a n«t. II}:'" srp.is'" c. Inhibition: Ami_{phospholipid_protein} antibodi .. =y inhibit th~ function of protein S. protein C. or factor V.'" ,''',''' d. AI; ajuine data indicate. protein C activity (not :mtigen) vatu .. in hralthy nronat .. « 24 hold) =y b. greater than rd"t .. na: interval. establiili..d for .dults."o," , C. Protein Z l. l'rotrin Z is a vitamin K-i:ul. lion, clinical IIUnifmalions .'" Ihrombosis or Ihrom~mbolism, not h.morrh>i:. ... D. A .. ria of spa:i:aliud t. m m.. y b. r, plasminogen {inaai"" zymogtn} binds to fibrin. 2. t_PA rel....d from slimulat"! .ndothelial cells bind, to the fibrin_plasminogtn complex:md proteolytically d •• "". plasminogO' b. Oecr....d ... nal function truly contribute to increased [FOP.] in some pati~nts with renal failure.'" c. Theoretically, d«reased MPS activity could contribut. to incr....d [FOPs]. E. Effect. of incre...d [FOPs] on other hemonatic functions and tests I. Prolongs valu .. for tests with clot .nd points {PT. PIT, IT, ACT, and Ltt_Whit~ clotting time} 2. Impairs pl.tdet function 3. M«hanisms of .nti~ation and .ntipl.tdet .ffecrs a. FOP. compete with fibrinogen for the active sit. of thrombin .nd thu. truly inhibit th. conversion of fibrinogen to fibrin.>.!'·'''' b. FOPs compete with fibrinogen for platdet_binding ,ites .nd thu! truly inhibit plotdet aggregation.""' c. FOP. associat. with fibrin monom.rs and m.. y disrupt normal polymerization.'1J.m 4. An incr ... sed concentration of FOP. promotes .n antithrombotic and proh.mor_ rhagic nat •.

29'

5/ HEMOSTASIS Ill.

Fibrin f"'l:m~nt D_dim~r A. Thalry: It an ~ UoN to asse .. inc",_d fibrinolysis auoc"'ta! with OO"'>"

BLOOD VESSELS {EN DOTHEliAL CELLS} Although blood ""ssds (esp.cially th~ endothdial cell.) are ""ry imporunt in maintaining normal hemost",is via prothrombotic .nd :mtithrombotic properti..."· their assessment in the clinical po.thology laboratory i. limited primarily to ti!SUe biopsy and hinologic evalu.tion (e.g.. for vasculitis or thrombosis). V.!Cul.. l..ions .re umally obvioll'l wh~n hemorrhage is the result of mrgicol or accid~ntal v:..culu trauma. Di..",.. involving """ll vessels •• uch •• RMSF and equine purpura hemorrh>gico. may be associated with petechiae and ecchymoses cousrd by rombin ations of direct vaocular damage. thrombocytopenia •• nd thrombop. thia. Hemostasis tening may hdp exclude other di",rders but will not provide. sp<eific diagnosis. MAJOR BLEEDING DISORDERS; FIN DI NGS AN D PATHOGENESES I.

Diagnmis; The diagnosis ofblttding disorde", requir.. knowledge of the general ty~ of bINding di50rd~rs. conoideration of clinical findings •• ccuraU interpreution ofhemo,wi, t.. t r.,ulu •• nd recognition of h~most"'is test p.tterns.

5/ HEMOSTASIS

301

A. TyJ>u, heIlliltomas .nd hemorrhage into lxxIy coviti.. suggest d~f«ts in =nd.'}' hemost>.
[).,f«t in surfaa-inducM and/or common pathway. Renal or intestinal loss, consumptive oo:oguJ.tion,

hq>. rin .dministration, or dec.... M production i Tim~

ThrombocytoptDi
BM BT Clot retraction Co"l:"l. tion factors

C

PT PIT RVVT IT

i i i i

vWF:Ag

,l. Conctntration

Time Time Tim~ Tim~

i Conctntration

consumption (may ~ hyp.tic production, .bnormal production (vitamin K .ntagonism or ab..,nct), [OSl, consumption (Jrulr b. hyp1Se1< :octivity. but th.re :ocr immunologic .. "Y' th1t....,., ronomm.tion. Protnam,mions "'" um.Jly det!itivity of th. PT =y may m.. k other abnormaliti." a, Acquirw PIT prolongations: This 1m}' be caus.d by h'p"tic disc ...., h.parin contamin.tion of the sample (',g,. inappropriate collection from. hep"riniud cath.ter). or heparin th ... py. and rardy is cau.w by vitamin K .ntagonism, 1Ur• • urfa.c!id.red, F.ctor VI I h .. th. shon.n half. life of th. vitamin K-J"",nd.nt faCto ... and thrtt of the five factors in th. combined TF .nd common pathway. a.. vitomin K d'pend.nt, Th...fo",. th.

304


PT may

~

:of&cc«i by vitamin K antagonism or abstn~ ~fo", th~ PIT,

~,~ialJy wh~n

a PIVKA·.. n';tin PT method is usa!. b. Inhuitffl or ooIli:enital PT prolongations (Tabl. 5.7): F.ctor VII ddiciencies are rare .nd :associatw with mild h.morr~, uma/ly in "'ponsr to surgical or nomurgical tnum ..

5. Pm.rn 5: Prolongrtrd in Devon rex cots and p,mibly found in a Labrador retri"""r}.'''''''' 6. Pm. rn 6: Prolongrd PT and PIT with hypofibrinog.n.mia and possibly prolongrd BMBT a. Acquirrd disorders: Hep>tic di"'''''' i, a consid"ation for thi, pattern {= the discussion of patt. rn 5}. Consumptive coagulation {•.g.• Die} could also b. conoid"rd. but thrombocyt0p"nia and inc".=' [FOP,] andlor [O_dim"] ." usuaUy expecrrd with Ole. b. Inh.ritrd or congenital disord.rs: A markrd decr..... in [fibrinog.n] along with prolongrd PT and PIT should prompt consid.ration of rare inh"itrd dJ"lfibrinog.nemia or afibrinog.n.mia. " Seve", hemorrhagic tend.ncies a" ex~trd. and BMBT may b. prolongrd. 7. Pmern 7: Prolongrd PT and PIT with incr•...d [FOPs]. hypofibrinogenemia. and thrombocyt0p"nia are typical of fulminant ole. what• ...,r the couse. Such a patient would app"ar very ill. likdy with .viden"" of multipl. organ durulg.. Findings with hepatic f.ilu" could b. similar. II.

Pathog.n.,is: The pathog.n.... of h.morrhagic d.f.cts in primary h.mon",i, rdat. to ,~ific .bnornuliti.. or d.fici.ncies in platd.ts. vWF. or the v. .... l w:.ll. Inherited disorders of strondary hemostasis are caus.d by various gt:netic .h"ations that r.. ult in d.er•• ...:!. ab .. nt. or .bnormal hemo,utic f.ctors. Acquirrd blttding disorders oft.n have. mo,"" compla pathog.n=s. The pathog.n.... of h.monatic .bnormaliti.. are di5Cussed for the foUowing .dected a.cquirrd blttding disorde ..: A. Hepatic di ....... '" l. liver di ...... con couse defn:" in the production and dearance of procoagulants. anticoagulants. profibrinolytics•• nd antifibrinolytics. The net result i, oft.n clini_ cally ,il.nt despite abnormalities in hemo,utic laboratory tests.

5/ HEMOSTASIS

305

2. Blttding is unconunon but =y occur ifhq>. tic f.ilur~ is 5tV~'" or asoociatffl with DI C. Oth~r J.bor.uory .-vid.n"" of hq>>tic f~ilur~ would ~ npa:1ffl in • pati~nt blttding b«:au.. of th~ h~patic failur~. 3. Pot~ntial abnormal h~mostatic test results .nd th~ir cau... a. Prolongffl PT. PIT, ACT, or IT {I} O,""",-d h~patic production of co.gulation factors b«:allSt of d,""reasffl functional hq>atic m..... (including pono.ynemic .hunt,"') {2} Abnornul production of vitamin K- {2} [nc",-d FOP production {fibrinolysi,} b«:au.. of aOJ Blttding complic;otion, in dog, and caU are mo", !Irongly associatffl with thrombocytop«:om. prolong«i (within 14 h)"" .nd hemorrhage may occur. 2. Yiumin K ddiciency (hypoviuminosis K) is rudy ddicient enough to COUM hemorrhage. a. Yiumin K i. absorbed in th. int..,in. aft.r i~tion or production by intestinal bacteria. b. Causes of clinically significont vit:mlin K deficiency have not bttn clarified in most species. but th. following mould be considered: (I ) Prolon~ anorn", or ingestion of an abnormal diet moy muse or contribute to vitamin K d.fici.ncy. In rontrast. normal diets contain ",a ss vitamin

mu,

K. ",~" (2) Gut st.rilization by antimicrobi;d, Im}' couse or contributr to vitamin K deficiency.'''''' {3} Malabwrption of vitamin K (a fat.solubl. vitamin)'"

{a} Intrahepatic or extrahepatic cholmasis (decrrased f.t digestion and absorption. :md ther.fore decreased vitamin K .bwrption) (b) Intestiruol mal absorption dis ....." (e.g .• infiltrativr bowd diM• ..,) (c) Exocrine pancreatic insuffici.ncy {drcr ......! fat digc:nion and .bsorp. tion. and th.... fo ... drcr ......! viumin K absorption} c. Dimini,h.d. but nOi absent. vit.min K moy lead to • subclinical mixture of normal cwgulation factors .nd PIVKA. Vitamin K supplementation wa. 'lSOCiatrd with a cor=tion of prolon~ PIVKA·..",itiv. PT values in cots with intestinal or h.patic dis .....".''' 3. Cause:! of abnormal h.mostatic test reswts a. Prolongc:d PT. PlT. or ACT (I ) Decre.,.d amounU of functioruol vitamin K-Jrpend.nt cwgulation f""tors participating in the surfa",. induced (factor IX). TF (factor VII). and common {f.ctors X and II} pathv..ays {2} Although PT is npected to be: prolongrd be:fore PlT. th.re may be: prolongation of PTf .lon•• PT alone. or both valu ... drpending on the optimization of the .....Y' and. perhap•• the .pecies involved.'" b. Thrombocytopenia {I} If p .....,nt. thrombocytopc:n", prob.bly .... ult. mOJily from coIIJumption .t multiple sitrs of hemorrhage. {2} Wh.n moderate or markrd. BMBT prolong.tion would be: rxpectrd • .. pecially if the patient is anemic.

Liver

,; "

.

Blood

Poorly carbai:e. ,hod:. or .igns of multipl. org.n failur., all1sffl by thromoo.mbolism or hemorrhagt. Sign, of the und..lying dise;o .. may al", ~ pr=m. 6. Consumptiv. cwgulopathy can "" rrcogniud when the typical laboratory and dinical signs .crompany ~ condition known to trigg'" the proa:s.s. Typical finding. are thrombocyto!",ni-m Without .d"'luate functional fibrinogen, fibrin clots cannot form, thus prolonging PT, PIT, ACT, and IT. B=
te«thl.,.

,.,,«

oc.

5/ HEMOSTASIS

313

27. P...... Mr. T • .....n... MA. lo ......n GS. 199!. Von Willobond facto,;n I,..." of .....bod ania, pla,d.... Am 1 v.. R... 51,119_ 125. 28. B.noon RE. loionoon GS. Dod.do WJ. 1981 . Ilindin,; of Jow..moIocub.-""'&b' =in< f.c"", VIII "",,,,lan, from "'" Wdkb....d pla.",. '" ani", farto. Vlll.....,h,od ""tivn- B, J H""""toI 49,5-1 I_HO. 19. S..Jli..an l'S, G..bbo ST. 0Id00..y TWJ. And, .... E\l . Wbit, JG. c. .. Ib."", JI.. Dodd PA. McDooald 11'. 1994. Bl«. th, bindin& of p ...... "'0 Wilkb...,d facto. to =Ilauo in pi .. ",.. fro", ""nn.1 do", and doc. ,.;th tI..ombin cim, ....,.. to facto. VII W 1l,71- 7S. 117. K...... M, S"'p"" Y. y .......ki N. Kit"..... ] . Hun.da Y. Horti I. 2OO}. Mod.ani .. """ obort...; .. , PT and Al'TT in ""'" and "''', Effect of u..~o on YT and APTf. J T osi.roI s.; 2.'j,jJ9--44J. lIB. Mi..hlr R. ZOO}. Hqoouin io .itro ..... iti.ity of th, .ainted parti.J thrombopl .. tio rim, in =in< pIa_oo "";',,. 2nd do ...... 170}-1717. N .... Yool, Chwdillillvi_nt. lll. Wdli.",. JE. H""""" RR. H"",u" J. McDo~ J. 19111 . ClwK'"iz.oion of tbt inh.ibioion of lib.in • ......bIy b, Iib.~ f_,ot D. BOod, .. J 197.661--66.'!. Il4. O ·Kant MJ. Wiodom GB. Dtai ZR. Aodobold GPR. 1994 . w.ibitioa of6btin ""'........ polymtri ....... by ""do",. i"' ......p.,bulin. J Clin PathoI47,z66-268. l}S. G ..,inc,"" DA. G"",.\1A. Danid. TM. Kyit RA. s.,..;, EJW. 1?91 . Inbibi"", of th, ... "'mbift tim, in .,...... " .myIoidooi., A «>apdation ab"""",aIi.,.. Blood 77,2637- 2640.

5/ HEMOSTASIS

317

136. Cu. ME J•• G.bdd DA. 19S6. H~,;""V"'mia .. a cao","( "",loop obrombin dottin& ci .... Sooth Mod J 79,S(;}-S7(I. 137. F.kkr WA. McDo ... ~ J. 1983. T!..ombin dottin, tim • ...d fibo.j""V" «>0«0'"'''''' io pati= .. ,,,,,od ..ith

0

~

Hi d H

I

~

j

•

..!:

·q"~F 1: ! ljh~; l ,q I! }J]lJj~~·I·f t ~~ij~j1 ~~j jl ~~ ~ ~ ~ ~!illo J -li"':

~b=:tj~",

i

li",

i< "~" . >~ ~~ ~f 1::' -;;1' i Ii 1 ~ j J .t !] ! ~ j ~" ! I ~ l Ii ~ ~ ~~ ~ Ii cSj '5 ] ~; J~ j • ! ~, ~ i j n I ! l~ 11 ~ L~ e ~ . uJ J -s ~s ~ I ,,~-s ~j J ·1
P.".."",

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This page intentionally left blank

Chapter 6

BONE MARROW AND LYMPH NODE Bono Marrow: Major Concepts and Terms ..................................... Bono Marrow Classif ications................................................. I. Bone Marrow Hyperplasia ....................... ........ ........... II. Bone Marrow Hypoplasia ....................... ........ ........... III. Bone Marrow Lymphocytosis ....................................... IV. Bone Marrow Mastocytosis ...................... •••••••• ........... V. Myelofi brosis..................................................... VI. Myeliti s ...................................... ........ ........... VII. Bone Marrow Necrosis ......................... •••••••• ........... VIII. Myelophthisis .................................................... IX. Bone Marrow Hemic Cell Neoplasia ............... ........ ........... Interpreting Results of Bone Marrow Examinations .......... ........ ........... Lymph Node: Major Concepts and Terms ...................................... Lymph Node Classifications ................................................. I. Hyperplastic Lymph Node .......................................... II. Reactive Lymph Node ............................................. III. Lymphadenitis.................................................... IV. Lymphoid Neoplasia (Lymphoma and Lymphosarcoma) ................ V. Nonlymphoid Neoplasia (Typically Metastatic) ......................... VI. Other Findings ...................................................

324 334 334 338 340 340 341 341 341 342 342 357 358 363 363 363 363 363 365 365

323

324


T able 6. 1. Abbreviation. and ,?',nools in lhi. chapler

ALSG AML

eBC CD CMMoL D NA

E"" F, FcLV G:E G_CSF GM_CSF M:E

M6_Er MDS MDS·EB MDS_Er MDS·RC MPD MPO

NK TCRo.~

TCR')':'i WHO

Animal uuhm;" Study Group Acuu mydoid lalhmi Complete blood count

Clune. of diff..entialion Chronic mydomonocytic I.uk-mi. Ckoxyribonucleic acid Erythropoietin [ron

Fe/iM leukemia viru, Gr:mulocytic to erythroid Gr:mulocyt. coionr-stimulating f.ctor

Gr:muJocyulmacroph"l:' coiony- Slimui.ting faclor Myeloid to ..ylhroid Amu crythrolcuhmia with erythroid r=iominance Mydodyspwtic .yndromc Mydodysplmic .yndrome--ac... blasts Mydodysplmic .yndrom.......,rythroid predominan"" Mydodysplanic .yndrome--rcfractory cyto!",nia Mydoprolifcmivt di",= MydoJ>ly basophilic cytoplasms lhat may form bleb •. b. Promr£llMrytXJlrS develop from megakaryoblasls and ha"" what appear 10 be two or four nuclei and scanl amounU of basophilic cytoplasm Ih'l m.y form bleb, (pt.le 9A [for all plales, J« th. color ..aion of Ihi, book]). c. Megakaryocytes vary in ,iu and ploidy. A> Ihey dcvdop from promegakaryocytes, Ihey b.:comelarger, have: more nude.r lobulalion., and have: more .bundant, paler cytoplasms Ihal break up imo :mud•• te platdels. Malure forms predomi_ nat. (Plat. 9B). B. Erythrocytelineagc: (Table 6.2) I. [n VCIerinary medicin., Ih. nuclealed erythroid precursors .re usually named using. ,...bri_ prefiL The cell, wilhin Ihe .. ries.re Ih. rubriblasr, prorubricyte, basophilic rubricyte, polychromalophilic rubricyte, normochromic rubricyte, and meurubri_ cyte, allhough Ihe.. is a continuum of dcvdopmem making cell subcl""ificalion difficult at limes. MCiarubricytes gi"" ri .. 10 rCIiculocyt...nd JrullUre erythrocytes. 2. A> cdl. proliferate .nd JrullUre (... F~. 3.1 ) from Ihe firsirecogniUlble ,tage, Ihe rubriblast. they decr..... in ,iu and cytoplasmic basophilia while incr .... ,ing hemoglobin conUnt and associaled eosinophilic ,uining {plate 9C}. 3. [n human medicin., :md somelim.. in VCIerinary medicin., Ih. nuclealed erythroid precursors arc named by u.

3.

Evid~n""

lysosomal IY.

of sp«ific dis""..,.: hinopl .. m05;., no~~ disnoe:s

l~jshmani ..

j,. plasma cdl mydoma, or

Mffhods A. Complete description. of. bon. marrow biop'Y {colla:tion, fixation, staining. and aamination of bone marrow from a living :mimal} are ~yond the scopt of thi. tnt. Procedur.. of a bone marrow biopsy are descrikd in S.ration •. (b) Ah"'IlItivdy. coU.crrd fiIlIt~riaJ am ~ plac.d in • watch gt... or P~ri illill with amicwgulam. :HId th~ panid~ am ~ e';(rKtrd and spmod onto s1id~ without th~ co"",rn of doning. Antico:ogulants m"}' indu"" anif:ocu. b. Aspiration may yidd a "dry tap" containing e=ntially no material. in which = additional :ospir>tion mempts or oor~ biol"Y .. mples a.. ~uirrd. "Dry tal"" do not indicote cru.t the nurrow i. hypocdlulor; th"Y may oo:ur with bon~ marrow hyp",,,,,llulariry in a variety of disord~ ... c. For roU!in~ microscopic naminarion •• th~ air-drird sampl.. a.. Slaintd with a stain thai is u.s.d for blood film. {a ROJrulnowsky Slain such as • Wright Slain or Diff_Quik}. A Prussian blu~ Slain Jruly ~ applird to ....... th~ .mount of ,tainable F~ in a sample. d. Proce ... ing requir~m~m. for cytoch~mical or immunocytologic procalures should ~ obtainrd from th~ rdevoom laboratory. 4. Proa'lSing cor~ biopsy samples a. Afi~r making imprims by touching or rolling th~ ror~ on a gw.. dide. the core ,ampl~ i. placed in a fixative. B5 or unk .... fixatin is pref~rabl~. but routin~ buff",td form.lin is adequate. (Note: k""p the air-drird sampl.. far a"oay from th~ finti"" kcau .. formalin fumes am sev~rdy alter th~ ,taining prop'cial Slain, can ~ tim ... ronsuming. Frequ~ndy. just :as much dinically useful information con ~ learnrd from a subjectin .....,ssm~nt of cdl population, by an np ....,nt;;uiv. of bon~ marrow tissu •. b. H~Jrultopoi~ic popul.tions {s,,", Figs. 2.1 .nd 6.1} {I} Numkr and struCtlm of megakaryocyus {a} Th~ apa;t~d numkr of Jrultu .. mq;akaryocytes in a .. mpl~ vari~. among sp«i.. and i, highly d~nd~nt on th. quality of the .. mpl~. ~ally th~ num!J.,r of bon~ marrow frngm.nts in aspirates . [n h~.hh, [h~r~ is usually a[ l~..,t on~ mq::okaryocyt~ ~r marrow fragm~nt. [f more mq::okaryocytes a.. found than a.. ap=ed, then mq;aka,yocytic hy~rpl",ia is p.."'nt. [f f. wer are p.."'nt, then m~gakaryoII bt d.t~rmin..! if th~ umples """ !lain..! with an F. stain such as Prussian blu~, {2} Th~ .mount of F. pigrn~nt in th~ ..mpl~ i, estimat"! and r~port~d by using a variety of t~rms: (a) Abstnt or d= ...,al (b) Ad«Juate, within normallimics, or mod~rat~ (cj Incr~a !etl or abundant (3) H...lthyem lock detocubl~ marrow F~ 'tores, but F~ moy bt pr=nt bta"", of h~molytic disorde .. , .ft~r a transfu,ion, .nd in m)'tloprolif~"ui"" disorde ..,'l,lJ Stores may bt absent in h~ahhy young animals of .ny 'pecie., 3, Comparison of hinologic and cytologic enminationt a, Hi,tologic enmin. tion of rore ""mpl~, (I) Adv,mtag •• (a) Tissue architoctu", (how cdl, ..~ arr.nged), nocrosi" infihrati"" pattern" focollesiono, and mydofibro,is em bt better :asse<sal, (b) Bon~ marrow "",llulority con bt btller ass.un!, (c) Megakar}'ocyt~ numbtr con bt bttt~r:use:sset!, (d) Abnormojities of bon~ and "",,,,Is con bt better as=sal, (e) Further tissue .ettions con bt cut for 'pecial ,uins, (2) Di""dvant:ag.. (a) It i. mor~ np<nsi"", with gre.ter turnaround tim., (b) Cdl diff~r.ntiation i, mo", difficult, especially if =tions a", not cut thin enough (wg~t .. 3jlm), (c) Phagocytooi, ofh~matopoietic cdl, i, difficult to detoct, (d) M~ny dyspla'tic f~.tur~' .'" difficult to detett, (3) Potential problems with 00'" "'-mples include .hort """pIes of un""ruin repr=nution, sampl.. con,i,ting mostly of oonical .nd ,ubcortical bone, sample damag~ rdatal to prior "'pimion, cru,h .nifact from traumotic collettion, impropte marrow 5ampJ.. provides the most complete information. (I) Cytologic ~:dl1ation of aspirate, is almo>! alw:.y. indiauffl. {2} Histologic aamination j. "",ful when marrow ",mit«tu,. is !nJuir«i to ",.ch a di:ogno.i., myelofibrosis is susJl«tal (conn«tive Ii ... "" afolia!.. poorly), or hypoplaSlic sUI.. are 'Il'l~{nl (•.g., when pancyto!"'lIi js pr=nt) and th.refor. an ..,pinto our yidd f
",.,m>w

h~matopoietic

6/ BONE MARROW AND LYMPH NODE

335

Table 6.3, Disordcn and conditions Ihu cau.e erythroid, granulocyti c, or n,,'Sakacyocytic hypcrpla.ia in marrow Erythroid hyptrpl",ia Eff«live erythropoiesis 'Sn::ond"y to hemolytic or blood loss disordm Sn::ondary appropriate erythrocytolic disord ... Righl_lo_l.fl munts, congcniul or ~cquired Chronic pulmonary di=.c Hyptrlhyroidi,m Sn::ondary inappropriate .rythrocytolic disord... Iknal ncopl",ms, C)"lIS, or dis ......,. Olher ncopl",ms {hepatomal Ineff«tive erythropoi.. is 'Immune-mediated nonreg.n.",tive an.mia 'Nutritional: F., copper, folat., or vitamin B" deficiency Cyclic h.matopoiesis of grcy oolli.. and F.LV_inf«ted cats Granulocytic hyperpl"'ia Eff«tive granulopoicsi. Inflammatory 'Infections: bacteri:d, fungal, viral, protozo:d 'Immune_mediated h.molytic ~n.mia 'N«rosis: hemoly.is, h.morrlugt, infarclS, burns, ncop!...ia, sterile inflammation Sterile foreign body Othe.. or unknown mechanisms p..",ncoplanic n.... trophilia Neutrophilia ofl.... kocyt. adhesion d.fici.my G-CSF adminimation Estrogtn toxicosi. {e:arly} Cyclic h.matopoi ..i, of grey collies and in FeLV_infccted am In.ff«tive g",nulopoiesis Immune-mediated neutroptnia Diphenylhydantoin and phenylbutazone toxicosis (suspected in animals) Chronic idiopathic nrntroptnia (G_CSF d.fici.ncy) Megakaryocytic hyptrplasia 'Recovery &om thrombocytoptnia: withdrav..al of myelosuppression or in ... poJl5C: to a disorder tru.t cau.scs d«reased platdet mrviv:d Inflammation: inf«tion, immun._mediated, surgery, t",um • • A rclllively oommon dis< ... or condition Notscic chang~' may b. pr~ .. nt. B. GrllnuUxyric hyprrpfil'ill: Unle .. nata! oth~rwi .., gr;onulocytic hyp<rplasia (also coHed myloid hJpnpiasill) typiGlUy i, char:ocurizal by an incrchn f~rn, ch~moth~rap"utic drugs, chloramph~nicol (cau), rstrog~n, gri=fulvin, ph~nylbuY7.0n~, diph~nylhydantoin [mmun.... maliatrd nruirop"nia Sd=i"" m~ryocytic hypopl:ui. Toxic: br>chn f~rn poisoning (ruminant.), ch~moth.rapeutic age:nu, rstrog~ns in dogs (aogrnous, ~ndogfulvin, mffiof~namic :>gttiud becou.. it i. mild or b.au .. roncurrent gr.nulocytic hyp<rplasia may mal.:. it difficult to d~ .. min. wheth .. th.", is an absolute or a ",latin d«r..... in erythroid precursors. However. the presen"" of nonregc:neratin .nemia in th. ah",n"", of erythroid hYJ>'rplasia supports suppre=d erythropoi..is ..."n wh.n erythroid hypoplasia i. not .pparent. 5. Sda::ti"" erythroid hypopla'ia cousn! by endocrine disord.r.;: The nonteg. ""'1 mild :md not ra:ognizM in routine bone marrow aamin.tions. The pr=n"'" of nonrq;en.rative anemia in the ab .. na: of .rythroid hyp<rplasia suppons suppr=d erythropoiesis. 6. Drugs: Chloramphenicol con indua: a lralllient erythroid hypoplasia in dog,>' :md cou." Th... may I>. roncurrent mydoid and mq;.karyocytic hypoplasia in

m". C. M/UtiW grtlnukKytir hypop/mill ("tr"nulocytmj,) is • pathologic state in which lh. numl>.r of granulocyt. (neutrophil ) precursor.; is decreasffl. but [h. erythroid .nd

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY m~'yocytic

cdl lines . "" not. Th~,~ a,~ not ~nough =inophil and luwphil pr«urson in health fo, • d«= in th ..e lines {o co"", gJ>nulocytic hypoplasia. I. s.-ver:ol inf«tion> and drug. han bttn r~po"al to co"", ",l«tive gr:mulocytic hypopl .. i. (fabl~ 6.4). How",""". ,in"" many of th~m han :also bttn associatal with hypopl .. i. of oth~, cdl lines. th~,e m.y ~ th~ app'.ran"" of sd"",i"" granulocytic hypopla.i •• but d:nnage to othor cdllin~. might not ~ det«tal in the .:nne marrow sample. In parvovirus inf«tions. the granulocytic hypopl",", could ~ amsM by damage to ""lJ. with mitotic potent",i. depletion of naltrophil pooh ba::."", of ex",,,i,,,, tilSl..l~ d~mand. or endotoxin_inducM d:nnage [0 marrow ",U,."'''' ln conin~ monocytic ~hdichiosis (Ehrlichia cani-I) . hypopl ..ia (typicolly gtn~ralizM) may ~ .. en in chronic inf«tions. wh.""as hYP'rplasia i. "",n in acur. inft.ctions. 2. Animal. with immun han bttn r~po"al to co"", ",l«tive megaka,yocytic hypopla,", (fabl~ 6.4). 2 Rare ca... of app.""nt immun
M~ar}'oqte

Unknown, miJ:eQ, or mult iple (II« thC' tat) Nonlymphoid hemic cdl N eutrophil Eosinophil Basophil EI},hrocytC' EI},hrocyte, ncutrophil, and megakaryocyte Mcpkal}'OC)1e Nonlymphoid hemic cdt Neutrophil and monocyte leukocyte, erythroid cdl, andlor megakaryocyte Mast cdl Mast u Jl Mast cell

lcu~ia Study Group of ~ Am«ican Sociecy for Vettrimuy Clinical P~thology." These Icu~i .. fall into the WHO category of_tr ~i" tn.~Ut "of othtTwiw ~1f1JfpriUJ.'" "TIx -M " .bbr",,;~cion syRnn i. uxd in the FrendH\mcrican. Bririoh d ..... fi ...cion .00 >Va> used by !he ALSG but i. no{ UHd in the wrn:nt WHO nommd.tun:. n.e ALSG clauilication ominN aam: myeloblastic leuknnia ""ith minimotl diffi:rentiation, a diagnosis requiring immunophmotyping.oo ultnstructun.l MlL1tion that ~ no{ availoble to !he study group. ' Human am ... pmmy.locytic Irubmia i. typically :wociatN with defined mumciolU:tnd" !herofon ca~i!Cd as AML wirh m-W'Tnft ~ obomlll/jti~J ... ,her than as an othe"";<e uncatcgori...t IrubmiL "!be ALSG did not ""paute M 5 into acute monobl""tic lrubmi:o (M50) and :acute monocytic kuh:rn.ia ( M 5b) kcauoe of difficulti... in difhrenti:U1ng rnDIlOblu .. &om pl'OlIlonocytes, but othen ~ m:>de .br

distinction in animals .. is donr 10 human dusdica.ion schetnes..

'!be current bWJl.1Il WHO system indudes a puu rrythroid kuUrni:o.. 'CMMoL U cIau~ here :l
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InJlum;a j, from the G,,",,k It,,h, ("whit.") + halma ("blood") = "white blood " .nd ref.", to an inCJ~ bullY coat lay". It j, the prestnS{ic proliferation origi""'ing in the bone marrow or, sometimes, th. spl..,n. Not all hemic na>pl"i. originating in the bone marrow is co,,,id.rkaryobl ... u, mono· blasts ± promonocyt... and .typical promydocyt.. ) must . crount for;> 20 % of .ll nucle;md ~lls in the bone marrow (ncluding plasma cdls, lymphocyt.., macrophage SO % of the nucleat«i cdls in the m>rrow ar~ .rythroid, th.re may ~ too ftw bl ... ts or blast equivalents to m..,t erituia for AML Diffuent crit.ria ar. uKu 10 st.,m from neoplas_ tic transformation of multipotenti:ol h.,matopoiplascidmydoproliferativt dist....,. (Table 6.5) include conditions that may havt mydodJ"Plastic and/or mydoproliferative fntures. a. Chronic my~fqm~nocytic Irulmn;Il fulfil], the crit.."- .nd occu'" in dogs. Th~ .. i. typically leukopenia .nd nonr"C"nerative .n~mi. with a hy~rcdlular bone marrow and .typical hyper..,gmented monocytoid cc:Us in blood, bon~ marrow, .nd often lymph nod... Fewer than 10 % of the nucl~atal cdl. are blasts. and the disorder hu a chronic cou",e. b. Oth~r condition. described in human pati~nt, havt not bttn recognized in .nimals: atypical chronic mydoid l.uk~mia. juvtnile myelomonocytic leuhmia, and uncl .... iliabl~ myelodJ"Plastid myeloproliferative di",a.-;e. 4. Chronic myloproliJirllnw dinllm: This group. which includes stveral ¥cific chronic clonal disorde .. of pluripotential stem cc:ll., i. charact~rizal by e~ive proliferation or .ccumul ation of differentiatal neoplastic cc:ll. that hayt few or no micro=pic or functional .bnorrruoliti.. (T.ble 6.5). Tools to detect donality .nd prove neoplasia are ~nerally unav.ilable for th= conditions in domestic .nimal •. Di.gnmi. i. olien b..ed on exclusion of oth~r conditions. but diff..ent"-tion from nonneoplastic conditions is difficult because th~ edt. a.. well diff~"'nt"-t.d {Fig. 6.2}. a. Chronic myrlogmow lruknnill (also known .. chronic granulocytic l.uk~mia or chronic mydoid lrnhmia) i. charxterized by. nentrophil"- .nd typically. leli shift. Chronic eo.inophilic leuhm"- {and po ... ibly hy~reosinophilic syndrome} .nd chronic basophilic leuhmia ar~ v.riants.


'51

b. Polycytiumw """ . nd p,imJl'] "JfflrtKJfIIfi, must ~ diff~"'ntiata! from oth" causes of ~rythrocytosis (~ Ch.pt~r 3). c. M(gaka'Jocyu mydo,u or (umrial timmbiJcytiumw must ~ diff,,~nti.ta! from markal meg:obryocyt~ hy~rpla!;' .nd r~3Ctin thrombocytosis. d. Chronic idiopathk "'J''''fibm,is with (Ja,amrdullary h(mJlwpoi"u must ~ diff~ .. n_ ti>!a! from =ndary myelofibrosis. Proof th>l idiopathic mydofibrosi. i, a n~plastic ~ntity in domestic .nimals is cUf",ndy lacking. 5. Ma" uU dh(/U( (mdSftKJ""U): Mmocyumia Jruly ~ rtypia. Orh" t;!S\le! may ~ in",,]val (e.g., Ii"", and Ju~). b. Most dogs hove a r~nerati"" anemia, thrombocyto~n",. hypoalbuminemia, .nd hypochoJesterol.m;", 2. Malignant hi.tiocytk saTCumd {"",/ifl"'nt histiucytl16u} of dendritic cdl origin is a malignant proliferation of interstitial dendritic edl, which npress, :nnong orh" m>rhrs, CD Ie .nd CD lie, but not CD lId." a. Plwmorphic populations of nroplanic ",ns are pr...nt in bon. marrow and 'pl..,n, lungs. Ii""" or lymph nod ... Phagocytosis may bt pr~ .. nt. b. Oth~r findings ar~ v>riabl~ and nonspaific, including anorexia, l.thargy, w~ak_ ness, and w~ight loss. 3. Th... nwignancir. must bt diff~ .. nt;"trd from {I} sy>l~mic histiocytosi., {2} nonna>plastic h~mophagocytic syndrom.. occurring in association with inf=ion. and oth~r malignanci.., (3) immun~_mffliatffl destruction of h~matopoi
na>pl"ia is d ... ifin! mon accumdy by oth.. m.,hods aft.. first ~ing id.mifin! by vis,",l imp«lion. 3. Cytoch.mical naim"''' a. Thest ar~ hdpful fur diff~remialing the lin~ago'(') of l~uk~mic reUs. b. Th~ !>.sic premi.., ~hind ,h~ usc of cytoch.mical mim i. tha, l.ukemic ",lis may ronuin ~nzym .. or compounds tha, are coounon or unique to ",nain ",J[ lin ... For a . mpk nrutrophil. and monocyt .. ronuin Jl
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! "i , -n - i ' < 1 ,J ~,,gr.nular lymphocytes (CD34+) from leukemic ph .... of lymphoma, j, Abe:rrant "'p""ion of CD IS and CD4S h .. bttn "",luatffl for recogniI.ing and classifYing .typical cdl populations. ..... 5, Electron microscopy may k u..ful in 5Om~ l.... k-mw to provide eviden~ of. particular cdlline: for aample, th~ ultmtruc{U", of l.... kemic cdl cytopl .. mic granules m.y be: distinctive for basophil, ro!inophil, or m .. t cdl granules, R.ardy, immunogold suining may k usn! to d~ect lin~.decti"" /lUrhl'S,


357

6. Mola:ulu and cytogen~tic studi.. may b. ~mployal to dffa:t C"netic abnorm:ditiel that Jruly pralict b.h.vior and outoom~ of som~ n~opwms. Chromosomal abnor_ malitiel in c;onin~ In>k~mia cdh han bttn dffrctal by karyotyping but have off..al litd~ prognostic valu~ to dat •. ChromosoJrulI banding studiel :md mola:ular C"netic tmniqu .. a.. b.ifll: ~:duatal. Th..., includ~ fluo .. =nt in situ hybridi7.;,tion, oomp..atin g.,nomic hybridization, and micro ..",,...,. Currently, th~ most Usffl C"nffic t.ronique is th~ polyroe....., chain rraction {PCR} for ousessment of clonality:"61 a. With only rar., ua:ptions, na>plasia of lymphoid a:lh i. an unoontrollal prolif~ration or a.crumul.rion of one clon~ of lymphocyt ... b. Antigen_binding regiom of B_ .nd T_lymphocyt~ recq>ton a.. enrodal by th., CDR) region of th~ immunoglobulin and TCR gc:nel. Th~ CDR) region is produced by various ra;ombinations of ~~ralC"n~., gc:nerating num~rom genetic combin.tion •. Prime.. are Usffl to amplifY con",rval regions of th~", genes, .nd th~ products .re ",p:".tal by sa.:. If th~re i. a donal upansion of cdh with on~ p:mirul" CDR] region d"'a:t>bl~ with th~ test prim~"', .. po.ration wiU yidd a dominant band. c. Polym~rasc: chain .. action a=ys for B_ .nd T_lymphocyt~ antigen r.aptor g~ne rrarrangc:ments a .. u",ful to hdp diff...,ntiat~ lymphoid neopl •• i. &om inflam_ matory conditions. {I} The pr... na: of gc:n~ ..ar"'ngc:m~nts supports neoplasia. B_lymphocyt. and T -lymphocyte gen. rrarrangements usually occur in na>plasms of th. resl"""liv~ cell tY]lel. {2} Th•• I=na: of a deta:talC"ne ... rranC"m~nt docs not exdud. lymphoid neoplasia. {3} Clonal rearrang.m~nts of th. TCR gc:ne have bttn d"'a:tal in dogs with Ehrlimill nmu infa:tions, .nd lymphocyt. receptor g.n~ ... r",ng.llYnts som",im.. occur in nonlymphoid leuk.mias." {4} Th.......y ",mitivity varies with the twu •• nd proponion oflymphocyt.. that a.. neoplastic, but don:dity am b. d.tn:1al when as linl. as 0.1 - 10.0 % of s;ompl. D NA i. from na>plastic cdls. Th...fo .., it em b. US
Int..pretation of th~ r.. ulu of bon. marrow ex:mlin.tiom is rasi .. if on. u"'. th~ bon~ mu row examination to an<w~r specific questions: A. Why d",. an animal han a nonr~n.rativ~ anemi.? B. Why d",. an .nimal han a persist.nt nrutro~nia? C. Why d",. an .nimal have a thrombocytopenia? D. [s th ... a na>plas{ic process in the bone Jrulrrow?

[I.

Complet. interp.. tation of most bon~ Jrulrrow s;omplel is only possible wh~n th... a.. CBC ..",In for the day the bone marrow WlI.! oolla:"'d.

3"

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY A. Hyp<rpJ:astic and hypopJ:.stic conditions can usually ~ r~ni=l jnd~pend~ndr of eBC findings, but th~ eBC findings hdp explain th. disorder. For ""ample, a hy!",'. cdlulu bone Jrulrrow with an incr•• G:E (M: E) ratio indicates th ... is mydoid hy""rpl .. i. {rardy DaJp[",ia} no matter what the eBC findings are. How~u. th. eBC

='

may indicate th". is indf«tivt neutropoiesi, {granulocytic hyperpl",", with ='" neutropenia} or .f&ctivt namopoi.,i, (gr:mulocytic hyp<rpla,ja with. marktd neutro_ phil",). The former cas< sugge>l' immun~m.diated neutropenia, wh.",as the lamr =

luppom an infLo=tory

p~.

B. When marrow ""Uu[:uity u ""i~ de"ly incml!al nor cl.",1y d=astd and ~r. js an abnormal G:E {M :E} r:llio, ~ eBC provides duo:as to th. cau", of th. abnormal ratio. I. If the G: E (M :E) mio is inc",=ly (coJJ«tion, fix.tion, st;oining. .nd examination oflymph node ti ......~ from a living animal) .. e beyond the Jropc: of this tat, Procalur.. of a lymph node bioJ>ly are d .. cribed in KVeral !Ourees,· ....,.

6/ BONE MARROW AND LYMPH NODE B. M.jor

f~atu=

35'

of a lymph node biopsy

l. £ampl~ coll«tion and p=.. ing

a. Typiudly.lymph nod~ 5ampl.. a.. coJl«ud from ~nla~ pe;t oompl~ed on a quality stained sample with a quality microsrope by a person who is tr.in«i for such aaminations. 3. Methods involv«i in the histologic ex.mination of lymph node sections are beyond the SCOJl" of this textbook. Such exarninatiolll should be performed by =erinary pathologists. E. Cdh in lymph nod .. of healthy mammals l. lymph nodes &om healthy mammal. are not oommonly evaluated. How"",r. microscopim should have a cl ... r image of wh.t should be ..en in normal lymph nod .. 50 that abnormal cdl populations or other .ignificmt findings will be r=>gnized (Plate lOA). 2 The expect«i cdl populations in lymph nodes vary with the locotion of the lymph node. Mandibul ar and m..enteric lymph nodes in hffithy mammals typically h. "" greater Jl"=n~ of resident macroph3J:'" plasma cdh. neutrophil ••• nd lar&" lymphocytes than do other lymph nod ... 3. lymph nod .. from healthy animals oonsist of a h~ero!:CI l~ad to th~ stimulation and proli~ration of lymphocyte>. If there is g~""ralizal lymph nod~ hYP'rplasia. a synemic illn= should be, consid~m:I. If only one nod~ is hyperplastic, a di..... within th~ drain~ fidd of that node should be, colI!ider«i. C. Th~ .. mayor may not be, a conrurnnt inflammatory lymphocyto5i. in mammals with hy~rplo!lic lymph nod ...

II.

R~a("{in

Ill.

lymph node A. A node classifi«i as rrlUtiw typicaUy has incr.....d numbe,rs of plasma ""lls and/or largt lymphocytes (Plate lOB). The p"'''''nt~ oflarge lymphocyt.. i, exp«t«i to be, < 50 % in a rtlctin nod~ and is usually < 10 % . An incr~= in plasma ""lls indicates B_ lymphocyt~ stimulation. B. Th~ cau... of a r~a("{ive lymph node ar~ .,...ntially th~ same as th"", for lymph node hy~rplo.i .. Lymphad~niti.

A. L}mpm"Jmitis i. charactrri=:l by an incr.....d numbe,r of nonlymphoid inflammatory ""lis in a lymph nod~. On~ inflammatory cdl typt might dominate {~.g .• neutrophil.}. or thrr~ COlI be, a mixtu .. of inflammatory cdl. {e.g.• neutrophil •• macroph"J:~s. and eosinophils} (Plm IOC and OJ. B. Th~ cau.. of the inflammatory nat~ may be, within the lymph nod~ or. more com_ monly. in th~ node', drairtagl' fidd. For example. an allergic d~rmatitis may lead to an eosinophilic lymphadenitis. or a lymph node draining a necrotic h~morrhagic lesion may hav~ many macrophages conuining cdl debris and F~ pigm~nts. C. Th~ .. mayor may not be, a concurr~nt inflammatory leukocytosis. D. OrganiSJllS ruch as pyogtnic ba("{~ria. Myrobllm,ium sp. ( Plat~ toE). Hisrop"''''''' sp. (plate 10F). B/a,tomyus sp. {Pl ate 10GJ. Ltishmalfi/J sr. (plat~ 10H) . Proroka sp .• and Nrcrid",mia sr. may be, pr=nt. E. Lymphadenitis is often associat«i with reacti", {proplastic} changt •• and the term "acti." IymphadrnitiJ is sometimes usa! to reflect both changes. IV.

Lymphoid nalplasia (lymphoma and lymphosarcoma) A. Anatomic classification. histologic cl""ification. and st"J:ing of lymphomas are bqond th~ >COpt of this book.

364

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY B. Cytologically, lymphomo can b. di>gnoud wh~n thu~ it n~arly a .ingl. popul>1ion of atypical lymphocytes rather than the heterogtnam, mixture of typi",! cd] typarations of the erH SlI,~nsiom, (2) immunohinoch~minry on erU blocks mad~ &om erH 'Il'l~nsions by ~ll~ting .nd fixing cdl., or (3) flow cytom
Oth" findings A. Ed~ma may be, suU.. ta! in aspirates by the 10>5< arrangemem of aH, that ,uu~'t' di,~rsion of erll. by fluid. B. The presrner of nonlymphoid h~mic p=urso" (rubricytes, mq:abryocytes, :md granulocytes) indicat.. ntramrduHary hematopoi..i, or, rarely, nonlymphoid hemic nropl ..ia involving the lymph node. Lymph node hematopoi .. is may occur when bon. marrow damagr is nUnsi"" and nimuli promote prolif~ration of h.mic prrcursors in extrama!ullary sit... C. Th~ presrner of .rythrocyte, in the ,ample indicat.. h~morrhagt. [f only ~rythrocytes are found, it may be, difficult to diffe .. miate pathologic hemorrhagt from hemorrhagr cousal by sampling. Th~ presrner of ~rythrophag .. and 'iderophag.. ,uppom the oonclu,ion of pathologic hemorrhagr .ither within the lymph node or it, drain~ fidd. O. A diagnosi, of m
"""o-

1.0""""

",,,,bin,..,,

60,6J6....6.j2.


,.,

JI. StoL.I T. Randolpb J. MocLrod J. 1997. Pw, ",I ",ll'plaai • .ru. =
APP BCG BCP

C3 COP

CRP DlC ECF

EDTA Fc FPT

H,'

I",

19E IgG IgG(T} IgM M, Na,50, NH :

PLE PLN

PP:F pll'. RlD SAA

SI SIADH

SPE .TP", 11'. 11' WRl ZnSO.

Toul prol~in to fibrinogtn in plasm> x oon"'ntnlion (x = a""IYIin fibrinog' form}. Mo,t f~rritin it in ti .. u~s. but .mall amounU I""", ctlls and em" plasma. u 2. Nrgath't APl'i are tho .. proteill1 that ha....., d""reasN pt..ma or ",rum collctmratioll1 ba:."", of all inflammatory P""""'" Th~ir collctmratioll1 d""re. .. ba:.u.. of d""r .... sn! production by hepatocytes due to the .ctioll1 of cytokilles mch OIl int~rl.... kin 6 .nd interlrukin I. The major n~ti", APP•• nd some of th~ir phY'iologic fullction. follow. a. Alhumin i, th~ major contributor to pl :asma COP ... rv~s:as. ",urce of .millo .cids. and trallSpom many cationic .... b.'lIances (e.g .• C .... Mg'+, and drugs). b. Tranifrrrin i. the major transport prouill for iron. 3. Drlnyrd "'ponsr prDtrint ar~ prot~ill1 for which pl:asm. or .. rum colI""'ntratioll1 in"' ...... 1- 3 wk .fter onset of inflammation. The two major det.ynl responst proteins • .., immunoglobuliru .nd complemem. a. ImmunDglobuum • .., producro by B_lymphocyte, or pl:asma ctll, and ar. cl:assifiw by their h. avy chain, :as IgG. 19.\1. 19A. or IgE. Subc/:w;ification, also ai,t. b. Compkmrnt protrim (primarily C3). part of the inn. te immune 'Y'tem...cnmu_ I.,. in pla,ma in some inflammatory conditioll1. ANALYTICAL PRI NCIPLES FOR TOTAL PROTEIN . ALBUMIN . AND GLOBUUNS I.

