Mosby's Review Questions & Answers For Veterinary Boards: Clinical Sciences

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Veterinary

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Clinical Sciences

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Publisher: John A. Schrefer Executive Editor: Linda L. Duncan Senior Developmental Editor: Teri Merchant Project Manager: Linda McKinley Production Editor: Julie Zipfel

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Introduction Paul W. Pratt, VMD Executive Editor, Mosby-Year Book, St. Louis, Missouri jeffrey L. Rothstein, DVM, MBA Hospital Director, Elm Animal Hospital, Roseville, Michigan

SECOND EDmON Copyright © 1998 by Mosby-Year Book, Inc.

Anesthesiology

Previous edition copyrighted 1993 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording. or otherwise, without prior written permission from the publisher. Permission to photocopy or reproduce solely for internal or personal use is permitted for libraries or other users registered with the Copyright Clearance Center. provided that the base fee of $4.00 per chapter plus $.10 per page is paid directly to the Copyright Clearance Center, 222 Rosewood Dr., Danvers, MA 01923. This consent does not extend to other kinds of copying. such as copying for general distribution, for advertising or promotional purposes, for creating new collected works, or for resalc. Printed in the United States of America Composition by Ibp Graphics

Printing/binding by R.R. DonneDey & Sons Company

Etta M . Wertz, DVM, MS, Dipl ACVA Staff Anesthesiologist, Alameda East Veterinary Hospital, Denver, Colorado

Clinical Pathology Carol B. Grindem, DVM, PhD, Dipl ACVP Associate Professor of Clinical Pathology, College ofVeterinary Medicine, North Carolina State University, Raleigh, North Carolina Barry Thomas Mitzner, DVM President, Southeast Vetlab, Inc., Miami, Florida

Mosby-Year Book, Inc. 11630 Westline Industrial Drive St. Lottis, Missouri 63146

Rose E. Raskin, DVM, PhD, Dipl ACVP Associate Professor and Service Chief of Clinical Pathology Laboratory, Department of Physiological Sciences, University of Florida, Gainesville, Florida

Ubrary of Congress Cataloging In Publication Data

Clinical sciences / edited by Paul W. Pratt.-2nd ed. p.

Colin I. Dunlop, BVSc, Dipl ACVA Advanced Anesthesia Specialists, Hunters Hill, New South Wales, Australia

Includes bibliographical refcrences.

ISBN 0·61 51-7462·4 1. Veterinary medicine-United States-Examinations. questions,

etc. l. Pratt, Paul W. 1I. Series. SF759.C56 1997 636.069'076-llOmmHg d. 100 to 105 mm Hg e.90t095mmHg 173. A packed cell volume of36% most closely approximates a hemoglobin content of a. b. c. d. e.

6 g/dl 9 g/dl

12 g/dl 18 g/dl 36 g/dl

174. Which packed cell volume indicates the lowest acceptable oxygen-carrying capacity?

169. Which species is least susceptible to the effects of xylazine? a. cats b. rabbits c. horses d. swine e. cattle

170. Which species is most susceptible to the effects of xylazine? a. b. c. d. e.

capnometer pulse oximeter Wright's respirometer Doppler ventilator

a. 91 mmHg b.150mmHg c.300mmHg d.52mmHg e.200mmHg

Questions 160 through 162 Vapor pressure (mm Hg) at 20' C Preservatives Stability in soda Hme Oil:gas partition coefficient Blood:gas partition coefficient MAC (dogs)

165. Which instrument is used to measure a patient's tidal volume? a. b. c. d. e.

20 to 40 minutes 45 to 60 minutes 4 to 6 hours 16 to 24 hours 48 to 72 hours

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Anesthesiology

a. 12% b.21% c. 18% d. 30% e.35%

Correct answers are on pages 25-33.

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SECTION 1

175. Which of the following is the least appropriate treatment for a mean blood pressure of60 mm Hg?

a. Decrease the percent of inhalation anesthetic being administered. b. Administer fluids intravenously. c. Administer dobutamine. d. Administer ephedrine. e. Begin intermittent positive-pressure ventilation. 176. Which neuromuscular relaxant produces depolarization at the motor end-plate, causing muscle fasciculations?

a. b. c. d. e.

propofol pancuronium atracurium succinylcholine midazolam

180. Concerning use of acepromazine as a preanesthetic agent, which statement is least accurate?

a. Acepromazine decreases the amount of anesthetic required. b. Acepromazine decreases the incidence of vomiting. c. Acepromazine smoothes the recovery period, minimizing paddling and vocalization. d. Acepromazine increases the amount of agent necessary for anesthetic induction. e. Acepromazine decreases the incidence of epinephrine-induced arrhythmias. 181. Concerning propofol, which statement is least accurate?

177. Which neuromuscular relaxant cannot be effectively antagonized?

a. b. c. d. e.

d. determine appropriate preanesthetic medications for the patient e. choose an appropriately sized intramedullary pin for fracture fixation

gallamine pancuronium atracurium succinylcholine vecuronium

178. An E cylinder of oxygen contains approximately 700 L of oxygen when full. Approximately how many liters of oxygen is contained in an E cylinder when the pressure is 1100 psi?

a. b. c. d.

350L 700L 175 L More information is necessary to determine the volume of gas remaining. e. 525 L 179. The pin index safety system is used to:

a. prevent overfilling of the anesthetic vaporizer b. choose an appropriately sized endotracheal tube for the patient c. prevent interchange of oxygen and nitrous oxide E cylinders at the yoke hookup

a. It is administered intravenously or intramuscularly to induce anesthesia. b. It induces apnea when administered intravenously. c. It induces hypotension when rapidly administered intravenously. d. Because the vial contains no preservatives, any unused portion should be discarded. e. It does not cause tissue sloughing following inadvertent perivascular administration.

Anesthesiology

183. What is the best preanesthetic to manage this case?

a. b. c. d. e.

oxymorphone and atracurium oxymorphone and acepromazine ketamine and diazepam atropine and acepromazine No preanesthetic should be used.

184. Which anesthetic would be the best for maintenance ofanesthesia?

a. b. c. d. e.

halothane in oxygen methoxyflurane in oxygen intravenous bolus of pentobarbital isoflurane in oxygen constant intravenous infusion of thiopental

185. How would ventilation best be managed?

a. b. c. d. e.

intermittent positive-pressure ventilation continuous positive airway pressure positive end-expiratory pressure spontaneous ventilation assisted ventilation

182. Which of the following poses the greatest danger during anesthesia?

a. b. c. d. e.

hepatic dysfunction kidney dysfunction hypotension hypertension hypercapnia

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c. procaine and bupivacaine d. mepivacaine and chloroprocaine e. procaine and lidocaine 189. Which local anesthetic has the longest duration of effect?

a. b. c. d. e.

procaine lidocaine mepivacaine chloroprocaine bupivacaine

190. Which local anesthetic is ineffective when applied topically?

a. b. c. d. e.

procaine hexylcaine lidocaine dibucaine tetracaine

Questions 191 through 196 ~~ a 40-kg German shepherd with osteosarcoma ofthe

186. Which method of noninvasive monitoring is necessary in this patient?

a. b. c. d. e.

indirect blood pressure measurement pulse oximetry tidal volume measurement electrocardiography capnometry

Questions 182 through 186 A depressed, 15-year-old golden retriever has a head tilt to the right. The complete blood count and serum chemistry results are within normal limits. To confirm your suspicions of an intracranial mass, computerized tomography (CT scan) is necessary. The procedure requires general anesthesia.

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187. Local anesthetics exert their effect by:

a. interruption of the Na-Kpump, inhibiting any ion exchange b. occupation and blockade of muscarinic cholinoreceptors c. prevention of rapid influx of Na into nerve axons, preventing the action potential d. inactivating slow Ca channels e. occupation and inhibition of nicotinic cholinoreceptors 188. Which pair of drugs are "amide" types of local anesthetics?

zllum, hemzpelvectomy is selected as the treatment. Preoperative blood studies are normal. Morphine and atropine are given as premedicants. Anesthesia is induced with intravenous thiopental to effect and maintained with isoflurane in oxygen. A morphine epidural is administered to help manage pain during and after surgery. Patient monitoring includes electrocardiography. capnometry. pulse oximetry. and direct blood pressure measurement. Systolic blood pressure is initially 100 mm Hg and diastolic pressure is 55 mm Hg. However, as surgery progresses, the systolic pressure drops to 70 mm Hg and diastolic pressure to 30 mm Hg; blood pressure continues to fall. A large pool ofbloody fluid on the floor under the surgery table is rapidly increasing in size. 191. What is the mean arterial blood pressure initially?

a. 70mmHg b.78mmHg c.85mmHg d. it cannot be determined from the information given e. lOOmmHg

a. procaine and mepivacaine b. lidocaine and bupivacaine

Correct answers are on pages 25-33.