[T oral proteill] A. Refractometry for measurillg [tot'! proteill] (pl"'ma or strum) I. Principl~ The d~grtt of light refraction in .n aqu~ou, ",IUlion i, proponional to the quantity of solid. in solution. ~u .. moll solid, in plOllma are proteiru. the degr~ of light ..,&action i, highly d",,"d~nt on protein colI"",mration. 2. The ..fractometer. totol protein 1C:ole i. c:olibratw with the OIlSIlmption tru.t chong.. in refractiv~ inda refl""t chall!;'" in prot~ill collctmration .!on~. A um""rature_ com""n!3.ted refractomet~r ;., recommended over • non-t~mp but mad~ reading of the dividing line ill the r~fractometer more diflicuh." d. Bilirubin coII"'ntntions at 0.4 mgldL did not interf~re with refnctiv~ index values." However, icteru. i. commollly listed as a cau.. of fal ..ly incre.~ values in clinical chemistry textbooks. Perhal" interferen", occurs at high~r colI"'ntrations. 4. Ullit conversion: gldl X 10 = giL (SI unit, n~..est I giL)" 5. Comment. a. The [TP..J is also referred to as the pIA,,,,,, "'tal ",lids roncmtrlltiQn b.causr=nts the total quantity of suin.d protein.

316


,

Ab

!

N.

'"

fiLl'

I

"

I I I I

IgM IgA

•

Celuose aaolate strip (shaded areas mpr"....,t stained prot...... ) Fig. 7. 1. &h.m .. ic ,.pnsenution of SPE r.,ul", (proteinemi. patterns. 3.

Th~ pe=nt"i:~ det~rmin~ th~

v.

Immunoelectrophoresi. A. This is a method of id~ntiJYing the pr=n'" of specific proteins or protein components. It can ~ used to id~ntiry- th~ pr=n'" of immunoglobulin cl..... or sulx:l...... h....vy chains. or light maim. B. Th~ .. rum prot~ins are first .. p..>tal by dearophor~sis. Appropriate antibodi .. are addal to long trough. cut paralld to th~ dearophoretic separation. Th~ antibody and the dearophoretically "'Parat.d .. rum proteins diffu.., toward ....ch other and form precipitant arcs if th,,~ is a r....cti"" antig~n {e.g.• he. '}' chain oflgG} for the antibody.

VI.

Sia euglobulin test A. A (uglohulin is • protein that doe< not dissol"" in pur~ water. Th~ Sid fllglubulin .ttI is simply adding 1 drop of serum to demin~raliRd H,O; formation of a precipitat~ or flocculates is a pmiti"" te
Table 7.2. Serum protein. Ihal conlribute 10 clearophoretic region. Rceion

PlOIcins

M, lin thousands)

NO{ ucoogniud in routine SPE of

Pre-albumin

Albumin

Albumin'

.,

"

a, _LipoprOlcin

180-350

a ,-Antitf}'l"'in'

54

a, _Anlichymotryp5in"

"

a.-Macroglobulin"

'"

,

Funct ion and oIlier inform~lion

H3IHoglobim" Tr:u"fe,rill'

80-160

~Lipoprol (in

2400

Complement (C3;I)"

,so

76

IgM and 19A

19A.: 160 IgM: 900

'gG

'50

C-reactivc protcin"

'"

:rnim:d ... t:I: indudcs thyroxine_ binding albumin and ~inol_binding prot';n Map- cont ributor 10 ona)!ic pressure; lrmspGm C.>+, .\1g". unoonjug~1ed bil irubin, fatty:acids, Ihyroxinc. and m:my ot~r mbst:ma:. T ran.port. lipid< (esprcially lory prolCln In:octivales proteasoes, incl uding chymolf}'l"'in, :rnd Ihus i. an :rnli_inf!:tmJrullory prorcin I n:OClivaus prole...,. and Ihw i$ an anti-inlbmmal0ry pror cin Bind and mlll! pon fm. Ilemoglobin Bind$ and nampam iron; measured as total iron_binding capxity in chernial assay. Trampom lipidJ (cholesterol and lrigl)'urick): alKi caUed LDL Promot.. inH;unm~lion; memot:lClic .ubouncc Bind to specific anl;Vns; conanmll ioll5 an tOO low in htahh 10 be _n vi a routine SPE Bind. 10 . prcific anl;g..M; many different i..,typos and idiolypc:s of IgG gin a broad and umally indi.tiner gamma region POJilive :KUlc_ph_ protein: rarcl)'_n in lYWlIm:dian SC't:I via rouline SPE

• NIiv. APP. are proteins whose plasma or ",rum con""ntr>tions decr..,... bn:;,,,,,, of dec",....:! production by hepatocyt .. during inflammation. Thi. group indud.. albumin and transferrin. {2} Due to the plasma half_life of albumin in various .nimal. (e.g .. .. 8 d in dog. and .. 19 d in ho .... ) and the variable degre,,, of rwuced produnion. an infl.mmatory h}'llO"lbumin.mia may not be ...,n ulllil inflammation has !"'rsi..ed for at least sevtral daY" in dogs :md .. lean 2 wk in ho ..... The magnitude of decre.", i. typically mild {i.~ .•• deer..,... by < 30 %; ~.g.. from 3.0 gldL to 2.4 gldl} if inH.mmation is th~ only re.wn for th~ hypoalbuminemia. {3} The plasma half_liv., of transferrin ..~ not firmly mablished in dom~"ic .pro... However. decr~asN toul iron binding capacity (as • m.... mre of transferrin concentration) may not be =n until inflammation has Jl"rs.istw for at least a wtt!glllffit (F) tbot ron..i"" an rntigon_binding .it< (ab) (F + .b = Fob). T h< toil of tho Y (wnic:d >egm produe«l by B_lymphocyt. "roplasi
J83 h~:IV}'

chain,. or abnormal fJ:lgm~m,}.17 Two da:trophore{ic~.ks wer~ d~ta:tM in a dog', .. rum m..t had an 19A.-producing mydoma; th~ two p indicotM that two don .. of 19A.producing pl• .m", cdls we~ pr=m.JJ {3} Con""mratioll5 of immunoglobulins oth~r than th~ monoclonal prouin frequ~ntly ar~ da:r .... ~. b. Mild to mod~rat~ hypoolbumin~m"- may bt couKands.~ um..!ly due to ~ith~r 19A. or IgM and not to IgG. High ron""ntration, of 19A. or IgM: a", not exJl"Clal in • nonneoplastic immun~ ""pon... {3} Comparal to cdlulo.. . ""m. m~thod,. :ogarost d=rophoresis or high_ /"<SOlution da:trophomic m.thods will impro"" d~=ion of prot~in !>ands; that i•• what 'p~'f1 to bt on~ band on cdlul"", a""tat~ may bt ...,n .. two bands on "Cam... How~er. th. pl"nltn"" of . single b.nd on agaro,. dOtid.. within th~ amyloid had .mino acid sequences very similar to 'equences of human 1..-chains. 8. Amplification of variable regions of immunoglobulin ~n.. by polym~ra .. chain reaction is being u.snl to ch..""t"iu the donality ofB_lymphocyte neoplali . ... HoW.-vtr, analysis of small bio!"'y ,ampl.. from .. ""tive lymphoid ti.!U~ may yidd what appear. to be a monoclonal prolif~ration b.cau.. of donal exp.nsion within a ~rminal center or b.ca...., of random amplij]ation of ,mall amount. of DNA"·" P....,dodonality is present if .mplifiation produce. one or mo .. di,tinct bands. but the r.. ults.", not rq>roducible.

HYPOPROTEINEMIA (DECREASED [TOTAL PROTEIN] IN SERUM OR PLASMA) The di"'.... and conditiofl1 th. t au", hypoproteinemia ..elist..,j in T.bl. 7.4. I.

Ina.....d protein I"" from vascular 'I"ce A. Blood I"" (primarily atthog.nesis a. Intestinal =:mions. whim are rdatively protein rich, typically are digtned :md absorbed in the small intestine, .nd th.n tra"'poned to the portal syst.m :md lymphatic v.... ls. Wh.n generalized small intestinal murosal dis.a ..s or lymphatic diseases prohibit the absorption or transpon of the pro_ teins, the proteins.re Ion in f"""s. When the ..e. of proe.in los..! exCtt,!. the capability of the liver and lymphocyt.. to produ"" proteins, hypoproteinemia occurs. b. In some disord.rs, inHammatory au""tion and decr•• sed protein intake contribute to the hypoproteinemia. c. Intestinal blood loss beca"",,, of po.rasitism is on. form of PLE. 2. Di ...ses a. G.neralized small intestinal mucosal di"""",s: lymphoma, histoplasmosis, and lym phocytid pl •• macyt id rosinophilic .nteri tis b. Horses with acut •• nt"iti. c. Lymphatic di .... se: lymphangiect.. i. or lymphoma d. Intestinal blood loss: hookworms, whipworms, or neoplasia 3. M.jor laboratory findings a. Mild to marked hypoprotein.mia with hypoalbuminemia .nd hypoglobulin.mia (or normoglobulinemia) b. SPE results: The pattern is usually nonsdecti"" but may be .dective. c. Oth" findings may indicot. or suggen the inciting pathologic nate (e.g., HitroplMma organisms or neoplastic lymphocytes in biopsy s;omples. or mel.n. or oth" top>thy l. P>thog.nesis a. Thermal or chemical bums allow pl"'ma proteins to exude from cuUneous l.,ions at a rae. greater than th. rate of protein production. If the animal is not sttn soon aft" the injury, the dy.protein.mia will reHret a mixture of cuUneous protein loss .nd:m acute-pha .. inlLommatory respon ... " b. G.neralized au""ti"" skin disease c:m cau.. a hypoproteinemi, 'W', but the dysprotein.mi . prob. bly ",Hects • mixture of protein loss .nd :m inH. mmatory dysproteinemi .. 2. Major labomory findings a. Early: non ..lecti"" hypoprotein.mia b. Loter: nonsdecti"" hypoproteinemia masked by either an . cute or mronic inlLommatory dysproe.inemia E. Pl.",n. loss caused by pat ic errzyme activiti... dec ....."':! urea cona:mratioll. or increa"':! bile a.cid or ammonium conO::lllratiollS B. M alabwrptioll or maldigtnioll I. P.thogtll.. is: A mal . bsorpei"" or maldig.sti"" sme r.. ults in • d.fici. m imak. of b",ic body fuels (G1rbohydrat ... proui",. or lipids) to "pl. "" fuds used by m.ta_ bolic p:uhwaY" for daily energy. Ono:: d rpleted. protein G1ubolism and th. 'ISr of amino ~cids for glucolleogenesis lead co a d~ficiency in en.rgy and amino .cids for hq>atoa:llular . nd lymphocytic protein sylllh..is. When anabolism a CNds produc_ tion. hypoproteinemia occurs. 2. Disorde.. a. Malabsorption: Small illl..einal di ...... with gtlleraliud mucoul inmlvem.m may G1U", malabsorption of digened proteins. G1rbohydrates. and lipid •. b. Maldigmion: fuocrinr panc... tic irnufficir ncy (becau.. of chronic pallcreatiti, or p. ncreatic .trophy) creates deficiencies in prot........ lira", and amyl. .. and thus maldigtnion of proteillS. lipids (f.e). or carbohydmel (starches). 3. M.jor l. boratory fillding> a. Hypoprotein.mi •• hypoalbuminemia. and normoglobulinemia or hypoglobulinemi.

7/ PROTEINS

389

b. SPE r~,ults: Th~ pm~rn typically i, nonsd'""tin (Pl.t~ 12H). c. Oth~, findings d~~nd~nt on th~ primary p.thologic stat~ {~.g., d,"",,,,snl trypsin_lih immunor~activity with noc,in~ paner ... tic imuffici~ncy, or POO' xylo,", ab,o'ption with malab50rptiv~ nat~' [,..., Ch apter 15]} C. Cach~ctic stau. I. Pathog~nesis: Wh~n ch~ rat~ of prot~in cat.bolism aads prot~in production, th~ negativt prot~in naN, caUst, hypoprot~in~mi •. B.fore hypoprot~in~mia d~nlops, gluoo", and most strum prot~in ooncentration> {espl .nd muscl~ m.... 2. Di""rd~ .. •. Chronic di......,. such a, chronic inf..aion> and malignant na>pl...ia {Plat~ 12J.I} b. Ma,hd malnutrition 0' starvation 3. Major J.boratory findings a. Hypoprot~in.mia, hJ'P""lbuminemia, and no'moglobulin~mia or hypoglobulin~mia

b. SPE results: Th~ pm~rn typically i, nonstl'""tiv~. c. Oth~, findings de~ndent on the primary pathologic stat~ D. Lymphoid hypoplasia or aplasia l. B_lymphocyus produce immunoglobulin> and not othe, major plasma protein .. A mild hypoprouin~mia pountially can be, cr~.tffi by lymphoid hypopla!ia if oon""n_ trations of othe, prouim a,e WRI. 2. Exp«:tM dysprot~in~mia a. Th~ [total prouin] i, WRI to slightly d,""r.asection} did IIOt."

III.

Fal",ly inc..=tioll d.t .. mintion [ncre.sed albumin synth .. is inducffl by g1uooconicoid drugs or hormones • A rel1tively common di...... or condition Noto: If lolbuminJ ;, ~.,mined by the BeG method, the BeG dy< m.y bind to proteim other thrn :albumin rnd tbw yitions of all proteins oth" than .lbumin, hyp"globulinem;" may r~SlIlt &om th~ incr~ conctntration of on~ or mor~ diff"ent globulins, D, SPE r~mlu typically will diff"entiat~ the hYP"rprot~inemi .. ofh~moconctntration from hy~rglobulinemi .. of infl.mmation and lymphoid ntopl .. ia, but th.y IIUy not be able to diff~rentiate inflamllUtory &om lymphoid ntoplasti, hYP"rglobulinemi ..,

H't'POGLOBUU NEMIA (... the Hypoprotein~mia KCtion) L

For .nimal, oth" than ntonms, hypoglobulinem;" commonly O in domestic IIUmmal. have oon reviewM,'" B, Ess.ntiaUy any injury that product. an arut~ inflamllUtory reaction can inc...", conctntration, of the "",itive APP., Th"", injuries aln be due to infections (e,g" bact..ial, vir:d, fungal, or protozoal) or noninfectious condition! (~,g" phy.ical trauma, burns, or na:rosis), As a group of protein!, the incr~"M con IS, hyporfibrinogenemia is probably c;ou...i by dehydmion, If th~ ...tio is < 10, hyporfibrinog~nemia i. probably c;ousffl by inflammation, (2) Hor...: If th~ ratio is :> 20, hypc:rfibrinog~nemia i, probably c;ousffl by dehyd ... tion, If th~ ratio is < 15, hyporfibrinogenemia i. probably c;ousffl by inflammation, (3) If th. simpl~r calculation, (TP:Fib).... tio, is u...i, • "I " should b. add M to guiddine ",lues to b. contion. Th~ highm ""lues w..e during the fim 4 mo oflact. tion. n • . If.n animal does not ha... an inflammatory di ...... a plasma [f.. ritin] t.nds to reflret iron storage in the animal. Thu •• if iron ,toral:" is inc",aW {e.g.•


'"

Table 7. 9. Enn'pl". of changes in aculc_phuc protein cofloenlnllion.

Acute_ph .... Protein

CoII""mration in

M>gnjtud~

he:dthy dog

re'ponst (x b....,linrj

(mgldL)

Fibrinogen C-reaclin protein Strum amyloid A Haptoglobin ct,.Acid glycoprotein

uruloplasmin

blishffl but ap~ars to ~ rd~ast from tissuo; oth.. th.n li",r. IMMUNOGLOBUU NS The mon common r... son for m~~.uring [lgG] i. to det~rmin~ wheth~r th~r~ has oon .uccessfu[ p"ssivt tran&r of IgG from a moth~r (rna .. or cow) to h~r foal or calf via colostrum. Aa:ord· ingly. passive transf~r is the focus of this Sffiion. Immunoglobulin con~ntrations may also ~ m.-asurffl when ",",,"l""ting cong 400 mgldL if .. rum form. gd .. 60 min, • [lgG) .. 400 mgldl if .. rum did not gd by 60 min, {b} Excdl~nt ag=ment with th~ RID assay wh~n [IgG) < 400 mgldL and v..y good ~gr..,m~nt with th~ RID a=y wh~n [lgG) :> 800 mgldL" {2} For ""timation of bovin~ [lgG) {a} S.miqu.ntit.tive value." • [lgG) :> 600 mgldl if the .. rum form. a firm opaqu~ dot by 60 min, • [lgG) .. 400~ mgldL if the .. rum forms a ",misolid gd by 60 min, • [lgG) < 400 mgldL if the .. rum did not gel by 60 min, {b} Comment. • To det .. min~ th. [lgG) .t the deci,ion th ....hold. for FIT (eith.. :> 1000 mgldL or:> 1600 mgldL), the ",rum would n.ed to "" diluted prior to analysi', • Th~ =ult, of the glutaralddtyd. coagulation tost (Gamm._Check_Bl w~'" unreliable wh.n whole blood was used. r1 c, Th. te,t is ""I)' inal"'n,i"" and .impl~ b..cou", it jun requi ... glutaralddtyd., r.:.ction tu""., and pipettet, It does requi .. that .. rum"" harvested from blood, 3, Lota agglutination (Foakheck) for foal ",rum a, Principle: Lota ""ad. coated with anti_{.quin. IgG} .ntibodies will agglutinate in the prestn", of .quin. IgG, b, R..mlts: [t i. a semiquantitativ~ assay that I:"nerally agr.." with the RID .ssay ..sult. but i, not as good a, the glutaralddtyd~ coagulation un," c, Comments: Th. test i, mod.ratdyapen.i"" but tak"" only about 10 min to compl~te aft .. the .. rum is coll.cred, 4, Znsa, turbidil)' t""t for foal or calf .. rum a, Principle: Sulfat~, sd.crivdy precipitate cationic protein •• uch as immunoglobu_ lin.; other protein, ... n.... tral or nq:ativdy charged, At. con",ant [ZnSO,.], a

7/ PROTEINS

401 great~r

turbidity correspond. to • high~r [immunoglobulin]. Sin"" th~" is very 19A or IgM in foal or c;olf .. ra. th~ amoulll of turbidity r~Haots th~ [lgG] in a sample. b. The results can ~ .......d visually or turbidimetrically. Turbidim""ric ,.,...ssm~1Il ""quires a 'P'""trophotom""" and ,undard ",lutions to esublish a nandard litcl~

curv~.

(I) In fools. visual turbidity occurs when the [lgG] i. n~ar 400- 500 mgldL. which does not match with the curr~nt daoilion thr.. holds for FPT." (2) In calv.-.: (a) With a ZnSO, .olution of 208 mgfL, suffici~nt turbidity to obscure nrw.print occurs when [lgG] ;> 1600 mgldL." In thi. nudy, th~ ZnSO, turbidity tm provided a good estirruotr of the [IgG] but was not consid"ed to ~ .. u.~ful ., th~ Na,SO,-prmpitant t<St. (b) In .noth" study, the results with a ZnSO, solution (208 mgfL) wer~ comp"red with RID :way results." Inad~uate turbidity woo. found in "'mples with [lgG,] value> [hat ranged from 0 to 2825 mgldL (m ... n, 955 mgldL). Ad~u.te turbidity (nrw.print not legibl~) Wa.< found in "'mples with [lgG,] valu .. [hat ranged from 1085 to 4305 mgldL (mean, 2219 mgldL). The rruorked variatiofl! in [h~ results ...,U"'t th.r the assaY' were too inaccurat~ to enabl~ confidelll daoisions reg:ording Jl"SSive transf~r in calv... (c) With high" con"'lIlrations of Znso, (250-400 mglL), low~r [lgG] produa:s the same degree of turbidity as high" [lgG] when 200 mgfL Znso, is used." c.

Comm~lIls

{I}

Znso, r.-ag~nts may ~ made from KrlItch or purchased in kits. Stock

solutions need [0 ~ ....led to prevent carbon dioxid~ .bsorption. (2) For foals. turbidity tests hav.- ....lIlially bttn replaced by mor~ .ccurate and convenielll """Y'. Th~ ZnSO, turbidity trn trnds [0 und~renimate [IgG] when;> 400 mgldL " {3} Th~ p"'~n"" of Hgb from hemolY'is will falsely increase th~ measured [lgG] if turbidity is =sed by .pectrophotom""ty (.r 660 nm): Hgb_ induced inc"m~n" are about 200 mgldL a[ I % hemolysi, .nd 1300 mgldL a[ 5 % hemolysis." 5. N .,SO, precipiulll test for calf .. rum a. Principk Sulfit...daotivdy precipit.te cationic prot~ifl! lUch .s immunoglobu_ Ii",; oth~r protrins.re neutral or neg>tiv.-ly charged. Higher con"'ntra[ions of sulfites h.ve gre.,,, c;op"bility of praoipitating IgG at lower ooncelllr>tions. Sin"" th~r~ j,; v.-ty little [gA or [g.\1 in calf .. ra, the amount of turbidity rdlaots the '1ualllity ofigG in [h~ sampl~. b. Guiddin.. for the illl~rpreution of ",ul" with 14 %, 16 %, .nd 18 % N.,SO, .olutions."' {Note: Estima[ed ron"'lIlratiofl! do not match . 1500 mgldL, precipitates m ... n in 14 %, 16 %, .nd 18 % solutions. {2} [f [lgG] .. 500- 1500 mgldL, praoipitat...re...,n in 16 % :md 18 % solutions. {3} If [lgG] < 500 mgldL, precipiur. is , .. n in th~ 18 % .'lOlution.

402

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY c. In ano{h~r nudy. results w,,~ compa'.d with Ih~ [lgGl from a RID :assay." {Not.: Th~ markffi variation in thest ,",suit, highlighu (h~ pot~nti:dly poor accuncy or b el< of p,a:j,;on of ..... ch >.<Says. ) {I} [lgG] nngffi from 0 to 2400 mgldL with no prrcipim • . {2} [lgG] n ngffi from 645 to 2450 mgldL with prrcipi u te in the 18 % solution. {3} [lgG] u nge
d. Comments {I} Th. Na,sO,_precipiunt tell is rd.tivdy innp<nsive .nd quick. Th. IIUjor advam~ 0"'" ZnSO. is th. cap:!bility of ellim. ting the [lgG ] in a bro.d rangt.

{2} Com"",..! to the RlD .ss.y results, the prrcipiuni em is at btu a ..,mi_ quamiutj"" ...... y. {3} The:way d~ not work wdl foal ..,rum. 6. Changt. in y-g1obulin oone;.,lIIr>tion that .'" determina! by protein d«trophoresis: The difftrene;., bet",,",,n y-globulin oone;.,lIImion in pr«olostral ",rum and p becom~ more difficult .nd unctnain when th ..e typical associations are not found; for example, possible monoclonal gammopathy in an animal with. chronic infection. Th~n, mo .. definiti"" ch aracteriI.ation of the inununoglobulim mayestabli,h th~ pathogenesis for th. gammopathy.

=y'

7/ PROTEINS

""

COLLOIDAL OSMOTIC PRESSURE (COP) (O NCOTIC PRESSURE) I.

PhpioloCic proce=. and con~pts A. COP i, al"" calla! oncotic pressu",; th~ prdix OruYl· com~' &om th~ Grttk for "bulk" or "swdling," which, in thi, context, ",f~", to 'po.a-. cont:aining rolloidal partid.. that .wtll with fluid. A mor~ common contat refu. to nnlpl ..Jns; th>l i" oncolocy· B. Hydraulic pressure g,..dients and COP g,..dients for~ the movem~nt of protein.poor fluid, out of and into copillari.. as described in Surling'.law (Fig. 7.3 and Eq. 7.2). In health, th= gndients a", imporunt for th~ maintenan~ of blood volum~. In ""'em•• touo, transudative, and audati"" disorders, alteratiom in the gradient, cous< pl,mill. H,O to move into intemitial.p:oces (..., Chapt~r 19).

Pressure gndient = tic p.am.. t-:a .... the pwm. [t<Mal pro .. in1 i.o g""'" than tbe i", ...titiallluid [total protein]. Th. [t<Mal protrin].....ui.olly doors.clung< in tho e>pillary bNs, and rhw tho """""ic plalure g.-.diu" (A1l ory wall

(neao1y ImlHH"moobio to I>lISma pmleln.) Plasma osmolamy > Inter;;titial fluid osmolality Fig. 7.4. Concq>t\UJ 'oprn,d",. 10' B..rti. CA. Aok--l E.R. odo. TUt. T tb.o ~ ofOi,w,J 0-.;"", 2nd editioo... 62s.-7H. Pkiladdpl.ia, WB S.""n RH . 1976. 1h< .d', .CID""trk d .... ",in.';"" of ob, ptot Phosphate including PO/'", HJ>O;.... 01 H, PO.Par.nhyroid hormone Polyuria lten.] plum. Row St:mdard dn'iation

SDS·PAGE Sl

Sodium dod~ lulfarc-poJyacryI:un;m: gd

SSA

Sulfosalicylic acid TOI:ll akiurn Uri n:ll)'sis (urine an:llysis) Urra nitrog~n Urra niTrogen 10 crealin; ne Urine sp«ific g ....vity lkf'r.Ktorn..r.ic urine sp«ific gravity

,a.' VA VN UN:Cn VSG USG ...

Srsre~ I nr~r",lI ion:ll

.~trophor~lis

d'Un;r&

PHYSIOLOG IC PROCESSES

(.

Thm: ma)o. processes coAlrol ren:!l a C'-':Iion of H ,0 ~nd KIlu.e:s: glomerular fill ..... ion (pm;ve), rubul~r resorprion (~Clive or pm;ve), and rubulu l«m:io n (XI;ve or pusive), The nel re:s.ults of Ihe ren:ll fimcrio ... on plas"", in M:IIthy ani"",is "'" sumnwiud in Table 8,2.

8/ URINARY SYSTEM Table 8.2. Net result of nonnalrenal function on plasma analytes ConstfVffl

H,O

Excmffl

u"'

Gluco .. Amino acids Protein,

Creootinin.

N,'

H"

ClHCO,Co" •

NH: LaCYt. ~t",,=ate

M,"

~.Hydroxybutyr;.r.

PO,

K'

Bilirubin H.moglobin dim", Myoglobin 'Ren1l """",tion of H+ may mult in oither ;ocidi" or albJj"" urin
Glomerular filtration A. A major rour. for wlul< ~nd H ,0 excmion from .n anim;;o[ i, through ..""I glom. ruli. The glom. rulu filtration l>arri.r i, compo..d of copillary .ndothdium. l>a.stment m.mb"ne. and glomerul.. cpithdial e.U, (podocyt..) with foot procc!MS (Fig. S.l). Th. fillarri.r, its ncgativ. charg' a1K1 imped.. transit. Albumin i. not apectnl in th. urin. of cats, hor .... or con!.. A small IDlount IIUy be found in th. urin. of app ... ntly h.a1thy dog,. Thi. albuminuria IIUy represent a subclinical disease or a 'peci" variation. B. GFR l. GFR is th. ralC fluid moves from pi"""" to glom.rular filtrate and i, mrasurffl by determining the rat. a substane. i. cl'~rffl &om pla,ma. 2. GFR d'rends primarily on th. rate of RPF . nd vari.. proportionatdy with RPF. RPF dep of ..nal tubule. are reflretal by th~ rat~ of urinary acretion of a pWIIU mbstance comparal to th~ rat. of inulin auetion. A. [f acretion of a solute i. greater than acretion of inulin, there i• • n", solute srcr.,ion by tubules. Ren. 1 tubular KC"'tion involves proces.ses by which solut~. from pl.. ma, interstitia! fluid. or tubular cell. are tran>f~r..d to tubular fluid. B. [f acrffion of. solute i. I. .. tru.n acr.,ion of inulin, th~", is a nff solute resorption by tubules or th. ,ub",ance does not frffiy pa.. through th. filtration barri...

[V.

Function> of tubules renaining to major solutes' (Fig. 8.2) A. N. + J. About 7S % of filtrat. N. + is resorbed in the proxima! tubules down a oo"""ntration gradient establi.hal by th~ N. +.K'".ATP ... pump (basolateral mnnbrane) .nd a Na+. H"" antiporter. Na+ resorption i•• nhanced by an d«trical gr;od~nt tion gradient cre.tM by Na+ .nd H,O resorption .nd through a format~.Cl- exchan~r.

2. Cl- i, r=>rbnl vi •• Na+. K+.2CI- cotranspomr in the thick ..""'nding limb of the loop ofH ~nle. 3. Cl- is p..... ivdy resorbnl in the disc.t n~phron by an dectroch~miao.l gradi~nt ~nablishM by Na+ movrm~nt (through . ldos{ '''''

: _ _ Ie.g.,

0-

ON

urea

J

.",

_

(+) ..

tubule

"'"""

> '''''

)l)l).eool_~

"' _ _ 'PKIO _

.... i . . . .

_

.

11.1.;0. pbyoioIogiC P' : " , .. of _01 rubulos dw ~ to ooIu... and H,Q. n.. ..lute _ .miom.,., p 2400 mmoUkg. o la the """"ading limb of the loop of Henle. wlu"," (mostly N . .. 0-. and K,) p .... vely Ie.".. th. tubul., fluid vi •• N. ' · K'"·20- corrier (energy provided the by N. +· K'"·All'... pump in th. b...,htent memo brane), but H,O ",,,,,,ins. Thus. tbe tubul:u fluid becomes dilute, and tbe fluid Ieoving the diluting "'"J!"'ffit h .. 10 osmoWity ""., 100 rrunoUkg. P... ive fCa" :md IMg'+ ,esorptioa depeads oa :m elect,ic:d gndien' promoted by the N. +· K'"·2CI- rotronspo,te, and the ",cyc~ng of K'", whe,e .. . ctive fCa" and IMg"" resorptioa is promoltion of N. · :md 0- and the .oec,etion of K' and H+. Tbe ",molality of tbe uri... typically;' > 600 mmolllq; and moy be > 2000 mmoUkg. o la moot he:dtby dome"ic m:unm>.ts, the net funcrioa of . nephron is to exc,ete ure •. C,~ K+, H· . N I·V. and po. and to oonserve N . · . cr. HCO,-. fCal+ . IMg"", gluro>e, amino.ad.,:md H,O. n.. "lui"" nephron . 3. Viumill D promot.. 0..'+ resorption in Ih. dinal lIq.hron by inducing production of a colcium_binding protein. Cakit,iol (1 ,2S_DHCq formation in the proxim:d ",nal tubul .. i. stimulot.d by incr~ PTH .ctivity and hypopho.ph . temia. 4. Thi+ in the disul nephron. G. PO. I. About 85- 90 % of filt"te PO, is r...ork
en

at. ,,,,reta! by th. proximal tubules.'"' Crt secretion does not . ppear to occur in hones or c:ou. ~' 2. In peapl., Crt secretion may occur through ~ pathway ili ..ed with org.nic c:otiom. s"rum [Crt] incr~ases wh~n oth~r organic cations lsuch as cimetidin., trim~thoprim, and quinidin.} int"r. .. with Cn secretion. M. Resorption of H 2 0 by tubules I. About 30 % of RPF b.roIm' uhr:l.fih"r.. About 75 % of the uhnJiltrar. H,O is passivdy resork
D~Jinitions

I.

CD~,mrating "bilif):

the .bility of kidn..". to «sorb filtr:l.u H,O in exa:ss of fihm. solutes; .bility to conc;.,nt"re solutes 2. Diluting "biuty: th. ability of kidn..". to rrsorb Jihrar. solut~ in uc= of filtr:l.le H2 0; . bility to dilute ",lut.. B. T "m, usN to describ. th~ concentr:l.tion of urine I. Many authors describ. th~ solut~ ronc;.,ntr:l.tion of urine with th~ t~rms hyponh~nu. ria, isonh~nuri, . nd hypenth.nuria (."l1m. mnn, "'t""ngth"). How.nr. th~"" is litd~ agr«n,.nt on th~ d~Jinition' for the .. terms. lsosth~nuri. should m.an same {iso- j strength (."l1m.) utin. (.uria).

424

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY 2 Our ddinitions (.~ Fig. 8.8 for rdationship of USG"" .nd urine osmolality) a. iumhmuria (working ddinition) j, the nate in which urine OIDlOJality is th .... me ~. plasma osmolality, wheth.r pJ..,/ruI osmoWity is [ow, normal, or high. W. ddin. "th. sam." as "-ing within [00 mmoUkg of pl",,1IU osmolalitY"' dut i,. osmolality. = osmolality, ± 100 mmoUkg. In mon domestic mammal._ such urine typirnlly will han a USG ... from UX)7- 1.013. inclusivdy (unpublishtd .uthors' dau). b. Hyplllfhmurkl is the ,We in which acretII osmolality that is I... than the isosth.nur;c vain ..; that is, osmolality. hron contain the concentrating process.. of th~ nephron, {2} ADH controls ptrm ... bility of th~ epithdium to H2 0, H,0 is r~50rbtd in th~ pr=nce of ADH if there is .n osmolar gradient becwttn th~ tubular fluid and mfflullory intef5{itial fluid, An osmolar gradient is cre~t.d by high roncent .. tions of urea, Na+, ~nd Cl- in th~ intemitial fluid thot ~r~ pro_ duced .nd mointain.d by segm~ntal functions of th~ nephron, {3} The H 2 0 rnannds through the epithdial cdls are c.. >I.d by m~mbrane_ :u5OCit.d protoins call.d aqu"p"rilf', When ADH binds to th~ renal ~pithdial cdl basolateral memb .. nes, it activ,u .. a cyclic adenosine mono_ phosphate (cAMP}-d.".,nd~nt 5«Ondary mess~nger .ysum by which aqu aporino are transported to th~ apiml membranes, .nd thus membranes ba::ome ptrm ... ble to H 2 0, ADH :dso 'P!""''' to inc ...... production of aqu'porino,' 3, For kidneys to concentrate the ultrafihrat~ , th~ following are necessary. a, ADH mmt bt p.... nt, Stimuli for ADH =",ion include hyptrosmolality, d«reastd cardiovascular pressures as =n with hypovol~mia, and, to a I=r d~grtt, increas.d [angiotensin], b, Epithdial cells of th~ dinal nq>hron must bt ... ""nsin to ADH, c, The.. must bt • con""'ntration gr.di~nt; th . t is, the o.mol:diry of the int..,;titi:d fluid of th~ renal medulla must bt gr ... ter than the mmol:diry of the fluid in the tubules, 4, For kidneys to dilut~ th~ uhrafiltrate, the following are n=ry. a, Na+ .nd ct must bt .ctin ly transport.d from th~ tubular fluid to th~ interstitial fluid by q>ithdial cell, of th~ ascending limb of th~ loop of Henl~, This prace.. r"'luites ddivrry of Na+ and Cl- to th~ loop of H~nle, b, Very little to no H 2 0 is remov.d from th~ tubular fluid by the distal n~phron, D, The osmolality changes that occur in a nq>hron during th~ formation of urin~ a.. illunmed in Fig, 8,3, CHRONIC RENAL INSUFFICIENCY OR FAILURE L

Wh>l is chronic .. n:d imufficiency or f. ilure? A, M.ny chronic diseases moy dam"l:e kidneY' suffici~ntly so that functional .. nal tissu~ i. iruod"'luate to mointain h... hh, Th~n, the anim.1 ent~" the pathophy.iologic state of chronic renal insuffici~ ncy or failur~ , B, Ther~ a.. no uni"""ally a.c:cept.d definitions or criteria for .taging impairrd r~nal function, On~ .yn~m seems to oorrdate with dinical finding> seen in many domestic mommal,," I, Diminished .. n. 1 .."'tv2400

-

, ."

r

--maximal coooonlration

;. J--""' ~----l---------~--"':-:---------!!>~"::"""'" --Plasma

PCT

Collecting Tubulall

Glomerulus

Fig. 8.). OsmobJjty ch1Dll"' in > h../tby momrrul'. nophron. (D.t:lils of tho movomont of ",Jut< and H,O in nepluons "'" dosaib. LOBO).

2. Chronic r~nal insufficiency: Th~ GFR i, approximatdy 2Q.-50 % of normal. Azot~mia and an~mi. ' Pl'='. Polyuria occun btall5< of da:r~ ron""",rating .bility. 3. Chronic rtnal failur~: Th~ GFR i. < 20--25 % of normal. Aro .. m;" and impair~ rono::ntr.ting ability (thu. polyuria) .'" prestnt. The kidnoy. connot regul ... atracdlular Huid ""lume or dectrolyt~ bal.no::. and thus «i~ma. hypocal 1.(40) with an estimatw 83 % loss in ",n. l function! II.

Why do animals 10.., r~nal conctntrating ability in chronic ",nal failur~? A. Mor~ solut~ than usual is pr=ntM to th~ r~maining functional nq>hrons, and th~ high solur~ ront~nt within th~ tubules rontribut~. to 501ut~ diur~.hrons.

progressiv~

V.

Eviden~

of chronic .. nal insufficiency or failure A. Eviden"" of insufficiency or f.ilur~ l. The", i. azot~mia (inc",asese3SO --------- ~ --

,,

polyuria

~

/

~

"'-- , ,

, ,,

.....

~

\

,'lIZoIomia

\ \

"./

X

,, \ azotem,a. ' patienfs ""rum [UN) ...

-----------------

J9':!l _____ _

---

~ oliguria \

~;:,----------------,:c:--------L-----------------------,:c,\''-' ' nuria 100 %

50 %

«I. Notl. «n>l. and postr.".] disorden mayocrur independently or m:oy oerur in combinations.

8/ URINARY SYSTEM acute "n. 1 f. ilu". Animals with "nal failure m. y .Iso b. hypovolemic. Accordingly. at the time of p".. ntation. an .nimal·s awtem", may b. the product of both renal and extra"nal factors. B. Th, major J.bomory crit"ion for diff"enti. ting awumi:u involv." the USG .... Ho"..""r. the diagnonic",n must ronsid" the "nal .nd atra"nal f. ctors that moy infJuenct an .nimo]', .bility to oon 1.040 (in alU). or :> 1.025 {in cotd•• nd horses} ba::."", the kidn')" ..., b.ing stimu!'talto oo"",,rv. H,O. 2. If the USG ... is b.low th= values in awtemic animals and th". is no ",id.nrption in pro:riaul tubuLos i, ."bonO«! by H,D ".sorption in p=inW tubul.. and by incr"""! ADH .ctivity in ,he medulhrycoJLecting dOCh. • Vr.. rnte,. tho intestinal t
.35

8/ URINARY SYSTEM

B.

C.

D. E.

blood. i, ..... y«l. Brcam. u",~ is ~ frttly diffusible mol«:U.J. fur most cdl m.mbran ... the exmOOlu!.r [UN] and imracdlular [UN] in blood wiU uSll:olly b. the same. Th..efu",. the [UN] in .. rum = [UN] in blood = [UN] in pla,ma (SUN = BUN = PUN). 2. Unit conversio,n a. mgldL o,f UN X 0.3570 = mmoi/L o,f ur.... (S[ unit. nearest 0.5 mmollL)" b. mgldL of u..... X 0.1665 = mmo,llL u..~ Sample l. s"rum o,r pla,nu may b. u..d in most 'pffirophotometric 2. Ur .... is ,ubi. for I d at room tem~rall1"'. ,,,,,er:ol doys at 4-6 ·C. and .r l.-as! 2- 3 mo when fro7.h:dosporins. and glu= caust
s/ URINARY SYSTEM prot~im. How~~t,

this corr~tioll f:>ctot is b. ~ on an HlUmptioll of a normopro_ t~in~mi .. If th~re i, a hy~rprot~in~mia, th~ rorr~tion factor would ~ inoo:l«l""t. ; if th~ro it a hypoprot.in~m;". th~ corr«:(ioll f:>ctor would ~ n=si"". Ill.

[lIcr~

[Crt] ill serum or plasma (not.mi. ) (T.bl~ S.3) A. [Cn] i, typically incr~a~ by pathologic p r = that cou"" d~r~a ~ GFR; th~ init;"ting process may ~ preronal, ronal, or postrenal. B. Inn~a.ffl Cn production and rd~ ... &om damaca! myocytes could contribut. to incro.,a! ",rum [Cn] wh. n r~lIal function is impaired (e.g., myoglobinuric lIephrosis ...rondary to rhalxiomyoly,is in hom.), but Cn is quickly clnred from plasm. if r~nal fUllction i. ad«\uate. B....,lill. ",rum [Cn] may V:lfy amollg individ""ls ~""'" of var;"tiom in totallxxly muscle mau or m~at imak., but th.", f""tors are not npecta! to cou"" moro than. mild notemia. Grqhounds have a grnt" mean .. rum [Cn] than the mnn valu~ for dogs in the general popul.tion, .nd "'m~ greyhounds h. ve values mildly abo"" the Crt up~r refer~n"'" limit." C. Neonatal foal, con have an illcreased .. rum [Crt] if born to dams with dysfullctional pla""'ntas chat pr....,ntNllormal clearan"", of fetal Cn by pla",,"tal blood. In rontrnst to oong~nital r~lIal f.jJur~, thi, '7.0t~mi. should diminish quickly .fm binh . nd resolve over """'!":II day. becou"" Crt will ~ nn~ta! v;" th~ urin~."

[v.

Decr~ .. a!

[Crt] ill serum or plasma A. A da:rnsffi [Crt] in serum or pla.ma is not dinicolly recognizal or dinicolly signifi_ cont. Animals with a d~reased muscle ma ... would tend to have • lower [Cn]. alld th~ pr.sen"", of a hypoprot.in~m;" could yidd • slightly lower [Cn] {Ott Croatillin~ Con"",mration in ~rum or Pl.. ma, sect.II.C.5}. B. [n most speci~s, th~ lower referen"", limit for .. rum [Crt] is nnr th~ detection limit of Cn assays, so documenting a tru~ d=~.", would ~ difficult.

UREA NITROGEN {UN} CONCENTRATION VERSUS CREATIN[NE {Cn} CONCENTRATION [N SERUM OR PlASMA I.

Concepts A. In most mammals, illcr= ill [Cn] and [UN] generally paralld each other. and thus the 5ame informatioll crill usually ~ gailla! from .ith~r value alon~. In hones, [Crt] t.nds to ~ mor~ ..",itive thall [UN] to d~re.... in GFR, probably ~use of ur~a excrotioll into the .limentary t!":let. Similarly, ill ruminant' with renal f.jJur~, urn excrrtioll into th~ alim~ntary t!":let may couse disproponiollat~ incru.e< in [Crt]. B. [n theory, [Crt] is • bett~r indicotor than [UN] of d~reased GFR becou"" th~ q""ntity ofCn presenta! to the kidlley. is more collstant . nd i, not roKlrbed by the tubules, wh~re., urea is teKlrbed. Oth .. factors that may a!fa:t [Cn] alld [UN] includ. the following: l. Hypovol. m;" increa .... ur~. resorption in th~ tubules ~use of d~ro.,a! How rat~ in the tubules, which allows more tim~ for ur~a diffusion, . lId ADH promot.. ur~a resorption in th~ distal nephroll. 2. Increased protein ill imeJIin.1 contents {high prot~in diet or massive intestillal hemorrhage} leads to increased generation of NH: alld SlIb"wlemi .. 2. If .. rum [en] is inCl.,."N propo,tionatdy more dun .. rum [UN], th.n the awlem", is probably renal or posIrenal. B. Publishal .. rum UN:C'I mios for 37.0temic dog'''' .rrlistal in T.bl. 8.6. The authors' condudrd the following: l. Th. most ~"e >zotem; .. occur with ..nal or postrenal 37.0um;"" wh.reas Ih. ~.{.n

.. rum UN:Cn r>tK>s ~r~ found in pr~rena! >7.Ot~mi ... Ho~r, r~nal awtem;" cannot b. co",ist~mly diff,,~miata! from extr>r~""l awt.mw by me;om of th. serum UN :Crt r>tio b.cause of the onrlapping range". 2 Con""mrations of UN and Cn in ..,rum should b. regardal a. crud. indi"". of renal function b.cau.., both lock di~no,tic 5tnsitivity and spa;ificily for renal dysfunction emstd by renal di..,ast. CREATIN[NE {Cn} CLEARANCE RATE

I.

Crt rk"raru:r ralr, which i. th~ rate Cn is d~ared from plasma by th. kidn~., i. a good e'timate of GFR in domestic animals but i. not aJuivalem 10 GFR. A d=rastd Cn clrann"" rale (if a valid result) indicote:s the animal has a d= ...a! GFR. However , th. COU5t of the d=ea..M GFR can b. prerenal, renal, or po'lrena!.

[I.

Crl

cle~nn""

rate formuJ. (Eq. 8. I)

.. cI.... rana: "te = [Crt l, xvo) C r.... WHn. ume. . ... lJme ... bw

[Crtl [Crt]. = Crt con""mration in coUecta! urine during a timal coll=ion pc:riod [Crt], = Cn con""mmion in serum from a blood sample collecta! during the tima! urine collection period volum~ = urine volume (in ml) collectal during a tima! collection period time = l.ngth of tim. (in min) during th. urine collection period bw = body weight (in kg) of animal unit, = mUminlkg = ml of plo,ma thai were de.red of creatinine/min/kg

(8.1. )

8/ URINARY SYSTEM

'"

Ill.

Endogenom Cn d~~ranc;., m~ A. Indication, l. To ousess GFR in noruo7.0t~mic, non..dehydrated animal, that are .usp«:t~d of having ,""ruol di",ast. mu:dly ~l1St thq :U~ polyuric 2. To obuin a mo", objective """ssm~nt of th. d
IV.

Exogenous Crt d .... ranc;., rate'" A. Ba,ics of the procedure: It is the same as the ~nd,,!:.nou. procedur~ ac;.,pt that Cn i, inj«t
Urin. clarity A. Physiologic p~ I. Clear urine is expected, but it may h."" mild turbidity due to sus~ndrd partid.. {e.g., .pithdil cdls and crystals} 2. Equine urine is frrquendy turbid or cloudy b.causr of th. prestn", of mucoprot.in {produced by kidn.ys} or calcium carbonate crystal •. B. Analytical con. decreased (in dogs. below 20). (I) A [prot~in) of I gldL adds .bout 0.00}-0.005 to USG .... but has .lmost no .ffect on O!molality. (2) A [glucose] of I gldL adds .bout 0.004-0.005 to USG .... . nd only slightly incr..,."" urin~ osmolality (about 5 mmollkg). 5. Ikagtnt mip for ~tim.ting USG (Bay~r Di"i:no,tics) a. The r'""i:ent strip m~thod is not =mm~nded for estim.rion of urine solute cona:nrration or USG of domestic m. mmals. b. Principle: Th~ ionic str.ngth of urin~ is r~lated to total ""lut~ cona:ntration. Th~ rrag'tes mdlitw Hyp Canin~ pyometra Hypokal~mi> Hypoodr~noconicism

+. + +

diuresis

.J.. Tubular respon ..

.J.. Malullary

toADH

tonicit!

. ADH

+ +. +.

+

-'

-'

+ + +

• • -'

+' +

1
1,030 in an oliguric dog, ;> 1,040 in .n oliguric cat, and;> 1,025 in oliguric horses or cow>

Table 8.9. Guidelines for inlerpretation of USG...- values in a dog Co..., infOrmation USG .." Im~rpmalion Nothing known

1.001-1.060

Dehrdr:al~

> 1.030 1.014- 1.030

1.007-1.013

< 1.007

Polyuria

;. 1.020

1.007-1.013

< 1.007

Oliguria

Glucoluria

;. 1.030 1.014-1.030 1.007-1.013 > 1.020

1.007-1.020

Hyposufremia and hypochloremia

> 1.0 20

1.007- 1.013

Could be found ;n a clinicaUy heahhy or sick dog ReAeclJ rem! anemplJ 10 conserve H,O appropriately Sugg.m impai.~ .em! cooormraling ability and pouibly rem! F..ilun:; could be 5ftf\ wilh g1uooouria. hypon:mmtialhypochlon:mia. parlial n:naI diabeles imipidus disorders. h)"p'»d rtllocon:icism Sirongly indicates defKlive renal oonuntt:ning abili()~ if arolrmic. then ",nal insufficiency or f.tilure until pro""n OIherwi.., Strongly indicates defKlive ",nal oonuntr.ning .bility bm nOt d~ 10 renal f. ilure. as kidneys ha"" ability to dilule ullrafi!rr:ate; consider cetltr21 or ",nal diabetes insipidus disorders Reflect> n:naI altemp" to conserve H,O and dm, not in ren:ol imuflicitncylfailun:; could"" £rrn .... i.h g1Ua.:4Uria, hyponatrmtialhypochlon:mia. partial cmtr21 or ",nal diabetes iruipidus disorders Strongly indicates d.r.ai"" ",nal oonuntrning ability; if u.otrmic. then ",nal insufficiency or f.tilure until pro""n OIhrrwi.., Strongly indicates dd"K1i"" ",nal concen!t:uing .bility bin nOI d~ 10 rena! F..ilure. as kidneys h.;ave ability to dilule ultrafiitrate; consider cetltral or ",na! diabetes imipidus disorders Reflect> n:naI aI.cmpts to conserve H,O :approprialdy Uncommon: suspect oCUle ",nal f.iJu", Typiol fOr oliguric renaJ F..ilure; acute Of chronic Reflect> n:naI concentrati ng ability but rnay be pmialJy impair~ by ..,Iute diun-sis or d«rcasft! m~ulJa.y hypertonicity (mined constmt from one day to ch~ next {150 mg/d}. 4. Rd ationship of urine ""lume and USG. ,valu.. a. If th~ animal it not in ren. l inmfficiency or f>ilur~. urin~ volum~ is inversely proportional to USG ... b. If th~ urimlry acretion of solut.. re"",ins constmt (~.g .• I g/d). but th~ urine volume doubl.. from on~ day to th~ nat. th~ USG .. is apn:ted to "hal..." from one day to th~ nat (~.g.. from 1.040 to 1.020). c. If the urin. ry acretion of solutes re"",ins ronstant (~.g .• I g/d). but th~ urine volume halves from on~ day to the next. th~ USG .. i. apected to 'doubl~" from one day to th~ nat (~.g.. from 1.020 to 1.040). 5. Use of conc~pts to int~rpret urinalysis r.. ulu a. Dog I with • urin~ [g!uoo..,] of 500 mgldL and a USG .. of 1.015 is rypically acreting just'" much glUOOK per day as dog 2 ""'t has a urin~ [g!urosc:] of 1.0 gldland a USG .. of 1.030. b. Dog 3 with. urine [protein] of 50 mgldL and a USG .. of 1.040 is probably not prouinuric. H~.lthy dogs may h a... urin~ prouin con~ntrations of

'"

8/ URINARY SYSTEM

4--65 mgldl;"" USG ... is typically 1.020- 1.045. Ho~ver, dog 4 with. urine [protein] of SO mgldl.nd a USG ... of 1.010 is protein uric. c. c.t I with a urine [protein] of 50 mgldl .nd. USG ... of 1.0lO is typically excreting just'" much protein ~r day as cot 2 th at h", a urine [pro,"in] of 200 mgldL and • USG ... of 1.040. Both cots are protein uric. 6. Conclusions a. In results &om rourine urinalpes, the USG ... helps determine the significance of estimoted solure concentrations. b. A po.itive chemical ",. ction .hould first ~ considered. qualitative result (substance present ), and then the .ignificonce of the positive .. action can ~ weighted according to the smngth of the rraction .nd the USG .... B. The physical .nd chemical pro~rties of urine may ~ different .fter centrifugation if enoUJ:h particles sus~nded in the urine prior to centrifug.tion. I. The .. following valu .. m.y ~ the same prior to and afier centrifugation (unle .. the heme pigment in erythrocytes interfer.. with the rrading of color changt.): a. Color (if due to pigmented solute .nd not pigmented ceUs or ouspended particln) b. USG ... {bur the line m.y ~ mo .. difficult to read if the urine is cloudy} c. pH d. Protein (unless hemoglobin i. prestnt in erythrocyt.. ) • . Glucos. f. Ketone g. Heme (if the positive reaction is due to &.., hemoglobin, fr.., mrthemoglobin, or myoglobin rather than erythrocytes) h. Bilirubin 2. The following values may ~ diffe .. nt prior to and .fter centrifugation: a. Color (if due to pigmented cell. or other sus~nded partid •• ) b. Protein (if hemoglobin in the erythrocytes is re.cting with the pad) c. Heme (if intact erythrocytes are present)

"r,,,e

II.

pH (neg.tive logarithm off= [H1 ) of urine A. Physiologic processes I. The pH of urine it affected by mony renal and extrarenal facto ... Carnivo... usually have acidic urine, where", herbivores usually have .lkalin. urine unless they are on milk dim. 2. Typicol urine pH in healthy mommal. val}' .mong .p«ies: dog. and cou (6.0- 7.5), and horses and cows {7.')-8.5} 3. Much of the W that is excreted by kidney>< is incorporated into other mol=Idoxical.ciduri.) Hypokalemia W production by Meteri. Proximal tubular acid",", (if HCO,- i. dq>Jered) Alkalinur;" 'Ex~ted in hr :dthy hrrbivor .. and .fter meal. in monog:lStric mamma], (:dkaline tide) 'Ur.,. degradation: spomana>u, in older ",mpl.. , initiated by ur.,.~ntaining bacteri. AlkaJ05e:'l, .ome meubolic and potent;"lly with respiratory Proximal tubular acid",;. (e.rly) Prouinuria r .. renal (ovtory:md som~ m~tabolic: Th~", is a n~t incr...... in H+ =retion (H+ and NH') by proximal and dist:d tubuJ.r cdls: the =retion is ~nhancffl by drer .......! atracdlular pH. 3. Hypochlo.. mic meubolic alkalo,i, (= p. thogc:nesi, in Chapm 9: Bicarbonate Con~nt"'tion and Total Carbon Dioxid~ Con""'ntration. =t. III). 4. Hypokal~mi.: H+ i. =ret«i. and typhron bc:ca"", of l~ .. nimul.tion of th~ H+_ATPa .. pump. 3. Distal ren:d tubular acidosis: Drer......d H+ =rffion by th~ di,t:d n~phron con leod to an inappropriatdy high urin~ pH {> 6.0} in th~ fa~ of acidosis. Th~ pH ""'y not

be

alkalin~.

4. Proximal III.

r~nal

tubular acidm.is (ste

th~

aplanation in

th~

pr<effling . 8.0), in mod.mdy alkaline urine if highly OODctmm.d," or in uriM th.t oonc.im quatern.ry :nnmonium ullS or chlorhaidin•. •. Analytical .. ruitivity and ,!=ificily

{I} Th. m",hod d",=, .lbumin !>HIe, than globulins, which""" Jess nrgat;vdy clurgffi. Protein in cdl, (• .g., .pithdi.] cdls and leukocytes) ",.el1 vur poorly with ttagenu.

oon"'ntntions nNdal to gi"" a tne;., to I + r~~ction: albumin {14-21 mgldLl. ct-globulin (20-30 mgldLl. ~_globulin {40-50 mgldLl. 11:lobulin (> 1,000 mVdL), light..roain prot~in' (26-52 mgldLl. and h~moglobin (5- 50 mVdL}""" 2 SSA turbidity a. Principl~ Proteins u e d~naturrd by acids and form a pr«ipitate that is Sttn as incrrasrd solution turbidity. Urine that i. hazy to cloudy should be e;.,ntrifugrd prior to SSA turbidity testing. b. Remit. may be apressrd on a visual turbidity ""Ie (I + to 4 +1 or vi.u..tly comparrd against nandard solutions to interpolate cone;.,ntrations. There ~re ..tso spectrophotometric SSA methods that provide more quantitati"" results. There i, a lack of interlaboratory nandardization for reporting SSA test results. c. SSA re~m with ..tbumin better tru.n globulins (reportrdly 2-4 tim .. as well) ~nd will det«t Bene;., Jone! proteins if cone;.,ntrations are mfficient. d. Fal.ely increased r.,.ding. con be causM by X_ray rontrast malia, tolbuumid~. penicillin {mas!ive dose}, mlfisouzole, tolmetin ,odium, and turbidity COusM by coprecipitation of c'}"uls bea"", of the low pH ofSSA. e. Falsely da:reased r.,.ding. con be causrd by highly bufferal alkaline urine."'''' C. Proteinuria (Tabl. 8.11 and Fig. 8.9) l. Prerenal (overflow, overl~, and preglomerulu) proteinuria a. A pathologic ,ute incr.,. ... the plasma oone;.,ntr.otion of a """II protein that p..... through the glomeruur filtration ru.rrier. [f the amount of filtered protein aettds th. ability of proximal tubules to resorb it, the protein is ncretrd in th. urine. Examples: paraproteinuria (light-chain protein. including monomers with M, " 23,000 and dime" with M, " 46,OOO), hemoglobin uri (dimer M, " 34,000), myoglobinuria {M, " 17,OOO}, and postoolostral proteinuria (include! P_uctoglobulinuri) in food animal •. b. Light_chain proteins, hemoglobin. and myoglobin molecule! are d..r«trd by routine urine protein assay•. c. O""rflow proteinuri.. do not produce hypoproteinemi. 2. Glomeruur proteinuria a. Glomerular disease damages the filtntion barrier and d«re.... .d«tivt permeability. The glomerulu. become! inc",..illl:ly permeable to largu proteins or to {2}

Prot~in

45'

8/ URINARY SYSTEM

Blood Pro
a, Hemorrhagic: hemorrhagt' into the !:"nitourinary tract due to impaired hemosta. ,is. including blood """",I "'' 'Ilag5 of th~ p.rhological renal cotq;ory." [n this ""h.m •• function'! proteinuri.. are consid~r.d to k mild and tr.nsi~nt proteinuri.. COusffl by phy.iologically altered renal hmdli"l: of notmal plasJrul proteins in the aboen'" of reruol l.. ions (~.g ..... n with nerci .. or f~er ) . E. Prot~n_lo,ing n~phrop.thy and r~nal faiJur~ con""pts (Fig. 8. 10) l. Ure •• nd Cn are sm.!l mol.cul .. th at p .... freely through the glom.rular filtration barrier (.i~e;) . Some fihrat~ urra is resorba! by tubule;. Th~ reJrulining u",•• nd Cn ar~ ncr~t~d in urine .nd thus do not .ccumul at~ in blood. It has bttn pr~_ suma! that albumin does not paM through th~ glom~rular filtration barrier in hrahh and thus remains in th~ blood (dogs may k an ncq>tionl . 2. With a protein_losing nephropathy, the glomerular · .i~.." krom. more porous, and larger protein> or charged proteins that usually are ..".lla! ~nter the remol fihrat~ via glomeruli. [f the ability to ..,orb prouins is nceeded, th.n a proteinuria will be pr~sent. Th. continu'! 10.. of protein willlrad to hypoalbuminemia. As long as the numkr of functional glom.ruli is .dequatr, ure•• nd Crt will k adequately ",mova! from blood .nd notemia will not develop. 3. [f the glomerular dise= destroy. more nephrons, then renal failure ocru ... The f...... "'maining functiomol glom~ruli connot ",mon urea .nd Cn fan enough from the blood, so .zotemia develops. Proteinuria continues kcouse the "'maining function'! glomeruli .'" !",rmeable to proteins. Th~ """,rity of hypoalbuminemia iner..... because of continued albumin loss, but d.fective ncretion of H,O (associated with N .+ .nd H,0 rff~ntion) m.y contribute to hypo.!buminemia. F. Benc~ Jon .. prot~inuria (immunoglobulin light..ffiain proteinuria) I. Analysis of urin~ for Ben", Jon .. proteins is not part of. routine urinalysis. [t may k indicated to clarifY the type of proteinuria or to investigate a possible lymphopro_ lif.ratin disease. 2 Bmcr jon" protr;ns ar~ light chains (~ither I( or Aj of immunoglobulins that havr unique therm.! propenies: th~ precipiuu ktw«n 40'C and 60 'C, return to a solubl~ sUte at 100 'C, and then pr~cipitate again when cooled. The thermal properties of B.n", Jon .. proteins .'" due to the variable portions of the light-chain prouins." As d.scriba! by Ritzman and Danids," these prot.in> were first recog_ nized by WJliam Maclntyre in 1845. Dr. Maclntyre..,nt th~ urine .. mpl~ to Dr.

Healthy Animal

'-/--,,-;;-;,;-..-;;-,!----1 Kidney

Protein-losing nephropathy

Kidney

@@

,:::::::::::::"~,~ ~"A':>":::" "'" A 0 "~c :--;j'I' ..A,. ",",~I(d'., •• !p."/", ., • c

U

, " A" , , A

....

: u:/

•

:".,:

•

"..}J.'

..... .",.

•••• y ••.•

. .

.I> • 'c'

:7":" ii,:c

cu

•. .~ .....'u:

.....

A

,·······u Au C"c A" ,. C A "c U

.'

c

A

Fig. & 10 . Pro .. in.]"";"!t nrpbrop. thy and I'ftW foilu",. iHUiIr:l';O ... dtffl to 56'C for I 5 min and ob",,,..! for floccul.nct or pra:ipitat... (3) If f1occulen"" or plmpit.t", are present (the test i. lIegat;", if thry :lr' absmt), th. urine "'mpl. is placal in a boiling waW bach for 3 min and n.:Iminal for a danasal amount of p=ipitat•. A d=_ in floccuJ.no: SU~, Iknct Jon .. prot, inoli .. (4) Fill« the hOI urine through a funnd with fihr paP" imo a tub. contoining a thelmOnt.uf. If Ikn"" JOII" prot~illS ~'" prestm, they should p=ipitat~ .r . bout 60·C and rali...,ln at about 40'c' Vuiatio", ill th~ hrat tes{ ""idiJYillg solutiolls, filtratioll', and tim~ im~rvals h. ve bttn d=iW, b, Th~ colI""mratioll of Bell"" JOII~' prot~i", IIttds to 145 mgldL to get a positin mult, alld r..gulatioll of th~ pH i. very important,'" c, Oth~r proteills m. y p=ipitat~ durillg h~.tillg {e,g" fibrillo~1I precipitates at 56--58 'C}, which m:d.:es imerpretatioll difficult without th~ filwillg alld ..... ssm~nt of p=ipitatioll durillg coolillg. Othu methods of d~Ut•• nd P_hydroxybutym. {both of which are anions} oblig.t.. acr.tion of cotions (• .g., N.+ or K') by the kidn'Ys. Prolongnl ketonur", may co .... N.+ or K' depletion that comributes to hyponatrem", .nd hypokal.mia. VI.

Hem. in urine (tm frequ.ntly labelrd blood or IKCUIt blood) A. PhJ"'iologic con~pts: H.me-ronuining compounds .'" nOi apectrd to be pre.. m at det,""ubl. amounU in the urine of h.althy mammals. B. Analytical concqJts l. Ik>gl'm mip m.thod a. Principle: In some syst.m., the peroxidase activity of hem. cotalyus the oxid._ tion of .... toluidin. to • blue compound. In other syn.ms, the peroxida.. . ctivity of h.m. catalyzes the oxidation of a chromog.n (e.g., t.tramethylbenudine) to • colorrd compound. b. Heme may be from h.moglobin, methemoglobin, or myoglobin. Ifimact erythrocytes . '" pr=m, the cdls .'" ly=' in the "'>gl'm pad to produ~ .ith.. specldrd or solid color changes in the pad. lksulrs m. y be described in .. mi_ quamit.tive terms or as .n enimatrd [h.moglobin] (T.ble 8.10). c. Falsdy increased reactions may occur with oxidiz.ing oompound. mch •• hypochlorite (bleach) and microbi.t or leukocyte peroxida... d. Falsdy d,""reased reactions may occur with. high USG or with urine that comains coptopril, aocorbic acid, or formald.hyd•. Erythrocyt.. may not be d.t,""tw if th'Y are not suspendrd in the Wt sample. 2. Hemat.. t ubl.t method a. Principle: It is the .. me •• with the r"'1:em p>d, with modificotions. b. The m.thod may be used .. a confirmatory test .nd al"" to test for fet"al occult blood. 3. Unfortunately, Iher. is not. widely av.ilabl.labo.. toty .....y for diff",.miating myoglobin from h.moglobin in dom.. tic mammals. Diff..emialion i. umally a.ccomplimrd by clinical drductive r,""",ning {s,"" T .bl. 3. l2}. a. A simple pr,""ipitam test using ammonium sulf. t. is oonsiderw umeliable. In theory, h.moglobin, bUI not myoglobin, pr,""ipiut.. in 80 % ammonium mlfa,. solution, wh ...... myoglobin pr,""ipitates in . 100 % ammonium sulf. t. ""lution. Howev.., d.natu",d myoglobin will pret:ipita,. in the 80 % souhion and thus be incorrectly classifiw .. hemoglobin.'" Also, a !imil.. erronellu. cbssificotion wiU "",ur if the urine pH is nOi adjustrd to 7.0--7.5." b. Immunologic methods ",quire species-specific amibodi... El,""trophomic and spectrophotometric procedure; may be .mployw. 4. Th. hem......y is more .. nsitive than the protein • ....y. Therefo"" when smaU amoum, of blood are in th. urine, the", may be marked hu"" positivity without the hemoglobin cou,ing. positive protein ",.ction. C. H.m.... positive ",xtion in urine (T.bl.. 8.11 . nd 3.l2) l. Hem.turia


'"

a. Erythrocyt~, ~nt~r th~ urin~ vi. h~morrh"l:~ into th~ urog~nital tract. H~mor_ ,hag
P''''''''' (•.

'''''If

,.dimom. 2. Hemoglobinuri.

a. During clinirn intnvaKulor hemolysis, pl •• rna hemoglobin dim." (M, " 32,000) Jruly form from hemoglobin (M, " 64,ooo), pas> through the glomerular filtration barri."., .nd .m.r the uh",fiilrate when haptoglobin i, .,tuntal {,'"" Chapw 3}. If not completdy resorbal by the ren.l tubul .., the hemoglobin dim.... are acreted in the urine. b. IntnVll.lCular hemolysis of sufficient severity to causo hentoglobinemia .nd hemoglobinuria an bt aused by. variety of di,orders that au...nemia {_ Tabl. 3.lO}. Hemoglobinuria may aho bt creatal by lysi' of erythrocytes .fw they enter urine. In such in healthy.nimals AMociated with glomerular proteinuria {especially hyaline cast.} 'Age. bur diff",.ntiation of glomerular .nd nonglomerubr hemorrhage by urine erythrocyte app"'rance h .. not oon reported in ""terinary SpecIes. 2. Iatrogenic hemorrhage a. Blood vessel. may be damaged during bladder palpo.tion, cystocentesis, or catheteri7.;Otion.

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY b. Animal, with h~mOS{"'is d~f~u or urinary muoos;ll di,,,,, .. may to iatrog~nic h~morr~. 3. w.nital mct hemorrhage (associated with ithdial ""Us}, erythrocyt~, leukocyte, fatty {lipid droplithdiaJ cdls, and dum!" of renal tubular q>ilhdium may look .imilar to lran,ilioruoi

.pithdium. 3. All cells d.uriorau in utine and thu, ,,~ best a.min.d in fwh utine. C. Clinical significmc;., of ~pithdial rell, in urin~ I. Epithd",l cdt. m"y ~ found in th~ utin~ of h~ahhy animal" ~lIy in cath~w. iz.d .ampl... 2 Mor~ tr:ln,itional qJithdial c;.,1I, m"}' slough &om inHam.d or hyp<rpl:ostic mucos;>. 3. Nwpl:ostic epithd",l cdt. truly ~ detaot.d in urin~ s.dim~nt. Diff~"'nt"'tion of malignant from nonmalignant lion' of centrifugal, fmh, n~ly form.d urine truly also ~ useful. How"""r, diff~"'nt"'tion truly ~ impossible. Dyspl>Stic and proplmic (re"C1ive) cdl, ar~ rommon in utine from animal, with cynitis and rextive hyp<rpl:osia. VII. Cryst:d, {plate. II K and L .nd 13A- G} A. Physiologic conc;.,pt, l. Crynals rqJresent the praoipitation of .Im~ms am .lr.r urinary acmion of subnanesmo ratio is proportional to th~ rat~ of urinary nn~ion of a subnance (Eq, 8.5b), Thostion of UN to pI .."", co~ntr.ltion of UN < Urin. ooncmtr:ltion of Crt to pJ .. m. oonc=' (Stt Ihe nnl =:Iion), st:mdardius Ih~ ",Iut~ concemralion 50 Ihal prolein con""mralions con k romparM wilhout using calculalions 10 ronecl for diffe .. nee. in urine roneent ralion. VI.

Micro .. lbuminuri .. A. G.n~ra.l cona-pu I. [n Ih~ drnic vi~ of r~nal functions, m.. mmalian glom~ruli ar~ nol ptrm~. bl. 10 albumin bec:.u", il h.... strong nq:arive ch .. r~ .. nd Ih~ .Ibumin molecular di .. met~r

8/ URINARY SYSTEM

."

{36 Al is clo,", to th~ di.m~" of a g1om~rular por~ (42 A)." How""~r. th~ glom.ru_ lar filtration b.rriu do.. allow ..tightly uruo]J" proteins to I"'ss into th~ ultr>filt .. t~, from which th~y are re.orkd by the proximal tubul~ .. If th~re i. minor domag.. to the barri" (. reducal neg.ri"" charge or damaged podocytes), then .lbumin .nt~'" the tubular fluid. Inromplete resorption of th~ .lbumin caus.. albuminuria. With incr..sing dom~, larC"r protei", (various globulins) also p:w into the tubular fluid. 2. In ",ndom urine umples from heohhy peopl., renal excr~ion of .lbumin result. in a urine [albumin] < 3 mg/dL or < 20 mg excreted per doy." In this oontext, micmolbuminuria is ddined .. a urinary albumin 10.. gr...ter than those values but less than 20 mgldL " Using rq;ular urinalY'is rragt the mild proteinuri.. in dinical healthy dogs represent ""idence of subclinical glomerular dise""' ... Consequently, assay. have been developed to m....... re low urine albumin concentrations; that is, to detect micmol bumin uri.. 4. Th~ current working definition of mimJll/bumi..urla in dogs and alU i. urine albumin concentrations from I mg/dL to 30 mg/dL in urin~ .djuned to. USG""of 1.010.";'' ' Concent"'tions:> 30 mg/dL are referred to as albuminuria or Dvm albumi ..uriil. It is imponant to remember that a urine [albumin] of 30 mgldL in urin~ with a USG ... of 1.010 would have :m [albumin] of 60 mgldL if the USG"" was 1.020, or 120 mg/dL if the USG ... was 1.040. 5. Som. authors sm~ that 30 mg/dL i. the decision threshold for microalbuminuria ba::..... common urinalysis m~hods do not detect protein concent.. tions < 30 mg/dL Ho~r, the Ch~mnrip p.ckag~ in",n nates that, in 90 % of urin.. t.. ted, protein concent"'tions ~ 6 mgldL producal a color ch anC". For the Muhinix system, • t",ce r..ction corresponds with an estim.red [protein] of to mg/dL When turbidity standord 5Olution. are u",d with th~ SSA t.. t, increastd turbidity am be detected wh~n [prot~in] is 5 mg/dL B. Analytical roncepl5 I. Quantitative immunologic ....y a. Th~ immunologic microalbumin .....Y' .'" .peeies .peeific ba::.u", of the .peri.. diff..ences in albumin molecul ••. Enzyme-linked immunosorbent .... y. (ElJSAs) :md nephdom~ric assay' h."" been d""doptd for c;onin~ .nd fdine urine." b. The stondord 501utions for the assays are canine or fdine albumin. For on~ ELISA, stondard solutions w..~ diluted to cr..te.n analytical "'''i:e of 1.930 ng/mL (0.19- 3.00j.lg/dl)." Urine .. mpl .. ~'" diluted (up to I ; 3200) to obtain urine .lbumin concentrations within the analytical rancr of the assay, but surn marked dilutio", c:m be a source of .nalytical error.'" 2. Semiquantitative immunologic ....Y' a. Comm~rcial""'Y'.re marketed as ImmunoDip C.nin~ and ImmunoDip Fdine; both are call~d E.R.D._HealthScrttn Urine Tests (E.R.D. is:m .bbr""iation for

482


"'''Y' .""

.... rly renal di..-a,.}. Thest similar to an ..say denloptd ror human urine (Irnmunodip, Diagnonic Chemieob). h. Aft.r the urine solute oonctntr:u ion has bt.on adju,eM to a .ptcific gravity n"", 1.010, the d~ict j, dip","", into the urin., and then the r.action is gnd.d

visually. A nrgatin ,...."cion is npectffi if the [albumin] jt < I mgldL. Higher oollctntration, . '" grad,"", from low posjtive to vuy high positive b ..al on color chan~ in the drnce. 3. Albumin to creatinine ratio a. B:I}"" Diagnonics mar~, a r~1II pad method of estimating an "'humin to en ratio (Clinitek Microalbumin ). Th. albumin .""c{ion is • dJ"'-binding method with oolor c.... nges .. pr=nting 0, 1,3,8, 15, and 50 mgldL. Th. Crt ,,,,clion is a ptrm:id..,,,,lih a=y with oolor rn:mge; ror ... ponding to 30, 100, 200, and 300 mgldL. When th. oolor change; are ,....d by rdl=anct photom~tly in a Ihy~r inS{rum~nt {Clinitd'J, an ~imated albumin to Crt mio is alruJ.ted. Th~ report.d units of th~ ratios v.ry: 300 mg/g = 300 J.l{;lmg = 0.3 mg/mg (or just 0.3). b. Th~ albumin as5ay is not s~fic for :oIbumin. Many oth~r protein! will r.-act with th~ dy~ including light chain" immunoglobulins, IJrmicroglobulin, T.mm_ Horsfall prol 5/hpf,:> 1+ heme reaction), and hemoglobin an bind to the reag.nt dye." Thus, "'m~ discrepancies may ha"" b.:c:n due to prot~in! oth" than :oIbumin binding to th~ reagent in the dip.nid,. 4. Comparison to other urine protein :waY' a. [Prot~in] mimated by rourine protein :u.s.ays of urinal,.. .. (i.e., the reagent pad method .nd SSA turbidity) rep...,..nu the rum of albumin and globulin con~nt"'tion'. Both method, detect .Ibumin better than most globulin" bur globulins do rontribur. to th~ reaction,. The detection limits of these: .....Y' vary (f.bl. 8. IOJ. b. Th~ SSA .ssay is :01'0 all.d the h"minlm beause it deteas :oIbumin better than globulins. %~n a .ample', r~,ult i, compared to .nandard solutions, turbidity can be detected .t .n [albumin] of 5 mgldL If. ""ry mild prot. inuria is aused by glom~rul .. diseas., albumin will be the dominant protein in the unn•. c. Th~ result. of these: routine prot.in assays are typic:dly not normaliud to • 'paoific gravity of I.OJ o. How...", their rerults ,hould be interpreted with knowledge of th~ .. mple', USG ... so that an estimated adjustm.nt an be mad •. In a ron""'ntrated urine ..mple in which microalbuminuria is detected aft .. norm:olization to 1.010, it v..ould not be unusual for common protein dipnick

8/ URINARY SYSTEM rractions to produce a trace or I + r~.ction or for th~ SSA :way to ha"" 1+ turbidity. C. Canin~ microalbuminuria l. Thu", h:IV~ bttn ~~ral pubJi,hal .bsu:>ets ptn:lining to th~ ""'" of th~ ImmunoDip Canine ten, but ""ry f~ pnr r
Urin~ bil~

.cid to

cr~atinin.

ratio

[Htumining th~ urinary excr~tion of bil~ .cids rdative to Crt excretion i, used as a m~thod to det""t .bnormal bil. acid metaboli.m by th~ Ii""r. D.tails of this dignonic m.thod ar~ p""ema! in Ch' ptu 13. H,O DEPRIVATION AND ANTIDIURETIC HORMONE (ADH) RESPONSE TESTS IN ANIMALS WITH POLYURIA AND POLYDIPSIA (PUfPD ) I.

R~nal

con"'nt"'ting ability i, a"'.JMd in • routine urinalysis by deurmining the USG ... T ypicaUy, [he USG .. along with oth~r at.>< information (historical and physical finding. and other laboratory data) ~n .ble:! vetuinari. ns to identify th~ prob.bl. cause> of a PUfPD disorder (Stt Table:! 8.8 and 8.9). Wh~n a more critical :usessm~nt of ren. 1 con"'ntr>ting ability i, nNd.d, and .. pecially if ",nt,..] diabetes insipidus is ru.pect.d, ~ith~r H,O

..

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY d~prjvatjon or ADH ... porut {~m may k oonsid,,«I. B~u .. im"p'etation guiddjn~' =y diff~r wh~n sptes ability to concentrate urine {the USG"", or urin~ mmolal_ ity criteria are a CNded l, the PU/ PD sUte i. a primary PO di"')f(I~r. 2. [f the animal d"". not demonstrate ability to concentrate urine, """eral pos.shour} may be present because of pt~

Caco,

c.Jciu,

aragonit~,

v.{~rite

Cynine Oxalate.

C.rbonal~"P.{i{.

S CH, CH{NH,}COOH eac,o•. H,O eac,O • . 2H,O Ca, (PO.},(OH) Ca,. (PO.Jo(OH), Ca,. (PO" CO,OH).{OH),

c.lcium hydrogrn pho,!,hou

CaHPO,.2H,O

Cystine

c.lcium oxalau monohydm. c.lcium Olul.u dihydm.

Phosphat.,

B.,ic calcium phosph>te Hydroxyap"titr

Cystine Wh..w.llite

Wald.Uiu Apatite Hydroxyal"tiu Carbon 'l~aJ>'l{il' Brushite

dihydrate T ri",lcium phosphate Ocucakium phmpru.te M'4:ne1ium ammonium

Co.,fPO,}, CaH (PO.}, .2 . 5H,O MgNH,PO,. 6H,O

Whitlocki ••

MgHPO.·3H,O

Npeignificom amoum, of 10m. ion, _re missrd. (4) they lackal method. for detrcting >ilico and )" that ln "f ""al dyofunction. A • ..d, of III cao DR. «I.. c.. ... , ,,,,,J F,/;'" N"I-Ioo _, U..iorJ, I. oditioo. 216-229. llaItimo", William. &: Wdkino. 2",. 80- KC. loy« T. 1979. Clinia.I..-duation.,( ~ .. ..Ju f.DCtio~. z.j.J.ow ,.. ati..io, d,......., io td,.."

S2. I'uliyanda DP, W..! DT. Bawo MA. H........,nd TG. H ..... HW jt. 200J. c.Jpain-m"",ed of calcium ""..tat< 0 • • tnnit< in .ptid~ Reduced nicotinamide ad~nine dinucla>tid~ Ammonium Calculated mmolalil)' M ....... red osmolality Diffcrena: ~tw,""n measured mmol. lil)' and calculated mmol. rity Part;"] prclSllrc of carbon dioxid~ - log [H1 - log (IC.) wh~re K, is th~ ioniz>tion connam for a partially ionized acid Phosphate, all forms R~nin.angiounsin ')"lum Syst~mc International d'Unite. Strong ion differena: Sulf. te, all form. T mal :mionic charge Tmal body water content T mal body potassium come", Total body ,odium com~nt Total cationic charg~ Total carbon dioxide com~m Unm ... sured anion charge Unm ... sured cation charge Within th~ refc:r~na: imerval

[' I And tt..y m. y ~tc< loss (•. g.. to pleunl >nd peritoneal caviti.. ). In "'m< p. thologic . ..... involving muscle. H,O or .kttrolyt.. .run be""".n th. ICF :and ECF '1'>=1 (_ the ",," for d.tails). Fluids (•.g., pl .. m. Of urinnormal

.

HypermtremJa => Hypomtr~mi.

t

tbN a' tbH,O

=>

norm:d nonrud

tbNa ' i => tbH,O normal

~r

,l. normal

0'

t

,l.

I

...

or .,., ~r

I

(9. 1a.)

normal,l. I 0' I I ... ......

(9. lb.)

nornul.w. or i ,l.

(9. 1c.)

(9. ld.)

9/ MONOVALENT ELECTROLYTES AND OSMOLALITY

."

B. A mo.,"" acrur>U rdatio.nship is mo.WII in Eq. 9.ld. in which Na+. and K". r~p",""nt th~ ~xdtang~able N. + and K+ in th~ body {io.m bound in mo.b:ul .. a.. not exchan~able}.' From this '"')uatio.n. it em b. =n dut the total body ",crungeoble K'" coment influencu plasma [N . 1 . Thus, when hypokaJemift Sodium Con""'ntratio.n, Sect. V.B. 6). Hy~rkaJemia tend. not to cou"". significom hy~rnammia for two reasons: (I) a marked hy~rkaJemiRS via kidnqs.lungs. skin, or intcnin~ may product dehydr:n ion. {2} Def. lor that Irif,!:"rs a thim r..ponst, or th~ thir.st ctnl~r ilself may b.: dam~ed. Hypodipsic hypernatremi. in minialUre ochn.uu:rs may b.: couscd by lob .. holoprosc:nctphaly .•

502

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY h. Purr H,O loss without H,O .. pJactm~nt {I} In .. nsibJ. 10.. ofH,O by panting. hypt"",milnion, or fenr: The animal ba:omes H,O d.pJeud by losing H,O via the "spimo!)' sySlem or ,kin. {2} Di.b.t.. insipidus {ctntral or nephrogenic} (a) [n the di.btt .. insipidu. dilOroers, diminish. d AD H activity or "'PODst in the roU'""ting ducts may re;ul{ in pure H,O loss {i .•.• urine with very low OOD"'niutions ofN.· .nd oth.r solutes: urine .p«ific gr:lVity app'''''ches 1.000). (b) Animal. with d"-"'I .. in'ipidul that h."" unrestricrffl :lCCpl:asm socreting oonioonerone and :.!dost.rone in a dog' (a) This disorder is uncommon, and th.labor:ltory feature; of the ""'" wl«i a salt.flour mixtu .. that was used as modding day." (l) Administration of hypry loss..: vomiting, diarrh.,., 'e<J..uestration 'Renal 1=: ren.1 disease. osmotic diuresi., diureti", Skin lou: ,,,,,,"ting in horses Net .. t~ntion of isotonic fluids cousing alema or transudau 'Congrni"" hean f.ilur~ 'Hq.atic eirrh",is 'Nephrotic syodrom~ • A ,.t.,i""ly rommon di..... or rondi,i""

'04

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY ~m, (~.g .• fi."os.mide or thi.z.id .. ) em", N.+ alld H,O loss through inu.fe""I1"" with C]- resorption.

{3} Mon diuretic

c. Cutanam, 10.. in horses: Th~ [Na+] ill swe~{ is ~bout th~ ... me as the [N~+l in ,erum or plasma. Thu.s, profu", ,~tjllg without incr..asnl H,O imak. could cau.. normon.t""mic dehydration. 2 Net raention of i50tOllic fluid, thai cau.., .dem. or transudation (Note: Ed.matou, dilOrders may crrate eithor normon.trem;" or hyponatremia, dep"nding on the

rd.ti"" mention of Na+

~nd

H,O.)

a. Cong.ui"" hean failure (causal by valvubr di ..as. or cardiomyopathies) {II "Forw..d" hypothesis: C"di.c di..,..., d,""",=, cardi"" output, which is ""mal by I>.rorN:tptors as decreasal df=ive blood volume, :ond {hut the .ymJ>'lth.tic nervous .)'Sum .nd the RAS are stimulated. If thest ..sponses do not ftt:'ltablish the dfn:tin blood volume. continual .ctivation of th~ RAS promotes ",n.l resorption of Na' and Cl-, which increa= pl",,,, osmolality. Hyperosmolality nimulates rd..,.... of ADH .nd th~ thirst "'nt~r, which =y calJ.5t mention of H,O .nd inc",a.o;al blood volume. [f the hypervolemia inc",ases venous hydraulic pre!lUre sufficiently, it promous mo""ment of isotonic fluid to extravascuJ:.r spaces and thus fOrmation of edema {pulmonary or d~ndent} or accumulation of H,O in th~ pleural or peritoneal cavities (transudation). {2} Retention ofNa' .nd H,O i. a compensatory procns th.t hdp" m.intain .n df=ive blood volume. [f df=ive blood volume is not achieved, the hypovol~mic stimulus =y promote thirst and thus iner ...... H,O intake. Mammals with. cardiac di ....., that decr..,....s cardiac output will Ita"" incr .... oed tbNa' .nd tbH,O ",""n without clinical edema. b. HqJatic cirrho.is with abdomin.l transudation {I} Three theories {und~diJJing. overflow, and peripher.ol anerial vasodilation} anempt to explain the peritoneal transudation that occu", with hep>tic cirrhosis.'~"

{a} [n the undafilling "1(ory, the initiating event is the IOSJ of plasma H,O caused by iner .... oed hydr>ulic pressure in hqJatic sinmoid. {caused by fibrosis or venous rongmion} and loss of protein_rich pluma into th~ of Disse {sinusoids a", highly perm~able to albumin}. This cau~ .planchnic pooling of blood and 10.. of H,O across the hqJatic cap"we to the peritoneal cavity and thus underfilling of vaocular .p• .".. Mo",,_ ment of fluid from ""... Is decr""'

''''''ry,


505

inc""ast. hydraulic pressur~ in h~patic sinusoids, which l~ads to transudation, {2} H}'IX>"lbumin~m", .nd hypoprot~in~m", play =ndary rol .. in ascites furmation, {a} [n h~.hh, plasma prot~ins cr~.u colloidal osmotic (oncotic) pr..mr~ (about 80 % from albumin and 20 % from globulins) th.t hdps main H,O in v~ssds trull ..~ im~rm~abl~ to prot~ins. Wh~n hypoprot~in_ ~mia i. pres~nt with hq.atic cirrhmis, th~ increases in vascul .. hydraulic pressur~ h. "" mor~ dfry Joss: vomiting. diarrh~~. sajueslr.otioll. Gl.llin~ whipworm in!ttiion, ex", .. ..livation, bovill~ h~morrhagic bowd .yndrom~ '!kn. J loss: hypo:od",nororlici,m, proJo~ diurn;i" ~onuria, N. +. waniJ\i: IIcphrop. thi .., hypoaldon~ronjsm Cutanams loss: sw excretion of N.+ becou", of dec ....ed N. + resorption, Thi, is "'~n more in horses than other dom~nic mommals, {5} Hypm~nin~mic h}'ll'O'lldost~roni,m (Ott hyperkalemia) c, Cut;m~ous 10.. by sw~.ting {I} Among the domestic m.mmal., only hor= .wrat JUffici~ntly to cou", dectrolyu and H,O imWLonce" {2} Equin~ sweat is . Na+., K+., Cl-.rich fluid {concentrations.", gruter than pl:uma concentrations but ~poration may rontribut~ to the inc......),",· Drinking of H,O or th~ ADH.stimul.ted ""~ntion ofH,O .ft~r sw~~ting Im}' l~.d to dilution.! hyponatr~mia, d Third.space loss (typically loss to pleural cavity or peritoneal cavity) {I} ~.ted drainage of chylou. thoracic effusions (a) R~peated removal of ilOtonic fluid &om th~ thoracic covity probably r~sults in. N~+· and H,O-dqJleted nat~ that is followed by intake of H,O and.n ADH =pon,. to come dilution.! hyponatr~mia,"'" {b} This 'YJl N.+ r~t~ntion) with or without ed~ma a, Edematous disorders {I} Congesti"" h~~n f.ilur~, hqJatic cirrhosis, . nd Mphrotic syndrome {2} Although th= conditions .re oft~n """",iated with normonatremi. {Ott th~ preceding sect, [V,B,2l , hyponatremia {typically mild} may also occur if th~ ratio of tbN.+ to tbH,O is decreased. b, Expanded ECF volum~ {but without «Iemo} {II Syndrom~ of inappropriate ADH "",,,,,ion (SIADH) {aJ This is chara.ct~riud by nonphysiologic rei..... of ADH in th~ prestnce of hYI""',molality and hypervolemia, Excess ADH with unr~strict«l H,O intak~ l~.d. to fiN.H,O ",""rption and dilutional hypon. tremia, R~nal N.+ excr~ion (perh. ps due to ANP) is incr~...d becou .. of activation of mlume receptors,'

508

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY (b) Nalfologic, pulmon.,y, and thyroid di""rd~n ar~ ow;oci>tffl with th~ 'rndrom~ of inappropri.te ADH ''"''retion, ••• '" many drug•. A f~ cast. h:IV~ oon reportffl in dome'tic marnn",],.'" {2}

fu~sivt

administration ofN.+_poot Huid.: Administration of 5 % dalro .. or 0.45 % ..lin. could lr.d to a dilucionaJ hyponatrrmi .. {3} Primary polydipsia moy cau.. hyponatremia but typically js • minor abnormality b.COUst funcrional kid"q' Gm nertl< Ih. oonsumal H,O."

3. Shifting ofH,O from lCF to ECF •. A markffl or ""n;sunt inc"",,,,,, in dfa::ti"" pla,ma o!JI\OJality (t.g., b«au.. of hyp 400 mgldL 1'J b. Conru ... m proe<SSeI {osmotic diu ... is and kffonuri.} :dso contribute to the Na+ loss .nd thu. hyponamm",. 4. ShiftingofNa+ from ECF to ICF a. AmI< dam"l:e to the ""II membrane of mu.de lib.rs :dlows Na+ to mo ... from a high con""m.. tion in ECF to a lower con"",mration in ICF." b. In thi, condition. th.", it a ronmrrem influx of H,O .nd fCo'+ and .ffiux of K+ .nd PO. to "'us< hypovolemia, hypoca.l""mi., hYJl to the l"'ritonnl fluid may ",u .. hyportat"'mia and hypochlo"'mia." b. Experiment:dly in dog" hyponar"'mia and hypochlo"'mia we", det«ted within 1- 2 d of the O"""t of utoperitoneum and wer. marked .ft.r 4 d." 6. K'" depletion cou,i"l: mifu in N.+ and H,O' (..e Eq. 9.ld) a. As d=ribed l. ter in thi, mapter {,~ Pou.!ium Con""mration, sect. V.B.2}, K' con b. Ion from the body duting a variety of gasrroimeuin:d .nd ",n:d dilOrd.rs. If these loss.. are not replacal by imake, the body will b.com. K'depleted. b. Th.,e K'" 10JSeS d«rease the atracdlul.. [K1, whim creat.,. gradi.m for K+ mo ... mem from cdb to the ECF. Bn::.u"" prolel :dt~r th . ..rum [K+] (Fig. 9.2) . l. An inorg:mic or min,,:d .cidoois (QluK
.0

alJ.

510

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY b. Acid~mja =y promote the Joss of K' from cdl., but the K' i. excretal in urine with [h. organic ani"", (e.g., L-1a.cYle or AcAc) that at• • 150 ncr.tal during locric .cido";, and k.{~idosi., r.,~ivdy. 3. Treatment of a normoblemic acidotic sUte may COUK hypokalemia that reH,""cs tbK+ depletion in an animal. 4. Meubolic albJosi, may am .. mild hypokalemia. 5. Respiratory acidoses and alkalSe'l are not associaud with alt ..ed ,libly hyperkaJ~mic p1 disord~",: Th~

dam~.


513

Table 9.5. Disca.... and conditions Ihal ca u.e hyperkalemia Shifting of K+ from ICF to ECF (no changt in lotallxxly K+) •Metabolic ~cidO!CS cau.s..! by :K:C\lmulation of inorganic acid, Rh~lxIomyolysi, or olh~r mmde donugt Acquired: sU~nuou, uerci .. , ..izUle;, .. Ienium deficiency Congtniral: hyp"rkalemic p"riodic paralysis in quancr ho .... and p"rh. !" dogs M ... ive: intraVllKlllar hemolysis in animal, wilh K' rich erythrocJ'us Other m ... ive: lisme necrosi, Afi~r uerci .. in hyporhyroid dog, Inc..asalrotallxxly K' Dec..asffi renal cxcmion of K' '!knal insufficiency or failure {primarily oliguric or muric} 'Urinary rracr obnrucrion or le~ into lxxIy H YP""ldo,reronism 'HYP""drenoconici,m (Addison'.) Angioten,in-ronvcning enzyme inhibilon Hyp"rr~ninemic hypoaldosuroni,m Trimerhoprim.inducffi K+ re{ention Inc,",asffi intake Admininmion of K+.rich fluid Other or unknown meduni,m ~~tal dnin:oge of chylou. thoracic ~ffu,ions Perilon~a1 effinions in caU • A l.tui",,[y oommon dio.... 01 condition N otcul,, hcmolysi, in mimals wirh K'.rich erythrocyte;: English 'pringtr 'Jl'Inid. with phosphofrucrokinaso: ddici~ncy have: hy!",rl.:alemia concur.. nt with their hemolytic epiwdcs which might involve: K+.rich young erythrocyte,," e, Massi"" rissu~ ncero.is (in lissu.. other Ihan mu.de or bIO<X!), which i, cau.s..! by Ihe rdea .. of r .rich ICF from d~ad cd!., i• ...,n wilh mmor necrosi" .nerial rhrombosi. with lissue ischemi., . nd wmerimcs just prior 10 dealh, f, Hy!",nonicily (c,g" cau.al by hyp"rglyco:mia in diabet .. mdlim,) leads 10 an osmoric shifr of H,O from 0::11, 10 ECF, thcr..by inc..asing Ihe intracdlular [K+] {bur norlotal K+ rontentj, K+ rhen .hift, down a ron""'ntrnlion gudient into ECF. Although rh~ K+ shifr deere .... the imrao::llular [K+], Ihe ne{ effecr on rhe pl"ma [K+] dep"nds on many other f:>lly if th~re i. renal compromi.. 3. Repe. ted drainage of rnylou. thoracic ~ffusions:"'" PathoC'"n~.i, of hyJlU.ffl by stimulotion of ADH ,.least and chint ""mu. by a d=easM df«tivr blood volume. concurr~m hyponatr~mja.

[v.

Normoblemi. in acidotic or :dblotic .nimah A. Normoblemia in an acidotic a!lim:.! l. Breaus. inorg:mic acidemia is exptct.d to incre;;o.., ..,rum [IC'], normoblem;" in the pr=n~ of inorganic acidemia mggest' an aninul h", a d«re=d tbK'. TheraJ>tion, Se it might ho"" da:r=d tbK+ ("'" Pot""ium Con""mration, sect, V,B.2), c, Exptrimental endotonmi. couses • hypoblem",,'~" Th. hypokal~m", nU)' drvc:lop kcausly '[ncreastd :.!im~ntary loss: vomiting, di.rrh~a, scquesr ..lion, acess .. Iivalion [na... std cutaneou, lou: .wnling in horsts Olher or unknown mecluni.ms 'Hypokalemic ren.l failun:: in cat, Hypokalemic myopathy of Burme.. kinem • A lel. tively oommon dioe ... 01 condition

(2) The ,""rily of hypoblemia wiU k ~nhan=:l if other proc= >Ie leading to K+ loss or shifting to [CF. b, [na . .. ~ acrelion of K' ( I) [ncre=d renal loss (a) [ncre.std tubul .. How (il [nc"",,~ flow of Huid through Ihe coll,""ting tubules allows for inc",=d """"'tion of K' from the tubular ctll" Rapid flushing of K+ IIUintaim a low tubular [IC'], which aUows Ihe paui"" move· ment of K+ out of Ihe a:1Is. (ii ) Polyuric nates th>t promote hypokalemi. include glucosuri. , N. +.losing nephrop.thi .. (pydonephrili., tubular internili:'! nephrilis, and possibly hyperala:mic nephropathy), and diuretic u.. (loop diuretics and Ihi".idc), (b) [ncre. std n::nal acmion of aniom (i) Kelonuria: AcAc and BHB (hlon~ bodies) .'" aniom thai are not resorbal in th~ lubules, Th. ir negative charges add 10 Ihe drcrro. chemical gradi. nt Ihat promotes K+ acrelion, es",""ially when there i. oonrurn::nt stimul. tion of Na+ rC1orplion, Animal, with hloaci. dotic diaktes mdlitus trnd 10 k hypokal~mic; however, the nel K+ balona: i, the re",1t of multiple concurr~nt p~, (ii ) Lacmuria: Uclal~ is a poorly """,rbal by renal tubules, Thu., incr~=d renal aCrclion ofL.la.ctate {in lactic a.cidosi,} oblig.tes Ih~ 10.. of eotion, such a, Na+ :md K',

5"

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY (iii) Biearboll.tu,i., Wh~1I pl.. rn. [HCO,-] exettds th~ renal ",pacity to con"'rv~ HCO,- (reruoJ threshold) or if th~r~ i. a tubuJ:or acidosi" the HCO,- th.t rellUin. in the tubllJ., fluid obligates the renal exc.. tion of corion, such :as Na+ and K+. (e) Vomiting or ~ue'Ithog.nesis of th~ hypokal~mia of chroni" ",nal f.ilu", is unknown and may b. du. to muhipl. factors: inc",asrd .. nal K+ exc .. tion, incr",...! colonic K+ exCl"~tion, .nd d""",asrd di...: ary K+ int:ok~. lkaU,. cats main .. nal cona:ntrating ability much longtr in r~nal di= than oth~r domestic mammals, possibly th.ir distal tubul., .. main ... pomin to aldon.ron. during hypovolemia and thus retain Na+ and """'~t~ K+. In ""prrim.ntal conditions, a N.CI_restrictffi di...: did result in hypokal~mi •• nd inappropriat~ kaliure;is wh.n th~ glom.rul.. filtration rat. was rffiua:d.'"' {2} HypokaJ~mic myopathy in Burmese kin~ns""" (a) Th~ Burm.,.. kin.ns had hypokalemia, mu.de wukness, .nd high .. rum cr~atine kin..., .ctiviti.,. The myopathy ~ pr""ipitatffi by me .. or ",erc,s,iv:nion Defsal intah of Cl- vi. or:d or N administr>tion of 5Olutiofll containing Clmay :dso le.d to hJ'P"rchlo""mia, b, Decreasal ""nal acretion ofNa+ {hJ'P"r:ddost~roni,m} (r>r~) {I } Ex~ivt aldosuron. promot~. a~ivt ""nal Cl- {and Na+} ret. ntion, {2} HJ'P"rchloremi. (.nd hy~rn.mmia) may <X'Cur ifH,O is romictal or ADH .ctivity is ralucal, Aldost~ron~ e"",,~ may prevent hJ'P"rchlo""mia {= Sodium Con""'ntr>tion, Sett, llLB,2b}, HJ'P"rchlor~mic me{abolic .cido';, a, Alimentary 10... ofHCO; {I} Vomiting or diarrhea th.t auses a 10... ofHCO;_rich inte;tinal serbal with N • ., . nd thus hJ'P"rchloremic me{abolic acidosis d~dops. {2} In dist:d ronal tubular acidosis, th~ imp.iral .bility to =:ret. W might k linkal to the failur. of aCt _HCO,- shurd~, thus imp.iring secretion of Cland ra:iamation of HCO,-, Respir>tory alkalosi. {chronic} a, As. com~nsatory change to prolongal hypocapnia and alkalemia, the renal retention of H+ is incre• ..d and thur th. renal consc:rvation of HCO,- is raluced, b, Th~ fall in HCO,- is Wlanced by.n inc""... in ct and oth~r .nions that ."" not id~ntifiw, " Dehydration of the sampl. (~.poration or sublimation): Exposure of .. rum or pla!ma to . ir may :dlow ~poration th. t auses hJ'P"rchloremia, This is especially true of air-conditioning systems that blow cool dry air ovtr the sampl. proassing or ana!ysi. areas, Sublimation of H,O from frozen sampl.. may au", hJ'P"rchloremia.

Normochloremi. : Recognizing the p" ",n"", of normochloremi . may k important when or decreased ",rum [HCO,-] is pr... nt, because it sugge;ts the presIu.. Cl- i, th. major ,"io" that hdp' maintoill d«tri",l lleutrnity ill tho ECF. di""rd~n that "'u.. hyponatremic ddtydratioll (via gastroint.. till:d. urinary. or curanam, 10M) t.nd to:d", cr.... t. hypochloremia (Ott Sodium CoIla.III.. tion. ,«(. V.B.I ). b. Hypochloremia ill the ab...lla. of hyponatr.mia SIlggem the pr..ella. of m.to· bolic :dbJo,i, (with an illcreastd [HCO,-]) or.1I increased allioll gap (with," illcreased rolla.lllration of.1I anioll other thall ct or HCO,-) beam.. dectrirn lleutrality mun be m.illlailled. Interpretatioll of HCO,- (or tCO,) alld ,"io" gap value, should be sufficient to id.llli!y these colldition,. but ",lcuJ.tion' for rorr«ta! [Ct] and SID may be u,a! {Ott th~ =tioll 011 Strollg 1011 Differ.nce .lId Suw:on', Method of Acid.Base Analysi, ill Chapter IO}. {I} M~tobolic .lhJom (a) Loss or srqummion of HCl (•. g.• vomiting. di'plac«i .bomasum. other upper g"'troilllestillal tract obstructioll. gastric ",flux ill hor .... or bovill. h.morrhagic bowd .yndrom.): Loss of Cl-.rich secretiom l....d, to dq.letioll ofCl- ill th. ECF .lId thu.s hypochloremia. {b} Bovin~ rrnal failu",: Canl. with rrn:d imuflici.ncy t.nd to become alkalotic. The a.cid.b ... change" may ... uh from .bo/IUSal atony. which cr....tes a functiollal obstruction:md thm srquestration ofCt (Ott Bicarbonat. Cona.ntration. =to m.B.I ). Aho. ",nl. excrrU more K+ via rniv. during renal failure. Wh," sw:dlowed. tho K+ may limit the absorption of Cl-.1O (c) Furosemide: Thi, rompet .. for th. Cl-.bindillg site in th. N.+. K+.2Ct trallspomr of th. lumin:d m.mbran. of th. thick asco:ndillg limb of the loop of H.nl•• nd thus inhibits Cl- resorption. Exct:s.l rxcretioll of Cl-


2, 3, 4, 5,

(rd. tive to H,O) couses hypochloremia. Concumnt hypokalemic mffilbolic alkalosi, =yoccur (Itt Bicorbo""te Con""'ntration, =t,IILB,Lb), {d} Thiazide diuretics act in the dinal tubule by interfering with Clresorption in. N.+_K+ cotransporter, Because thi, pr",,",ss occurs in the coni",l nephron, it doo; not dimini,h medulJ.ry hypenonicity and thus the kidneys mainuin conantrating ability, Thus, when S(imul.rrd by ADH, H,O re;orption will cou.. hyporuotremia:md hypochloremia by dilution, {2} Meubolic .cidoses with inere""rd anion g'''' {al In ketoacidosis .nd lactic acidosis, there is .n inerrasrd filtration of untuorbabl •• nions (htone bodiu and L_lactate, respectively) from pl""ma, The", :mion! obligate the renal excretion of N.+ to m.inuin decrrical neutrality, Thu., I... N.+ i, """rbed in the proximal.nd colla;ting tubules, Because Cl- resorption in tho.., tubules depends on th. ela;trochemical gradient establiJted by Na+ resorption, the dimini,h.d Na+ resorption dimini,h .. the Cl- rerorption.' {b} Ingmion of a foreign subsun"" that gtnerates anions (',g" ethylene glycol): Pathogtnesi, of the hypochloremia p:orallds th.r found with ketoacidOJis :md lactic .cidOJis, b«aUst the filtration of unresorb.oble anion, obligat.. N.+ loss, As ct resorption de~nd, frequenrly on Na+ resorption, Na+ loss lrad, to Cl- loss, Other examples of exogenous anionic mbst:m"", .re listrd in the Anion G.p section, (c) If there is .dequate renal function, the reruol response: to an .cidemi. i, to iner.... the excretion of H+ by the following procc:..e. that incr..... the excretion ofH +:md Cl- :md the production of HCO,-, The ne{ effect i, to rrdu,,", the ..""rity of the acidemia (excretion of H+ . nd genemion of HCO,- for buffering) :md rrdu"" plasma [Ct], (i) Acidemia stimulates the type A int.rcalatrd cdl, {Fig, 9A}, Iii} Acidemia stimulates th. incrra"'! ",ruol excretion ofNH ' in both the proximal and coUa;ting tubular epithdial ""lI, (Fig, 9,6), Thi, m.ro..nism of acid excretion in the di,ul nephron may be impaired with .norexia, possibly to help maintain muscle mas.!' H,O-= group (tnmn.. H' ..l....d from the H,O is :ov:oibbl. for ==rtu mpo't.rated CO, diff....,. into a H CO,- solution with • pH dectrode. Changc:. in p H rd.u to the amount oflil>.raud CO,. 3. H iuchi .nd Olympu. analyze", a. H CO,- ",.ct. with phosph~nolpyruvau in the p .... na. of NAD H to produ", oxalo.a.t. u. PO ••• nd NAD+ in the p.... n". of Q1u lytic .nzym... The


529

Table 9.9, Disca .... and conditio"" that cau.e increasc! would otherwi .. han been resorbed), and thus it .ccumulates in plasma, (2) Concurrent hypovol~mia .nd hypochloremia l~..d to incr~a=' renal con""rvation of HCO,-, Hypovolemia nimulates th~ RAS to cousc th~ tubular resorption of Na+ . nd ct, If the anim:d is Cl- deplClffl, resorption of N.+ without Cl- in the dinal nq.hron incr~ases th~ electrochemical gradi.nt, which promotes H+ o«n.lion and thus th. gc:neration of HCO,(Fig, 9,3), (3) Cattle in r~nal failure may d~nlop a metabolic alkalOlis, The pm,.iling thcory is that th. cotd~ d"",lop . bomas:d .tony that l....ds to HCl sequestra. tion, which gc:n~rates th~ :dkalosis, b, Rcn:d loss of H+ ( I) Loop of Henl~ diuretics: Furosemide and oth~r loop diumics (bum=nide and ctha.crynic xid) block th~ .ction of a N.+. K+.2Cl- tn"'potter, thus, the

530

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY r=>rption of Na+. K+, and ct by tho """"nding limb of tho loop of Honlo i, da:r ...saI. Tho ...uhing impairal H,O =orplion :md incr ...saI fluid flow in Iho dist:d nophron promo" H+ sa:retion by maintaining. favouble H+ gradiont. Also. hypovolomi.> and hypochloremi.> I...d 10 increastd sa:retion of H+ .nd thu, increaKd HCO,- ~neralion. In .ddition, incr ...saI ",nal ncretion of K' may I~"" to hypoblomi. thaI :dro promo", alkalO!is {Figs. 9.2 and 9.4}. {2} Thi.>z.id~ diu",i", inhibit ~ Na+.CI- cotranspo"'r in the disc:d nq>hron by competing for the CI-.binding site. As notal in the pra::eding po.rag.. ph. hypo",lemia :md hypochlo .. mia promo" the form.rion of meubolic alkalo,i •. {3} Secondary to respiratory :ocidosis: Chronic respiralory ~cidosi, allows time (3-5 d) for ",n:d compensation comining of inc.....M W sa:retion by tubular ""II, (proxim:d primarily) and Ihu. increa=! HCO,- gtnemion {Fig. 9. 7}. The inc",as.d H+ KCrttion i, probably stimular.d by Iho acidemia. {4} Hypokalemia stimulate. H+·K+·ATP.", in the disul nq>hron, thereby promoting K+ retention, H+ KCretion, .nd HCO,- gtn~ .. tion (Fig. 9.4). Hypokalemia may also promot~ alkalO!is by shifting of H+ into ""II! in nchangt for K+ (Fig. 9.2). {5} Aft~r endu.. n"" ra"". or during intminal di,ord ... (e.g .• colitis). horses can d""dop m~ubolic .Iblosis. Sometimes th= alkalo!es ..., explain.d .. being causal by contraction .Iblosis {Stt Bicarbonate Con""nt .. tion and Tom Carbon Dioxide Con""ntration, ""'t. 1lI.B.4} or g.. tric ~um .. tion of HCI; such ma:hani,ms may be prestion of HCO,- . olher mech.nisms nuy be in",lvaI. (a) Ext~nsivo sweating ""'y occur during ~ndu .. n"" .."",. Equine sw...1 is K+ rich and ct rich compo.r.d 10 pi ..""" so .w...ting mult. in hYp"rtonic loss of th= da:trolytes in addition to tho 1= of body H,O [hal m.y not be replacM by drinking. {b} W.rery diarrh~a dq>lm. ct and H,O. If tho ho"" i. not ...ting. l:ock of fttd intoke would r.du"" tbK+. {cl As nplain.d in th~ for.going """ion Sol.a :md in Fig. 9.4. th~ concur· rent su", of hypovolemi., hypochlo .. mi. , and hypokalemia increa", renal "",,,,,ion of H+ and thus inc ...... production of HCO,- . T h.." process<s cr ... le ~ metabolic :dblosis. 2. Shift of H+ from ECF to [CF due to hypobl.mia a. Alkalosis can I~ad to hypob l.mi.> , but hypoblemi . am .Iso rontribut. to an .Ikalosis. b. If the", i. tb K+ dq>lrtion, a f. ll in [K+] in th. EC F promo". th. mov~m.nt of K+ out of th~ ""II :md tho mo""m.nt of H+ into cdh. T he higher intra""lluiar [H'] .Iso promoles W sa:retion by ren:d tubuJ .. cdls and increa=! goneration of HCO,-. thu, promoting :dblemi .. 3. Administration of sodium bicarbonal~. organic anions thaI gtnerate HCO,- , or magnesium hydroxide in ruminants or hone. a. Ex=< .dministration of sodium bicarbonat~ (whiJo t",ating acid.mia) m.y incr.... s.rum [H CO,-].


531

b. M",.boli,m of som~ org:mic anions {~.g .• l_lacrat~ :md cimll~} by h~patocyt~. I.... and pathogtneses (T.bl~ 9.1O) I. G..nuation of ""(".« Tabl. 9.(2) D'""....«I renal ""cretion of H+

'!knaJ

f~ilur.

'Urop",itoncum or urin.ry lract obnruction Di,ul .. nal tubular acidosis {cyp. I} Hypooldo,{croni.m lnn"ased HCO,- loss 'A!imcntory [SSt.: di:orrheoo, ...quc'tration, or vomiting of ""oCIutic KCrclions Iknalloss." proximal rerud tubul>r acidosis (typo 2) Dilutional ""idosj, (npid infusion of 5alinOnffi in • mar., but th~ om,. was not d~t~rmin.d." 4. Dilutiorut! .cido!is m. y occur with rapid s:din~ infusion, which may dec",as. [HCO,-] by diluting ECF HCO,- . How.""r, .bsolut~ chang. caused by dilution is ""rectal to bt minor .nd thus cau.., • minor ch.IIV' in blood pH. S. In vitro loss of HCO,- from th~ .mpl~ {ott Bicarbon. u Con",ntration &ct. II.B.2} C. Decr~a.sed [HCO,-] or [rCo,] with hy~rchlor~mia: HJ'P'rchlo .. mic m~ubolic .cidosis mongly mggests th~ prestn", of .. rut! tubular acidosis, ~ith~r th~ proximal or distal form. \. For proximal .. rut! tubular acidosis, proximal tubular di ...... rffiu= tubular secmion of H+ and decre;;ose; rons ..v.tion of HCO,-. As shown in Fig. 9. 7, proximal tubular HCO,- coruc:rvation normally I..ds to th. mov~m.nt of HCO,and Na+ ions from th~ cdls into th~ int~rstiti:.! fluid .nd blood. IfHCO,- ions.", not bting formffi in th~ proximal tubular ",Us btcat= of inhibition of carbonic anhyd .... , th~ Na+. K'.ATP ... pump cr.... t...n dectric:d gradi~nt that ~nhan= Clre;orption. Th. n~t result is decrea=! [HCO,-] , incr .......! [Cn, and ther~fo .. hJ'P'rchlo .. mic meubolic xidosis. 2. For dist:'! ren:.! tubul .. xidosis, disul tubul .. di ..a,. impair.; the secretion of W and thus d= ..",s th~ g mC' = ([N .+) + [K+j) . nd mK = [CJ-] + [HCO,-) , th.n ([Na+) + [K+)) + uC+ = ( [ct) + [H CO,-n + uK. R.~rr.lllging th. equ.tion, uK - uC* = ([Na+) + [K'j) - ([Cn + [H CO,- j). A.. anion C.P = uA- - uC', th.n .nion gap = ([N . 1 + [K*]) - ([Cn + [HCO,- j).

(9.4.)

C. Th. major purpo.. of eokulating .nion gaps is to id.ntify incr ... scd [uK) and th.",fo", an increaK in circulating anionic molecul.. (e.c. , L-lactat. and ketone Ixxiies) in stat.. of met. bolic acidosis {Fig. 9.9}. l. A> shown in Tabl. 9.1 I, uK ;> uC* in health; that iI, the mm of ch .. go; due to prot.ins, org.nic ions, PO" and SO, is cr ... ter than the sum of charges due to Jt:a"', fMC .... and H+. Also, the 'unmeasured" ~nion concentrations eon chan!:" mo", markedly than eon the "unm.asured" eotion roncentrations. 2. Clini",J]y signifieont chan!:", in the anion gap are usuaUy the result of chango; in uK. Major chang., in [fea"'] and [fM g"] are li~_thr ... t.ning. Only minor chanc., in [fCa" ] and [fMC"'] .rc ..en dinicolly, and thu. "'UK only minor chango; in amon g. p. 3. Most changes in . nion gap arc due to increased ronccntrations of the anions of organic acids. Th..., organic .cids ~ he endo~nous substances (e. c., L-larute and keton< Ixxiies), or they may be ~n.r:lled from eIO~nous subst:mc.. (•. g., ethylene glycol). 4. [nc",aSC's and dec ........ in protein roncentratioll!, especially albumin, eou"" mild incr ...... and deerea,." respcctivdy, in the .nion g.p. Most plasm. prot.ins ... in the uK group.


'"

, I ,

,.

«'-

--

-"--

,. "," "",. .--" "'. ,.

~

"---

"-

~.

,,'

---

,,'

,,-

~,

---

~,.

-"',,'

6

----

~.

~~

"---

-

- --

,,'

--

.-----

~

"'.

r:"c

--

,,' a-

- --

a-

6 A

B

c

D

E

F

Fig. 9.9. Bll diagnms of :onion Il"P concJ>COon. n,. Ole' is d ... mwtly to cb. "i!'" from Ie.... IMg'+,:and rom< glooo~ru • ..1..",.. th. uK is d"" mostly.o mUG"" from po.. SO •• :ond .mom of org:mic . cids :md pro..,u", {Prl. ProtOivalent to d.. combined phJ"iologic concenm.'io", of mio", of org=ic , cids and pro",jn~ PO" ond SO, _ a [n 1 no,modt]o,.."ic mouboJic .Odos;' (th.enfOf< low [HOO,-l), tit. ina.osed rnion S"P "'1'",.. nOl imn...d macen.mio", of uK (organic .cid rniom, po•• SO" or other anions ofm. :ooids). Tb ... :ocidooes rruy b. orgrnic (• .g., u. with allY cakul>lrd valu~. th~ ,"ioll gap will be, only:as .ccurate :as the m~. !Ured value,. If IIttdrd. n&r to prior KCtions 011 the illdividuod dectrolyt ... e. The [HCO,-) uK
Table 9. 12. o;""UC5 and condition. that cause an inaeased anion gap Metabolic .cido... 'Loctic .cidosi" illc",....:! lactat. {eith.. l-1actat~ or D.1act.te} 'Ki. in ~riph"ral tissues •• nd l-I.ct.r. to glue.!< via gluconeogtne.i, in h~patocyt ... H' p"tocyt., can also u.. L_lactar. for ATP production vi. the Kreb, cycl~. C. s..-c,u.. mammalian .rythrocyt~ lack mitochondria. glycolpis in erythrocyt.. produce L_IocY",. AI"". l _lacYt. from mu",l~ .m~", ~rythrocyt.. vi. thrtt m.thods: (I) diffusion .cross cdl membran ... (2) transporYtion via a monocarooxylate tran.poner. and (3) mnsporYtion via th~ inorganic anion-achangc: transport.. {band_3 pror.in)." Erythrocyt.. may .."", as. tr;m 'port.. ofL-lact.", .nd al"" a "I.ct.te .ink" that enhana:. L-Iactat. diffusion &om muscle to plasma (i. • .• mu",l. to plasma to erythrocyt..).

9/ MONOVALENT ELECTROLYTES AND OSMOLALITY gl""""" + 2 NA[)+ + 2 ADP + 2 po. POH

~

2 pyruVBtt< .n"'", mitocbondri.. pyron.. ~"'" the Kreb. citric ""id eye!. (trie>rbozylic ""id eye!.) with pyrun.. dohydrog< rebtionsbips of tboo< molerul<s in ",thologic " ..... n,. redoction of pyruY::l'" by LD in< rrujor fonn produced by aumm.Ji.., ""Jl~ . nd D·bctil'" is produced by bact .. i.. Of tbe th",. htone bodies. only A* ..,d """to... are truly ketones. A* can be converted to ~iti>n ",Us via the gIyoxaldsr pathway. which metaboJi= m~hylglyox:d produud durillg g1yroJ)"lis or vi.> con"""ion from a.ceton . ... III h. :dth. pl:.sm. colI",mrations of D.Ja.ctue are ""ry .m:dJ romparM to tho", of L...lactat~.


II.

Analytical con""pu A. L_I""ut~ I. Common clinical :w~ for I""ute mU'lur~ th~ L_loctat~ produ""d by animal ""II •. L-loct.t~:w~ us< eith~r LD (s~rophotometric methods) or L_lacuu oxid.." (e.g .• i_STAT .nd NOVA). 2 L-loctat~ con""ntrations a", m=red by many blood gal analJ'Z"rs. but. depending on the aruolytical method. ~ith" whol~ blood or pwrruo is th~ prd'erred sample. In the NOVA instrum~nu. a plasma [L_l""tat"] is m.... ured in. whole blood sample by allowifll: only plasma to ~nt" the reaction chamber. B. D_loctau ron""'ntrations c;on b. meamred by high_performan"" liquid chromatography or by D_I""t>t~ dehydrog~n ... ~nzyrruotic methods. Th~se ..... Y" ar~ not commonly availoble in clinical l.boratories. C. Unit: mgldL X 0.112 = mmollL (SI unit) (Nou: Thi. i. a conversion for th~ .nalyt~ lactote. Th~ conversion factor for lactic .cid is 0.111.) D. Sampl~ for [L-lacute] I. Blood .an'pl.,. should be p~ or .nalyz.nl quiddy so that l_lacute produced by ~JYIhrocytes does not inc",... th" plasma [L-lactot,,]. If the sample c;onnot be p,""""ssed immediatdy. L_lactau production am be reduced by collecting blood into a tub. containing sodium fluoride .nd chiUing the blood until th. plasma is "'Parated &om th~ ~rythrocytes: fluoride inhibits phmphopyruvate hyd .. rase (.ynonym: ~nol ...) of the glycolytic p:uhw:oy. 2. Id..lIy. blood should be collected from fr..,_f1owing blood (without. tourniquet) '" that blood nagnation doe. not r<sult in incr~a.ffl L-lacuu production. 3. L-loct.t~ con""ntrations .'" also m=red in bovin" milk. as in indic;otor of ruminal xidosiJ. and in lxxIy c;ovity dKuions as roden"" of bact~rial infection (= Chapter (9). 4. Special coUection methods for D_lacuu .amples we", not found. E. SUMan"". that int~&'" with th~ m"asur~m"nt of [L_loctate] will v.ry with th~ method

""".

~

[L-lactate] detetminal by the i-STAT L-lactau oxida.. method. but limilar interfen::no:: is not d=ribcd for the NOVA L-lactat" oxid... method. 2. Th~ pm.,n"" of fr.., hemoglobin and hemoglobin_b..ro oxygen c;orrie.. in th" sample will result in falsely low L_l""tat" con""ntlOlliom if measured by th" L-Iacute oxida.e assay. probably b.c.u"" th" peroxidase activity of h~m., romo= the H,o, produ""d by th~ L-lactat" oxid... r..ction.I. Bromide falsely

Ill.

de=a...

IncreaKd pwrruo L_loctat., con""'ntrations (hypr,filctaum;Il) A. L_I""ut~ accumulate> in plasma wh"n its forrruotion ",,tions. b. Dd'"clin glycolytic p"thw.". (I) Hypuammonem;" (a) This may occur from ncessi"" production of ammonium k.g .• urea toxicosis or .mmoniatffi rorage toxico.is). &om various causes of hep.ric insufficiency. ~nd &om urea cycle def.a. {b} High [N H:] may interf..e with the Krd>s cycle .uch th.r the . erobic production of ATP is defective. Generation of ATP switch.. to an""robic glycolysis. which produ= L.-laaar.." ~ {2} Pyruvate dehydrogen= deficiency in Sus=< spaniel. and Clumber spaniels =ults in excess rorm>lion ofL_lactau. " '" Pyruvate ddtydrogI physiologic pH value!, n •• rly all of Ih • .., mol.cules a,. in Ih,;, anionic form •. B. K.tog
Upt

at - 20

'c.'"

D. When ketone lxxIies .re detected in blood or serum, they should :dso be in urin •. However, when comparing r~sults, the type of .....y .nd it. aruolytic properties should be considerw. For exampl., the BHB might be inc..ased in .. rum and urine, but the urine tm for htones (AcAc) may not be po.iti"". HoW{~ estim. c. of osmolality • .. p«ially if (he", j, hyponm.mi. and hyperkalemia. Howenr, ba:au.. ""rum [K+] cannot chang. much (± 2 mmollL) without ""ious mfflical constq...,nres, nujor chang." in ..,rum [K+] co...., only minor chang.. in tot:d .. rum ""molality, {3} OchUI appro.ch the concq>tu:d contributiom of the d~trolytes with the concept tha t ] mmol of NaCI contributes only about ],75 mmol becau.., N .Cl, like oth" plasma . is in"",,,,,",,. bea .... the ""ogenous wlu.. inc"' .... the Osm. but is not included in the Osm,. formul .. E. When hypooomob~ty i. coused by bypona~mia:and hypochlor<mia, the ",mo. Il"P is not changed. bee""", the Oun. :and tl>. Os"" :ore dec .....d by the = amount.

,,,,.a.

b. If the formul. u=I for O.m, is optimized to match Q,m.. v:due•• the osmo. gap .. f..ence interval would be near uro. c. On. cannot reliably interpret osmo. gap values if a labo .. tory has not d~ .. mined the rdation,hip betw«n paired values for Osm, and Osm.. for values d~ .. mined by th., J.boratory •• lthough markal incr"".." m ay be readily apparent.

[v.

Ev:duation of .. rum o,molality and osmo. gap. The major conap.. are ,hown in Fig. 9.13.

5"


Table 9. 16. Disorden and condition. thar a u"" abnorn,a1 .crun. oomolality or incrcued o.mo. gap. o~

Osmo. gap

Abnormal [solut~l

Disord~rs.

'lncr~

WRI

[ncr~a= in

[ncre~

Incrrasffl oonctntration of a nonanionic oompound other than urra or g1UOO5t Indicatrs a lrue hrpoomrmia

Stt ch~ Hyp
total ion con~ntration if th,,~ w"e illc...,..., ill cation ron~ntratiom oth" thall [N . +] or [K+]. Howenr. incrrases in [fCa'+] or [/Mg""] of2- 3 mmollL would cr.... t~ pathologic ,tates but inc..ast the ",rum osmolality by no mo .. thall 4-6 mmollkg. (Ifl.~ illcrease ill cation clt..r-ge colI~ntration could k m>lmed by all incr."... ill anion mar-g' con~ntmion. or by a r.duction in [N . , and/or [K'"]. ) A mangdo< ,,o" MD. Con A1'. 2002. H""' ........... and h"""W....ia --.doted .. ith ,10.."".. phuland p'~ ..ncd dfuoioo, i" • cat. Can V .. J .(},610-1}. 27. B,oitodo... odt ED. R..ot C R. 1m. I_pd.", "",rtioo. of ""tidiourtk 10,,,",,,,.,, in , .J.o&. J Am V.. Mod Aoooc

,aI K. 1m. Ptimuy bypa-aIdo.""",;"" in ..... """ I AmAt.i .. H",p Jw.oc J5,jll ...... l6. 58. ~,CE.. Robi ...... WF. Hort.bk CRR. I~j. !'.imaty . !dot"",,".m (COOn·. oydrom
i6 -~ Cl. €, ~

I".

1 -, ,I l' I i < ' I'

•~

Ii ~ 1 ~ I" , .' ~ 112 j h'. ~ !! " U 1 . ·.,~. " i."

. ,,~;, • I,,! "'" PI. 2001 . Drt..mination of "'" acid_b." ...... in loO hon.. admitted ..;t!o oolie ............ D«m> .... 1m and M., 1999. C.O Y" I 41,70}-707. lOS. au';""""", M'\l . Edfd,d, IH, E"... JW. 1990. Pro"yl"" pyool iov rtioD ca •• ", D·lactk ocidooi •. Ub Im'''' 62,)1 4-118. 106. Sa0,0

p.co, p.~ p.~ p.~

P~

pH Plo, P~

PO, Po,:>P~ P~

S.o,

SID SIDa-.....-. SID,_ SID. So, Sp~

tCO,

"SA WRI

SOl

Conumralion of x (x = an. lyll" oX)"g~n lension gradiem Sum or IOI3J of nonvolatil~ ~k acids Base exc;.,,,, in blood Base exc;.,,,, in exlrac;.,J]ular fluid Base exc;.,,,, in plasma C"bon monoxide G~u. arbon dioxid~ C"boxyh~moglobin

phosphate

Biarbo""l~

Hemoglobin D""xyh~moglobin

(rffiuccd hemoglobin) Hydrog~n phosphate 0xy\:"n comem P.rtial pressure of carbon dioxid~ in .ncrial blood P.rtial pressure of :olva>lar arbon dioxide P.rtial pressure of oXJ'C"n in m~rial blood P.rtial pressure of :olva>lar oxygen Pmial pressure of carbon dioxid~ - log [W ] P.rtial pressure of inspired oxygen Pmial pressure of oxy\:"n Phosphal~ including PO.:>-, HPO,'-, or H,PO,Phosphate Pmial pressure of carbon dioxid~ in ""nous blood Pmial pressure of oxy\:"n in ""nous blood P~rc;.,m h~moglobin 5aruralion with oXJ'C"n in m~rial blood Sirong ion diff~ren"'" Sirong ion diff~ren"'" using rorr«lal chlorid~ conc;.,n1ralion True sirong ion diff..~nc;., Sirong ion diff~r~n"'" alcu!.tal using x slrong ions P~rc;.,m h~moglobin 5aruralion with oXJ'C"n P..c;.,m h~moglobin 5aruralion with oxygtn of mcrial blood by pul.. oximetry ("pO i, fOr "pul .." oxim-

" , ,"" ,,, "" ,, '>-

,

".,..."."..-

--

-..

,

0 f>

W + Heo, "

H2C03 ~H20 +C 02(g)

~

,

" ,, " -',," -- , , "" , "

I H+ from metabolism

D. Metabolic alkalosis ----------------------------- 1,-,

- -

" ," ------------------""

~

E Respiratory alkalosis

f I

w+ HCO,

H,CO, _ H,eJ •

C02(g) expIred ~-~

- -

~g )"

" ,""

- ..,.'-

'- ,

, """".. ,, "" ,, "c ~

101

BLOOD GASES, BLOOD pH, AND STRONG ION DIFFERENCE

563

l. Bwm.. blood [H+] is ""I}' low romp.=! to [HCO,-] (mio .. 1:600,000), thi,

p""""ss does not low~r [HCO,-] unless thu~ is ace .. i"" g~n~r;Uion of H+, 2, It may ~ hdpful to con!id~r the bicarbonate ,yu~m going through H,CO, (Eq, 10,20), but th~ .ctu:ol reaction catalyud by c;orbonic .nhyd...e invol""s the diswciation ofH,O, rdease of H +, .nd r....crion of hydroxide ion (OJ-t) with CO, to form HCO,- without. H,CO, int~rmediat~ {Eq, 1O,2bj, Th~ .. ""tion is =",rsible, H + + HCO,- H,CO, H,O + COl((}

(IO.2a.)

H+ + HCO,-' ....... .......... ,H,O+ C O ,{, )

( 1O.2h.)

B, Hyption, [HCO,l ,..,will WRL

-=,..

564


Inspired Air

Tracheal Air

PIo,. 159 nmHg PIco, ....... 0 mmHg

Po,. 149 mmHg

P"o,-l00mmHg

Alveolus

Expired Air

P..,o . 47 mmHg

PAco, . 50 mmHg

PEco, < 50 mmHg

0, Venous Blood P~·40mmHg

-----------------r, ,

co,

P.,co,. 45-50 mmHg

Arterial Blood

,

P. o,_l00mmHg

,

,,

P. co, • 40 mmHg [H+) • 40 nmoIIL [Hea,l • 24 JT to Hgb (O,Hgb) to u,=t< th. oxyg
2. For th~ .. to k adaJuat~ oxygenation of blood, seve",1 pJ"OCCSS" in metabolic path"l>}"l. • CO, (from "",ubo~c p>thw.ys) diffuse. into pl .. ID1 10d then into . rythrocytos. Vi. tbe carbonic :mbydn>< (Gf) reaction, CO, and H,O .,. ron",,""" to HooJ-:md H·. 1be HCO,- moves to pWm1 in uclung. for CI-. Most ofthe W is buffered by the d.eoxyg.ted Hgb. Th. 00, proth> 60 mmH g (d .. b«lUfO'V). When Po, vol .... .,o > ]00 mmHg. tho So, .. ill ... neo.. 100 %. [ncn...d [H1 . incn...d orythro. wiU ,hift the o.trV< to the .. ight. If Po, " 'J" es " 25 mmH g. ",ttl. .. 26 mmH g. peopt. .. 27 mmH g. dogs .. 30 mmH g. rnd c. .. .. 34mmH g......

..,=

101


569

c. Som~ blood ga> instrum~nts calculat~ th~ So, from m.... surffl pH, p.co" and P.o, v:olu .. by using fOrmul:as that an~mpt to corr«t for umpentur< var;"tiom ~nd a compla formula that an~mpu to describt th~ 0, dissoci~tion curve.' Th~ colcul.tal So, m.y bt ~rronn>us btcaus. of ,,",umffl normal 0, .ffinity for Hgb and """mffl normal [2,3_DPGj.' {I} If th~ pH i. constant. but th~ po, d«r ......., th.n So, d«reases. {2} If th~ po, is ronnant, but th~ pH deer ....... (acid.mia), then So, d«r= If Po, is COlmant, but pH incr..,...,. (alkalemia) , then So, mcr ......,.. 8. PAo, (in mmHg): alveolar 0, pre ...... re {sometim •• abbreviatffl :as A} a. PAO, is the pani:ol pre...... r< ofo, in the :olveolu air (g:as). Two fOrmuw incor_ por.oting Flo, .nd P,co, con be uK
(IOAa.)

Complne: PAo, = Plo, - p.co, (1 - Flo,(I - R)) R wh~re PAO, is p. nial pressur~ of :olveolar oxyg 57G


10. alA (unitb'l is the arterial alvUsN by changes in body tentpc:rature or other f:>eto",? 4. If. loboratoty .. ports tempc:rature-corrected values. it mould also report the valu.. measured at 37 °C. If all in vitro valu.. are reported at 37°C regardless of the body r.mpc:rature. then changes in Po, and Peo, values will reflect changes in 0, .nd Co, content of blood.

T able to.2. Correction o f hlood gas and J:!H valu .. for variations in bod! temperature

'C

'F

,H

"40

105.8 104.0 102.2 10004 98.6

- 0.06 - 0.04 - 0.03 - 0.01 None

39

"

37

Notu", to air, th. n...dl. mun b. sralal with cork or rubb.r immal",tdy aft.. coJ]""tion. Air should not b. in the 'yring in blood gas v:dues but m.y cause significantly d=..sed [ft:a>+] and significantly increased [Cl-]. Lugrr .mounts :d", cau.. lower Peo" [HCO,-], [K+], and lactate concentration. and higher Po, {if b",.thing air} and [Na+]." B. Erroneow blood gas .nd pH v:du .. b.c.u .. of poor .. mple coll""tion or handlifIJ: l. Exposu", to .ir (induding .ir bubbl.. ) or acess h'p"rin in the ..."ple" a. The Po, .nd Peo, valu.. for arterial blood and room air .re different (fable 10.31. The Po, and Peo, ofh"".rin will b. the .,me as room air if hep"rin i. exposed to .ir. b. The Po, .nd Peo, of blood .nd air quidly equilibrate; th. blood Po, incr..... {unl... the p"tient is on 0, therapy} and blood Peo, d""rra .... The lou of CO, from blood cau... d""rra ... in the [HCO,-] .nd [H+] of the . ample. c. Net result: i pH, i Po" J.. Peo" :md J.. [HCO;] 2. Delay in sample anaIysi. or failu", to chill the sample adequatdy {but no .ir aposure} a. Aerobic metaboli,m of leukoo:yt.. and platdets cau.., d=....d Po,. Ba..d on ,tability ,tudies for equine blood p.o" an,,",l blood should b. an:dyzed within 10 min {if kept at room tem!"'rature} or within 2 h {if stored in ice bath}. Th. p.co, and pH we .. stable fOr up to I h at room tem!",ratu""" b. Glycolysi, in leukoo:yt.., erythrocytes, and platdet, causes increased W production and thus d""reased pH. c. Net result: J.. pH :md J.. Po,

T able 1003. Differences in Po, and Peo, values (mmHg) between air and blocity of the body and thus allows H+ to .ccumulot. {Fig. 10.1 B}. C. Disorders and patho~n= (S« Tabl. 9.10 and th. OUOOCi>lffl tat) l. Ex~ .. generation of H+: lactic acidosis (including rumen onrlo.d). kff"",cidmi., and ingtnion and meuboli,m of ""ruin compound. k.g., ""hyle"e glycol} 2 D«reased renal excmion of H +: reruoJ f:ailur" uroptritoneum, dj,uJ reruoJ tubul" acidosis (typ< I), and hypoaldosuroni,m 3. Inc",,=to!}' proa:.. of adding a r~nt to produce. given .ffect k.g., adding acid to d~.rmin. the concentration of. b...,}. Th. decr ... sed [HCO,-J is cmsed by buffering, not by titrating. HCO,- i. on. of several buff... in blood and i, used to asse.. alt.rations in the con""ntrations of buff.... 2. 5«rftOry fU"idq,ir. [HCO,-] decr.,..., because it is b.:ing lo,t from the body {e.g., excess salivary 10.. or proximal tubul ar acidosis} or not b.:ing produced {distal tubular acidosi,}. Th. hallmark of the.., .cido"," is the roncurrent hyperchlo .. mia. 5«rftOry i. an .ppropriate adjective wh.n HCO,- i. b.:ing secreted {e.g., in ..Iiv.}. However. in the context of th. tubular acidoses, UCTftOry is not.n appropriate adjective beca...., the decre=d [HCO,-] i. not caused by the secmion of HCO,into the tubular fluid. 3. Organk acidosis: Th. deer.... in [HCO,-] is linked to the accumulation of.n organic anion (' .g.,lactat., .""toacetat., ~.hydroxybutyr>te, or citrate). The organic anion may represent th. incr ... sed production of an organic .cid ('.g., .""toacetic acid) by metabolic pathWllY', but wmetim.. the organic .nion and the H+ a.. b.:ing produced by differ.nt pathWllY" {= the L.lact.t. section in Chapter 9}. 4. /lUJrganic ad,u"is: Th. dec ..... in [HCO,-J i. linked to the .ccumul.tion of.n inorg.nic anion {•. g., PO. or ,ulfat. }. Th. metabolic acidosis of renal fuilu .. is som.tim.. called an inorganic acidosis {due to t [PO.]}, but th ... also IIUy b.: incr ... sed concentrations of organic anions {'.g., citrat.}. 5. Di/r;tional ad,u,iis: [n the SID appro;;och to .cid.b.s.:: diwrd ... {... the Strong [on Diffe",nce section},. dilutitmlll adJolh occurs wh.n an exce.. of fIN H,O in plasma dilute! the electrol),!.. proportionately (•. g., decre .... both [Na+] and [CI-] by 20 %) . However, • 20 % deer.... in [Na+] (' .g., from ISO mmolfL to 120 mmollL) results in • gre;;oter absolut. decr= than the 20 % decr..... in [CI-] {e.g., from Ito mmoliL to 88 mmolfL}, .nd thus the SID dec=ses. In the traditional approach to acid.base disord."" the excess of free H2 0 also dilut .. the [HCO,-] and thus causes a metabolic .cidosis ('.g., from 24.0 mmolfL to 19.2 mmoIIL).

101


575

Some pmple ..ho comid" the hy!",rchlo"mie ..cidosis that is omS«! by the rapid infusion of ... line (IN.+] + [Cl-] = 154 mmoUL, but [HCO,-) = 0 mmollL) to ~ • dilutional ..cidosis, &oline is not fr.., H,O but does cont .. in ~ high .. !",rcular di50rde ..: right_to_left shunu (e,g" patent ductm arteriosu.) • A ,.t1tiY
[v.

Respintol)' alkalosis A. fUipirllttn] Illkal~lii is. pathophy.iologic nate in which. respiratory disorder depletion of H+ in blood .nd a deere • .., in blood Pco, values (hyJ>OC'lpni.).

COU'ieS

101


577

Table 10.5. Discases and condition. thai cause respiratory alkalosis (hyperventilation) Hypox~mia

(nimulation of ~riph,,:d ch~mor=ptors) {s"" T.ble 1O.9} Pulmonary di ...... {stimulation of nociccptin r=pton} Stimulation of respiratory cent~r 'Metabolic .cid",is Sqlticcmia (Gum nq;ati"") H~t nrnke or f"""r Drugs: ... Iicy!'tes and aminophylline Cent..1 nrurologic di~ t.. um., neoplasia, in!L.mmation, ccrd>rovaocular .ccident, and hq.atic enccphalopathy M.rnaniGll hy~rventil.tion p.in or .nxiery • A ,el1tively common di..... 0' condition Note: Wh.n determined by the i-STAT. the Peo, can be Wscly dCCRucd by the p''''''''''' of thiopental in the blood umpt.. s,,~=: tors (carotid and .ortic bodies) stimulated by hypoumia initiat~ hy~m::ntilation th at causes the increased loss of Co, and thus loss of H+. (Stt Table 10.9 for di ..a= .nd ronditions that Gluse hypoxemi .. ) Pulmonary di ...... may result in poor oxygtnation of blood {hypoxemia}, which stimul.tes h~rventilation. Ba:aUst Co, diffuse. more ..... ily than 0" hypc:rv~ntil.tion may caUst exccs.s loss of Co, and thus a respiratory a1ka1osi,. If there is acut~ hypoxemi., loss of CO, may k som~ha t sdf_limiting ba:....., th~ resultant alkalemia inhibiu respiration. How""", with chronic hypoxemia .nd respiratory alkalosis, the remhing romp«1"tory r.. parnes.

Fig.

respiratory or metabolic .yst.m, han romp"nsatro apptopriatdy. [f the data indial.1< that an .nimal has not achi""'" up"cted comp"nsation, th.,. may indicate the following: a. The animal has not had time to romp"nsate. Thi, i, e'p""i.Jly true of "nal comp"nsation for .cul< respiratory di""rdw;. b. Th •• nim.l has mo .. than one di""rd" that is alt..ing the ocid.ba.. statm, and thi, disorder is preventing .n exp<eCal comp"nsation. 5. To atuntpt to deurmine up<eCal romp"nsatiom in dog., eXp"rimenul ""id.I,.,. disorders were er•• tro and chan~ we", monitoral. Th. finding' ITom """,ral ""p"riment' we .. summarized in a r~i= aniek " data we" extractal from that article for T abl. 10.7. The proposed purpose of the rorrection f.cton i, to deurmine wheth" the changes in [HeO,-] or P,co, "pr...,nt a phpiologic comp"nsation to a 'ingle .cid.basCC< b.~ "",. mred and ap 8,

Th~

eseiJrultM compcll5atory factors in thi, sa::[ion a", for dogs and w... det~r. minM during exp 90 % ...ell whell O,Hgb p'rcentage daoreased to 30 %, bec.u.. the oximet.. does 1I0t diff... ntiate COHgb from O,Hgb. Similar but I.... """,re, f.l .. positivr interf.rence w .. S,""II with increasing con,entr>tions of methemoglobin. A> mown ill Eq. 10.5b, the O,Hgb p'rcellt>ge will dec ..... with illcr....ro collcentrations ofCOHgb or mffhemoglobin. C. III ho ...., the Spo, ulld .... timated the S.o, by.n average of 4.4 % whell S,O, was ~ 90 % and ov..estimated the S.o, by.n averat:e of 4.1 % whell S,O, was" 90 %.l1' The erro .. might ~ due to diff... nt prop'ni.. of .quine blood compared to humall blood. D. III dog, with S,O, of~ 70 % , the avrragt difference ~tw..,n Spo, and S,'" was about 3-4 % {e.g., Spo, of 87 % .nd S,'" of90 %}, dep'ndillg 011 applicatioll sit. (tollgue or tail) alld type of pro~ {ear or fillger}. The ...son for the diff..ellce is 1I0t known." As with the equine dot>, pul.. oximetry ulld .... timated the S,.o, when it v.as high .nd o""... timata! the S,O, whell it was low.

STRONG ION DIFFERENCE (SID) AND STEWART'S METHOD OF ACID_BASE ANALYSIS I.

Ev:duation of dectrolyte relationships led to all .hemate mffhod of assessing m=bolic (lloll... piratory) a.cid_b ... disturballce. (Stew:ln's quantit.tive .nalysis of a.cid_b ... chemistry) .nd the calculatioll of SID. A complete description of Stewart'. method .nd SID COllcepts is beyond the 5COp' of this book, but major asp«t. alld a compariso" with mo", traditiollal a=ment of acid_b .... disorders is presented. For a complff. allalysis of Stewart'. mffhod .nd SID. additiollal ..f..en= should ~ studied.""" III Stewart's method: A. Electrolyt. disturballCe! are approacha! ill the context of phy.iochemistry with consideratioll of equilibrium equations, con.. rvation of mass, alld balallce of charge.

101

585


B. Nontraditional ddinitions of ""id, and balO; ar~ usM. C. All da::trolyu. in biologic fluids >r~ considorw to b. involval in acid.b..., WLon"" and Jrulintenan", of d'""tric;;d neutr:dity i, uf"""Iw (Eq. 10.8a). [N. +] + [K+] + [f-, lacute, act:l"""'t>t~ . p.hydroxybutyrate, othor acidic anion. of m~uboli,m, and uOg-] + [Alb~] +[POr] ) - ([W ] + [NH.1 ) .trong cotions - strong anion. = w~ak aniom - wuk cotions [fSID,_ = "rong cotion. - 'trong anions Th~n 5[0_ = weak anions - w.... k cotions 5[0_ = ([OH"]

+ [H CO;] + [CO,>-] +

[Alb~]

+ [PO.'""]) -

([W]

+ [NH.+])

( lO.gb.)

(1O.8c.)

D. Analyees involvw in acid.~ bal.n", ar~ consid..al to b. e ith~r independ~nt or depend~nt variables. l. Th. independ~nt variabl...re those analye .. that are regulatrd or chang..! ind~pend~ndy of oth~rs: Peo" SID, and Arm (= th~ ddinitiom in th. nat "",,tion). 2. Th~ depend~nt variabl.. are thOR .nalye.. that chanets :as St.wart. loI Sin~r .nd H.ning,"': ddinw buff.. w,.,. which i. id.ntical to Stewart'. S[D.'

SID
mrn '"

Givtn Eq, 10,9a and 10,9b,

( 10.]0,)

SID_ = SID, + ([ft:a'1 or SID, =

+ [fMC"]) - [uSA] SID_ - [fCa1+]_ [f},1C ] + [uSA]

rdationship be.twttn S[D_ and th~ oth~r formulas u..d to estimat~ SID (Eq, ]O,9b----.,) varies with the analyt .. that a.. or ... not included in the formulas, It i, mo.. difficult to com!""" SIDa-____ with th~ oth.. SID formulas, How",,"r, th~ S[Da--.t would also ov.rellim.t~ the SID_ if th~ .. w~r. an inc=sed [uSA], C. Th~ ch:mCO' in SID valu .. that are ca.m by ch~nCO' in ",e:ok ion con"'ntr>tions can be >ttn by 'x.:Intining Eq, 10, Ila- f (Eq, ]0, Ila is th~ ... m. as Eq, 10,&), As shown in Eq, ]0, II~, chanCO' in SID, occur wh~n the .um of [HCO,-) , [Alb~), [POr), .nd [uSA) ch:mCO', L [f [Alb~) , [par), and [uSA) stay constant, crunges in SID, ..11= crung~' in [HCO,-) ; th.t is, t SID, ..1I«t, t [HCO,-) and thus a metabolic alkal",is, or J,. SID, rdl«ts J,. [HCO,-) and thus a metabolic acidosi" Ho~r, the rdation,hip betwttn SID, and [HCO.-J is less predict.bl~, or i, not present, wh~n th ..~ ... ch.nges in [Alb-), [Par), and [uSA], 2 Equation ]o,lle also mow> thot SID,_ depend, on two rruojor facto ..: [HCO,-] and [Aror], Thu., if PO, :md protein con",mratiofll do not change, chanCO' in [HCO,-] change the SID_, This is wh ..~ ch~ traditional . pproal""mic or dilutional

i ct-

HYP"rchloremic acidosis

"

Non.' Variable"

Mec.bolic .cidmis :md i [uSA]'

" ""

,l.

p.co,

;

; ; SID/SID,'

"

"," ","1WRl "

"It

"",;..bl. chmg.:

in

Na+

R.spiratory acidosis

Hypoolbuminemic . lblo,is

.lblo,is'-

acidosis"

Metabolic .cido.is and

i

[uSA]'

"

• If byp<rprottions of two ions m.y cou", a mixffl acid· b.... disord,,; for n:lmp[~, [ms of plasma H 2 0 could result in concurr~m hyper"". t .. mic alkalo,is and hyperalbuminemic acido,i., Th~ roncurrem alkaJosi, and acidosis in th. Suw:m method rai,es th. question of wh~th" th~r~ is noSIO",i, ,1O VI.

AI ru:omm~ndffl by lOm~ authon, SID valu~s should ~ imerpretffl with routine blood gas valu .. (pH, Peo" and [HCO,- j) to d~t~mlin. whether th~ ani"",l has an acid. b"", problem and wh~her th. probl~m i, respiratory or nonrespir>tory (metabolic)," Jl If the probl~m is • nonrespiratory acid. ba", disturb:ma., th~n th. contributions of nonbiearbon. at~ dectrolyt .. con bt explorffl with Stewart's method,

VII,

Prior to th. propoord USf of the strong ion theory, an und~rst;",ding of:m :mimal'. acid. ba.. :md rlectrolyte disord~r was obtainrd through the interpret.tion of pH , Peo" [HCO,-] , BE" [N . 1 , [K'] , [Cn, :mion g' P, .nd albumin ron""'ntration (Itt th~ prrcrdiIll:

101


591

Acid_B... Abllormaliti.. =:tioll .lId Ch ' pt" 9}. Evalu.cioll of such illform>tioll h ... provid.d . lId wiU comillu, to provid••11 ulld.malldillg of all ,"imal', pathologic nar..

VIII. Tho.. who study SID theory alld its . pplicotioll star. that th. SID .pproach r"'luir.. 'J>'Ci..-spa;ific valu .. for ATQT; th.c is, the sum of the colI~m .. tio", of 1I0IlvoJ.til. buffers, .. rum or pl ... ma proteills, . lId PO•. " AI; st.ta! "'rli" (ill Ih. pra::.dillg sea. 1l.B.5) .lId ill Eq. IO.II e, pl ... ma Aror collsists primarily of th. variou. alliollic forms of PO. alld proteills {albumill and globulins}. A. Th.", h . "" bn.1I art.mpu to calrul. r. pl.. ma ATOT valu.. for h",lthy cotd.,"'" dogs!' cots," alld birds." Th. calcuJ.t.d valu .. (mnll ± sd) w... obtaill.d by u.illg ",ttlu from ollly to dog., 10 cou, 12 pigwll', alld 9 colv.. (or pool.d bovill•• lId oville pl ... ma) . For most of the dola, the variatiolls ill the calrulot.d pl ... ma ATOT valu .. .. p.... m the a pect.d variations ill pi.."", proteill alld PO. colI~mralions ill such samples from healthy , "imal •. B. Usillg Ih~ calruJ.ta! me.1I pl ... ma Aror valu...lId m... ural [HCO,-], all SID value COli b. calcttlal.d (Eq. IO.llc). However because ther.... biologic variatiolls ill Ihe ",rum COllctmratiollS of PO. and pror.iIlS, a mean Aror value may 1I0t b. . ppropriate for all heallhy allimals . lId will ddillitdy 1I0t b. . ppropri. te for :mim. ls thaI ha"" abllormal pror.ill .lId PO. collctmratiollS. Also because of the lock of "l:retmem ill ""'"y dillical assap, pl ... ma Aror values calculot.d for 011. set of assaY' may 1101 b. appropriar. for . 1I01her set of assays.

Reference s

.I""""',......

t. Hruod. JW. Soot< MG. 1?99. Pb,oOol+] i, th~ ponion of [rCa>+] th.t is hormon:dly r~latM .nd contributes to pathologic sUtes. b. Anion_bound c,>+ {I} Bound to anionic prot~ins: About 40-45 % of tC~JIivdy ch ..gffi sites on prot~ins {80 % to :dbumin .nd 20 % to globulins}.' Sinct binding is charg. d.~nd.nt. changes in blood pH slightly :dter c,>+ binding . nd thus .+ ktwttn bound .nd frtt fractions. {2} Bound to nonprot~in anions: About 5- 10 % of tCa" is bound to citr>l". PO, . loct "'~' .nd oth... mall. diffusibl~ .nion5. 2 U.ing a filtration 'Y"l<m to "'parat~ prot~in_bound Ca>+ from oth~r c,>+ fractions and mrasuring [1Ca>+]. th~ distribution of Ca>+ fractions in 13 dogs anragal 56 %

111 CALCIUM, PHOS PH ORUS, MAGNESIUM AND REGULATORY HORMONES

595

Bones

Parathyroid glands Blood

· 1 ~Ca'+]

• t [PTH] • t [1,25-OHCC)

• "'" • 1 ]1,25-DHCC] Kidneys

Intestine

" ]ICa2'"] " ]Ca"/A-]

· 1 ~C"'+] + t [PTH]

Kidneys

.. -- .

. t IPO.J

,

. t [PTH]

"

" Mammary glands Fig. 11.1. IM1tio",hil" of calcium kinetics and tb. production of PTH and I ,25·DHCC. (No"': Ho,... kid ... )" lad I <x-hydroxyJu.: rnd thUll do not f[ion." b. Vitamin D enh.Dces Co" r=>rption from bon. by promotiJll: ost.ooa,(ic 'Clivi!), and by .nhancing =pon.., to PTH." c. Calcitonin blocks ostroclastic ostwlysis through dir""t changes in ostroclasts and by reducing activation of os{rption through th~ form.rion of calbindin, a Ca .... binding prouin in th. dinal nqJhron. b. Angiot~nsin II nimulot .. th~ resorption ofN.+ in th. proximal tubul~, v", a Na*. Ca>+ ootr.mpon ,ysum. Ca'" i, concurr~ncly r~,orbed. Co.'"':md PO, inur>ction. I. Th~ [lei+] and [pO.] in pla,ma ... gr~at ~nough in h~althy animals th.t C.,{PO, ), complex.. would form if inhibitors "-"lbumin~m", when Ihe animal does not h :IV~' defect in regulaling Ih~ [fC~""'] . To eslim'l~ Ih~ dfecl of lower prol~in and :dbumin concemralions, correction or adjusling formulas h. "" bttn proposed. I. Canine adjusIM [ICa""'] considering :dbumin con",nlralion (Eq. Il.l a)' 2.

Canin~

~n:rz.o

.djusted [rCa""'] =

m~~IUr..d

[ICol+] _ m.... surM [:dbumin] + 3.5 {± 1.3}

(11.1a.)

Example: If [ICa'1 = 8.0 mgldL &: [:dbumin] = 1.0 gldL; Canin~ .djusted [rCa""'] = 8.0 - 1.0 + 3.5 {± 1.3} = 10.5 ± 1.3 = 9.2 10 11.8 mgldL Im~rpreulion: If ch~ dog WlU not hYP""lbuminemic. its ,erum [ICa'1 would ~ from 9.2 10 11.8 mgldL in 95 % of conine sample•. Canin~

.djuslffl [rCa""'] =

m~~IUr..d

[ICo'+] - (004 X measurffl [TP]) + 3.3 {± I .6}

( 1I.Ib.)

Example: If [ICa'+] = 8.0 mgldL &: [TP] = 4.0 gldL; Canin~ .djusI. d [rCa""'] = 8.0 - {OA X 4.0} + 3.3 (± 1.6) = 9. 7 ± 1.6 = 8.1 10 11.3 mgldL Im~rpreulion: If ch~ dog WlU not hypoprol~inemic, iu ..,rum [rCa"'] would ~ from 8.1 10 11.3 mgldL in 95 % of conin~ ,ampl~. ,ulhors do not includ~ Ih~ "± 1.3," which i, ~n .S!imale of Ih~ 95 % of Ih~ publi,hffl dal .. b. The formul. ,hould ~ USffl coutiously for Ihrtt r=ns: ( I) Ih~ ~djuslffl [rCa""'] is .1 besl .n eslimate; (2) Ihe formul. v..as g~ner:l!ffl u,ing conine rCa""' and albumin con",mralions dff .. minffl by one..,1 of assays, and .n id~mic:d formul. would probably not ~ oblainM if olher :assays w..e used: .nd (3) Ihe formuJ. does not ronsider Ihe v:uialions in Col th. basi, for th. ,.f,ten"" inurval, u,a! to cw.u!jr ... ulu as incr••Krption &om bone and incrra..,. Ca>+ absorption in the intmine, Renal excretion ofCa' + m.y ~ inc=std becau,. h~rcal"'mi. cau..,. an incrrasal filtered load (more filter+ mobili7.;,lion from bon~ or absorplion in immin~ Incr ... scr PTH a=ys are usn! to det«! suppressal PTH production . ssoci.l excme excess dieta,y C .... Renal diseases that decr""" GFR impair renal excretion ofCa'"' and thut aouse or contribute to hypercal""mia." lowering dietary Cal+ intake by switching from alfalfa hay to gmt hay aon r..:!uce or diminat~ the hypercol""mia, but the impairal GFR l"",im." Alfalfa hay aon cont.in 2- 10 tim .. the Ca'"' ront~nt of gr:w or mix..:! hay." {2} Hypophosphatemia =y be p...~nt. {3} Ho,"", with hYl"rcal""mic renal f. ilure have a dec",as.d [iPTH]." b. Dogs . nd aolS with acute or chronic ",n. l dise... {I} Occasional docs .nd aolS with acute renal f.ilur~ are hYl"rcal""mic. Hyper_ cal""mi. m.y be du~ to an incr...... d ron""ntration of C." bound to citr.t~ or PO,. Rai.in .nd gr. pe toxicoses frequently result in hyperaol""mic .cute ",n.l failu",.'" {2} Of dogs with chronic renal f.ilur~, 10- 15 % are report":! to be hypercal""mic, which 'Pl"'" to be primarily du~ to binding of Ca>+ to retain":! anion •. " However, mon docs with chronic r~nal f. ilure have a low_normal to mildly deer.....:! [tC."]. Binding ofCa'"' to retain":! anions may also yield normocal""mia {[rCa'"'] WRI} that mad". decr""" in [£CaU]. 2. HYI""'drenocortici.m {Addison', dis"",,} in dOf:s .nd aots a. About 30 % of dogs with hypoadrenocorticism are hypercal""mic.' .... Hypercal_ ""mia has also been described in car. with hypoadrenorortici.m."-'-' Th~ r""son for the hYl"rcal""mia is not esrabli,hed but prob.obly is at le.. t partially aoused by decre;;osed renal excretion and might be aoused by increas.d C.'"' binding to protein or citr.te. b. Renal Ca'+ excretion in adrenalectomized dOf:s is dec ..as.d by excessi"" tubular reKlrption ofC? ... The reason for enhancM tubular resorption is not esub_ lished but m.y inml"" angiot~nsin II or corti",l deficiency. {I} When dogs with hypo. drenocorticism become hypovolemic beaou"" of mmiting, diarrh~a , or impair..:! renal con""ntming ability, angiot~nsin II a.ctivity inc ....... Angiotensin [] promotes Na+ r..orption in proxim. l renal tubul .. via a N.+-C.'"' rotransport 'Y't~m." Thus, enhancM resorption of

602

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY No.' may :d,o promo{~ th~ proximal rubular r~50rption of Co.>+ .lId cau.. hy""rcal",mia. Concurrent h.mocon~mra{ion ;t.df =1 ,lightly inc......., the ..,rum [rCa"]. {2} Administration of glucocorticoid. dot. inc...... tOruli excretion ofC,>+. Thu., • ddici.my in cortisol may allow more C,,'+ to ~ resorbd. 3. RupturM urinary bladd.r in foals: Th... foal. =1 d~dop hypercabmia (.uthors' unpubJishal data), but most do not. When pr... m, tho hyptrcalctmia i. probably cau~ by tho re;orption of urinary eo'+ from th. pu;rone:d Clvity. 4. Thi".id. diuretics: Th... :oct in the dinal lIq.hron to promote hypernatruria and, =ndarily, volu"", d.pl~jon. Hypovolemia promor.. . nhancnl proxim:d tubular resorption of No.+ and, =ndarily, proximal tubul" ,<sorption ofC,>+." Thiazide:! abo promot< th. resorption of Ca ' + in Ih. diSl:d tubule •. " This form of hYP"rcole;.,mi. is rardy repona! in dom+ in proximal tubul ... 3. Junnil ... onset hypothyroidism:" Thi. may be COUIffl by inaUKd int.. tinat.bsorp_ tion .nd dec,..,asaI renal ncr.tion of c...>+. 4. A maina! fetus .nd endometritis in • doC" 5. Idiopathic hypc:rcohmia: This wa. found in a group of colS that did not have rerocnizc:d hypercale;.,mic disorders. Som~ of the cats had calcium oxalat~ urolithiasis."

IY.

Hypocale;.,mia (T.ble 11.3) A. H)'I'O"lbuminemic hypocale;.,mia (hypoproteinemic hypocalcemia)' l. Hypocalcemia r.. ulu from. decmued concentration of nogativdy charged proteins and therefore of protein_bound c, ... The regulation of the [1Ca"'] would be adequal< in th... animals unbs then: is a concurr~nt defect in th~ regulation of the [1Ca"]. 2 It has b..:n called p"udo-hyptJ€ilktm;a becausr the [K:."] does not decrease and clinical.ing ~meropathy in dog, Dietary vitamin D ddici~ncy (rare) Vitamin D- rcaptor d.f'""t rickets (viumin D-Jq>ra. thyroid suu and hypocal",mi .. Th. dy'!unction may be due to two proc....s: {I} Mg>+ 4+ on the parathyroid cdls and thus a lesser [1Ca""'] is able to inhibit PTH ""retion." b. The.. m.roanisms may explain the hypocalcemi+I IP~

605

WRI WRI

11,25.IJHCq WRI liPTHI WRI

Fig. 11.2. 5.<J... nti..l ....na during tb. developm«x>ooory rm:d byp<rpautbyroidi,m in dog •. cats. and CI,d• . am" "'p",.. nt ",f.re~ in",,,,:. " for GFR OJ . .ch arulyt< con""n,mion. • lniti:d renal .wn.1l": n,. "'quem" of . ""nts desaibed in Fig. 11.2 initially compo".."" for th. +. b. Jntrav~nous HCO,- infusion. in cats" {I} Both th~ [iCa""'] .nd Ih~ [fCa"] ar~ rq>Onffl to ~ da:rnstd in som~ cots ra;tiving intrav~nou. HCO,-. {2} Th~ p"thogtnesis of Ih~ hypocaletmia woos not upl.inffl, but pcts.!-ibl~ m«hani!ll" includ~ d=~• .ffl C." .. wrption in proximal tubul .. ~u,," ofCa""' oomplaing with Uet... HCO,-, alkal~mia resulling in d«r......d [fC.'+] , or increastd .. nal Na+ ucr~ion coming concur.. nt hy~rcakiuri .. c. M~.bolic alkalosis contributes to th. hypocaJetmia of parturi.nt hypocalctmia in cattl~ by rfflucing mgt! etll r~spon'" to PTH." 3. Furo.. mid~ Ir ... tm.nt: Furos.mid. dir«dy inhibits N .+ .nd ct r~sorplion in th. """'nding limb of Ih~ loop of H~nl~ .nd thu.s ..condarily inhibiu Ca>+ resorption in Ih. """'nding limb ba:;ou,," th~ passive resorplion ofCa" d.~nds on gradi~nu mablishffl by Na+ resorption.'~" T hu., wh~n furo .. mid~ is used to promol~ diur~sis, hypocaJetmia con d~dop. Thi. calciuric df«1 offuro..c:mid~ is u..d Ih.. a~utically to 1",. 1 hypc:rcalctmia. T hiazide diumics should not ~ u..d in such ca... ~u .. thry actually promote Ca>+ resorption in the di+ binding with dilfusibl. anions I. Ca>+ binds wilh EDTA . onlal~, ot cilrat~. given syst. mically or presc:nt in blood coll«tion .yst~m'. 2. T ~I",eycline is a C." _binding agent, :md its rapid intra",nous infusion may low~r Ih. [fC.1+], but th~ [tCa'·) ",mains WRI.'" Ca>+ d~posilion during fractu .. healing: S
FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY und~rs{ood,

but loss of pro{~in.bound Co.>+ into

th~

intestinal Inet may

contrjbut~."'"

6. Myopathies a. Hypoc:olc;.,mia may occur in a ..:ui~ty of «iujn~ ffiyop. thi .. k.g., tn ntpon t~any, enrtional rh . bdomyolysis, enduran""-tr~ enrci .., mon.min {oxirosis. postan.,{h~jc my",i!i" m aUl!ffl holSt syndrome, .typical myoglobinuria, malignant hypenhermi a, .nd .d,"ium myopathy) ......... '., h. The path0C"nesis of th. hypocalctffi", Jruly bt multifactorial (e.g., d=UKd intah, inn.asal renal Joss, incroasN mo",ment ofCa""' into damag«i + Free: 4 Ca'"

pH = 7.5

Prol~ .,

bound: 6 C,.:'res th. effe.:. of the [l-I.] in plasma on the binding of Ca ' + to neg.tiy.,[y cb .~ pro",jn~ A similar efi'«1 oerun ..ith Mg'+. • At. pH of 704, thor. "'" Ca":ond H+ ions bound to pl .. m. or >
Phy>iologic process~. A. Pi rnsts ill diff~ ..nt form" deprllding on pH: H,PO. ..... H+ + H,PO.- ..... 2 H+ + HPO/· ..... 3 H+ + PO.'-. AI a pH of7.4, pralomirumt form, are H,PO.- alld HPO/-

616


Parathyroid glands amir.o __'Cl",~,_"-,,J_-. acid. ' + I [1,25-DHCC)

I (rca"]

+ fl PTH]

. t (PO, I

Intestine

+t (PTH) +1(1,25-DHCC]

Kidneys

+

Bones PO,

Blood

+

,b

+ l [l,25-DHCC]

,.....

--~,

Cells

'0,

,

:\' "Erythrocyte --'" :1 -

, po;,.

t di!uric ~nt. In the pr=n~ of PTH, less of filt".d PO, is "K1rb..i in th~ distal tubul ... PTH ;octs throlli:h ~ cyclic . denmine monopholphat~ m~...,ng" syst~m to inhibit th~ cotrallSport of Na+ and PO,. Absorption of PO, in imestines a. If ~nim.h are nting, th~n th.y wiU typically oonsum. lu&" qu . miti .. of PO, th>! are .bsorb.d in im.scines. b. Absorption is mhan=l by 1,25_DHCC, either directly or through Co'"' complexes. Resorption from bon~: PTH stimulot.. osta>crt.. l"pid dfect} ~nd osta>dam {ddaya! effect} to rd ...", PO, from bon •. Becaus< of th~ pot~m phosph.turic action of PTH, th~ rd~= of PO, d",. not increa.. the [Pi] .. long .. "n.1 function it adeqUOning phosphat. in SI units of mmollL. 2. Rehtion,hip bttWO'tIl [POJ and [Pi] a. I rumo] of H,PO.- weighs 97 mg. [n I mmnl ofH,PO.- th ... are 31 rug of P. Th...fo .. , a solution of 97 mgldL ofH,PO,- comains 31 mgldL of P. b. I mmol of HPO,J.- w~iChs 96 mg. In I mmol ofHPO,>- th~ .. are 31 mg ofP. TIm. fo .. , a solution of96 mgldL of HPO,'"" contains 31 mgldL ofP. c. B~u .. of th. equilibrium among th~ diff~"'nt PO, mola;ules at a pH of 7.4, I mmol of PO, a""rages .bout 96.2 mgldL D. Unit con""",ion for [Pi]: mVdL X 0.3229 = mmoliL (S I unit, n..,..est 0.05 mmoIIL)"

[[I.

H~rphosphat~mia rr.bl~

1l.4} A. D«..~..ffl utinary PO, ac..-tion. l. Oisorde.. that d=rasr GFR {Itt p.. renal, rrnal, and postrenal :lWtrmias in Chapter 8}: Hyperphosph . tem;" oa:urs ba:ausc: PO, is not filtered oodeqlL>tdy from plmm.

Tablc 11.4. Oi"""".. and condition. that cause hrperphosphatcmia D=rasrd urinary PO, excrrtion 'Oa;",asal GFR {S«: pmenat ... nal, .nd post",nal azotemw in Ch ' pter 8} Urinary bladder rupture or urin~ I~akagc: into tissues Deem=' [PTH] or activity (hypoparathyroidisnt) Acromrgaly Inc",ased PO, absorption from intestine Phosphat~ ~nrm. or in~ion of phosphatr urinary acidifier Inc",asal vitamin 0 (S«: Tablr 1l.2) lochrmic intestinall.. ions (may~ also mift from ICF to ECF) Dirt with ~ low Cal+: PO, ratio (rarc) Shift of PO. from ICF to ECF Myopathies: endurance: rid., in horses, aertional rh. bdomyolysis, malignant h~rth..mi. Acut~ tumor Iy,is syndromr Other or unknown mechanisms Hypc:nhyroidism in em uctic . cidoois Hypc:roodrenorortici.m in dogs • A rel. tively common dioe.... or condition Noto: n,. [Pi ] in gro.. ing ID1ffim:d.s m. y I>. up to 3 mgldl bigher tb1tl Pi ",!'.ron", intrrvili for .dul", of tl>. sprci. In vitro hemolpis or d.e1' J"'d r<mov.J of .. rum OJ plau= from blood .+ is bound to anions such '" citrate and PO,. B. Mg>+ is loc;;otal in bon.. (about 60 %), in 10ft ti ....... (about 38 %), ~nd in th~ extracellular Huid. including blood (1 - 2 %). EJt""pt in C>ttl~, th. [tM g"] in erythro_ cytes is greater th. n in pla,m. (or ",rum). e. M.jor factors that det..min~ th....rum [tMg'1 I. Hypoproteinemia deer ...... the amount of bound Mg>+ and thu, may cau", hypo_ magnesemia (d«r..,...,d [tMg'+] ). 2. Ab,orption of Mg'+ in the gastrointestinal tract'O a. In ruminanu. Me is absorbed by the rum~n (and mayb.: int5 KCOlldarily to d<errasN I'TH .Clivity.'" 4. Thytoxin~ t~nds to dn:reast th~ pl:lSJIla [tMg"] by increasing Mg'"' exc.. tion in urin~ and ~ ,., 5. Aldost~ron~ promotes incr~aIM f=l and urinary Mg'+ excretion. Exptrim.nully. aldoneron~ infusion> dn:rras.d ruminal Mg'"' .bsorption.'" CHcreaset! .ldost~rone activity inc",_s the ..,rum [tMC11 in one row},'" For tC'lany to ~ ""OCi.tM with hypomagne",. mi., concurrent hypocal"",mia may ~ required, 2, Calv.. on a whole milk diC'l can dcvdop hypomagnesemia beaUst Ihe dietary Me requi .. ment of growing cal.",. is about 50 % gr....ler lhan the amount of Mg'"' in milk.'· 3, Grass ICtany in cotde'''''' a, The hypom:ognesemia i, considerM 10 ..suit from decreased ruminal ab""rption of Mg'"', but there .'" multiple thcori .. for the .bsorption defn:l, b, A lush grass diet is high in PO, .nd K+ content .nd low in Mg" and Na+, In rome lIudies, Ihe combination of high K'" and low Mg" was Ihe key factor th.t led to hypomagnesemia. Olh.r contributing faCIo" in ""me COWl! include high nilro~n fo~, increa!ed diC'lary org. nic anio"" and high aluminum fo~,

624


T able 11 .7. Di""a..es or conditions thai cause h ypomagnesemia

• Hypoprol~ill~mia lllad«iuat~ rumiruol or intes{inal.b,orplion ofMgl+ • Prolongnl ano.aia or poor fN
:or.

nol cnablishM, but "'do,lcronc might ~ Ih. link ~tw""n K+ .nd Mg""'. Mg'" .bw'ption Jruly bt ralo=:! by factors ind.pend.1It of aldo,terone, such as the low N.': K+ ratio of rumen romcnu., t> d. Grass t"' :my is difficult 10 di>gllost postmon.m b«:.u"" of th. Jack of gross or micro,copic J..ions. A.ho, Ih. p"s[moncm pl:asm •• amples cannot bt u,rd for dct. e. Excess uri nary excrgnesium ion {Mg'"'}, fr.., magnesium ion (fMe), and toral magnesium ion {tMg'"'}. In clinical jargon .nd in =ny veterinary publiatiom, fMg'+ i. often called i~niud ma~'ium and it abbrev:i. ated .., iMg, iMg'"', or just Mg'"', and thm there is a pot.ntial for mitoommuniation. B. Sample: Mo. • group, Ih. [fMg'+] in the dog. with uncomplicatal di.btu. mdliru, was much more v.ri.ble (.ome low and some high) Ih:m th. [fMg"] in the h""'thy dogs. IMMUNOREACTNE PARATHYROID HORMONE (iPTH) CONCENTRATION I.

Phpiologic process." A. PTH is. polypqltid. hormone (84 .mino acid.) produ=l by p.rathyroid gunds and inactivaud or dq;radffi by kidn~ .nd li~r. PTH is = ..Iffl by parathyroid gland, in respon .. to • danaMd [1Ca'"'] in blood, wh.rra, vil:omin D .nd an inc=std [ft:i'+] inhibit synthuis of PTH. l. PTH sa:,etion is priJrulrily mediated by £lor activity and hypocalctffi", or hyp+ mobiliution .nd d""",.. ~ plasma [Pi) by promoting phosphaturia.

[I.

Analytical oonctpu for iPTH assay. A. RIAs d.-vdopM for human PTH h:IV~ suflici~nt .p«i~, cross-r~.ctivity to b. valid fur domestic m:munab." l. iPTH v:dues g~n">IM by RIAl for intoct PTH or N_t .. min:d fragm~nt' rorrd>l~ wdl with a~M biologic PTH activity. Ba:aUst som~ immunoauays may r.... ct with preproparathyroid hormon~ . propa.. thyroid hormon~, intact PTH, or. PTH fragm~nt, th~ an:dyr~ of these .uays con rolJ""tivdy b. callM immunomutiw PTH (iPTH ). Only if th~ =y wa, 100 % .p«ific for intoct PTH v.ould [PTH) ~ual [iPTH). 2. iPTH ....,... t~nd to b.limitM to ~ndocrinology and larguble if the .ample remaim frozen during .torage or transit.'" In • subility study at 21 'C and 37 'C, the .strum [iPTH] remain.d nabl. for 2 d with two prot"'" inhibito", {Pefabloc SC and 4_[2-..minOHhyl]_berrz.ene=>ndary to decrnsed [ft:.""]}. B. Howt""r, many dog> with hyperra1cemia due to primary hyperpamhyroidism do not have.n increas.d [iPTH). Insttld, the [iPTH) is WRJ but inappropriatdy high in relation to an incr~ [fC,>+), thus reHecting a defecti"" neg.ti"" fttdbad: on PTH secretion C. In one study, many dogs with hyperadrenocorticiun had unexplain.d iner.. ",s in plasma [iPTH) and concurrent normoca1cemia.'"

IV.

Ckcrea..d """m or plasma [iPTH ) (Table 11.9) Table ll .8 . DiseUC5 or conditions that cau.. increased fir T H) Increas.d PTH production by naJplastic cdl. NaJplastic pamhyroid gland (primary hyperpamhyroidism) Multipl~ endocrine neoplasia (type I or 2A) Increased PTH production by hyperplastic par.lthyroid glands (idiopathic or >=>ndary hyperparathyroidism) 'Chronic ren.! dis ..... Diet with a low Co... : PO, ratio Hypocalcemic di",rd ... (with a decreas.d [fC,1+)), other than hypoparathyroidism Pstudo_hypoparathyroidism {decrrased PTH receptor re.pomivene ..} Hyper.drenocortici.m in dogs • A ,.ll1;""ly rommon di..... or ronditi"" Table 11.9. Diseas.. or conditions that cause decn:ued fir T H] Decreased PTH production due to damaged or removed parathyroid glands (hypoparathyroidism) Decrrased PTH production due to inhibition Hyperviuminosis D Hypercalcemic di",rde .. {with an inc ...... d [ft:a'+]} except primary hyperparathyroidism Hypom:ognesemia due to Mg" de ple"lion

628


PARATHYROID HORMONE-RElATED PROTEIN (PTHrp) CONCENTRATION I.

Phpiologic proa=. A. PTHrp promot~' C~lllcif.rol (vitamin D,). Vitamin D, can .1.0 bt of ditor asiaY.'" The assay uw;. viumin D r=:ptor from calf thymu •. The [1,2S-DHCC] am b. measurrd also by a

RIA.'''''''' 2. [25-HCC] con b. m.... surM by R1As, though the :mtibody might oms_r ....ct with 1,25_DHCC.' It am also b. measurrd by. prot.in_bindiIll: ....y.'" 111.

B=use of th~ limitrd availability of 1,25_DHCC .....Y" thue a.. f~ rq>rts of .bnormal [1,25-DHCC] in domestic IIUmmals. Th. following lim ... ba...d on .. ponod or aprctM conuntr.uion! in various di,ord .... ' P05Sible r.latrd d~f«t. in I ,25_D HCC pathv.ays "" within parenthes ••. A. lncrea.od [ 1,25-DHCC] aptctrd or rrponrd l. GranulomatoUl di",...,: Macrophage:! IIUy produa: 1,25_DHCC. 2. PrillUry hyptrparathytoidism:'lO PTH promotes let_hydroxylase activity, which =ult< in incr.... rd 1,25_DHCC production. 3. lymphollU .nd other HHM di"'rd~n:'U" Either PTHrp promo"s let-hydroxylase: a.ctivity or neoplastic cd], produ"" 1,2S_DHCC. 4. Viumin 0 intoxicotion:"· 172 inae• ...d inuke. 5. Vitamin D-=ptor d.f«t richtmd.

l. (kn.] f. ilure, induding prouin_losing nephropathy: This may ~ CJUIM by

2. 3. 4. S, 6, 7, 8. 9,

dre,.,....! functional renal riMue .nd th.",fore deere.=' production of 1,2S_DHCC, or by a lou of the vitamin D-binding protein .. '"'''' HYP",phosphatemi. not causal by incr•• =' vitamin D: Incr.......:! [PO.] inhibiu l a-hydroxyl"", .ctivity. which dao,,,,,,,,, 1,25_DHCC production. Hypom3i:n=mi.: This may cr..,• • pstudo_hypoparathyroidism, which dre,,,,,..,. I ,25-DHCC production, or hypomagno=mi. may impair PTH s«mion. Hypopuachyroidism: L... PTH activity c;m= l~<s l a _hydroxy\= activity, which d""rra= I ,2S-DHCC production, P.. udo_hypop.r.uhyroidism: uss ... porut to PTH caus.. l~ .. Iet-hydroxyla .. activity, which d""",ast. I ,2S_D HCC production, HHMJth yro idi!JI\ Humonl hypC< int References J,

Eod... DB, R...k RK. tm, Min .. '! aod bon. ... ,taboIi.DL]'" lIurtio GO., A.b......J ER. cd •. T"", T_.J.

ai""./ o"",u",.. 3..1 edition, 1}9l-tWh- 1%oIO}-IOS. 32. M ..."" DI. Pric< SM. s.a.. RM. Krook L 19~. Gaatric wciDoou...ru. p....d.obyp«paopacti", ....tu.ti.on of 4J (1991r-2002). J Yrt I"""" Med 19.66J--6N.

DG. T.,...,..

do,.

634


59. Sd"..c1 PA. C ..... DJ. 2003. Drt..n.inatioD of calcium &",tionation in D<mtoatiooo io two dop wi ... proti. in fo •• cato. I Am Y" M«l A.ooc 215,) 127_1129. 79. YOURJ: DM. Capm. CC. Block HE. 1971. Calcitonin Kcivity in..ltimobtand.ial noopl .. ",. fro". buJI •• Y" Patbol 8,19-27. 80. Fmu' CK. 1998. O1ootd, .. of colci.," m".bol.iom. In, Rud SM. B.yly WM • .do. bj. ;"'/."",J MuIid.,. I_ odidoo. 92j....9Joj. Ph.il.ddpki", WB Sawod .... 81. I""'" LF. 1999. HoJovtoo poiooninc; in ~ I Not To";", 8,J9s-toJ. 82. c"...,."ll WA. Whitlock RH. Sto., RC. T p.. DE. 1979. Edo.:rI=' dyoool. toxioooio in conk. Co""ll Y" 69,272-279. ...d cat. I Am kim Ho'l' A.ooc 8J. G .."", GF. TI...n MA. 1982. Edo.:rI=' w=1 (""'""'=) poi"";n, in .... 1s.l92-t97. 8t. G .."", GF. TI...n MA. H""" SA. G.."", RM. Hamu DW. 19I1-l. hdy dinioopatholo"" 6 .... in,. in in",";"'; ,th,"'" dy=!. Am I Y" Reo 45,2299-2303. 85. a..... DI. Lro .... d M. Mui. W HI. 1989. Eif=t of.....tium b.who..... in~ on ioniu
rr

do,

do,.

oooe< 21 h ll92-139S. 9J. Vad,o SL li.e hn=PI•.,. pl"mnia, hypocok.mia and h~ io • cat . I Am kim Ho'l' A..oc n.J9.--.oII. 9';. Gucia_i.opni oyndrom, .uod"od .. id. ,,0.1 d,. pb.ti. io "'" ..... "'" ,,,,,;,tL j Y" [ot<m. Mod 10,,12-419. IR. Btrtttd.w,.J, EB. 1976. Gluoo •...;... ooci.tod .. id. "",I tnbuIat dytfuncion in du«!laomji doJ: •. I Am Yrt Mod A.toc 16S,9}S-94}. Bo..It KC. jJ"to< in pu ....yroid r1 •."J pby';"J.v. Am I l'h,..iol Rcnal PIoy';"[ 286,FlOO5--F10 II. 160. R..m ......yl. 2006. Rocm.,""""",, in pb,...lot;ical aid ........ "'oootasio. Cli" o., m lob Mod « ,lJ7- Zl}. 161 . E.tcpo IC. Gaolia B. Goo PR. C&nto. T. R"d,;"", M . Apill, .. T oj,,,, E. 200}. Validation and cli..ical ~tilition

alblin. phosph.t= Co'lirosl~roid·indua:d alkalin. phosphat= C,ealin. kin""" C.nin~ p:mc""lic lip""" immuno"'.ctivily Enzym~.linhd immunOlOr~m :way Fdin~ p:mc"'~tic lip""" immunorexlivily Glom~rula, filtralion r>t~

GFR GGT

I·ALP ID L·ALP LD

cr~~linin.

.d.nin. dinudO

.. 5 h (conine)'" 7- 8 d (~quine) '''''u, < I d (conine)"""

.. 2 h (equine) 'lt,'" < 2 h (conine) '"

.. J d (equine) '"

.. 14 h (oovind" .. 4 h (conine)''''

< 6 h (conine}""

.. 2 h (conine)'"

wurces

a vitamin sourct (e.g., P_S _P from vitamin B" and NAD from ni:ocin) but also may be ions (e.g., Ca'+, .nd Mg'*). I.

Sou=, of .. rum ~nzym .. (Table 12.2 and Fig. 12.1 ) A. Serum ~nzym~. deocrikd in this chapter originate from cdl, (nogtocyt .. (ALT. AST, GGT, GMD. 10. LD, . nd ALP). bj~ary epith.lial ""It. (ALP and GGl), .hle"J ond c:udi. e mwcl< /ib.rs (CK, ASf, LD, :md Ai 1), ost.oolans (ALp). :and pone,,,,tic acinar aUs (AM.'>..,d LPS). In vitro of AST.oo LD from ded rm:ymes rnd .nzymtM on the ,,"ruJirular tit.., th. ,inusoid.J "",mbnn«1 from th< .inusoidtJ membn .... St i, not applicoble unless th~ cdl. are cop"ble of quick rq>:Iir to limit th~ 10.. of ront~nU. B. [ncr~'!ffl ~nzym~ production by individual cdl. b=iu.e of induced .ynth~s.is l. This is th~ prim.,y mechanism for membrane enzymes and may ~. mechanism for mitochondrial .nd cytoplasmic enzymes. 2. buiucrion r~fe", to a nimulated incr~= in production of the enzyme protein via modifial transcription, tr:mdation, or othu processes. Endogenou •• ubnances (e.g., bile acids) or drug•• urn •• phenob.,bital, prednisolone. or prednisone m.y trigg~r induction. [ncr= in .. rum ALP activity r~SlIlt mostly &om induction (Fig. 12.3). C. Mor~ ~nzym~ produced by a ti!S\l~ b=iusr of ""U prolifer.tion, pmicularly for m~mb.. n~_'HOCiatal enzym .. l. NwpJ:..ia of the enzym~·s cdl of origin (e.g., increased ALP and B_ALP with o.tw ... rcoma, or increa!ffl LPS with pancreatic or extrapancre.tic nwplasia) 2. Hyperplasia of the enzyme'. ""II of origin (e.g., increa!ffl GGT with bile duct hYl"'rplasia, or increased B_ALP with bone growth or repair) 3. Convtrsdy, d~cr~.sed tissu~ mass may ~ associated with decreased .. rum enzyme activity or con""ntration (~.g., TU with p.ncreatic .trophy). D. Enzyme r~mov:ll from pI..,,,,, is decreased {enzyme has.n increased half_lif~}. l. Some enzym .. (e.g., A,\.lS and LPS) .,~ inactiv.ted or acr~tal by kidneys. Decreased r~nal blood flow l~.d. to d~cr~.sed ina.ctiv.tion of AMS .nd LPS.

121 ENZYMES

645

2. Some t< drivtional units, because .. bitrary uniu may b. ddined by mark«ily different ......y conditions. It is difficult to impossible to mnwrt the arbitrary units to internation.l uniu acruratdy. Fortunatdy, moJl current methods haw been defined in international units {UJ. 4. The international unit does not normalize methods. Different assays may measure different amounU of enzyme activity in the same sample. a. Because of v:uitions in some assay methods, enzyme .ctivities mrasu...d by two different assaY" may b. markedly different. Figure 1.5 ilJumate. the nwk..d differences that can b. found when one s.omple is analyzed by diff• ..,nt method •. Thus, aCetIrate interpretation of ... rum enzyme activity requires th at patient

121 ENZYMES

647

Table 12.3. Approximate changes in enzyme activities if Ihe .ame ,ample is analyzed al differenl assay lemperalures 25 ·C Common

~nzymes"

60-80 %

Rd.tin ~nzym~ ~ctivily al 30·C 32'C

"''''

110-125 %

37"C 130-210 %

• Including ALP. CK. lD. ID. ALT. and AST No..: Clunges :or«l on 'eported oon...."ion net""'.'" In 2002. th. In .. m. Oorul Fffilalyzes (e.g.. mlll,fer .mino group = lransamina .... lransf.. phosphate group = kin ....... nd oxidizc or r90 % activity .. mains} in equiM .. rum lOr up to S h at 21 ·C, 24 h at 4 'C, and 48 h at - 30 'C; 73 % of ID activity w'" lo.!! by 24 h at 21 'C .nd 28 % was lost by 72 h at 4 ·C.' c. hoenzyme LO-5 i. heat labile, wher.."s LO_l is cold labil~. It is best to leave. sample for LO analy.i. at room temp""ru", and analJ'Z" it within 24 h. d. Some ALP isoforms ar~ h~t labile (B_ALPj , whew.. oth... are heat suble (I-ALP .nd C_ALP). Thaw.-d .. ra may have greater ALP activities than fresh .. ra. e. GGT activity in hep"riniud equine plam'" w'" suble for 1 mo at - 20°C'· C Sampl~ quality l. s"ra or plasma with hemolY'is may yidd errOnalllS results lOr thIN =sons. a. Enzym.. of erythrocyte. may b. .dd.-d to .. ra or plasma to inc=sr activities; lOr nample, incrras< nJ ... ocrur~ atiti., cirrho.i. lnh..iud: ropp...ed by both .peetral in!erfer~n"" and the addition of ALT from th~ ~rythrocytes," In . noth .. study using canin~ ",ra, Jrulrko-d h~mol)"is had no effect in som~ assay' and a moderau df= in oth~"" '4 IV,

lncr~

A,

B,

C.

D,

",rum ALT . ctivity (Tabl~ 12.4) Hepatocyu damage (",,,,,,,,ible or irr~er1ibl~) may occur bc:cau.. of a vari""y of insult. (inflammation, hypoxia, toxicants, trauma, etc,), Al T Jruly be: rd~ased from hq>. tocytes also during reparati"" "ages of liver di ... "" lnn~a ... in amin~ ",rum AL T activiry th.r ..~ associated with glucoconicoid th~",py Jruly be: caused by glucocorticoid_induced h~patopathy inst.,d of true ~nzym~ induc_ tion, Glucoconicoid. did not increasr ALT synthesis in cultured hq>atocytes," Canin~ ",rum AL T activiry may be inc",asaI in dog. t",atM with ph~nobarbitaL In a study involving 12 phenobarbital_tre>ted dogs, data from th~ histopathologic examina_ tion of li""r and ch~mical .nal)"is of li""r homogtnat .. indic;>ted that induction did not cau.. the incrra~ ALT .ctivity," Spont.n~ous mmde damage: typically is nO! associated with increased .. rum ALT activiry, but incrrased ALT activity d"". occur with "'m~ musd~ di...ases in docs .nd c;>ts, l. Young dogs with musruiar dystrophy may h. "" marknlly increased .. rum CK activity (::> 500 X URL) and have mild to moder.t~ incrra= in ",rum ALT activity « 7 X URLj,l7 11 Som~ dystrophic docs occasionally hav~ extr~m~ AL T incrra= (values 20 times a. gr~at a. those in nond)"trophic docs in the same rolony), 2, Dymophin-deficient c;>ts with acute rh alxlomyol)"is had m. rko-dly incrra~ C K activity (89- 2000 X URL ) and incr~a..d ALT activity {6-19 X URL),"

652

V.

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY Spm~. diff~ .. nct' A. In dogs :md catiologic process~" oo""qm, :md facts: AST is a cytoplasmic and mitochondrial ~nzym~ th at catalyzes • r.ve",ibl~ rraction invalva! in the deamination of "'p.nau to form oxaloa=at~, which can ent~r the Kreb, cycle.

II.

Tissu~

III.

Analytical oonctpn: Oth~r than v.riations in .....y t~m~ratures, variations in .. rum AST activity ar~ minimal :mlong asiay syst~m. if ... ult, are rq>Ontd in UIL. How"""r, as for AL T, assay m.thods including the cofactor P·5·P may gc:n.rat. diff.",nt results from th""" lacking P·5·P.

IV.

IncreaK
",urct' of in"'~asal .. rum AST activity and AST half.lif~ .'" li. group C was in rtmi ... ion. and group D had recurrtnt di......,. Th. dogs in group' A. B. and D had grtattr ptrctntages of LD_2 .nd LD_3 and low~ratdy, it i. hdpful to considor th~ diff~ .. nt isoforms of ALP wh~n intorpming ALP activity. C. Th~ rdatin contributiofll of th~ diff.r~nt ALP isoforms to total ALP .ctivity can be, d~wminM by ~nzym~ d.crrophoresi., sd""ti", inhibition, th~rmal subility, or ..,]""ti... pr""i pitat ion.' I 's-"" I. Affinity d""trophoresi. i. the connntional or stand.rd method but ..quires 'I""'ial "'Iuipment and i, tim~ and labor inl<nsi",."" L-ALP, CALP, .nd B_ALP am be, id~ntifi«i in c;onin~ .. rum. 2. ~isol~ .d""tivdy inhibi.. L_ALP .nd B_ALP activity, but CALP is rdativdy resistant. Mumr.m.nt of strum ALP activity with .nd without the ~ddition of Irvamisol. can hdp d"~rmin. wh",h.. mum of the strum ALP activity is du~ to CALP. 3. CALP it ..lativdy h""t nabl~ at 56'C :md 65 ·C, "'n~= L-ALP :md B_ALP~ .. h~ .. labil•. M~asur~m~nt of strum ALP .ctivity prior to and aft .. incubating strum in a h~."d waUr bath em hdp d~t..min~ wh"h~r mum of th~ .. rum ALP .ctivity is du~ to C_ALP. 4. B_ALP .nd C_ALP .'" stl.crivdy pr""ipitat«i by wh~at C"rm I""tin, wh~reas L-ALP i, not. ALP .ctivity be,for•• nd after th. pr""ipitation am be, usn! to ...imare B_ALP activity when combin«i with d",ormination of CALP a.ctivity by I"",misol. inhibition.

[V.

Incr.....d .. rum ALP .ctivity (T.ble 12.6) A. Cholmasi, {intrahepatic or p!th.patic} I. [nc",astd ALP activity 'Pp'au to be, primarily caUstd by iner•• """ production of L-ALP by hepatocytes .nd biliaty epithdium during obstructive mol.stasis. It is not known wh"hor ALP production is increastd in functional molestasis (..., Chapter 13). 2 M.ny di ...... l~ad to imp. ir«i bile flow, which leads to .n accumulation of bil~ acid, in hepatocyte.. Incr~..«i bile acid con""ntrations stimulal< L-ALP production, promol< accumulation ofL_ALP on sinusoidal hepatocyte membranes, .nd .. ~ linl.:«i to iner.. """ strum ALP .ctivity {Fig. 12.3).""'" Bile acids may promote L_ ALP rd..... from the hepatocyte membranes by promoting .ctivity of g1yco,y1phos_ phatidylinositol pho,pholipast D ...." 3. [n mol~tic or posmq>atic (L_ALP) ·Degcn~r.lli ... : necrosis or hepatocyt~ ,vidling tru.t l~",h to impaired bile How 'M~ybolic: lipidosi., diaktes mdlilUl, hy~radrenoronicism, choldithiasi. 'Neopla.tic: ba~ duct carcinoma, pancrutic cucinoma, lymphoma 'Inflammatory: ~riporyl hepatiti., cho!."'giti., choungioh~patiti., panc"'~titi. Toxic: pyrrolizidin~ alkaloid-amYining pum., alsik~ do... r toxicity, .porodesmin toxico.is Induction by drugs or honnon .. 'Ph~nobarbital, dil.min, primidon~ (L-ALP) 'Corticosteroid. (L-ALP and canin~ C_ALP): cndo~nou. or exo~nou. 'l1tyroxin~ (B-ALP): fdine h~rthyroidi.m Increased o.teoblastic activity (B_ALP): onoooarcoma, f.. ctur~ repair, riam Canine mammary neoplasm., knign and malignam B~nign f.mili.l h~rphosphata .. mia in Sikri:m hun:i .. • A rel. ti",ly oommon dioe ... 01 a",dition Notithdial erll, in m ammaty neopl:um, do h:IV~ ALP .ctivity." &rum ALP activity in dog, with oth~r neopl:u.ms wa. not ..... ssal. E. B.nign familial hyperphosphat=mia in Sib.rian huskies" I. Of 42 pups in eight rdatM litt~" of Siberian huskies. 17 pups had .. rum ALP activities .bout six tim .. the activities found in oth~r ~_matchM Sib.rian huokies. B_ALP wa, the i,oform cau.ing inc ...... d total ALP activity in.ll fi"" of th~ puppies for which isofornu wer~ a=ssal. 2. Th~ alUX of the incr .... xd ALP w:u not detuminM. &rum rona.ntration, of total mkium. inorganic pho,phoru •• and parathyroid hormon~ wtr~ not diff~'""nt &om tho .. of m atchM pups. F. Pregnant women IIUy have an incr .... xd .. rum ALP activity b.cau.. of incrnxd plaerntal ALP. ALP .ctivity did not incr.. ", in pregnant nur ..." Th~ incr~.'" in .. rum ALP during p'""gnancy in bitches i, too smaU to .ff~ ALP intuprffation." Plaerntal ALP m.y rontribut~ to .. rum ALP activity in th~ l at~_tum pregnancy of ailS."

ru.vt

h.""

v.

Speci.. and brttd diff~ren= A. Dogs I. ALP ha, high di3i:nostic sensitivity for dff~ing rnolestasis. ALP .ctivity may b. iner .... xd b.fore ict~ru, 'PP"'''. ALP valu~, may range &om < 2 X URL to;> 20 X

URL 2. Inc,""asffl ALP activity inducal by rortioost~roid. result, from inducal synthelis of l-ALP and C_ALP. ALP values may rang
ahih

PhcnobarbiuJ, dilantin, primidonc Co'licosuroids: cndogcnou. or rxogcnou • • A ",t"ivoly common dis. ... or condition.

Noto: lng,";on:and absorption of colltnun by ....,...,n calves and PUP' m.y inc ....... rum GGT activity.

[I.

Tissue rourct, of inc",asal..,rum GGT activity:md GGT half.lif. "c iislw in Table 12.2.

Ill.

Analytical oonctpu A. s.rum GGT a.clivity vari .. minimally :nnong ......y .y&cms if result< arc .. porlM in VlL and ... ay tcmptntur. , "c the sarut. B. In .. srudy involving rat sampJ.. , hcr:uin was mown 10 nearly double Ih. GGT activity in an a=y u•.d r_g1utomyl.p_nitroanilid. as a substm~."" H~parin ~I.lO am caUst

cru.1

reaction fluid, which v..ould int~rf~" with tnn!JIIission photometry.ll Th~" w!" .. rum CK activity th,n adult docs. Comparal to adult dog. (> I yr old), the mnn CK activity WlU about 60 % ~a{" in the 6_ to 12_ ffio.oJd doC" 280 % g,ra,er in th. l _ to 6_mo-oJd puppies, and 410 % great" in puppie, less than I mo old." Also, th. me.n CK activity in small_brttd dog. « 10 kg) ~ about 70 % than activity in larg~breffi dog. (:> 25 kg}.'" Physiologic explanation, for th. "i:" and lxxIy.ju diff".nces w... not fuund.

gr..,.,

KlU'''''. of inc",asffi ",rum CK activity and CK half_life are li,rN in T .bl. 12.2.

[I.

Tissue

III.

Analytical oonctpu A. Orher than v.riation, a1~ by differences in :way I.m~r>rures, .. rum CK activily ha, minimal varialion among ''''''y 'Y'1~ms if ..",h. a.. rq"Jn«i in UIL The an. lytical r:m!';O' of som~ comm"cial =ys are 100 narrow for "'m~ domenic mammal" and Ihu, .... fr"'lu~ndy may nm to b. dilUl«iro oblain numeric resuh, when CK .ctivily i, incr~..«i, B, In .. mples from healthy dogs, Ihe CK activily in strum sampl.. i, about 2,5 lim.. thaI of pla,ma .. mples," Th~ diff~ren"" may b. c;mstd by Ih~ rd..... of CK from platdcts during clolting," conine pl'ld~u h""c b..n ..""rt«i to contain CK .ctivity," Thi, diff..en"" m.y not b. clinically rdevant when the incrn.. in CK aClivity is moderate to mark«!, Incomplff~ r~mov:d of plaldm from plasma could lrad ro mildly inc......d CK .ctivity, C. Canin~ CK a.clivity in pla,ma WlI5 nabl. for I wk at - 4'C .nd for I mo .1-20

-c,"

IV,

Inc=std .. rum CK aClivity (Tabl~ 12,S) A, A v.ri~ty of insults {pathologic and i.lrogtnic} may damage muscle fikrs .nd cou.. th~ rd...... ofCK from muscle fikrs, CK may k rde....d b«au.. of na:lOSi, or ..""nibl. ""II damage,

Tahle 12,8. Diso,den or conditio"" Ihal cause increased C K activity Musel. ~ (mosdy .kdel:d, ocauionally cardiac, r>rdy unooth) ·D"tgt. 2. From a .ingl~ insult (• .g .• recumbency or other traunu). there am bt vuy rapid inc= (hours) .nd a rapid dedine (hours to da,...) brcau", of the short C K half_life. B. Mild to mark~d inc=ses in serum CK .ctivity were .. ported in .no=tic cots with n ..oesoph3l:e. 1 tubt •.17 The exact p"thogtnesi. of the inc""ased activity is not known but prol>.obly involves muscle damag lOx URL}, b, In em with 'pontalla ",s paner~.titis, .. rum AMS .ctivities rang.. from WRl to mildly incr.,....! {< 3x URL},'· '-'" In a~rim~lIIal pancr~.titi. in six em, .. rum AMS activity did not illcr.... ~.'·, c. M~asur~melll of .. rum AMS activity has not """n u..ful for di"l:nosillg panc",_ atitis or other di ..as .. in hor... or ",nle. 3. P.ncr.,.tic lleoplasi call .lso I~:od to incr~...d .. rum AMS activity. B. D~iologic process.., concepts, .nd facts A. I'IIncrrilfic LPS is a cytoplasmic enzyme that r~qui ... Ca'+, coli!""", alld bile sal" as cofactor>. It "'taly= th~ hydrolysis of triglycerid ... Th~ panc"'.tic LPS mol«ul~

'"

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY (M, = 48,OOO) and colipo... ar~ ,maU ~nough to p .... through ch~ glomuular fihmion barrj~r 10 be, inactiv:nal or acretal. B. &v,,:d [ip"= .r~ in Ih~ body, and ~ach has sptcific roJ .. in lipid metabolism. Mor< inform.tion .bout lipid mlyu. Ih~ hydroly.is of stor«i TG .nd the libtmion of fatty acid.; it i, ,timulat~d by ~pinephrin~ and glucagon. 6. L}""Dmal aew IPS i, ~n intr:lcdlulor LPS that cotaly= th~ hydrolysi' of chol~u~rol ~u~ ... C. Compar«i to p... urgical m=urem~nu. ",rum LPS activity in four of fin dog. dec",as«i by 50-75 % by day 7 after panc=tectomy. Ho~r. LPS activity incr~= indiau«i that Ih~ p.ncr .... was a oontributor to .. rum lPS activity. but ther~ wer~ oth~r tissue source, in some dog.... Th~ nonpancreatic LPS in ",rum might"" gastric lPS or hepatic LPS. ar~

li,tM in T .bl~ 12.2.

II.

Tissue JOur"". of inc",=
121 ENZYMES

667

B. P. nc",. tic ""in.. cdl d"",~ l. Acut~ pancreatiti. i. th~ most common cou", of dam"l:" to pancr~~tic acin:or cdh and will ... uh in th~ rd..... ofLPS. esp«ially in dog .. Th~ dallU&" Jrulyor may not caus~ acinar cdl nectosis. Th~ LPS may gain a.cetivity in dogs with ""ute p"ncreatitis ranges from WRI to extremdy incr lOx URi}. b. In .pomaneous fdin~ p:mcreatitis • ..,rum LPS activity ranges from WRl to mod~ratdy incrmechason~ .ither at 2 mg/1q: or 0.2 mg/kg. In dog, with neurologic di",=. hyperlip"..,mia of incre~.ing ...... rity {mean value. 4.6x URi} ocrurr: em) .nd 54 % for caU with mild pancr.atiti, (eight mts),''' PU mrasur~m.nt' had mo", di:ognostic ",n,itivity th an did TU measur.menU or abdominal ultrasound.

12/ ENZYMES

669

OTHER SERUM ENZYMES M~ny ",rum ~nzym .. ru.v~ bttn ........d in an m~mpt to find btuor indialors of p.lhologic nale, involving hepatocyte, or olhor edl, (Table 12 .10). For a v .. ioplu.taoooph."'" i""",'Y""" in anin, .. rum. Y ... Oin r.thol20,51- 55. }6. SyoLlinu. M, Tili(>Kki M, Y.....d. I, H .... imotoA. 1m. Sq-atioa and q~nof {{.

q

i6'

~sh

Hi- ;j'.,.!,

nI

l,~ 8W . ~~ J~ ~~

.

.~ t t ~ ~ j I! ,I," ii ;.••I

~i'j !~ s~ l:;;j

0 ..

j~~ ~ j1'0

r'

~ ~

1H I

El

~h! i I ,

~ ~';'o 1. li

~"'. ~! ,"! O. 11 ~ ~ i ' Ji~'o ~","I. i .31 ~~f.,!; 2 ~~ ] f~ :~ J ~lrj~~ ~ ~~J~i:: l §3 1 ~~.; ~~,g 1H-J.:J.1!....:, •• l l t_1 i~tl' I I] I ~tl'61Ii.~I~.,-~I'. ~ .i ~ ,i. I'J~ ..l18!· . :; BR~·5 :i1:i . j~~Udi ~": ;",,;;! .~ ::91u '~~~1 JJt!~~~_ j ·t~t~~i~~ ·f ~i11~iittI~~~J~~111~~ ~;Jf ~ ~~~~~~il "'t">~2.1 - : : . .; "~~~' J,-€~ .~ ;!l~!j~ .'E,~1!0~J·il" "~~j ~'" e .,;c_'~ .l' 0 ,-'< , .. )0 . , 1 ·""" BP. YaoSt.a. CK. G...., FB. G...". DM, Frttman MJ. 1997. H""ci, ~piidi.n. Y" RL< I" S,U 1-487. 89. Sat .... T . Fwl[ M . 200 ... =tin. kin... ...d "P'''- uni""" .... f..... iD "'"'" .. indica_. /'0, -]J21. lOS. robin DI. 0 ........ CA. St.nn. IS, H.yd", DW. 19BJ. 5.""" ....yIuDgen_ esis is the major wurer of gluco", in th. blood of fasting animals,

13/ LIVER FUNCTION

677

C. Lipid m~uboli,m: Hq.atocyt.. mak. fmy .cids, triglycuides, chol~n~rol, and .polipo_ prouin' for lipoprot~in!, and .. urifY chol..wol for pho,pholipids, H~patocyt .. degrad~ chylomicrons from ponal and .ysumic blood and .. mon lipoprot~in remnants from .ystemic blood, 11.

Storag~ functions: H~patocyte. no", including iron and cop~r,

glyro~n,

triglyc.ride, and a varilocym modifY or degrade ~ndogenou. compound. {e,g" uric .cid, neroidal hormon~', poly~ptid~ hormones, .nd hemoglobin} and exo\:"nou, compounds {e,g" st~roidal hormon..} via a wid~ rangt of ch~mical "'.ction!, including conjug.tion!, oxidation., r.duction., and hydrolysi., Hq.atocyt.. a", a major siu of NH' fixation (i,e" NH' incorporation into ur~a or .mino ""id.),

[V,

Actions of mononucl~ar ph:ogocytic ,ysum: The liver filt~rs blood (.ynemic and poru!; apability =nd only to 'pl..,n) through the action, of Kupff~r "",U., Th. mauophagt. ",move: damaged "",J], {erythrocyt.., l.... kocyt.., and platdm}, inflammatory m~diaton, organi,m" and endotoxins &om the blood (.nd thu. also d 678

13/ LIVER FUNCTION

679

Table 13.3. Urinalysis, coagulation, fccal., and perironeal fluid tesr re.ult
Pathologic finding Uriruolysi. results Ammonium (bi)urar~ cry,talluria"

J.. Functioruol mass Ur .... cycle d~fb:r

or

Cholestasi, J.. Be tran'port J.. Functioruol mass

Ur.II~ crystalluria"

J.. Function:'! mass

Bilirubinuria" Hyposth~nuria

isosthenuria"

of finding"

InadaJuar~

fixing ofNH' into ur .... and J.. oonnrsion of uric .cid ro :.!lantoin InadaJuar~ bili"", naetion of bilirubin J.. Ikruol medull.ry tonicity du~ to decreased ur~a t N H: acrffion may inhibit oonccntrating mechani,m J.. Conversion of uric acid to :.!lantoin

Co~.tion

assay resuh, Prolongnl parti:'! thromboplastin tim~ or prothrombin tim~

Cholestasi,

J.. Functioruol mass

J.. Vitamin K-Jepend.nt oo:.gulation factors due to impaircd intestinal absorption ofviumin K J.. Cl .... rancc of inhibitors of roagulation f.ctors such '" fibrin or fibrinog~n degradation produm (fibrin fragm~n1' + fibrinogen &agm~n1')

J.. Production of most ~lation factors

Fa::.! a.m r~,ult, St.... torrh....

Cholestasi.

Defrcli", lipid digestion because bil~ .cid, are not ddivtred to inlestin~

Peritoneal fluid analf'i, Transudat~

J.. Functioruol mass Cirrhosi,

i N .+ .nd H,O ret~n1ion, J.. pl asma oncotic pressure, pon:.! h}'Jlr~ not 50ldy h~patic in origin. incr~:asffl activiti .. of th= ~nzym~ do not dir~("dy indiat~ loss of .ny Jiv.. function • • nd Jiv~r function am ~ grrady rMUcM without incr~a.fflstrum ~nzym~ .ctiviti... To ~mphasiz< th~ last canctpt. would th~ strum activity of. hqJatic ~nzym~ inc",asr if on~ r~mov.-d an .nima]"s liver?

[yo

Ikcr~

functional hep. tic IIUS.'l A. Hepatic inmffici~ntocyte, rnd . n"'" tbe blood. it ern p ... tluougb tho glomerulu filtf1tion bartier . nd be """",,,,d in the urine. Beau.. Alb does not p'" tbrough the glomerulu filtr:otion buMr of most rrucnmrn. Bu/Alb doel not en"'r .... utine in thoo. . nimrn. BuiAlb. Bu :woci. ted .. itb 1lbumin: 11.1,. mocropluge: Sb. ''''rrobilinogSC\1]" hemolysis {= T .bl. 3. lOJ D«....«I Bu upuke by h.patocyw 'Fasting or anora"- (csp«ially in horses) 0«",,= [Be], it supportS the concept th at tho icterus is directly rdated to extravaKular hemoly.is. When dinirnl da'" indicate a hemolytic anemia .nd [Bu] < [Bc]. concurrent hq.atobiliry disease should be ronsidered. d. Oth.. expected laboratory findings with hemolytic icterus {I} Anemia, reCC'nerative if of sufficient duration, moderate to marked ","«ity {2} Hemoglobinuri and hemoglobinemia if the,. is mfficient intravaocular hemolysis {3} Bilirubinuria if sufficient Bc '''''pes from hrpatocyt .. or. with intravascular hemolysis, if thore is sufficient renaltubul .. home drgradation and bilirubin excretion into urine {4} [f pw.m. hopatic enzyme activities.re incre.=', hepatocyte dam,,!:, or cholest .. is rould be due to anemic hypoxia. 2. [nc..ased Bu production not :wociated with hemolysis a. Besid.. Bu from erythrocyte d.. truction. heme degradation also occur> with drnruction of erythr0C)1r precursors {ineffective erythropoiesi.} and degradation of other heme proteins (myoglobin, cyt:ochromes, .nd peroxid ....). b. By themselv.., these proce;ses arr not consid«ed to Gluse inc" ..ed [Bt]. HoW (AL T, AST, LD, [D, and GMD) may be inctused bemuse ofhepatocyt~ damage. chol~nasis, th~n

'88


Fig. n.l. Obstructin dtoLe.utic ict
FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY C. Clinical laboratories may subj«;'" and ,h. ob.. rvds ex~".nct.

BILE ACID (BA) CONCENTRATION" I.

Phf'iologic process •• (Fig. 13.3) A. [n h~.hh, the enterohq>. tic circulation of bile acid, i, highly efficient, and llrarly.ll bile .aIlS excretrd in bile .'" return«i to the livrr vi. intestinal .bsorption .nd ponal blood flow.

Hepootocy\ll

..., \

PhJ"iologic procosses of bi!. . cids: ChoJ..ttin) involving hepatocyt~s callS< sufficient dallU&" to redu"" functional h'1"'tic IIUS.'l ~nough to impair BA de"an""."''''' b. Congtnital . nd acquired ponosy"emic ,hunts ~nabl. bile ..Its . b",rbed in the intenine to bypass the liver. =pt the enterohep>tic circulation. and ~nter the systemic blood."" c. Mild inc",a.-;.. in [BA] may occur when f=:l is withhdd from hors ..." The incr.... is prob.bly caused by. d=.....d hepatic dtlran"" rate of bile acids! 2. O,""",ased biliary BA excretion a. A variery of hep~tic and "",thepatic disorders can imp.ir bile flow and thus impair acretion of bile acids. Concurrent impairment of &: acretion is apected. but it m.y not be enough to cause hyperbilirubinemia. Similarly. when hepatic or ""nhepatic hyperbilirubinemia is p....,nt. increastd ",rum [BA] i. apected. b. Ouring obstructi"" choleswi •• th«~ is a down_regulation of caruolicular BA transport proteins. and hepatocyt.. may pump BA into sinu",idal blood insttld of into canaliculi. This process may aplain the "regur-gitotion" oon""pt of BA l.... ving hepatocyt ..." c. BAI are toxic to cdh. Thus. accumulotion of BAs in the liver may l... d to cdl dam"1:e .nd rel...... of BAs and other subst.n"". from canaliculi . nd hepatocytes. d. Cytokines {notobly tumor necrosis f. ctor alpha} have b«n shown to dec ...... BA transport proteins in hepatocyte canaliculor membranes .nd thus impair BA s,""retion.""" The /"<Sultont imp. irment in BA acretion is calledfonNional clnlmasiJ {see Bilirubin Coneentation. sect. III.E.2}. C. Mild incre. ses in ",rum [BA] occur in healthy :mimals after m....h. Postprandial inc",a.-;.. are also aaggerated in some hepatobili.ry disorders. Th... findings "e the basis of the bile acid challenge test (= stet. N). o. In hor .... increased serum [BA] was found in nearly all ho .... (36 of 38) with hepatic n,""rosi •• lipidosi •• neoplasia. or cirrhosis. In contran. only 2 of 78 sick ho .... without liv« dis,,..., had incr.,...J .. rum [BA] (",ferenee interval not stoted but upptr limit estimated from a graph to be 18IJmoUL}.>1' E. In cattle. the diagnostic sensitivity of .. rum [BA] varied .mong liver disorders: f.scioliasis {I 00 'Job. n = II I. biliary calculi (100 % . n = 2). hepatic . bscesses (53 % . n = 15). leptospirosis {71 'Job. n = 7}. and hepatic lipid""is (86 'Job. n = 36) {",feren"" interval not stoted but upptr limit estimated from a graph to be 40 J.lmolfL)."ln another rq>On. values for .. rum [BA] wtre incr.....d in cattle with hepatic lipidosis. hep>tic absc.:lRS.leptospirosis •• nd foucioliasi, with mean con""ntrations of 90--225 J.lmolfL at initial evaluation." IV.

Bile ""id challengt ten for dogs and cats A. Principle: A 12 h f"'ting [BA] provid.. a baseline assessment of the .mount of BA that escapes the enterohepatic circulation .nd ente" the .y.temic blood. After ingestion of. standardized meal. g.Jlblodder contraction release. bile ..Its to the intmine. from which they are ab"'rbed :md then em« the ""nal blood. Thi, influx of endogtnous bile ""id, challenges the . bility of the hep>tocytes to keq> bile acid, within the emerohepatic circulation.

694


Table 13.8. Re:.u1u of the bUe add challenge

l eU

in dog"

P~r
,

54 indud..d a

call

USBA;Cn ).lmoJlmg

UNSBACn ).lmoUmg

(USBA + UNSBA);Crt ).lmoUmg

0.Q....0.9 0.(}....42.6

0.Q....6.0 0.3-2377. 0

0.4-6.6 O.Q....23n .O

0.Q....1.9 0.Q....14A

0.7- 1.2 2.Q....12.9

0.2- 3.9 0.4-35. 7

multip~cation

So""",: Tr";nOI . t al." and B.tkm.rn .. al.'"'""

bctOI of 100.

697

13/ LI VER FUNCTION

T able 13.11 . Diagnostic f'ropcrtic. of BA.Cn ratio. in do!!" and cat
Do,. BA (serum) USBA:Cn UNSBA:Crt {USBA + UNSBA}:Cn

Diagnostic semitivity

Diagnostic >p«ificity

Positi"" prffiicti"" value

Negative prffiicti"" value

(.o)

,.o}

(.o)

(.o)

"" 63 6i

67

96

(00 (00 (00

(00 (00 (00

Om

"

10

" "

" "

BA (serum) 96 USBA:Cn 94 57 UN5BA:Crt 96 {USBA + UNSBA}:Cn 96 65 Not
"" ""

'" '"'"

"

li""r disea,.., beause there we", no f.lse positivo •. How""",r, the decision th=holds yiddffl only f.ir di>.gnostic sensitivity v:du.. and poor nq:>tive prfflictivo values beause of frequent fal .. neg"i""", 2, With use of the sda:tffl deci,ion thresholds in the population !ludiffl, the ratios for fdine urine had ""ry good di>.gnostic specificity and positi"" prfflicti"" values beause there we .. few f:dse positivo., The decision th ... hold, yiddffl good di>.gnos. tic sensitivity values and fair negati"" prfflicti"" v:du .., 3, Prfflicti"" v:du .. =y vary comid.... bly with v:oriations in the prevalence of hepatic disea,..,. in populations of int...st, D, Esublishing the diagnostic value of the urine BA:Cn ratios will depend on the use of appropriate deci,ion thresholds and comp:"ing the remits with other methods of detecting livor disease, AMMONIUM (NI-4*) CONCENTRATION IN PLASMA L

Phpiologic process Table 13. 12. DillellSa and ooAditioA' that "....e hrpenmmonWli. ' Dry infn:tion with uuasc.contoining ~eria and ooncurrent urMral oMuuaion (nlcstin,.1 disease in horw. Incr ...scd NH.· imakc NH.CI minim.ttion pcr o. or p"r r'""tum Ammoniated ro~ 10~icosis in can le Exposure to NH, from anhydrous NH , • A manvely common diotaH 0< condition Notr-li,u of tpeci6c: disordon or condino", ... no< complete but ,.,., p"""dood to gt... ."""f*o. A f..lldy incrnood [NH.1 m:o:y OCOlr if d.l.yed 'rWyUs of tt.. ampk reru.l .. in pro...",.. .. o. NH: produc""n by the blood «lb.

Hepatocyte cytoplasm

.... -.. ----.-._--- .. ,

" NH.'. HCO,- ~C,,,,~_.

Omihne

Mitochondrion

"

",

CylOSOl' • - •• ' . • _ Citruline,'

A8pw~~~'

lk.. Cyolo

Argi .......

Argin.....:cinBta

V'S. 13.6. n.. urea :damin ddici~ncy {Stt Chapt" IS} may cou .. m~thylmalonic ~cid to ~ccumul~t~. which d,""r= the con""ntr>tions of N_aatyl g1utaJrult~. A d,""reasnl N_acrtyl gluum>le con""ntr:ltion couses d,""reasnl .ctivity of corbamoyl phosph at~ symhdulu. The pathogenesis of th~ hyperammonemia in th • .., pups was not d.t~rmined. but Irish "..olfhounds do h"". a high inciden"", of ponosY"'temic shunts." 5. In 69 dogs with hepatic encephalopathy causM by ...."al linr di ....s.. {including 14 congtnital .nd 29 acquirM munts}. th~ [NH.1 in art~rial plas/rul . nr:agtd 1.5 tim~s the [NH<J of venom plasm •. The venom concrntr>tioIlS ~. be lower ba::.use of enhanud NH.t cl~...n"" from . mri. l blood by kidnqt~. NH, that com_ bines with H+ to form NH'. This ""h. ruminal fluid mo", alkalin •. Wh~n th. rum~n pH i.;> 8.0. the NH,:NH.+ ratio mift. toward NH ,. which diHU .... from th. rum~n to plasm •• whe .. it combin~. with H+ to inc",as
Dog 3'

F:ming [NH:l fJ.t€IdL) 30 min [NH:l (llgldL)

88 ± 36' 155 ± 71

100 1000

370 1400

'60

R~sulu

10 h""hhy dog.

Dog 4"

Dog 5'

Dog 6'

for =y 2

'SO

56 ± 14 Fmi"i: [NH:l (J.tt!dl) 'SO 30 min [NH:l (Ilgldl) 76 ± 30 550 6SO 900 , Th< f.,ting [NH:J w>s WRI, rnd th ... h<potic function..,.. .uJlicient to hondl. th< NH, to.d during th< f.ning " ..., Th< rr=kod hyprr=on<mi. in the 30 min >1ffiplr is oonsi".nt .. i,b • pon",y"rmic sbunt Of h<potic inruflicimcy, • Tb. hsting bYJ> WB Saw.d, ... }. B..k PD. Nor'" C. 1m. Bilirubin mrtaboIi.n and th, b,.../itary hypbilirubin<mi ... 2. H<patic upakr. bi.,.jiD" oon;., .no.., and =>rtion of bilinobin. &min ll".. Dio 14,JJI- J4J . ... "kDon-ch AF. !'alm. LA L.."« /J. Wu TW. 19/1.. . Drip.. ~f m .... malian biliprotdD ...d '''~'''' of bifu.bio ~ in vi", in...., at. I Oin 1m·", 74n«ntrationo fot di."",.;, oH,patobwuy di ..... in "",".) Am Y" Mod Aoooc 199,217_226. Z9. c...",SA. E..I. HN. )0""", SA 1995. ~,,( ....... bit, Kid. oo"" ...... tio ... fot di~. ,,(t..p..tobiliuy dioca" in cat>. I Am Y.. M,d A.ooc 207,1048_ 1054. J(I. B..onanoo A.\l . c..loon GP. Kanno..... B. 1988. CliDial uod di."",nk fea"",. ,,( .I"..., in • fooJ. I Am Y" ModAoooc 192,.J.Il7- J89. JI. HolTmann WE.. R.I." G. Ri"" oS. Do""" IL 1987. Alt, ..';",... in odccted ....... bOocbm>icd ",... titu", .. in "I.uid. aft.. induced b'patk halopatloy. R.. Y.. Sci Jl, 17_11. J9. Sdi,oon D. Hioab". K. 1957. lb, rom"' .... "" of .mmooi. in ..t.ol, blood. ,i... oocl"od..ru. '''''od in .h. ""all in.... int. f..".. which they "".... porral blood and rho .. blood if not

'r"""'''

........«1 bj-

hq>a~

,ole,

• Ponc..u: Ins .. Un..,d gluocagon Of" ...1oru«I from p....,..,acic fkdIs and a-cdl~ , .. poa;"dy.lnsulin orcmion" nim .. l.trd by ina.,.sed blood «>«n' .. 'iono of gluooo ocids. G1uagon _ ...ion is "imul...d by i~ blood
.ampk" c. Erythrocyte. are prone to lysi. wh~n exposffl to NaF . nd potassium oxalat~, .. ~ially if th~ .. i. not . n optimal .mount of blood drawn into th~ ~vacuat.d blood tul>.. Th~ rel ..... of .rythrocyt~ cont.nts (~.g., Hgb, inorganic phosphot.., ~nd K1 rruoy l. corr«t in an~mic or ~rythrocytotic sampl... " Som~ whole blood =Y' me.. ure molality and not molarity, .nd thus variations in th~ H,O content of blood (~.g., du~ to di.pla""m~nt of H,O by protein. or lipid.) will influen"" m~.. ural [glum..]. '"'' Th~ .. han btt:n ..nral reports of comparison. of [glUcost] m.:asu=i by differ~nt blood g1uw.. instrument. or :assays. Som~ of th= nudi...'" difficult to int~rpret b.aUst the types of [g1uco..] (i.~., blood, pl:asma, or strum) w~re not sp«ifial and diff~ren= due to differ~nt Hct valu.. w~ .. not consid~r.d. 2. Whole blood vc:rsu. pl:asma or se:rum [glumse] a. Glucose i. uniformly dinribut~d in H,O component. of whol~ blood (glucose: frec:ly diffu ... I>.twec:n pl"'ma and ~rythrocytes), but the .. are . bout 71 mL of

Fig. 14. 1. «m,;nwa o Muod.: Gluros< upuk. by myocyte< i.s promot«l by inru~n tltrough 'f'lis (,.m~ concq'" as with .,"reme leukocytosis): A la>kocyt~ need. more gluco,. than an ~rythrocyu, but typically th~re.re .bout 1000 times as many erythrocytes •• leukocyt ... Markal rubricytosis would .1.0 prob.bly cause increase-d gluco,", consumption." F- or

bromid~;

~iviIll:

Ill.

HYP"rgly""m", A. As in summarized in th~ preceding Physiologic Proa:s.ses section. pl"'ma [glucose] is influencnl by many factors, so it should not bt surprising that ther•• re many couse. of hyp"rglJ'C"mia. I. Th~ ddinitions, diagnostic criteri., .nd clas..ifications of DM uK
ami.). (2) Th. np"n commin... recommendal th., th~ dassificotions of "insulin_ dep"ndent" and "non-insulin-d.".nd~nt" OM bt droppnl btcau,. of th~ confusion ~n~rat.d by th~ir u,.. 2. A proposed cl...ification syst.m for conine DM" is simi!." to the classifications of pathologic hyp"rglJ'C"mia in Tabl~ 14.4. It consim of two major group": (I) inmlin-d.fici.ncy diabetes (IDD) includes those disorders th.r couse a progr=in loss of P-cdls (e.g., type: 1 DM, and p:lflcre. titis), .nd (2) insulin_r..isran"" diabetes (lRD) includes tho"" disorders in which there is insulin antagonism by hormones (e.g., tYP" 2 DM and .ndocrin~ DM). 3. For th~ p.rhologic hyperglJ'C"mic disord~", "",~ra.l other abnorm:d laboratory finding. may bt p....,m .nd can bt uK with acul< mcubolic d 250 mg/ 150 mg/ tioncreaticj OM: acromegaly, glucagonoma, hy~rad .. noconicism, hyp<rpituil>rism, hyp ha"" .nti-IJ-a:ll antibodies," b, Ty~ 2 OM {inmlin resinan", with inadequat~ rompcns>tory insulin secretory re.pofl5C:}; previoudy callM non--insulin-d.".nd~nt OM, typ< 11 OM, or .dult_ on.. t OM {I} Thi. JOrm of OM i. mon common in c;ots .nd i. c;ousffl by d. fca. in inmlin secretion .nd poninsulin =cptor defecl. in target cd]', th~ two major crit~ria for ty~ 2 OM,'"

716

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY {2} [n em, ""id~n"'" indicau. that .mylin (amyloid polypttll colled diabetic dermatopathy, n=olytic migmory erythema, and SIl~rficial n..:rolytic d.. matitis. The pathogtne;is of the hyptrglJ=mia is not e:sublished but /ruIy illvol"" illsulin ruiJlallct, glucagon. GH. or alterations ill amillo acid, fatty acid, or rille meuboli,m. It ap~ar:s ,hat the di.betic .Ute devd0p' after th. O"""t of hepati, dist.... , but it has not }"'t i>ttll esublished if th. li""r di",.... caustS the diabe.tic state. (3) Drug_induced OM: ~"istem hyptrglJ=mia (2 or more dap) associated with u .. of. drug (a) Sr.roid. (glucocorticoids) (Stt GluC0.!e Cona:mratioll in Serum, ""'. 1I1.B.l.c) (b) Thytoid hormones: Studies ill cats.uggest that hyptnhyroidism creates a nate of ill.ulill res.inalletocytes, myocytes, :md adipocytes .nd decr~ased gluCSt production by hepatocytes, Inmlinomas may cous
14 1 GLUCOSE, KETOAM INES, AND RELATED REGULATORY HORMONES

121

inmfficiency i, npttt":! (e.g., incr.~,ffi h'1'atic enzyme .ctivities, hypoalbu_ min.mia, da:reas.d [u",~ nitrog:p«t":! to b. marketUy und."""ight or em.ciat.d. d. D=ra,..:! glyoo~noly.is: Cong.nital ddici.ncie, of .nzymes nttd.d for glycoge_ nolysis may contribute to hypoglJ'C'mi •• nd accumulation of glycog..n in cd], {glycogcific ,ozyrnat;" d.f= w:as not .,ublish«l. Th. dogs did nol han malonyJ~nzym. A (CoA) d=rboxyl= ddi_ ci.ney .... Da:,rasffi gluconwg.n .. is probably rontributrd to lh. hypoglyami.>, kcau .. incrrasN [nulonyl_CoA] inhibits pyruvatt cuboxyla.., :m aic animal may c;m,, , hypoglycrmia b«:au.. of th. = utilization of g1UOOR .nd deere=
Probl~m' that moy b. r"""ala! by .. rial blood [gluro .. ] curves includ~ th~ following: a. Insufficient insulin do .. : [f so, incr~= th~ do ... b. Too short an inmlin df'""t: If so, us. longc:r_.eting insulin or givr q12h. c. Ovrrlap of insulin df'""t b.cw.,.,n inmlin doses: If so, use .hon~r_acting inmlin. d. Th~ Somogyi eff'""t {= Gluro.. Cona:ntration in s.:rum, =to 1II.B.3.j}: If JO, ra!ua: the insulin d"" and rq,..,1t the curv. in I wk. B. Unexptcra! hypgents in .. rum could cause fal .. _positive remits. In rontr>Sl. th~ fructosyl lY'in~ oxid= =y is conlid~rffl to ~ specifie for fructosyllysine. a .pecific glycatal amino aeid. a. In a romparison study. th~ fructosamin~ ronctntrations in conin~ .... d~er_ minal by th~ nitroblue tetrarolium . ....y wer~ .bout 3-4 times thou d~t~rminal by th~ ~nzyJrultic =y {about 100 J.l moUL}.'·' This study rai.es • conctrn about the validity of the [fructOiamin~] .. ponal from th~ nitroblu~ utrazolium assay. b. Modificotionl of th~ nitroblu~ tetrarolium :assay to ",mo,,", actions of rfflucing sUNtan= other th . n fructosamin~ rqrortally ..suited in [fructosamin~] of . bout 10 % that of the origin:'! nitroblue tetrarolium .ssays. '«l 2. Wh~n mu.ural by .pectrophotometric ......Y'. hemolyzed and icteric .amples can cau", e"on""us remits. B. Glycatal Hgb conctnt ration! or per""ntage'l l. Glyaual Hgb has bttn m~mral by chroIlliltographic. immunoturbidimetric, and chemicol ..... ys. ~ch with its own limiutions. Some ...... ys w~ .. d.. ignal to specifically det«1 hUIlliln hemoglobin A,cO wh~",... oth~", {e.g.. chemicol methods} det"'t multiple forms of glycatal Hgb. 2. Results.", um:.!ly reportal as th~ per""nt"l:~ of tot:'! Hgb th. t is glyaual. 3. If lipemi is p.... nt. the a.... y should ~ rompletal after washing the erythrocytes; lipemia wiU f. hely inc",...., perctnug.. in some .... ys.' ... 4. Th~", w;o. good agr..,ment ~tw..,n • rolorimetric =y .nd • chrom. tographic method with canine blood.'" 5. An immunoturbidim~rie manuf. ctural for m~a.!uring hUIlliln [glycotal Hgb]. has bttn u=i to m=ur~ canine [glycotal Hgb] ...·'..

.t.U)'.

Ill.

Inc==! [fructosamine] and incr~ glyaual hemoglobin perctntage or con""mration (Table 14.6) A. Di.~tes mellitus: Inc",=
14 1 GLUCOSE, KETOAMINES, AND RELATED REGULATORY HORMONES

125

Table 14.7. Di""ases and condition. Ihat decrease [Iretoamine] Fruelos;omine

Glycatffl hemoglobin

• Hypogly""mia (persist.m)' Hypoprol.in.mia Hypttn .lSOCi. tffl with azotemia .nd hYl"'rlipidemi. in normogly""mic dogs.'" However, the report did not describe whether the ' 7.0t.mic or hyperlipid.mic dogs h.d dysprot.in.mias. 4. Cau with hypcnhyroidism ha"" .ignificantly lower .. rum fructoumine concentr._ tions than healthy cats.''''''' Similar findings arc found in people with thyrotoIirosis. In B. D«reasal glycatffl Hgb perccmage or ooncrmration l. lnsulinoma: Persistem hypoglycemia caUsffl by an inappropriate ...I.... of inmlin can lcad to • d« ...... d glycatffl Hgb percrm.C" or con""mration.'07.l 00 2. Anemia: If [erythrocyte} is srable, then the dcgrtt of glyauffl Hgb formation will primarily dcpc:nd on blood [gluco..} during the lifr span of the erythrocyte .. a. If there i. an .cute .nemia (e.g. , bccaust of hemorrhage or h.molysi.) and. subsequ.m rcC"ner.tive "'porue:, th.n the glycatcd Hgb oon""mration and per""mage will be rcductd bccau.. young erythrocytes h. "" Ial glycat.d Hgb .nd blood [Hgb} i. d«,..,asal.

'"

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY b. If th~r~ j, anemia of any origin and th •• nim.l has not bttn hYl"'rgl)Umic, then the [g1ycotal Hgb] will b. da:rrasnl ~"'" the blood [Hgb] j,

da:,easM. ,..

w".

c. Th. glye.tM Hgb p. Th~ ~mino .cid sajuen"",s of i",ulin molecules of dogs and pigs .'" id~ntical .nd have one amino .cid difference from hUflliln insulin. Equin~ i",ulin Ita. one amino acid differen"", &om porcine insulin. Fdine and bovin~ insulin molaoul.. ar~ similar but have minor differ~n""'s &om the molecu.les of canine, porcine, and human i",ulin.""2
tide, . nd .plit ppl..i. (insulinom.): NeopJ:.stic p.cdh may comismuly or .pondically product inmlin, which cau..,. hypoglycemia kc.UM of cnhancnl g1yrolysis, rMu=! g1uoon""&
Immuno.. xtive: insulin to glUCOK (IRI: G) r>tio A. Ba:au.. insulin pnxluction and rd~aso: from p-cd h d~nd on pla"n" [gluco",], an lRl: G ratio should indicat~ wheth" the measured [lRl] is appropriate for th~ degr.., of glUCOK stimulation. Wh~n uK
IRI:G = [IRlJx 100 [gl ucos. ]

(14.3.)

with [IRI] in ).lV/mland glurosc: in mgldl: thus IRl:G ratio unit i. ).lV/mg glucose l. d: of analytical agrttment .mong insulin =Y' requir .. that r~fe .. no:: intervals for IRl:G ratio. ~ osublished for ~och .....y, which is a task th.c is not commonly accomplished. C. Interpreution of th. fasting lRl: G ratio {assuming valid cono::ntrations of I RI and glUroK .nd comparison to . n appropriat~ ref~reno:: int~rval for lRl: G ratio I I. Increaso:d a. If associated with hypoglycemia, then illlulin is rontributing to th~ hypoglycc:mi •. b. If associated with normoglycc:mi. or hyptivdy rdiable method for assessing in""lin sensitivity compared to "",eral oth" methods. m 2. Within the ref.rence interval a. If associated with hypoglycemia, then. pathologic state oth.. th.n hyperimu . linemia i. causing th~ hypoglyo::mia. b. If associated with hyperglycemia, then. factor oth.. th.n insulin deficiency is causing the hyperglycemia. 3. Decreased: If ow;oci. ted with hyp
Th~

730

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY [glum..,]. If th~ modification was valid, Ih~ .. would bt a dirttl rd.tionship bttw~.n insulin .nd g1u= con~mra{ions ov.. 30 mgldL; thot is. x IlU of inmlin for rv0l}' J mg of gluoo..,:> 30. 2. [n 1973. Tum,r, Oakley, and Naoorro ,. ponrd changes in plasma [insulin] during .thanol_inducal hypoglyc. mia in ob...,:md nonol>.] of 4O--6S mgldL TIm. w.r. only thIN .. mpJ., with a [gIurosr] < 30 mgldl; insulin values in thOst sampl.. nngn! from Q.-2.0 ).IV/mL.

b. They did writ., "lb. fall in plasma insulin w>s • function of Ih. fall, nth.. than of Ih. abwlut. values of Ih. pum... g1uco .... " c. Anoth., va,i.bl. not oomjd.rffl was Ih. diff~ .. n"" bttwttn insulin ron""ntn_ tion, in portal and ~riph~ral blood. Ba:au.. much of the "",..,,,"d insulin it rrmov«i &om ponal blood by h~p'IIOCyt .., asst:SSm~nt of insulin ,a;retion ,timuJ.ted by gluco .. i, bettu ,"",,-lmu«i by m~asuring portal blood ron""nt .. _ tion" which i, a technique gtneraUy limited to ex~rimental im~tig.tion •. 3. Many ve{uinary publicnion, have indud«i the use of the amended [RI: G ratio to evaluate [IRI] .nd [gluco..] in dome'tic and nondomestic .nimal•. Thu~ h.ve .ho bttn se-ve..l.ttempts to squdch the use of the .mend«i IRI: G ratio. but it .... m' to h.ve. life of it, own., ..... ,,.. The amend«i IRI: G mio .hould not bt usa!. [MMUNOREACTIVE GLUCAGON (IRG) CONCENTRATION [N PLASMA

I.

Phy>iologic process~. A. Pilncrrilfic g/u('(lgon (M, = 3485) is a 29_amino-acid polypOnrd in some dog. with th~ disord~r.'~l""""" 2. [n. study inmlving 22 dogs with m~rficial n«rolytic d .. matiti., pancr~.tic nroplasm. we .. not found (19 of 22 had histologic pallcreatic a.minatiom), alld immunor~.ctive glucagon concc:ntratiollS w~ .. withill th~ rdi:r~ncc: interval in th. fi"" dogs that we .. .val""t...!.'''

References I. Adamo HR. 1995. AJ..n..p, "&",,in and ""eoem ... tio ... in do, • ..itb Ioypotb,..,idiun. V" Rto Coanm"" 26.SJ I- H6• .. S. H..v. AM. St< ... m,IIi ..... "' ... [ ....yIoidoo .. ond thrombooi. in pw"-d l>6 J--966. 60. Knam .... SS, Ant~..d" AC. M • ..,,. CA. .loa", PC. Su.n.l'in Me. Mort cs, Mi....dol. RM, Ortolaai EL ZOO" A modd for """"""ia poi •.,.,in, in attic. Y" H ..... T oxi.roI 4:\,274-277. 61 . Stidk IE.. McKnido' CA. Willi ... , K/, c. .. EA. 2006. Di ... b" and byp«P~"""""1 ....1 obdomj"al paiD ..id.ou., ~ of Ji.... mpliati.o... io. a • ..itb inndinoou.. I Am Y" Med A.ooc 223,~1;4I14 . 7J. Rd...,. SB. Pdooi A. F""k ID. StdicnD«nmtloo in th, dia&nooio of =in< di.bm.o mdlitwo. V.. It.. Coonm"" 17,IJ--lJ. Rnod.. CEo H ....... B. 2001. &aJ.";"n,,( fn.c~ in d.op ...d ca.. .,;tb bn- o. kyp<rp«>t« of..p.in< an t..d to OYte abwrption of nutrients, I. Dog. and alU with EPI typically ha"" la'll weight .nd produce malformed f=., Pancreatic maldigmion Jruly .. mit from inadequate srcretion of LPS, AMS, tryp>inogen, chymotrypsinogtn, corboxypeptidases, or combiruotions of the .. zymogtns .nd enzymes, 2, Thr.., pancreatic ronditions are recognized •• couso; of EPI in dogs :md cots, EPI is not recognized in cottle or ho ..... The.. must be extensivr loss of .cinar cdls before there is clinicol evidence of m.ldi~tion COUsM by EPt a, Pann7atk acinar atrophy (or juvenile pancreatic atrophy) in dogs: Current evidencr indicates this condition is caused by. hertditary immune_mediattd lymphocytic pancreatitis (atrophic lymphocytic pancreatitis) in German shep_ herds and rough-ttd colli..," When presenttd for w.ight loss, there is nearly • rompl",e .~nce of pancreatic .ciruor cells, U.ing • decr.....d srrum [TUj value as • marker of affecttd dogs, a study involving 134 German shepherds indicottd an .utosomal r=ive inheritance pattern,' b, Chronic J>'Increatitis in dogs' and cats:' This disorder is typically.n idiopathic, recurring pancreatitis that causo; exrensive destruction of .ci ... r cells, If there is concurrent destruction of islet cells, the dog or cot can develop diabetes mellitus, c, Pancreatic duct obstruction in dogs and cau: Impaired secretion of pancreatic enzymes into the intestine rould GlU,. nuldigtuion, However, the obstructive lesion would probably lead to a.cute inflamJrultion, and thus the .nimal would be p"""'nttd for an acute illness and Jruly not develop a maldi~tive state that cau... chronic weight loss or chronic di arrhea,

141

15 / EXOCRINE PANCREAS AND INTESTINE

B. Dogs:rnd cm with EP[ m"}' drvdop ~rx!.ry intOSlinal . bnormalilies. such :as inc=std muco..aJ maltast and suc'""'" activiti"" ioc=std microvillar membran~ prol~in', or bact~rial overgrowth. Th~ lmor could Iud to muro..aJ m~ thaI "'.... malabsorplion.' 11.

Pancr~alilis

A. E""n though Ih~ iniliating factors for pancr~>Iic inHamm.lion . '" not Ihoroughly und~mood, it i. known Ih . 1 p.ncr .... lic acinar cdl d.magt i. a mojor roll5~u~n"" of Ih~ inHammalion. B. [n .cut~ p:mcrntiti, (from mild td~m'IOU' to ~ .. n,""rolizing or h~mollh"1:ic) , Ih~ rd~",~ of cytoplasmic ~nzymes from th~ dam>gffi :>cinar ",n r~sull in inc=d ..,rum aClivilies of AMS :md LPS (..,. Chapl~r 12), incmutd .. rum [l1l] and [PU ] (Ott Chapler (2), and increas.d urin~ and plasma [TAP] (... Trypsinogtn Acliv' lion Pq.tide (TAP) in Dogs, 5tCL IIl.A). Among domOSlic mammal" .cul~ p. ncr .... litis is mon common in dogs. Alfecttd dog, frequ~ntly h. ve an .cul~ onsol of clini",l sign, ,uch .. .umiling and .nurior .bdominal pain. e. Chronic p:mc",alili, may resull from ra::t1r",nt ~pisodes of acule p>nc",alili, 01 slowly progressive destruction of pancre.lic acinar ""II.. Wh~n """..~ . the p:mc",.. may not bo able to ,,",,ret. ,ufficient ~nzym .. 10 digest food, .nd Ihe animal may devdop EPl. Chronic p:mc",alili, occurs in alU and I.".. commonly in dog" and moy ... uh in EP[ wilh clinical ,ign. mch .. progressive weight loss :md soft or malformw f=,. Endocrin~ p. ner .... li, d,..filllction moy .lso .ri..,.

""U,

Ill.

[ntoninal mal.bsorplion A. Sevoral .mall intestinal d~, "'.... inad"luate absorplion of nutrient' .nd thu, inteslinal malabsorption. Th. nuL.bwrptive nale amid bo locali=:l {e.g., proximal ,m.ll intenin~ 01 il~umJ or diffust.-. il oould involve malabwrption of mony nutrient' (e.g., .ugars, proteins, .nd f. I,) or bo very specific (e.g., cobalamin). When intestinal malabwrption i. not ",,"u,ed by. specific absorption d~fect, the .nimal i. prestnted beau.. of w.ighl loss 01 malformtd f'""t>. Acule enteric di ......... lhal ",use diallhu for a few daY' prob.bly ""lISt. I~mporary mal. bwrptive nale, but .uch disorders .'" not Iypi",lly ron,idorw in discussioll5 of mal. bwrptive disord~" beau.. Ihe .. i, not • concurr~nt malnouti.hed ,Ule. B. Intestinal di ......., lhal l~ad 10 mal.b,orplion occur in mo,1 .nim.l species, but laboralory tests are u.td mo,tly to ffif vi. th. lcidn.y> and is ""Cl-.! in tb. wi .... Actin.ion Oftrypsin"ll"D to trypsin by..,"'rokina>< in the in... ti"" aho result. in th. form. tion of TAP, but this TAP is no. m.orb.d :md tit"" does not ..,"', th. pl .. m .. • PLl: Most ",ncr.. tic LPS it =:",,,,d in rnzym«r (probably cc, ,,,mtitrypsin); thll'l the nam. TU. In h....hhy animal •• nearly all TU i. trypsinog'in), LPS, or TAp· from panc""~tic acina, cdls 'Acimor ""U damatft p,.""nal, '~nal, and pomena! :rrot~mia in Chap, 8) Cobalamin drfici.ncy in cats ((TUll • A rel. tively oommon dioe ... or condition 'In"",....:! winary =r .. ion of TAP i, ilio IOund ..ntb d:ur..g. to pancr •• tic .cinar ",It. (.... be _t),

• Th. [Tlll b .. oo.n mo"",, to inen= after food intake, 1br '""'" dung< b ..

"",,,ted for [PUI or

not

oo.n docu-

[TAP] ~,

B, Assays I. Canin~, fdin~, and equine [1111 a.. m~~m,ed by sproes_spa;ific immun=ys,

Trypsin's enzymatic aclivity is not mnsu,cd ba::au.., of Ih. p ....,n"" of Iry]>'in inhibitors in .. rum, 2, [n cat" ""r.r~n"" imerval, for [TUI m...sured by a RIA (17-49IlglL) v.."" diffe'~m from those m~asurw by an ELISA (I2---821lg/L).' C. Sampl~ Serum is Ih. p",ferrw .. mple, but EDTA pla!ma 0' he"",iniud plasma can be UlW, Sampl.. mould be nored at 4 °C or - 20°c" ilL

Ina"""'! [trypsin_like immunoreactivilYI [TLiI {Tabl~ 15,21 A, [nc..a""" ,d~ from p.nc, ... tic .cinar edl, I. Acinar ceU damatttn rq>Onw 10 be about 33-50 % (I."" tru.n tho.., fo, .. rum LpS activity), {2} D=om.tha",n. {Q,25 mgllq: P'" os daily} v..a, associatw wilh inc, ...,cd [TU I by day 7 of t..~tm.m .nd was Wilhin the ,.r.r~nce im~rval again 7 d aft~r withdrawal, Th. m.~n inc' ..... wa, Ih,,,,, lim... baseline m~~n, bUlonly 2 of 12 dogs had [1111 ;> Ih. URL, Th. authors SUggt'lIW Ihat Ih. [TLI] was inc=d ba::au.. of toxic df=, of dcxamethason~ on Ih~ ""nct.as," c, C.U

{I} [n. pro,pecti", nudy involving 28 cats with clinical 'igns rompalibl. with panc""atiti" the .. v.. .. nol .ncreatic tissue ...spcctivdy. by th. investig.tors. 3. Refc:r~nce interval, vary wilh the mffhods usal and .mong laboralories. C. Sampl~ ~rum is Ihe p ..ferrM .. mple.

111.

Incr.-..M [p>ncrralic lip... immunorraClivityl [PUI (Table I 5.2) A. [nc... ...:1 rd~ from damagnl ""ncreatic acinar cells l. During ",!",rimental and spontaneou, p:mc ....uiti •• LPS i. rd.-..M from damagM panc'"". tic acinar crll. and ~nters th~ blood (probably via lymphatic ""...ls). 2. PLI te,ting has the . dVlUltagt over moll routine .. rum LPS assay, of king specific for ""ncrcatic lip .... and testing i, OffcrM by some la,!:" '~terinary ..fcrrallaborato_ nes. How~~r. rcsu!ts may k too delayed to be u..ful for diagnO!ing and managing patient, with acut. pancreatiti ..

".

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY 3. Dog" Wh~1I d""j,ion th ...hold, of th~ URL or of.n ~mpjrical ...Ju~ g=t~r than the URL w~re u~, the [Pll] had a di.gnonic .. mitivity for acut. pancreoltitis of]oo % and 82 % , re'Jl"Ctive/y. " Diagnonic ..,nsitivities of LPS and TU were

I.... 4. Can: Th. [PLI] (with dros.ion thro;hold of 10 IlgIL) j. ,.portal to han ~{{.r di"i:"o,[ic stnsitiviry for P>flC'''''{;lj, than d"". the [I1.I] in cats." Aft,r uperirnen_ tal initi.tion of p"ncrratitj. in mIS, the [PUl had g,rater incr= {SOx basdine '" 35x baseline} .nd more penistem increases (IO d vs 3 d) than did th. [TU].'" B. D«r••.ffl renal drannc;., in disorders chat au .. da:,rasnj GFR l. The kidneys at. involvffl in the ,.mov:.! of pancr",,{ic LPS from plasm. {= Chapt.r 12}. When th ... are disordm that muh in d,"""asM blood flow through th. kidn"Y' (i.•.• p",.."al, .. nat or posIten:'! disorders), th~n LPS h... a 101lg~r circulating h.lf_lif~ alld thu. COli accumular. ill plasma. 2. Usillg the collin~ PU ELISA. the [PU] was mildly illc",asal ill dog. with aperi_ m~mally illdu=:! chronic renal f.ilur~. but 1I0t above th. suggested diagnostic threshold for p""u... titis. "." Lock of illcr .... ed .. rum lPS activity in this srudy suggests that the modd =y not have bn,1I .ppropriate for ...... illg changes ill [PLI] cousal by rellal failure.

[v.

Decrnsal [p""creatic lip"'" immunoreactivity] [PU] [Table IS.3} A. Rd.... e of LPS from p,"creatic acinar cells may k dec",... ed ill disorden associated with redu=:! functional p"nc ....tic aci""r tissue. :md ther.fore .. rum p,"creatic li~ immulloreactivity oollcemmiollS =y k decreasal. The primaty disorders ill dog. and cots .'" chrollic p,"creatitis (which l... d. to destructioll of most aci""r cdls) and, ill dogs. p:mc",atic acillar .trophy (an immune-mediated disorder of ~rman shepherd. and rough-coated collies). B. [n. study usillg an ELISA. .1125 dogs with EP[ (... d.fined by havillg a decreasal [TLI]) had decreasal [PU]." However, TIl i. prefer=' over PLI for diagnosis ofEP[ kc.u .. TLI .ppe.n to differ.miat~ affected dogs from healthy dogs more d ... rly, and it may have ~.ter diagllostic .. nsitivity for EPI.

TRYPSINOGEN ACTIVATION PEPTIDE (TAP) [N DOGS

I.

Phy>iologic processe" After ingestioll of. meal, ttypsillogell from p"ncreatic aci""r "",Us emers the intestillal lum," :md is de.ved by the .ctioll of enterokinase to produce trypsill and TAP,." ~ight"""mino-a.cid N_termirud deavage peptide. [n theory, the TAP is not absorbed and thus d~ not ~nt.. pl ... m• . A millut. [TAP] con k foulld ill plasma .lId urine of healthy dogs, p remmably from .ctivation withill the p:mer......"

[I.

Analytical oollap" A. Ulli" l. Plasma: nmollL 2 Urille: nmollL; also ..""ned as • TAP: Crt ratio B. AssaY': An immuno......y (either enzyme immun<W.Sayor RIA) detect. TAP; ftve highly ooruc:rv.d amillo acids .llow for cross_speci.. "nillg with a sillgl.......y. Th. analytical detection limit of the enzytU~ immunoassay is near the lower pla,= oolla:mrations found in healthy dogs and thus canllot k used to detect decreasal pl",= [TAP]. """"Y' .re lIot widdy available.

15 / EXOCRINE PANCREAS AND INTESTINE C.

147

Sampl~

I. EDTA blood is collttted and a.mrifuged at 4°C. and pt.",ru. is ..""rated within 1 h. EDTA pl .... /rul is frozen {~t - 20°C} umil just prior to analy>li •. 2. Urin~ is rulb:ted into EDTA_containing vacuum tube; .nd frozen {at - 20°C} until jll'lt prior to analysis. Ill.

Inu~ pl:.S/rul [TAP] or inueo.ed urinary TAP: Crt ratio"''' (T.bl~ IS.2)

A. Acinar cdl donug. caused by pancre~titis: During paner .... titis. trypsinogtn is cluved to form trypsin:md TAP within th~ panc ...... through a.ctions of cath~psin B or through autoactiV:l1ion. TAP prob.bly ~nt~rs plasm. vi. lymph. and some of it i, cle.red via kidneys. I. [n dog, with inu~~K Blood

Erythrocyte

,

D \ ''''.

,

Cell

Fig. l S.l. Phyoiologic ~ th.t infl"...o, pw.n. at >lophi~n or haplOCOlTin; R rn...-.piJ<XJb.bmin 1 (fnDII). a nv ~ during • .."pJ. <x>llectioa con inc", ... mu,w,"" .. rum lfol". I. • Rot.tiomhip of cobabmia rnd fob ",. Cob:ol:omia is • nquired rohld~ Preabsorptin d~fecl in doc' and cm £PI: pancre>tic atrophy, chronic panc'''''litis Intestinal oocc"i;d o,,",rgrowth: EPI, impaired emrie acid stCrelion, em,,;c di,ordw; (Stt the text) Dd'r and caU 'Ileal di~ inflmunation, I=;on, villous atrophy (viral, hy~mnsitivity, cytotoxic drug.) Coo/:"nirai ddicicncy of r~{or in giant Khna~rs and Border colli." ~ve"" cobalamin ddicicncy in a cat (probable congtnitod malabsorption d.f= ) • A rel.tively common dioe .... 01 condition Noto: lins of .piologic process.. A. Stt Figs. 15.1 and 15.2 for basic p =..... B. Cobalamin and folat~ m.taooli,m a"" linked in a r....ction in which a methyl group is transf.rr~d from N'_methylutrahydrofolat. to cobalamin in on.-caroon pathv..ays. [n

15 / EXOCRINE PANCREAS AND INTESTINE

751

Ih~ abs.na. of cob. lamin, Ih~ m~hyl group is lraprffl in N'_methyltelrahydrofolat~, and the ... uh i. a funclioruol folat~ deficiency, B.caUst N'_m~hyll~trahydrofolate contributes 10 th~ toul m~asurw [folat~], strum [folat~l =y not ~ decreo.w even Ihough Ih..e is. functional fol'l~ d~fici~ncy {i,e" Ihe manifestations of. folat~ ddici~ncy are pr ..~m},

[I.

Aruolytical cona.pu" A, Turns ~nd units I, Spn;ifically, folale is the anionic form of folic acid, which is compost
III.

~.ted

[ncreaKdstrum [folat~l (Tabl~ IS,S) A, Incread .bsorption of folat~ in the small intestin~ L SmaU intestinal baet.. i:d overgrowth: Excessive folate produced by enteric bacteri a is ab50rbed in the small intostine, The overgrowth could ~ KCOndary to EPI or cu.ed

Tahle 15,5. Di..... es and condition. that au ... increased 5el'1Im [folate) IneteasM absorption of fol. le in MillIll intrnine Inteslinal ba.cterial overgrowth: EPI, imp~irM gaslric acid stetetion, enteric disorder> (.... tat) Low intestinal pH: EP[, excessive gaslric acid production High dietary inuke p.",meral mpplellYnution Cobalamin deficiency in cats • A ,.t1tivs.soci. lcd with inte'tinal bact«;:.! overgrowth in w,rman shq.h.rd,. '" 2. low ;mmin.l pH: Mnimal folate aboo'plion occurs in .n acidic cnvironmem. D~",..ro inte'tinal pH (inc,rasN abwrption) moy occur with EPI (irnpair«i HCO,- "",mioo) or excess;"" gastric acid production. 3. High dietary imak.: Folate .bOO.plioll usually occurs by" f:..cililated tnmpon ,)'Sum, but, OIl high inteninal con~ntrations, .bsorption occurs by pas,;n diffusion." B. Par~IItthi.. (•. g.• ulceration ot cminoma). but it may .lso b. due to hemorrh"J: A. D-Xy{"u is •• jmpJ~ ~nto .. thai j, not commonly ingm""', and nry li{d~ is pr...,m in blood or livtr. If ingesta!. jt is p:wivdy absorb«! in th~ duod~num and proximal j~junum, from which it ~nt~'" porru blood. Aft~r byp:wiJll: th" lin•. it p"'" through the glomerular fi]tr:uion barr;" and is aa~M in urin • . B. In pn>pl., xyJos.. Ih. glucuronic :ocid- xylulo .. pathway in h.p"[ocyt ... It i, oma/ly :assumM that "''1 liul. of Ih. absorb«! xy]"'" i. dq:rad..d by hq>.tocyt~ of domestic m:omm. b.

.nt."

[I.

Analytical oonctpu A. Unit 0011"""';011: mgldL X 0.06661 = mmolfL (SI unit, nr. rest 0.1 mmoUL)" B. A..ays I. MllhipJ. xyl= =ys are .vail.bl., but clinicalloboratori.. do not commonly off., thrm. 2. A oo]orim
F= fail"'" 10 liqud)' gdatin .dequaldy Undigestal mu.d. Ii"-"

PABA·

pr=nt D«reastd plasma [PABA) or d"",..asN urinary PABA

P[",ma turbidity un

excretion Absen"" of plasma turbidity .ftc, inge,{ing lipid meal,

M:ddigestio,n of di=ry mu,cl~ {protein} [kCJ~~.ed chymotryJ>lin ",l~~,ed nom pancr..,.. [kCJ~a.ed

pancreatic LPS activity in intestin~

but turbidity p.uent .ft.r ingesting r=iigellallipid. IUdiographic film digestion Starch digtSlion res!

F= failed to de .. gdati" from film Fl at g1UCOst .b50rption curve

[kCJ~~.ed f~

prota>lytic activity M..ldigtstio,n of SUM or nul.b"''Ption of glu<X>St

• PABA: N.ben~J.l-tyro .. rum .ctivity within ,be ref.,.""" interv:ol in EP[ aseI. &rum AMS rnd LPS 1CIivity c:on be d.cn...d .. ben rn wnW doos no' b""" EPt

OTHER METHODS OF EVALUAT[NG D[GESTIVE OR ABSORPTIVE FUNCT[ONS I.

M~ny

oth.. labo.. tory assays or mffhod, ~r~ used to, ",,:dU

S!ructur~

Motil~

Dirrct f.-cal H . m F.-cal flotation test

!",rasit.. Parasitic ova, ooc)'l~" or

SmaU intestinal bact..ial onrgrowth V ..ies with th~ hi!lologic lesion; rypica.lly inflammation or neapl"'in tm

lnc",asal d=>njugation of bil~ .cid, by an onrgrowrh of imestinal bact~ria lncreasal dq:radation of tryptophan by ~nt~ric

lncr .... snl ","rum ron"",mrations P""iti"" for indican

b.ct~ria

Urine nitrosonaphtholtest

P""itiv~

'"'

lnc",asal bact~rial degradation of tyrosine by .nt~ric bacteria

nitrosonaphthol

No..: This is no. 1 comple'" Ii ... Other >pryti.c I""'""titio. V.. P.tl.oI. J6:HO- S4l. 2. Wtbrq; ME.. lOOt . P""""tic odo", atroph, ;0 Gr"""" aIr.pI..,.J do", ...d ""'rh..... t«I oollier: E.q.,drovn""'[ .tuody. B..J Mwoob Tk.arrtJ Wodtrtud.. J 16,J40-J4 S. 23. Can T, William. DA. 1989. Rd,,;omltip brtw .... di,....,. "",«in "''''''' .. ..;.,n aod " rum trypti ...Jikr inua."",,_ in dop. Am ) Yrt Rr. 50,2105-2107. 24. William. DA. Bat, RM. 1988. S....ici';dotioll of lipoprouill f"'ctions and subf",ctiolls .mong s~~ •. a. Dogs, cats, alld horso; ho"" predominalltly HDL molest~rol "'th~r thon LOL cholmerol. LDL mol~nerol pr~dominat .. in peopl~. b. Predomill.nct ofHDl cholm~rol is associated with decr......d or .b.. nt moles_ t~rol est .. tran,f.. activity (t"'nsf~rring molesterol from HDL to LOL) alld d,""rease called lipnnu. elta,ing/Mto,. 4. lipoprot~in ",mnallts ar~ cl.. red from pla,m. by hq.atocytes. LOL molecul .. are ",moved from plasma by many types of all .. LPL incr..,..." LDl uptake by promot_ ing lDL binding to ""U recq>ton.'

16/ LIPIDS

767

B. Apolipoprouir" are criticol for normallipoprot~in m~abolism. inHu~nciIll: lipopro"in .tructur~. acting as cofacton for ~nzym .. involval in lipid m~t>bolism. and .cting :as ligands for r«:q>tor_m.diat.d cdlular intJl" for lipids. one fOlendog<now md on< fol uogenow ~pids . • &ogenoWl 01 ~ary ~pids: Ingest«! TG in the p'." " "" of bit. ""ids and lPS undergoes ~poJy.is to fonn MG md FA. Aft.,. . !>sorption by en'orocytes. MG md FA:or~ '..... mbkd into TG. Entorocytes:Wo produce CE, phospbo~pids. and .poIipoproteins A.,. in. p = involving B apolipopro"'ins.

'68

16/ LIPIDS

769

Cholm~rol .. t~rs ~nUr cdh by ra::qJtor_mMiatM endocytosis of lipoprouin fragrn~nu. Thq ~r~ ddinrM to lysosom... wh~", acid lip....., promot~s th~ir hydroly.is. Choles_ r.rol can th~n "" rd.-astd for ""'" by the ""U. F. Wh~n cholmerol ruch.. hq>.rocyt.. via lipoprot~in ",mn:mIS, il may "" reu~ for lipopror.in .ymh..i., ",crerM unchangM in bile, or degraded 10 bil~ .cids.

E.

II.

Aruolytical oon""pu A. T urns ~nd units l. Serum [cholmerol] r.p .... nts the total [chol.. terol], including cholest~rol and cholest~rol est~n that ar~ hydrolyzed during .nalysis. Th~ r...cting chole;{~rol molecul.. are within Jipopror.ins. typically in chol.. t~rol_rich LDL and HDL molecules. 2. Units: mgldL X 0.02586 = mmollL (SI unit, nearest 0.05 mmoUL)' B. Sampl~ l. Serum

e.

is the p..fertM sample. Total [chol.. t~rol] is suble at 4 °C for 5- 7 d, al - 20°C for 3 mo, and .1 _70°C for y.ars. R'p"'tM tluwing ~nd refrttring should "" avoid...!" 2. Dog. and caU mould"" f:lSI...! onmight or for about 12 h to avoid ponprandial h~rlipidemia, which may ~ffecl [cholesterol]. Methods l. Mon automata! ous;oys are .nzymatic methods that hydrolyze cholm~rol esters :md then US< cholenerol oxida", to oxidize chol.. r.rol and geneme hydrogen peroxide, which then reocts with .n indicator dye. Some assays us. .n O,_s.ming dectrode to meam .. 0, conmmption.

Fig. 16. 1. «mtinwa • Endogenow ~pids produ=l by hepato: H'patgenu to ""mo"" th~ df":l of ascorbic .cid, III.

HJ'P"rchol~nerolemia

A,

[ncr~ • ..d

.. rum [cholesterol] indicat.. there arc ineru...:! ron"",mrations of lipoproleins

thaI contain chole;leroL B, Disord~" or conditions (Table 16,3) C. Th~ pathologic P""'"'SS" Ihat cau.. hy~rcholest~rol~mi ••"" describal in • lat....ction on lipoprot~in di50rd~", (Hyperli~mia, HJ'P"rlipidemi., :md Hy~rlipoprol~inemia Disord~,,) ,

[V,

Hypatoc)'i'" and ~m~rocyt ... O. Wh~n lipoprot~im conl:lining .polipoprol~in C-11 bind 10 LPL on endolhdial "",lh. fmy acids .. ~ cl~'vN from TG mol,""ul", and ~nUr cdl, {e.g.• adipocyus .nd myo_ cyt"'}. With .. ~ated proces'ing. th~ lipoproteins krom~ TG d~plSting hyptrtriglyuri. d.mia. HowrY,t, ""pon.., to h' p",in in Ih. son w;;u limi!." to" control dog', =pons can conlribu[~ [0 the d. fecti"" metabolic pathways." a. C.t.rnolamin.. and glucagon stimula,. hormon ...."'itiv.lipa.. in adipocytes to inc ...... rd.""" of fatty .cids. Insulin [ypicolly inhibiu thi. enzyme. and thus dmm~nda! term is fotfJ adds. b. Units: mEqIL X I = mmol/L 2. £ample a. ~rum or plasma from EDTA_anticoapdata! blood (not hq>:uin or coll,"",ion from hq>arinizal p.tienu) mould be usN." b. ~rum or plasma should be "'p"rata! from ctlh as won as pos.anum cotde, sample. should k coll,"",a! shordy befo.. f.aling time .nd 2- 14 d kfor~ calving. Th"}' con k processa! and stora! frozen until calving occurs, at which time it will k known wh~h indian. ponpnndi:d hYJl-. hl odition. 8.J-II S. s.., Acad.mic. G..,.. Kt.. WcddoiDd KJ. CowdJ CS. Sdoonob ... WD. Jnvdl DE.. Zki .. SC. Dd>c...kd", J. F...,. RA. 2000. N."","". [0' H...d MS. notd." CD. Rrmilt..d RL. ~ P. cd •. S-Ilkm../Cs..;,,J N"",·';"' . 4d. cdition. 21_ 107. T opeb.. KS, Mad. Mo .... Inrtituttors and stimulm:. the productioll:md rd.~.., ofT. and T, from the thyroid gUilds. All circuutillg T. is produ=:! by the thyroid gum/s. but a minority ( 10-40 %) of circulatillg T, i. produoN by the thyroid gUilds.'''' Th. rest ofT, is gell.mal from T. ill cilyvariatiollS in [tT.] have bttn r<pon..d. a. III homes, the highest ooncOn«i as mUlL (or J.IU1mL)

5. TI}'\A: positi"" or

n.

or

P"=nt"1:~

of. known positi ... sample

Sample A. Canine [IT..} is subl. in EDTA_plasma and , ..urn when

B. C. D.

E.

III.

n
17 1THYROID FUNCTION

787

"'.
".,,:S 1noT~

l2 ' .

@

"·"1

Dog 1

Y,. t,

• ]

t'

lO -----------,--

•"

withT~ Dog 2

'~

't,

Fig. 17.2. EifK:ts of T.AA on me .... rod ltTJ in a soJid·pb ... RIA. RIA.. >t< compS1>J'" in .. bich the p. tiont', T. rompmount of T1(liooc~ T, {,T,) fOr a ~mit«l numOO of ontibody.binding .ites (~.g .• in a tub< co. ted .. itb anti·T 4 antibodies). Tbus. a gr~~t .. con«ntr:ltion of p.ti~nt T, resul", in kss bound *T•. • In th. on.Jy.is of dog J', .. rum. i", Satod tub< (''''p a). During inrub.tion (''''P b). som< of the p. tiont T. and 'T, bind comp"ti~ly to :mti.T, antibodi .. on tb. tuOO: other T. mot.cuks r..",.in unbound. Af"'r inrub.tion. tl>. unbound T. is rinsed from the tube. and the bound T, ":OY> in tb. tub< (''''p c). no. tw,.·, ndioactivity;, tben mea.sws within th. ,d'",e""" interval, from 66 % to 90 % when .. rum T . _binding cap:ocity incrt ..n." Th. degr« of diff.",na was not ,eport"! for dog .. r.. '" C. [tT,) and [IT,] l. (rl,n.ralJy. the sam. basic principl.. for T , .....y. (tT, and IT,) apply to T, ItT, and IT,} assays. Unlik~ tT, assay•• assay. designed for mnsuring [tT,] in hUllUn set:> han .d"luat~ .nalyrical ran~ to m~asur~ [tT,] in dogs :md cats. 2. RIAs ha"" the analytical sp«ificity to diff~"'ntiat~ T , .nd T , mol«ules. Ba;;>...., of low.. ron""mt:>tiono. assay. that m.."".. [t T,] .. nd to be, less rq>roducible than ..... Y" that m~.JU'" [tT,]. D. TSH l. Canin~ TSH a. Th~ .. a", romm ..cial .... Y" {immunoradiom",ric .nd chemilumin=nt immunometricl for canine [TSH] . but it is not known wh"h .. they det«t aU glycosylated form. ofTSH." The canine TSH :ways lack ""fficiem .nalytical range to enable documentation of d«r...... d [TSH] .... The", WlI.I good agrttment betw«n two immuno.... Y" when the measured [TSH] w:as "" 0.5 ng/ml :md fair :agr..m~nt when the [TSH] w:as betw«n 0.1 .nd 0.5 nglmL ,.. b. The ",fe",nce interval, for canine [TSH] and the m",hod. uK
E. TgM l. A rommercialenzym~ immuno .... y {EIAI for TgAA v..as developed during the 1990s {produced by Oxford Biomedical R..~.rch}. Prior to its availability. the .. w:as

17 1THYROID FUN CTION

789

a lack of =y standarda.tion. Thus. results from diff,,~m l. boratori.. wer~ difficult to im~rpret. Another EIA for TgAA w:" devdopffl. :md its results wer~ in good agretm~m with th~ oomm~rcw :way." 2. For th~ oomm~rcial :assay. TgAA results ..~ rqrortrd as • Jlttn reponed to occur in .bout 2 % of hYJl"nhyroid m(S," b, Thyroid ad~noma or .denocarcinoma in dogs; About 25 % of canine thyroid neoplasm. produce sufficient T , to muse hyperthyroxemia and diniml .igns of hypenhyroidism, I c, Thyroid ad~noma or adenocarcinoma in hors..; Hypenhyroxemia is rardy reponed in horm with thyroid neoplasia, In one ho"",,, the [tT,J ~ about doubl~ the upper reference limil," d Multiple endocrine neoplasia {type II} in dogs; Thi. rare dilOrder involns neoplasia of APUD (amine p=:ursor uptak~ and decarboxylation) ceUs and is characterized by thyroid medullary ao.rcinoma, ph~romocytoma, .nd p:mnhy_ roid hyperplasia or neoplasia," 2, Administration ofT" TSH, or TRH 3, Administration of rompound. comaining iodide; Hor..s may have temporarily incr.,.snl [t T,.] beau"" of inn~ased production ofT, .fter ""posur~ to iodide in ""!"'Ctorant!, coumerirritant!, comrast medi., leg paints, or .hampoos,' 4, T"AA may cau.~ po.iti"" imerference in some tT, :mays {Fig, 17,2}, B, Hypothyroxemia (Table 17.3) L D«re...,d production ofT, a, Primary hypothyroidism (c;ousnl by thyroid gland dis.,. .. ) {I} Primary hypothyroidism is a common di""rder in dogs, {2} The most common pre""ming problems indude weight gain, lethargy, .nd symmetric :dopec;" The more common .bnormallaboratory data indude mild anemia {nonrq:JIUDOn d...... or oondition Notl)."

792

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY {3} Lock of TSH ',",,"'Iioll caus.. atrophy of thyroidal follicular cdb and thus drc,,,,,sal T. and T, production. c. T~r{",ry hypothyroidi.m {caUoN by TRH ddiciency} (on. form of umral hypothyroidism): Th. alImO," are not awn, of documemM cas •• in domestic mammals.

d. D.f«tin T. production {I} In dog., iodin. org.nification d.fecr'" or roDl:"niral thyroid p,",oxidase drficiency in toy fox urri",;"" {2} [n foal" iodin. ddici.ncy from drctrasN dietary incako {fool :md dam}" {3} D.frctin thyroglobulin synth .. is in M ..ino ,h, Dutch goats, .nd mj"", prod"""d hypothyroidism. How"""., d.frctive thyroglobulin synthesis in

Afribn.r (Afrikand,,) cattl. and Bongo .ntdo"" produaJ euthyroid con~nital goit"';'" 2. Multifactori.l {may include d.crUsffl T. production} or unknown ma:runisms a. Nonthyroidal disrases {I} '\hny infLommatory, neoplastic, metabolic (e.g. , rrnal f. ilurr), and endocrine di",rde", {.. p«ially hy~radrrnoconicisml a", known to d",,,,= [tT..]. Sick euthyroidism {ru from Grttk, meaning · w.U"} is th. condition in which a di,.a", outside of the thyroid hormonal .ynem cr•• t.. hypothyrox.mia. {2} Nonthyroidal di,....ses =y lo~r [tT..] by on. or mo .. of the following processe" (a) O«rra..ffl protein_bound T. beau.. of d"'r~ concentration or affinity of binding proteins {b} Inhibition ofTSH ''''rHion (c) Inhibition ofT. production {2} Ass=ment ofTSH and [IT.] .. =y hdp diff... nt iat. nonthyroidal illness from hypothyroidism when [tT..] is d",,,,....:! in dog. with clinicol signs of hypothyroidism. b. Many drug> (esp«ially glucocorticoi.u) a", known to low.. [tT.] . {I} Dog. with hy~radrenoronicism f=iu.ntly h. vt decreased [tT..]," but changes in [tT.] in dogs receiving glucoconicoid th.rapy a.. variable. Th. [tT..] did not changt in one study,'" wh .....s the [tT.] dec",....:! in .noth.. study.' Th... is evidence that the changes in [tT.] are COU..ffl by multiple f. cton, induding reduced TSH KCrHion," and th at the thyroid gl and. are Ie .. responsivt to TSH." Th..e i, also evid.nce th at glucocorticoid. reduce the oonvtrsion ofT. to T , in ~riph.ral tissues." [ncr~ [TSH] is not ap«tni {2} [n dog., prednisolone,' trim.thoprim_sulfadiazin. ," trimethoprim_ sulfamethoxazol.," and phenobarbiuP'" treatm.nts havt bttn shown to couse hypothyrox.mia. Sulfonamides int.rf... with the iodination of thyroid hormones by inhibiting thyroid ~roxidast- activity,'''' so [TSH] =y bt incr ... sed. {3} [n horses, phenylbutazone and glucoconiooid trratments ru.vt b..n shown to cou.. hypothyroxemia." {4} Clomipramine (ClomiCalm) administered to dog> for n... rly 4 mo d",rr....:! [tT..] and [IT..] ... Th. dec ...... in [tT.] was detectable .ft.. I mo of treat_ m.m, penisted for the duration of the aperiment, but did not drop bdow


793

the low.. r,f... nce limit." Clomipnmin. is usa! for. v. ri"y of bdt. vioral disord .... c. Th. following h.ve bttn mown to produce low.. [tTJ in horses: (I) Diets high in . nergy, protein. copp'r, or rinc {2} Ingestion of endophyt._inf«1ed f.",ue grass" {3} Food d.priv.rion for 4 d (m • • n [t T J decr",,""" from 19.9 nmollL to 7.6 nmollL)" d. C.nle fed foliage from uurJlma !tu~«pha'" (rommon ruome", mind. trtt, ipil_ipiJ. uazin. pje, and kub.bul.) developed hypothyroxem", .nd hypothyroidism." 3. c.n:ain dog brttds t.nd to h.ve lower [tTJ th.n oth.. breeds. In one study, the m•• n [tTJ in !.rge_breed and medium_breed dogs v..as about 0.5 j.lg!dL low.. than the [tTJ in the .mall_breed dogs." Grryhounds, . nd pouibly dogs in oth.. sight_ hound brttds. ha"" low....f..ence values for [tTJ . nd [IT.] than most oth.. dogs." Th. di"i:nosis of hypothyroidism in sighthound dogs may ..qui .. d. u oth.. than [tT.] {e.g., increased [TSH]}. Unpublished dau for dogs in [h •• ighthound brttds indico" that diff... nt ..f... nce interv.ls are need.d for [tTJ and [ITJ. but not for [tT,] or [TSH]. [I.

[F= thyroxin.].. ([ITJ .. ) A. [nc... ...:! [ITJ .. (frtt thyroxin. roncentmion by aJuilibrium dialy.is) I. Th...me disorders that couse • truly increased [tT.] (Table 17.2) a.. apectal to ao.use a concurrently incr=d [IT.]... About 98 % of hyp'nhyroid cots haY< incr",,""" [IT.] .. when tested." 2. [IT.].. does not al"",)" mirror [tT.] . a. A hor.. with diniao.l hyperthyroidism h. d a normal [tTJ but an inc... ...:! [IT.]...... b. Concurrently finding decr",,""" [tT.] and iner..""" [ITJ .. in cm suW'u the p.... nce of. sick .... thyroid state." For unknown ",asons, sick ao.ts occasioruolly ha"" an increased [IT.].. but • [t T J that i. WRI. 3. T,.AA may com. p",itiv. int..f... nce in some IT. as",ys. but ""lues for [IT.].. a.. not .ffeclal. B. Dec..ased [ITJ .... (f= thyroxin. concentration by aJuilibrium dialysis) I. Thyroidal disord.rs that couse decrnsed [tT.] by dec",.,ing production ofT. are apeclal to have concurrently dec",.,ed [IT.] ... 2. Oth.. disord ... or ronditions that =y couse dec......d [ITJ .. include hYP'",d .. noronici,m, infLommation (interleukin I, interl.... kin 2, int..f.ron." and tumor necrosis f. ctor m.y cou.. decr=ed [ITJ..,), and """tmenU with prednisolone. sulfon. mid... or phenobarbiul. 3. Dec..ased [fT.] .. was found in horus with arerim.nully induced hypothyroidism and in ho .... with • v. ri.ty of illne,s.. {especially with s",ere disorders}.'"

TOTAL TRI[ODOTHYRON[NE (tB) AND FREE TRIIODOTHYRON[NE (fT3) CONCENTRATIONS I.

B.,al [IT,] .nd [IT,] ...... ronv...ion ofT. to T, but have less diagnonic .. n.itivity for hypothyroidism .nd provid.linl. u..ful additioruol inform.tion 0"" [tT.] . nd [IT.]. In dog., diurnal vari.rions in [tT,] we .. less th.n the variation. found in [tT.].'

794

II.

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY ItT J is m=urrd to mOllitor T, supp.... ioll test.

th~npeutic

OOllctlllr>tiollJ alld to

asses.!

oWII~r

compli.llct ill

th~

III.

If a ",Iid.ph ... RIA is u..d to mum", ItT,]. th~1I T,AA call cau.. wOllmusly illcrea..d values just lik~ T.AA in tT. assays (Fig. 17.2). [II some =)'1. T,AA f:.!.dy da: ...... [tT,] alld f:'!sdy illcr ...... [IT,].

THYROID.STIMUU.TlNG HORMONE (fS H) CONCENTRATION I.

Dogs A.

[lIn~~..d

emilie [TSH] I. Primary hypothyroidism: Lack of lI~tiw fttdb.od: b.-causs 24 ng/mL) during and .fter .dmininmion ofT..

c. [eT,] should bt incr have not i>ttll widdy used, .nd th~ir di"l:nostic value compared to oth~r .....'menU i, not firmlyesrabli,hed. lnaCCllrate [TSH] at ve.ry low concentmions (the =y's detection limit is llrar collcentrations found in .... thyroid dog,) could resuh ill inaccurat~ :md pc:rha", mislrading ratio •.


799

Table 17.4.1nrcrprctation of thyroid profile result. in dg£ [rT.(]

[IT.(]..

[TSH ]

TgAA

lnt~rpreurion Rul~s

WRl

" "

WRI-i
ry hypothyroidi,m cau..d by lymphocytic thyroiditi. Prim>ry hypothyroidi,m cau..d by thyroid atrophy or possibly ~nd-lI"l:e immun~ thyroiditis Saxlfldory hypothyroidi"" caused by pituitary gland dysfunction Sick .... thyroidi,m. nonthyroidal illness" Hypothyronmia caUoN by dfecu of drugsNonthyroidol illness (sick euthyroidism) Prim>ry hypothyroidi.m (lymphocytic thyroiditis) with T.AA incr~asing th~ [tT.(] (..e Fig. 17.2) Thyroiditis without thyroid dysfunction or f:.ls< positi"" (e.g.• nonspecific binding) Thyroiditis with comp"nsatory incr~a", in TSH production Pounti:.lly '""hd,~ .J "f

=1""'''0",,,

•

,.1'...,,,,,,, in",rv:o\ anno' I>< ..Ji.bly cstablisW.

• Sul£omethaumlc_ttinmboprim. pr«!nisoJone. 0' pl><nob.rbiuJ < lfT.J ... ..-iU vary. ~",J" depend on wh..e th. illness.. or drugs intorfe .. ..-ith thyroid honnone prodoction (_ th. _,). No ..: ltT.1 """ Iff. 1.. near , .. pectin rd'"rene< Jimits (borderline r.... I") should I>< in"''P'''ted A. Majo, patterns of thyroid profile results in dogs (T abl~ 17 .4}"~""""""" B. [tTJ can b. u.=I to help monitor thyroxin~ th~rapy. Fo, dog. r~iving .ppropriat~ thyroxin~ SIlppl~m~ntation. [tT.] i. expectffi to b. high_normal to inc,~as.d 4-6 h .fter thyroxin~ :administration and [TSH ] should b. WRI."' C. To "'as=< a di"l:n05is of hypothyroidism via hormone assays in a dog r~iving thyroxin~ SIlppl~m~ntation. thyroxin~ should b. diocontinu.d for.t l=t 4 wk prior to t~sting. in ord~r to ",mo"" th~ inHu~n~ of treatm~nU on thyroid profile results.'

[I.

Major

pan~rns

of [tT.] and [IT.] in caU (fable 17.5)

BOO


Table 17.5. 1nrcrpretarion of [IT.] and [fT,l .. in caU

Clinical hinory,',( signs mggest

[tT.]

Hypmhyroidism

i

Euthyroidism

[IT.] ..

.l..WRI

WRl_i

WRl

WRI

;

""_WRl ~J "" WRl_i

Hypothyroidism

" "

[m~rpre{ation

Strong rv:id~n"" of hypmhyroidi,m (a ooncurmll t [IT.] provid.. additional ev:id~n"" but i. typically not nttd
Sa."""'..

Sa."""'..

171 TH YROID FUNCTION

0"

II. Stn"".,m HP. ArpI ..;. in. do" / Am Y" Mod A..oc 181),1476-1478. J6. G..b .... PA. N~ RF. Rd'oal KIt ~BoII ~ , AI.. 2001 . L,....pbocytk tl.J""'iditio. Y" CJin No"," Am SmallAoim p,." }h91~J}.

BIl2


So""""',

J7. B.to.. RL. HoonofWJ. 19l!2. im.&inc fo. d" ovaho";"n eltl.Y""id ""'pl.... ...d Ioypotkyroidi.., in • doc. J Am Y" Med A_ 180,)("77_ lon. 4S. a. .. t>inCB, McN«ISV. G ......... CL. P,..ani", SC 19l!J. ~nital kypothyroidi.m in " dor; du, to on i
oo< a,"", kypodtyroidi ....1 J S...n Ani .. [',"'. 40,152-1 57. S5. Kaotroow .. LB. P''''toO M E. T "P"'"" ]A ""tim C. Nicl.ol. R. 1999. s...... tot,) ... ,....;.... total ttiiodo"'yro· ..itt,. fto< ...yro.;"' . ........ pctropin oon«ntn.tion. in y

SI WRI

SJ"l' mclntcrnational d'Unit6 Within ,.I'",.""" illt.rval

PHYSIOLOGIC PROCESSES I.

Regulation of cortisol and :ddo,teronc 5tCmion {Fig. 18. I} A. CRH from the hypolhal.mu. nimul. te, the production and ,.I...... of pituic.ry ACTH and oth~r hormone,. Low [corti,ol] promotes on:retion ofCRH and ACTH . High [conisol] inhibits 5etl"etion of CRH and ACTH . B. ACTH nimulatr. th~ production and rd~ of cortisol. :ddost~ron~, and oth~r st~roid compounds from th~ .dr~nal gland •. Th~ .dr~nal gland cortice, produce most circulat_ ing cortisol. C. Aldost~ron~ «tors and oth~r proteins inmlval in glucon",,_ gen~';., protrin cataboli.m, lipolpis, immun~ responses, and H,O Wlance. G. .\ion conirol i, remm.ffl from plasma by hepatocyte.

IS/ ADRENOCORTICAL RJNCTION

."

Fig. 18.1. R.w>I>tion of coni",]:and ald05tero ... ..anion. • CRH ",1.1>«1 from tbe hypothal>m"".timuJ. ... the p,odoction and "'I.... of ACfH from the pituiury glmd. ACTH stimula... the production :and ",lea>< of cortisol :and aldostisodic aagg.rated srcretions or because: of. mild but continuously increased production of cortisoL A [coni",l] is btn interpreted in either d"""meth.50ne supp ... _ lion un. or ACTH stimulnion test. {s.. later sections}, Historicol, physic:d, and preliminary laboratory data may clearly indicate that an anim:d h •• hyperadrenoconi_ cism but may not clearly differentiate the cou.." of the pathologic !late, Adren:d mppression and stimulation tests (covered later in thi, chapter) con be hdpful for this, and diagnostic imaging methods (i,e" radiography, ultrasonography, computw axial tomography, ot magn.",ic """,,,,,no:: imaging) con locate the pituitary or .drenal neoplasms but c:mnot determine wh",h.. the abnormal tiMue is producing ace: .. ive amounts of hormones,

18/ ADRENOCORTICAL RJNCTION

B09

Table 18.2. Discascs and condition. that cause hyperoortisolemia Inc ....aI production of oortisol Spom:meou. conditions •PilUiury-dCJ'< rnim:d h.. clinical manifest. tions (~.g .. polyuri. or .Jop"rad .. nororricism a. Chronic administration of glucocorricoid drug. (~.g. , pralnison~ or prednisolon~) may product clinical 'ign' co",in~m wilh h}'J>"radr~noconicism. b. Th~ aogenou, glucoronicoids will caUst • n~g.rin f,""db""k on th~ rd~.st of CRH .nd ACTH, and thu, .dr~nal glands will atrophy and produ,,", l~ss conisol. B.. din~ [corlisol]lypically will ~ d,""r ....-d {< 1.0 ).lgldl}, .nd th~re will ~ a diminishal responst in Ih~ ACTH srimulalion tesl. Slow wilhdrawal of th~ 'r~roid rr~.lm~nts ~nables m~ adr~nal glands 10 r«:over. 2. latrog~nic hypoodr~nororricism a. Tr"lm~m of dog, with op'DDD (mirOlan~ [ly>n~ ralucel [coniwl] by inhibiling 3~-hydroxrsuroid d~hydrog~n ... , an ~nzyme m>l caulyz.es an imermaliar~ r"clion in sreroid synthe,is."

812


C.

O{h~r common routin~ labomory finding' with hypoconi",J.mia {exc:qJI with iatrogenic hwrad .. noconicism C;>U.ffl by glucocorticoid .dministration} I. leu\rogram: abstnct of suroid Jrukogram in messa!, ill p"tienc, (""niculn]y a Jad,

of lrmpho~nja; and possible lymphocytosi' or eosinophili.) 2. Chemistry profile: hypon. mmia, hypochloremia, hy~rkaJ.mia,

hy~rcal""mi ••

hypogl~mja, and ""otemi. 3. Urinalysis: inappropriatdy low uti". sJl«ific gravity with O7.Oumia

URINE CORTISOL TO CREATININE (Con:Cn). RATIO I.

AI d=rikd in Chopt.. 8, ooIDp"rison of. urine .nalyt.'s oonctntration to utine [etrat;. nine] will provide a rdat;"" m. of urinary exc.. tion of the analyte (mrn :u conisol) oompara! to c,..atin;ne. [n thall}', the {Cort:Crt}. mio should d~= a hyptradrenal sUt.

ktter dun a basal [coni",]] ~U'" the cortisol that accumulat.. in uriM WlU producnl ov" a long~r !",riod and thus is not as su=ptibl~ to vui.tions amsN by ~pisodic conisol « con cou"" fluctuation> in • r~ndom .. rum [cortisol]. How~nr , th~ incrrasN urinary conisol acrHion could ~ ~ith" a ph)"iologic or patho_ logic nat~. [I.

The (Con:Cn). ratio should ~ calculated by ming molar conctntmions of urin~ coni",l and cr~atinine {Eq. 18.1}. A markedly diff~«nt mio would result if [conisol] and [cr~ati_ nine] we« apr......:! as J.1g1dL .nd mgldL, r.. prctivdy. Inst~ad of stating th~ true ratio val"" {~.g., 20 X Ia-'}, ",metim.. it is short~ned to "20" in clinical j.rgon.

C) . urin~cortisolconctfltration ( "~ \.Alrt: n • ",uo =-'C'=========':: urine cr~~tinin~ conctnt"'tion

{18.1.}

with cortisol in nmollL &:: c",atinin~ in mmoliL Enmpl~: urine conisol conctntration = 200 nmollL urine cr..,.tinin~ conctnt"'tion = 10 mmoUL (Cort:Cn) mio = 2°OnmolfL • 10mmolfL Ill.

200 nmoljL lOx 10" nmoljL

20 X I 0....

Conclusions from published rq>o>rts {Fig. 18.2} A. Dog,"~7 l. A {Cort:Crt}. "'tio chat is WRl i. mong ~id~nct chat • dog d""s not h."" hy!",,,,drenoconicism. but incrrasN (Cort:Crt). mios .'" freq""ntly found in dOl}! without hy!",,,,drenooonicism. [n oth~r words, the (Cort:Cn ). "'tio has a high di"l:nosti, .. nsitiviry for conine hYl"rad«nooonicism (r~lativc:ly f~ f:d .. negativ.. ) but has a poor positive predictin v:due and poor di"l:nostic sp«ificity (r~lativc:ly frequent faJ .. po,iti=) (Fig. 18.2). 2. Basal (Con:Cnj. ratios connot rdi. bly diff"entiatr PDH from FAN, but th~ gr~atm ratio. are usually associated with PDH, as is suppression of {Cort:Cn}. ratio in conjunction with . HDDST." B. Cats:" Th~ (Cort:Crt). "'tios in 15 of 32 cots with h)'l"rthyroidism w,,~ greatrr than the up!"'r r.f"enct limit of th~ fdin. ref.",nct interval (8.0 X Ia-' to 42.0 X 10""'; n = 45 ). For th~ h)'l"nhyroid COtS, the median mio v:due was 37.5 X la-', with two values .bon 100 X 10..... The gr~.t" (Con:Cn). ratios may ~ ",fl~iv~ of the stress


'" "" ""I ~450 ~

-'00 -"

'"

i

study A

' 'I -=':1

Sludy B

~1000

:'i

~ '00

..,...........

None ... .,..

oorII<MI ",. «I)

""...,_

I"' 2lJ

Fig. 18.2. (Co.t: Cn) , " ,I i " , in to. studies. , In.rudy A, tb. (Con:Cn) , " , I i " , from theN grouP' of dog ...... oompar«J to. group of h..lthy dogs (b.ckground g"'y fc< in..rnk Th. background gr with FAN b. Y< dec ......d ACTH ooncm""boru. n,. background ws defin«l ... postdenmeth...,,.. [oonilOl] . o If r.. ula from LDDST :md HDDST .,. e""mined toll"tbrr ." the", .... in:odeq"'''' rupp",uion of corsi",1 ooncrntr:otiom in both ..... in ",,:uly:ill dog. with FAN (D ..,d H: 94 %) but in . minority of dogs with PDH (B. C, ..,d G: 24 %). A f... dogr witb pDH (14 %) ..,d two dogs with FAN (6 '!O) had i",dequ,,,, Sllpprersion witb tb. LDDST but had :odr
'''' suppression with the HDDST. Two dogs with PDH ppr .. sion witb tb. LDDST but inadequate ruppr ... ion with tbe HDDST. (I %) had HD. high d ....: . nd lD. 10.. 00...

.dr
." ....

816

18/ ADRENOCORTICAL RJNCTION npa;t«i to bt da;t""...,j dramaticolJy >t 4 h and 8 h (Fig. 18.4A). v.lu .. . ", usually i""d'"'juatdy suppress.d at 8 h with both PDH and FAN. (I) Mon _"inarians int~tpr~t a pondn;;omecha>one [ruttisol] < 104 J.Ig/dL (< 40 nmollL) to indicate th~re was .d'"'jlIate suppression of coni""l secretion. This da::ision threshold . ppear> to h ave been calculat«i from data rulJa;t«i from 22 healthy dogs; it repr~..,nt«i th~ m""n concentration (0.5 J.Ig/dL) plw 3 sundord deviations (3 X 0.3 = 0.9 J.4::ldl).t

8 h. ,~'" {2} Some authors propo.., th at suppw;:sion i. present if the postdnamethaoone [coni",l] in the 4 hand 8 h samples i. < 50 % of th~ pralexamethasone concentration. Such .n interpr~uti"" guiddin~ i. comistem with the half_ life of plasm. coni..,l. b. If hYP"rad .. nocorticism is cou.«i by PDH or ~ctopic production of ACTH. th.n a low do.., of dnamethasone m.y or m.y not l.ad to supp ..... d rdease of ACI"H by nalplanic pituitary cdl,. and thu. cortisol production from hYP"rplanic adrenal glands mayor nuy not da;",ase (Fig. 18AB .nd C). {I} In som~ ca5e'l. the 4 h postdu.. methason~ [cortisol] is btlow th~ da:ision thr.. hold. but the 8 h postdnamethasone [coni""l] is .bove the da;ision threshold. In such the escapnl suppression i. highly indicotive of PDH if the clinicol 'igns suppon • hyperadr~noconicism diagnosi •. Nonad",nal disorders may aloo bt associat«i with this pattern (Fig. 18AE). {2} Suppr=ion i. demonstm«i in mor~ PDH """,. if the "< 50 %" criterion (Fig. 18AC) is us.d rumparal to the "< 104 J.lg/dl" (< 40 nmoUl) criterion {Fig. 18.4B}. c. If hYP"radrenocorticism is cou.«i by FAN. then low_do.., dn;;om~tharoM is not npa;t«i to da;r"".., the secmion of coni501 (Fig. 18AD). Even though suppres_ sion criteria a.. nor fulfiJl«i. rurtisol concentratiom may Huctu ate during th~ testing. btcou.., of variations in cortisol secretion by nwplastic cells. binding to prot~ins. or plasma clearance. The WDST has high diagnonic stnsitivity for FA N. d. Supp..ssion may not bt .d'"'jlIate in dog. with nonad",nal illness (Fig. 18AE). e. In two dogs ..",iving phenobarbital therapy. coni",l concentrations were not suppr~ss«i ad'"'juatdy. possibly because phenobarbital·, dfa;u on cl""rance of synthetic steroids enh.nce duamethaoon" d""rance rate. HoW
3. Int.. preutiotlS for T.ble 18A w..e made by using Fig. 1804 •• a guide. lkst int.. pr
~\e

latrogonK; hypontdraflO. corliD.m (n - 28)

t.jpo, , Criteria used to det .. mi". "Ppropri. «, inaeO: of .. tract.d d ..., tbc antho,,' ai",ri . ..... wed, , In all bypoadJenooo.sicism c-., the ....... '" inadequ ... ""'po ...., to AcrH stimul. tion, Tbe 225 C>SeI included 220 = of p.im1ly idiop .. bic bypoad",noa>rticism and live = of oeronduy bypoad«nororticiun," In.JI.....,. of u trogrtic;""" od«nooo.-tio.J .t«>pby « ... b.d;n ;.,.0.,,, to AcrH stimuhtion," , In 84 % ofPDH easel and in 51 % of FAN aoes, the •• we .. .,.:ogg ... tesl ""'po ..... to AcrH stimuhtion, ,,,,,,01,7 'c;. , In 14 % of dog,..ith nonad«nal iUnes>es, tbe« ..... engger:ot and the zona n:"tirulari,. {2} ACTH stimulation tests con b. usw to monitor destruction of .dr"nocorti. col tissu~. Typically, the goal of op'DDD m.tm"nt is to ~ the post.ACTH [coniKlI] to b. < 51lgldL {< 140 nmolfL} but not """'" .ufficient dmruction to creat" a hypoad",nocortical !late. f. Aft"r trilost:m" (Vetory! or Modrenal) tr .... tm.nt {I} Trilostan", which i. an .It.. natin to op'DDD for tre.tment of PDH, rwucts neroid synth ....is by inhibiting 3p·hydroxysteroid d..hydrogen"", .nd thm reduces the synth.. is of cortisol, aldoneron., and oth.. steroid hor. mon~'. Trilo!lan. rwuct. [cortisol] in dog. with PDH and .Iso reduces [aldo!lerone] , but to a I.... r degree." {2} ACTH stimulation test, can b. used to monitor th~ effectiveness of trilo. ,tane tr .... tm.nt of PDH. [f the dog has continuing clinical .ign' and the po,t.ACI"H [cotti",l] i, :> 91lgldL (:> 250 nmollLl, then th~ d=>ge i.

021


incr .... sn!. If th~ dog h .. continuing clinical signs suggrni"" of hypoad .. nooonicism and th~ post_ACTH [conisol] is < 0.811g/dL {< 20 nmollL}, th~n tr~>tm~nt is discontinu«l."" 11.

Cats A. Low-do""

de:um",h:ason~ ,uppr~ .. ion

Ie;{ (LDDSn: not recommend..,j

I. Procnlu~ B..,ically Ihe same procedure as for Ih~ emine LDDSf aa:pl daamelh_ ason~ is given at either 0.01 or 0.015 mg/kg IV. Some people ..ftr 10 use of a 0.1 mg/kg IV do"" a. a LDDST in em, bUI il is oofl!ide=l a HDDST in thi, lal. 2. Expect..,j ... uln" {Sp«ifi, I"'tient =uh. should be int.. pret«l by using ",f..ena: interv:d. and interpreYlion guiddine> provid«l with ... uln.} a. In h..lthy cats, the 4 hand 8 h cortisol oona:ntralions a.. um:dly < 1.0 ~dL {< 30 nmoUL}, but Ihey ..e nol suppress.-d thi. low in about 15-20 % ofh .... lthy cats. Coniwl suppression may :dso fail to occur in cots with non. drenal illness. Therefo.. , the lDDST has poorer diagnostic specificity than the HDDST {for which conical suppression fails to occur in very few cats} :md thUl i, not recommend«l. A postdeum",hason~ [cortisol] of 1.001.411g/dL (30-40 nmoUL) is con'ider.-d a bord..line r~sult. b. In cots with hy""rad .. noronicism, the 4 hand 8 h oortisol cona:ntr.ltiofl! a", apect«l to be :> 1.5 J.lgldL (:> 40 nmol/L). B. High-d""" deum.thasone supp.... ion t.. t (HDDSD I. Procnlu", a. The initial protocol is the same as with the conine HDDST, but I mg/kg daamethasone is aho used. Som. Jl"Ople ..f.. to a 0.1 mg/kg d""" as a low dose in cats .nd oonsid.. I mglkg a high dose. Others cofl!id.. th. I mg/kg an ulm_ high dose. b. em m.y the supprnsive: dfecn of de:um",hasone fm .. th.n dogs, I 30 min and 60 min or jun at I h. 2. Expect..,j ..sui,," a. S""cific I"'tient results should be int.rpret.-d by using ..f... na: intervals and int.. pretation guiddin.. provid«l with results. b. A healthy cat should have:. p",_ACTH [cortisol] of 1.0-6.0 llg/dL {30-170 nmollL} .nd a pon_ACTH [oortisol] < 13.0 J.4:/dL {< 360 nmoUL}.

=""

.22


c. Cau with hYp'rad .. noconicism =y han a p, .... ACTH [oorti""l] WRl or incrrasnl. and a 30 min or 60 min post_ACTH [cortisol] :> 16 J.lgldL {> 440 nmoUl}. Ho~""r. only .bout 40--50 % of em with hypOnal variation in [ACT H] . results of the '"'Iuin~ daamrthasone suppression test " r.,,~ diffe",nt in January rompar 1.8 tim .. th~ p..s;omple·s [rorti""lj.

c.

COMBINED DEXAMETIlASONE SUPPRESSION- ADRENOCORTICOTROP[C HORMONE (ACTH) STIMUlATION {RESPONSE} TFST The major advancag. of th~ combin«i tost i, that it combin~. adrenal :as.=sm~nt into on~ diagnostic procfflu",. and thu, only one ~ of s;omple; is submitt«i to a rd'trence laboratory. The major disadvantage in doC' i, that it doo; not han the ",me diagnostic power as the combination ofWDST and HDDST don~ individ .... lly. I.

Canine m~thod" A. A ,ample for a ba",l [conilOlj is collect«i. and th~n daameth. lOne is :odmini'l .nd incre.s.d "!dost~ron~ to pla,ma r~nin activity ratio,." Th~ cats we .. not hyp'rnatr~mic •• nd "'m~ d~lopal ren..! l.. ion, ron,istem with p'"i!l~m hypen~n,ion. 3. Anoth .. cot hod an .d.. nocortical carcinoma that produa.d exct.. ivt .mount, of "!doneron~ .nd prog~steron •. The resulting clinical Jign' w..e due to the effect, of progtsterone (i .•.• diabete'l mellitu,) mo .. than to "!doneron~ effects."

Ill.

Aldosterone con""mrations in oth.. conin. disorde" A. Th... is not a cleor "'p'.. tion of pr ... ACTH aldosterone oon"'ntrations betw..,n h."!thy dogs .nd dog, with hypoadrenoconici,m. How"",r • ..!do't.roM roncrntratiom in the pon_ACTH "'mples w..e lower in dogs with hypoadrenoconici,m than in clinicaUy he..!thydog, (Table 18.5). B. Dog. with PDH hod ..!dosterone roncrntration •• imil", to th"",,, ofheahhy dog. in both pr ... ACTH and post_ACTH sample'l (T.bl~ 18.5). C. Som. dogs with non.dr~n..! dilOrde", had. vtry high [..!don.rone]. The high con",n_ trations ..~ probably rd.trd to hypovolemi.> or dec ..... ed dfc:ctivt blood volume (T.ble 18.5). D. Result, of. study of 31 dogs with PDH. S dog, with FAN .• nd 12 h... lthy dogs:" I. Aldosteron. oonctntmion. we...ignificontly lower in the PDH dog, than in the h~..!thy dog,. The authors suggc:ned that und .. chronic ACTH nimulation. some of

T ab .. 11-'. _ " ' .. 00&< • •

" " ; '. .

f, .... ACnl ,,;......... toot. i. dar Al. 2 Failu.. to , .. a dec ..= in [wsillophil] or failure to..., .n illc..asaI n.... trophil to lymphocyte mio nt...dmininmioll of ACI"H sugge;ts the pr=lIC< of hypoplastic or atrophi.d ad",,,,,l gland •.

IS/ ADRENOCORTICAL RJNCTION

027

B. lncr~a~ ~= of obtaining ""rum or plasma conisol con""ntrations and th~ir sup..ior diagnostic va.lu~ ha", mad~ th~ Thorn t~st and mooifi«l Thorn t~st nrarly obiOl.te. Howe""r. th~ rdationship be{v..""n blood [conisol) and blood leukocyt~ con""ntrations should bt ",membtr«l when int~rprffing routin~ romplet. blood count results. II.

Con,entrations of oth.. steroid hormon~. A. Adrenal glands produce other ,uroid hormon~s. induding int.. mediates in the .ynth~tic pathwaY'. l. Inc",ased pro!:"st~rone com:entratiom han b.",n r~ported in dogs and a cot with FAN."'" 2. In a study of 53 dogs with confirmed hyperadr~nocorticism {including PDH and FAN o>« .. "atioo, in ..."'" and pi ...... of oi ... , HS, ru;ob..k A. van trow kcause they com";l1 • dear waury fluid in h~.lth. Pleural alld ptriton.al fluids are form":! by simil.. processes that illvol"" th~ forces of Starlillg's law alld an.romic muctures. G~lIer:olly. a pt.srna filtrat~ I~.vrr"'nts .n effusion. Equine pleural . nd J>
o.,finilions A. Effolitm i. Ih. aa:umul.tion of fluid in • lxxIy 'P= or cavity. and .n ~ffo'ion is th~ fluid th aI ho. aa:umulated. B. Mcilr' is Ihe fluid .ccumulaled in a ..,rous cavily (Iypic:olly p"rilon",,1 cavily). II can be a u:mmdate, exudale. or oth" Iype of effusion (e.g., hemorrh:agic """il"). C. Tranrudation i. the p"""l:e of fluid or solute Ihrough a m~mbr:me bccau.. of chang.. in hydraulic or oncolic pressure gradi~nt •. D. A """",da" i. an efll"ion produced by chang.. in m~.nic:ol faciO .. SlIch :as oncolic or hydraulic pressu"" Wilhin capillary bcds. Such chang.. influ~nc. Ih. loss or resorplion of fluid. E. Hydroiftltic prruur~ i. Ih •• n~rgy (pressure) of. fluid al resl. F. Hyd,,,u/ir P"'''''' i. Ihe energy (pressure) of. fluid in mOlion. G. Exudation i. an exuding or oozing out Ihrough pores. H. An ~xuda" is :m .ffusion produced by incr""scd va.\Cular p"rme. bility 10 pl"'ma prolCins bccaust of inflammalion. I. Hmto"""g~ is th~ =p< or 10.. of blood from blood vessd. or hearl. J. LJmp/nrrl",K' i. the ..cap" or 10.. oflymph from lymph ves•.!.. K. A modifi'" tran",dau is • lransudale Ih al ru.. been modified by Ih. addilion of prolein andlor cdb. This classificalion is nol r«:omm.nd~d by the amho ...

'"

FUNDAMENTALS OF VETERINARY CLINICAL PATHOLOGY l. P>thologic proc= that produ~ thest ~ffu,jolls ar~ V. riM and not consjn~ndy

d.""ikpillary b.ds. th. major variabl.. a.. illustr.u.d in Fig. 7.3.

NM

N......p.ilo ... .........

Bod\.0

N......p.ilo .. ..........

no

> ).0

Ncutropb.lt ..

,-

"0

<M

H..,. ,. do..dy

"0

Ydlow, """"', K , ••

~2,0

> , ••

-~ ~

~2, o'

< 10.0

Sao .. I)mpboq, or oth~r laboratory dan) is n=:lal to inwpm ,ignifiCOln", of .rudysis results or esublish th~ patho\:"n..is of:m dfusion,

th~

L

Transudat~s

A, Pathogtnesi, L Transudau. typically accumulat~ in plau:d andJor I"'riton..J COIviti.. wh~n th~r~ is an a", .. diffusion of pla"na H,O from th~ vascular 'pa'" ba::.u"" of alterations in hydraulic and/or oncotic pressures, Th~y =y also .ccumubt~ wh~n lymphatic drainag~ from a COIvity is impai=1 ("'" F~, 7,3), 2, For most ti .. u~s, • transudate is prot~in poor ([TP..a < 2,0 gldL), but transudation from a liver COIn crnt~ a prot~in_rich peritone:d transud.t~ if normoprot~in~mia is pr=nt, [f. markal hypoprot~in~mia i. pr~.. nt, th~n th~ transud.t~ a",oci.ud with hq>atic transudation will ronuin a lo~r [TP] than if forma! wh~n th~ plasm. [TP] was not d«r~"""", 3, A tr.Insudativ~ pl~ural ~ffusion is COIU.ffl pri=rily by incr~aud hydraulic p.... u.. in the alveolar COIpiU.ries, Most of th~ pulmonary transudat~ r~mains in th~ lung {i. ~ " pulmon. ry a!~ma}, but it may flow into th~ pleural COIvity ba::.u .. of damaga! vi=ral pl~ura. Concurr.ntly, venou, coIIJ:atic fibrosis), {I} Port:d hypen~nsion COlUSa! by right h... rt failure i, posthepatic .nd pominu_ soidal, B«au.. there is incrnla! hydraulic pm..u .. in th~ h~patic ,inusoids, the resulting effusion is protoin rich, {2} Port:d hypenension COlUSa! by hq>atic cirrhosis is intrahq>.tic but =y be .ith~r p... inusoidal or sinusoidal, Whon the incr~.sffl hydraulic pre .. u", is presinusoidal, th~ resulting ~ffusion is prot~in poor, Sinusoidal hYl"'rt~n,ion may COIU.. protein_poor transudation when hypoprouin.mia is marka!, B, Protein_poor transudares (Tabl.. 19A and 19,5) L Th= t.tic cirrhosis and prouin_losing n~phropathy (f.bl. 19.4). P.thologic prouin_ poor transudat .. a.. unrommon in cats. horse;. and canl~. [n both cirrhOli. and prot. in_IOling n.phropathi~s. tranmdates form baau,", of th""" two major factors:" a. D=~..al plasma oncotic pr i, an uncommonly rNDg_ niud disord~r that Jruly b. caused by pon..! ""in hypoplasia. Dogs with this disorder hove protein_poor ~riton...J tran,udates and many oth.. labor:uory data sugge;tive of. port"'yst~mic shunt or hq.atic insuffici~ncy.>1 C. Prot~in_rich transudat~. {Tables 19.4 and 19.5} l. Prot~in_rich transudate, typically occur when th~ .. i, increa.o;od plasma hydraulic pressure in th~ liver or lunC' because of venous cong.

B44


C.

Th~ l~~

of pro{~in' into th. interstitium rffiu~, the onrucie pr=u,", gndiem

bttWttfl pla,JruI .nd interstitial fluid, :md rhm plasma h.., less ability to reuin H,O.

The pl.mru, hydr>ulic pressure push.. a protein_rich fluid into the inurstitium. and Jess fluid rffurm in the nnom .nd of the capill:.ry W A pleuriti, or p",ilonili, moy dam"l:e mesothdium so that the protein_rich interstitial fluid . ..ily rno"". into the covities. D. Exudates are causffi by inf«tious and noninfa::tiou. "l:em •. The typt of audat. (i.e., infectious or noni"f=ioll'l) cannot'" rdiably determinal until the cou"";",, ~nt or """m Ita. bttn establimffl. I. Exudates "e &«\uently caUoN by.n infection with bacteria or other organisms. Some pwpl. consider >lptic and blle.friill to "" .ynonyms, but "p.is ,eftrs 10 .ny microbial infa:r;on (e.g. , ru.ctoriaJ, fungal, viral, or protozoal). To reduu th~ possibility of confusion, it may k ktt~r to ref.. to th~ inf«tiom exudm:s by the appropriat~ inf,""tious ~nt (e.g., b:ocurial nudate or fung:d audatd, when known. 2. Exudates ar~ :dso rommonly formed during noninf,""tious inflammatory responses. For enrnpl~, th~ inflamm>tory respo",e may bt du~ to n,""rotic tissue (~.g. , ~ndary to isch~mia or ntopl..,ia), th~ presonct of a st"ile for~ign body (e.g., surgical 'pong~ or barium), or th~ p ..,.nct of an irritating fluid (e.g., bile or urin~). E. When an ~ffusion i, protoin rich and Ita. a high [neutrophil]. it is not difficult to r'"""gni", th~ effusion as an nudal/",um;a sp.) a.. uncommon in the United Stat~'. A/lUStigote, GIn bt found in /lUcropbai:"S.

Ill.

Hemorrhagic effusions (fables 19.4 and 19.5) A. Wh~n the primary reason for .n effusion is hemorrhage, th~ fluid is a hrmorrhagk rjfo,ion. Rdativdy minor hemorrhage is • compon~nt of many nudates becau.. of th. vaocular damage a.tsociated with inflammation. Also, minor hemorrhage commonly occu'" during the collection of an ~ffi"ion; thi, is commonly GlUed traumIltk 100,0 X 100IJll} may, Whell"""r ill doubt, the values of Huid with suspended cdl. con bt romp. red to the Huid', suptmatant, 6, A vari 100.0 X 1001J.ll} . ", found in exudate> and neoplastic lymphoid ~ffusions. VI.

Micro..::opic examination A. Wh~n cavitary effusions are d= and colorl~ .. (i .•.• look lik~ H,O .nd th ..efore ..~ prouin_poor and cdl_poor transudates) •• microscopic examiruotion of the fluid typically yidds very linl. useful information. For all othu ~ffusiom. the microJCOpic examin. tion of scainal cytoprepo.rations is frequently the most imponant p. n of the fluid analysis. Part of th. microocopic examin. tion is th~ aamination of ""n •• but examin.tion of oth.. structur.. and f.~tures is ~u.ntly imponant. I. Scains designa! for blood films ... fr~u.ntly used for the routin~ scaining of cytoprq>.rations. On~ major adv.nt"i:~ of using the blood st";m i, that people are f. mili.. with th~ staining of blood cdh and similar f•• tur~s ar. found in th. nud~ta! cdls of ~ffusions.

852


2

Th~ microocopic examin ation should indud~ .11 pm. of on~ or mor~ cytoprep."'. lions ~"'" of th~ potenti'" un.nn distribution of ~Us :md ocher microscopic

structur ...

B. '\hjo. :up«:ts of th. ""amination .'" as follows:

!'"'"

l. Nucl~t«i cdl diff.",mial count is done to determine pe=nt"l:"" of ....ch nud.... tions of ram cdl typ< can b. Gl.kulated and int.rpmed. For n.:Impl•. 60 % neutrophil, in a fluid with" TNCC of 1.0 X IO'fIlL is intupr.tn! differ.ntly than 60 % neutrophil. in a fluid with a TNCC of 100.0 X lo'llJL. If cd] ooll",lIlra· {ions are calculated from the perctnt"""., thpl~ indud~ ntesothdial ""US in th~ diff,,~ntial cdl count, .nd othm do not. If th~:are not indudtd, it is mo .. difficult to interpret thelNCC, and con""ntr>tions of oth« nud... ttd cdl, cannot bt calculottd or cominendy esti_ m. ta!. Mesothdial ""lh ar~ oft~n in dust~rs, so th~ir indusion may l...d to incruKd vari.bility of the diff"ential munt, deperoph~ ... or tran,ition pha.., occur in fluids. but they may aU ~ lumped into a m:>eroph~. category once the cell, have left the vasculature. b. Th. cytoplasms of m.croph:oges f""<J.uently contain vacuol ... lipid. or cellular d.bris. and might contoin .ngulfed celb {•. g.•• rythrocyt .. and leukocytes}. organi,m •• or foreign material (Plate 14M- 0). Ceu" organism,. or foreign mat..ial may und..go phagocytosis within 30 min in vitro (Plate 140).

854


{I} Erythrop/uge; ar. rdatively common in .[fusions wh.n blood comaminat" a fluid thor comains activaud macroph"l:" and wh.n cytopr'p"r>{;ons '"

not mad. fOOlI aft., ... mpl. ooU«I;OIl. {2} Leukophag.,,; ... rdativdy common in .om. fluid" e:sp«iIlly in Ih. ptriton.al fluid of hOrK'. F~u.ntlr. Ih. J.ukoph'gcuolata! cytoplasm, or contain .ngulfnl m at"ia/ :u. =;Iy recogniud. How.ver, som. r~{ive lymphocyt •• and ,mailer monocytoid or hi,tiocytic cdh a", not ~asjJy difftr~ntial [I.

[Ur~.]

and [Crt] A. Wh~n a diagno,i, of uro~ritonalm i, king comid~rM. th~ m= .. m~nt of tho [uru] and [Crt] in tho ~ritonnl fluid md a tim~_m>tchM ",rum sampl~ may hdp esublish a diagno,is. It i, imponant m.t the dfusion con""ntrations k compar~d with r..ant ",rum oon~ntmion' ~""" of the rapid diffusion of ur ..... nd Cn from the caviury fluid to lymph and blood. B. U",• • nd Cn a.. t diffu", through capillary wall.; uru diffu.s.:s quichr than Cn. [n h~alth .nd most p.thologic sUtes that creat~ effusion>. the ",rum and ~riton~.l fluid oon~ntration' of ure> md Crt .r~ n~.rly th~ sam~.

C. Wh~n th,,~ i, • r..ant .ddition of urine to ~riton~.t fluid. the r=.tlting fluid wiU h.n. gr~.t~r [u.....] and [Cn] thm pl.,IlliI con""ntrations ~= th~ [ur~.] .nd [Cn] in urine a.. typically much gre>t" thm pl"'ma or .. rum oon~nt .. tion'. With tim•• nd with diffusion of mol",ul .. du~ to con~ntration gradi~nts. the [u",.] .nd [Cn] in the extravascular . nd intnv;oscul.. fluid, will b«:om. similar :again • • nd both wiU k inc",asnl. I. Aft~r 45 h of ex~rim~ntally inducnl uro~ritoneum. the [Cn] in th~ ~ritonnl fluid woo. about twi~ the .. rum [Cn]; Th~ m~an ~ritone>l fluid [Crt] wa.< 11.6 mgldL (rml:". 5.5-15.6 mgldLI. wh"•• , the mun ",rum [Crt] was 5.2 mgldl (ran~. 1.2- 6. 7 mgldL). How"""r. th~ [u... ] in the effusion .nd ",rum at 45 h w~ .. nearly tho same. Th"", dau support the fact th>l u",•• nt.rs the blood fast" than does Cn. Azot.mia (.ith~r an incrn=\ [ure.] or [Crtll was det~ctabl~ in. f~ dog, within 5 h bur in :all II dogs by 2 I h after "ruptu ... " Th...rum [u",.] .nd [Crt] oontinun! to inc..... onr the 3 d study." 2. [n. retro'pectin study of 13 dog. with uro~ritoneum. th~ cr.atinine oon""ntn_ tion, in ~riton~al fluid w",e at l~.. t twi~ the "blood·· con""ntrations in II dog•. Th. durations of the sponunu>us rondition, w... not known. (Note; Th~ .uthon did not specifY wheth~r the "blood" c.....tinin. oon~ntmiom w~ .. ",rum or pl"'ma oon~ntntion .. )" The ratio. for .ight dog. with other ~ritonnl dfu,ion, were from 0. 7 to 1.2. 3. Ratim of ~ritonnl fluid [Crt] to .. rum [Cn] han ken r~ported for other anim:al, with uro~ritoneum; foal, (mun. 3.5; and ranI:". 2. 7-4.6)." horse. (;> 2.0)." and cats (m.... n. 2.0 md rang.. 0.8-2.4)." Th~ ratios can k u..d a,. guideline in the interpretation of data. but oth~r .. peets of the ca.. .should k carefully ron,id"ed. For enmpl •• a cat with a urinary tract ob,truction IlliIy ha"" bttn """"rely .7.0temic kfore th~ uro~ritonalm occurrM. Thm. the .. tio m.y not k;> 2 wh~n the cat is first enmined.

858


D.

U""~ (or ur"" nitrog
Ill.

[N.1 , let], :md [K'] A. N"" Cl- . and K' are f.edy diffusible through moS{ capiU . ry walls, and th", th.ir oonctntmiollS in plasma, intemitial fluids, .nd mOS! pleural and ptritoneal.ffi"ions .'" nearly th. sam • . Th. major exaption to this COnetpl occur.; in uroptritoneum. Comp""'" to plasma .nd most exmctUulu fluids, the urine [Na1 :md [en are las and th. urine [K+] .'" gr.... t.r. Thu., in Ih. early st"!:" of urop",;loneum, the ptrito_ ne.l fluid [N. 1 and [en will bt I... th,n ploUII" ron"'Dtmions, .nd Ih. ptritoneal fluid [K+] will bt gr....m than pla,ma concentrations. With tim~. diffiuion of d=ro_ lyt.. and H 2 0 will rrdu"" th~ diff~ .. n"" •. B. In a mrO!ptctiVUst conjugata! bilirubin is diffu,ibl~ and pl.. m a proteins ar. pre.. nt in most nontranrudative effusions, th~ [bilirubin] in most ~ffu,ions should bt .imilar 10 the strum [bilirubin]. Th~ major exctplion to thi. con""pt is =n with bile p"ritonitis and th~ formation of a bilious exudate. When damage 10 bile dum or gallbladder r.. ults in th~ l~akage of bile into the p"ritoneal covity, ~rilonitis will devdop and the r.. ultant exudate will have an increasa! [bilirubin]. B. The", >re stveral potential COUstS of bile entering the p"ritoneal covity, induding blunt or p"netrating lrauma, bile duct rupture secondary to manual expression of the gaUbladder, necrotiz.ing cholecY"titi. or cholangitis, rnoldithiasis. and neoplasia of the biliary tissu ..." C. When the effusion d"",lop.'l .econdary to bil~ l~~, "rults of Huid anal,..,.i. reveal the p".. n"" of an exudat~ that typically h .. a [TP...] :> 2.5 gldL, a T NCC :> 5.0 X lo'lJ.lL, and:> 80 % n.... trophih." I. Microscopic ex;omination may deta:r a .mall to large amount of intra""Hular or extra""Hular amorphous yellow to brown bil~ pigment, or bilirubin crynal" extn_ ""Uularlyor in macrophages. 2 [f the bile l~ is secondary to a baclerial infa:rion. th. exudate may ronuin intracdlul >r or exlracdlul>r bacteria. 3. Typically, the [bilirubin] in the bile-rontaining effu.ion. will bt at le ..1 !Wi"" an animal". strum [bilirubin]."-" 4. When a gallbladder l.. ion ~nabl .. in mucoid secretion (coUa! whit~ bil~) to ent~r the ~rilon..aJ covity, the resultant effll'lion may contain light basophilic mucinom m aterial wh~n ,uina! with a Romanowsky stain." D. Rerults of blood and urine analy.is will depend on th~ COUst and duration of the biliary lracl leakaj:e; for example, if the animal had obstructive rnolesmis prior to bile leakage, hy~rbilirubinemia may h ave pr~ed th~ bil~ ~ritonitis. However, with trauma_ indu=! bil~ l~akagt, the hy~rbilirubinemia occurs aft~r the onstt of the bile p"ritoniti •. Likewi .., an inflammatory leukocytosis may bt Ihe result of a bacterial cholangiti.

19/ CAVITARY EFFUSIONS

86'

that couses bil~ l~~, or an inHammatory l~ukocytosi, may occur aft~r th~ on.. t of arut< bil~ ptritonitis, E, Bilirubin assays that a.. design.d for .. rum or plasma ... mple. {."" Ch'ptu 13} typically em k ustd to analyu th~ .uptrnatant of ~ffusions. Bilirubin is d
References t. R.. ..... R.E. M"", DJ. lOOt . Alto. .fC.,,;'" • ..d F.ii", C)JtO"o . Pbiladdpbia, WB Sa.od. ... 2. Co...!l RL. Ty\« RD. t992. CytolOCJ ",,,J H"""","o 'f'b. H"". Gal .... CkAmakao V-23 Adrenocorticotropic bo"""",,, (ACTH) conomtr1tion, 813_ 14, 814f cortisol, pt.rrruo ratio to, 814-15 "imut.tion test emu.., 818-21, 819f < (All), 6OW- 52 octivity, in=»«l ..... m, 651. 651. uulytical con""p". 651J.-51 psychoLogic process<s. 650 .. rum, 6'51. 651' ti ..... sour='" for tot:d, 370-72 pby.ioLogic pr0=s
""~ ddinition.

83S hypoalbuminemia rnd formation of. 505 hypoprot';nomi. rnd formation of. 50S Asp ...... turi., 518 Bilt :ocid uulytic:d concr>, 690-91, 690f . nt,ic cirrubrion of, 690 excr .. ion bilivy, 691, 692f dra.=ret.rion, 691 uri"", '0 COl .. rio, 485, 696-97, 697, Bilt 691 Bili..,. di ..... , 6n Bilirubin cholrnui. rnd, 6tH conc'" of, 683 phJ"iologic p"""'.... of, 681--.'13, 682f conjug.t«!, d.cre:ased rxcr .. ion of, 687--.'19

C,''',

m"',

rlJwion rn.!";' with, 861 hemolJ"it rnd, 684-85, 685' hrp>,ocyte up ..... of, 685-87, 685' byperbilirubinemi., 684--89, 684, icterus, hemolytic rnd, 684-85, 685' m
p>'bog'" in, 565-73 calcul,,,d, 567- 70 comp" ....'ory cbang ... in, "'P""tthog ..... is. 381...'12 BMBT. Sn Bocc:d mUCOJ'" for. 7...'1

umpte...7

""~ c..". 596

_..

neopl ..i. in. 60 I Bo ... murow. 54-55. 323--65 1Jl1ly>i1. methods for. 328-34

""I..tic.

338 clostific. tion md r"'P"n
'"

nu,ririoruJ defici.ncies, 336 pos'mortem S1ffiples of. 334 reph""men'. 'brombocytopeni • ..,d. 237 umples.357- 58 Brodypneo. 561 Bromide. L-uc .. te m,,,.... ,,,,,,,,n' ..,d. 540 llucc:d murow bt...ding time (/1MB!) :m:dytic:d oonc< kine"". hypoblemic mY"P .. by in.

'"

Burr cell. 147 Co'+. 5., C:dcium Cocbectic ....... protein oyn,hesi./",ubolism.oo.

'"'

C:dcitonin ronunmtion. 630-31 C:dciwn (Co'",). 593--631 ..,iom. dilfusible binding of. 608 ..,rioo>glll..,,, binding, 611 _ 12 bo .... 596 chloride. do'ting .00. 281 conc
.. rum, 535, 535.

"rong. 586

c..

GGT in. 661 glocororticoid, in. ",usod by bypofellomi • •

a,.PI, fKaJ in, 753 ACTH in, 813. 814f .ruenorortie>J function tens in, 821_ 22 ALP in, 659 azotemi. in. • bnorm:d routi ...... urn ch<minry wru.lar) hrmoglobin roncrntr:otion mrrn Chrdiak_Hig .. hi .yndromr. 99 Chemistry .... y>, 8 Chlor:unphenicol •• rytluoid hypopb.i. ""d. 339 Chlorid. (0·) o.limmucy tnet funetioJU p<eoooary, 3'W Dy"";' and, 507

normon.n.mi. in, 503-A. ~03. EDTA. &t EthyJen.di..ru"" .. r.. cotic 1-16 Ehrluhia, J.ukocyt •• 95 ElAV. S" £qui"" infoctioUl """"'.. virus

Ekctrolyt.. conam.... ions :mAOrnW. 498 in .. 'P .... tion of. b .. ic concOnov~ •• 49'>-5~3

_:tk. 586

EUiptocytes. hypoc.hmi. :ond. 609--10 G..,.,im distribution. 18. 19f G~iul 'nct hemonh>g •• 472 in8.rnm1tion.471 GFR. 5« Glomrrular filmoon n'" GGT. S" 1"Gluumyltnnsfrr.... Ghos, ceU. 137 Gibbs_Donn:on equilibrium. 405. 407f Globu~n

rn:dytic:d princip!', for to ..l. 372-79 grnrr:d roncq>'" for tot:d. 370-72 pbysiologie pro=seo. 370- 71 toul. m..suring. 375 Glomuular filtntion. 417_ 18 conomtf1tionldilution of. 424-25

B83 Glom.rubr filtntion,.", (GFR). 417_ 18 po. :ond disordrn deau,ing. 618_ 19

G'" for. 709- 13 pbysiologic P"""""" fOf. 708-9. 710f . /fusion rn:dysis with. 86i1--b1 hypergly=ni. :md. 713- 19 hJ'l'te<Jlut.r di ..... , 677 Hep>tocytes, bi~rubin "Puke by, 685-1!7, 685. Hep"ocytes, functioning, 680 H.","'uon am,"mnu"" leukocyte, 95- 97 H.","'"""n ",~is, leukocyte, 97 Hen\..bao.d testing for conle, 48-'50 abnorm.Jities in, 50 rn.Jyt~ "", .. in, 49-50 ..oo, 166 Hyperferremia, 203, 203, Hyperferritinemi>., 207-.'1, 207, Hyperfibrinogenemi., 394-96 di.eues/oonditions awing, 394, 394, PP : F ratio, 39'5--96 IT, prolonged rnd, 285 Hyperglobu~nemi .. 392, 404 hyperprot., 731 Hypergly<J<mi., 713- 19 cl. .. ifica,ion, 713, 715' diilij, of, 501 - 3, 50lt H,O inuh.oo, 501 Hyperounob~ty, ooroo, gap and .. rum, 552-53 Hype'P'rathyroidiun frlint, refractomrtric USG.oo, 452 primuy, C. ".oo, 598 Hyperpbospb ....emi., 658 Hyperpbospb.temia, 618_ 19, 618t J" :anemia cawsuring, 540 pbsma, H0-41 Loctote dehydrogerw>e (1D), 653 octivity, incrr»rd orrum, 652t, 653 Loctotion hypom..."... mio.oo, 625 Loctooe toler.,,~ ttlt in h''''et, 756-57 Loctosuria, 517 lAD, Sn u..kocytr odhesion deficirncy u..r /low crU cytometer, 64-65, 64f rJYthrocyt., 125-27 pbtekt; :on:oIJ"is with, 230- 31 Lota >gglutirution imm=J", FDP, 2% lD, Sn lac"" clebydrogrn ... LDDST, S" lo....-do.e clenmetlu.onr mppression

"""'y,

~,

LE, Sn lupus rryrherrutosus (lE) lre- White mrtbod, 279 lrft dtift bLood ..... trophil roncentntionr rnd, 70-71 cIDsmc1tion, blood neutropbil ronerntr1tioas ...d,70-71 clrgrnrntive, 71 nruuophili. rnd, 72, 73f r tbat b..... 99--100 mi"",Umeous con"i""" in, in, 97- 98 J.ukognm, 60, 62 MJtemic lupus erythem1ton" lympb. denitis. 363 lympb. denop1tby.358 lympb noo.... 58. 323--65 analysis. methods for. 3511-63 .. pir:ltion. 362 biopl)".358 m.jor fe. tures of. 359-62 colis in. of ho:dtby mom .... h. 362-63 clusification. 363--65 hyperpl .. i•• 362 lympbocyte< in. 59 ID1jor conc<J>",/tetrru. 358-63 noopwi •• 351. 363--65 re:octi"..363 umpJe.. cytologic. 359--62 lympboblm•. 363 lympbocytes. 56 blood. 58 processes infl.,."cing. 59 bone autro..... 332 conamtr1tions. mnorm:d. 81-35 effusioru md. 86'5 hem.topoietic cells rnd. 326 kin1tby hypl",mi •• 610 hypohlmic. in 519

C,'''.

N . +. St, Sodium N.,SOJ' Sa Sodium ",16.. N.·:K' mio. 519-20 N 1£'hth.t.n.. Hoin. body fOfm1tion . nd. 186 N 1tion.J I"'tim" of Sunpwi. B_Iymph, 75 Neutropbils, S" Ciratbting neutrophil pool; Margiru"'" neutrophil pool blood, 57 abnormal concentration of, 70-81 Left .hili :and, 70-71 p=s>es in8.,."cing me .... r«l, 57 right dtift and, 71 - 72

"Is.

giant, 92, 93 granulation, hereditary anomaly of, 99 hypeu"gmente
,"'-"

Osim< (PTH). S" tW. lmmu""",,,,,ti,,, PTH: PTH.",btCmOWity, . nd rrg»l .. ion of, 499 UN,477 uri"" ""nY" to, tory mul", ond, 31 mo ..und v:ol.,.. ou",id. ai, 19 multipt. to" ",""l~ 19_20 .Uw.d distributions and, 18, 19f .ynonymous ",rms, 16 u .. of, 19-20 R.ferenco limi"', 16 d.cision thresbolds v., 20 dot .. mining, 18 Refer..,,,,, popuhtion, 16 R.fer..,,,, ron&
<s. 498--500 ",mu/ unit> fo" 500 tion md. 499 .lJwion m . l}"is with. 858-59 e = group, 502-3 H,O :and. 499 hYl"" ... oemi. md. 501 - 3 ion activity. 500

,-

H,O Jo.. . nd. 502 ,,,,,,.ring :and cut:meow. 507 third... p'''''' 507 nephron ",.bsorption of. 499 pwm. osmoWity regulation md. 499 qumtiution ... mpLe fol. 500 lenoJ tubule function :and. 418-19 mining. 501! ..... ting 111 CUW>eOUS Jo.. of. 507 Sod.iwn mUi", (N. ,SO,). 401 _2 Solu",. 5% Spectrin delici.ncy in Dutch golden reo~. 201 Spherocytes. 143. 150

',,-, a>ntnction, erythrocytosis .:w....! by. 196

erythrocyt ... 111 _ 12 pl>",Lets in. 2IJ Spo:.. S« P.. cent hemogLobin ..",... ion .. ith ozygen of lIterioJ hLood by pulse o:xUnftty SSA. Sn Sulfuulicylic ocid Suining 1ZUrophi~c. 62 I=ophilic, 62 bLood. 61--62 """inophilic. 62 neutrophilic, 62 Surling" bw. 405, 406f aviwy .ffiuio... 1I1d. 836-37 Stem ",lis, 55

Steroids. hypeoglJ=mi' 1I1d. 714. 718 St....,t·, "",thod of ocid_b.se ' M}"is, 584-91 delinitioru.585-116 Stooutocyt inf'K1ions and, 231'>-37. 242 irndi ..ion.oo,237 marrow "'ploc"mont and, 237

mn>t:ol alIoimmunpl .."",.oo, 242---43 pbt<J.t production, dKRn«! and. 23~37 drug. causing, 23'>-36 r"''''J.ts ..,d dinribution. obnornW of, 235 mrvinJ, iologic pr""""",/coJ>C-27 renn i..... llici.ncy, cbronic, 42'>-27 renn rubuJ. functions in, 418_23, 420f UA.oo, H41--41 qes in, 628-29 endogenow, "'Ul"'" of, 600-601 nogenow, """"'" of, 600 fonn1tion, 628_29 hyporviumi""";" neopwm.... oc .. «d, 601 hypovit:uninooi., 604 rid"", rnd, 604--5

umple,629 Viumin K rntogonittt, 305-6 bt...ding dilOrden rnd rnugonism or deficiency of, 305--8, 307, deficiency, 306 hemonh>ge rnd, 306 hemotu,it rnd, :abnormal , .. ul", in,

,.m

,,'-'

Vomiang, K· lots through,S 18-19 Von WiUebrrnd disen. (vWD), 265-66

""quire
908

INDEX

Von Wilkbrrnd di ..... (vWD) pbyUo~cp~,

(RI~riud)

265

."..ui6 Von Wilkb,rnd bctor (vWF). 265--68 uulytic:d con""p". 266-67 ....)" ..,d, 267 umpl< :md, 266 units rnd, 266-67 rntigen utio to, 267--68 d.a.osed, 267--68, 267' in"''Protiv. co.wde",ions fo, 268 g""',;c tests for d.t
X_ny diffnction, 489 Xybzi .... hyp. ""PIucr. .... "'do ........... ~ 1.. NNlmpIUI_ """'" boo m.l ... iW. at.

•

r .... 2. i'hooooU.o"'V'P/U of kukocyt< .boo.m.!"" (oIJ w,;p, ...u..d blood Iilmo wd. .. 0.I ....... 1. cot. G. ~", ""kai< hc' .. 11"'1'10 ""'"

"'I'int ..
qt" ;. th,......o.l .oIi.uy 11.01. •.&.-..y " .... "P"'" I"","",«l lrnopb ""'" "'I'int,). dot;.

-

, ..... 1 2 3

4

-

,,~

rw. ll. ~ of win< (..t) ...d photomK~ of """" ~ 6odinco (B-L). s.J;""", .... ~ =c .1Up.J.y .l.jo
.""roph;l.

r-"

~~

IP

.h",,-

~

. ,.''"- 2 f . ,

,.. H,,,,,-

H-H u~.

I ...... ,.......

... • 1..... ~ a... U,,;a.

Ctl ~IO'Y

discn-. TP

T

u""

" pfIjI.

~ 0IiIb '-, u\lI.

''''IfO' u g'" ....... ,

_.

I "".

...

"-,~

,I :'" i:=

•

rw. 12. s...... protrin d.rt"'l' ..... ,; • • " , - . , . toad",. ,.!k.l- "rut< ~ • ...d "N" protdn """",...ioo. Irom. d.op ...d pIao;. i.odkotod tho, d., J.rp.'I''''''.......... b)]>al. bwaio.<m; • ...d ~ ..... du. duook ;o/bmm.oo... F. Doc. 10..1"", lb, &..; ........ " "'"" ; ......... aprocd ....... "" "'.Ithy d.op ..d ;, ~ ... ..fm,,,,,, potto"'" ....... ~ ;" .... J;~ of pn>trin 1Dct"'......Id b. bnd;. ""'" hoolthy dop. F. Doc, ;"&",m",,,!, bJP=«I poIyd.o...J """....".thy. I. ,IUO ""' . dind ';P' aod .....=cly h;p. tit" .. E,i,,{J,I,,,, ''''"' ;".d;,cotod thz tI., hrr
'0

bino,".

J.

~_n.....; . boc.uo, tal protdn COOK . . .oat .... _ " .......,.od by th, Coom ..... b.&nt bI"" ....y. n.. ...., "",pi....." CODCttO".otod [G.o.td p...... .1," ...... _ .... ~ ""'ant ....ioo ......

•

,

).

,

..• • •

," '

o

-

.~

•

,

.. '

...• ,

•

0 0

• 0

0

"

Q

.,l

•

~

•

0

,

. ~

~ u.~nritrifu~ (.4, H. K-M ...d

....................... ,-.x..,.........

cmwr

D. W""/" aI., 1OO1~ G. ~'" of c..,/;,,/o .... and

d.moc«I ..........

cdl.. p'P . ........... ~ ~ .. aod >t

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