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192. At what mean arterial blood pressure would you begin to suspect inadequate perfusion of vital organs?

a. BOmmHg b.70mmHg c.60mmHg d. SOmmHg e. The mean arterial pressure does not indicate this problem. 193. What is the mean arterial blood pressure after the decrease in blood pressure is observed?

a. SOmmHg b.66mmHg c.70mmHg d.43mmHg e. It cannot be determined from the information given. 194. What is the estimated blood volume of this dog?

a. b. c. d. e.

2400 mI 3200ml 2BOO mI 1600ml 2000 mI

195. Intraoperatively, blood should be administered when the packed cell volume falls below:

a.4S% b. 40% c.3S% d.30% e.2S%

a. packed cell volume 30%, total plasma protein concentration 6.S g/dl b. packed cell volume 20%, total plasma protein concentration 7.0 g/ dl c. packed cell volume 40%, total plasma protein concentration 2.S g/dl d. packed cell volume 3S%, total plasma protein concentration 4.S g/dl e. packed cell volume 4S%, total plasma protein concentration 7.0 g/ dl 198. A 45-kg dog is seen after acute loss ofblood, and you decide to administer intravenous fluids as . treatment. The dog's packed cell volume is 35%, and total plasma protein concentration is 4.2 g/dl. Which of the following is most appropriate as the initial fluid therapy to prevent vascular colfapse?

a. 2BOO mI of 0.9% saline solution infused IV over 4 hours b. 4S0 mI of lactated Ringer's solution injected SC at multiple sites c. 1BO mI of 7% saline solution infused IV over 10 minutes d. 2S0 mI of plasma infused IV over 30 minutes e. 4S0 mI of whole blood infused IV over 1 hour 199. Midazolam is classified in the same category as:

a. b. c. d. e.

196. Approximately how many milliliters of red blood cells have been lost when this critical packed cell volume is reached?

a. 160 mI b.320ml c. 4BO mI d.640ml e. BOO mI

197. In a patient with which of the following blood values would it be appropriate to administer only a colloidal solution (e.g., plasma)?

diazepam atipamezole mepivacaine neostigmine propofol

200. Medetomidine is classified as:

a. b. c. d. e.

a hypnotic an amide type of local anesthetic a tranquilizer an "z agonist an opioid antagonist

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Anesthesiology

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Answers 1. d Premedication agents, such as atropine, are used to minimize undesirable reflex autonomic activity. 2. d Atropine acts by competitive antagonism of acetylcholine at muscarinic receptors. This competition can be overcome by increasing the concentration of acetylcholine at receptor sites (as seen following administration of anticholinesterases). 3. a Atropine stimulates the vagus center in the brain, which can slow the heart rate initially in response to IV administration of small doses. 4. b Glycopyrrolate causes less of an increase in heart rate than atropine. S. e A 10% solution = 10 g/100 ml = 10,000 mgllOO mI = 100 mg/ml. 6. b Phenothiazine tranquilizers are sympatholytic (cause vasodilation). 7. a Acepromazine is one of the most commonly used phenothiazines. B. c Acepromazine can cause persistent paraphimosis or priapism in adult intact male horses. Working stallions are at higher risk for these problems. 9. c Guaifenesin causes muscle relaxation by its action on internuncial neurons in the spinal cord. It has no recognized analgesic properties and so should not be used as a sole agent for restraint for surgery. 10. a Diazepam is a centrally acting muscle relaxant. 11. d Overdosage of guaifenesin is associated with skeletal muscle rigidity and often cardiac arrest preceding respiratory arrest by several minutes. The therapeutic dosage is 100 mg/kg. 12. c 3S0 mI x SO mg/mI = 17,SOO mg/2S0 kg = 70 mg/kg. 13. e Atracurium blocks postsynaptic acetylcholine receptors at the neuromuscular junction and so causes paralysis of the intercostal muscles and diaphragm. 14. b Atracurium's molecular stability depends on an alkaline pH and low temperature. This method of limiting the drug's action is known as Hoffman elimination. IS. c Succinylcholine is a depolarizing neuromuscular blocking agent that initially causes rigidity, tachycardia, and hypertension. It has a short duration of action because it is metabolized by plasma cholinesterase.

Atracurium is a non depolarizing blocker and causes relaxation alone. Some muscle groups are more susceptible (e.g., extraocular and limb muscles) than others (e.g., facial muscles, diaphragm), so different doses are required to achieve equivalent relaxation. 16. a Neostigmine inhibits acetylcholine esterase, causing increased levels of acetylcholine at such receptors. This increases preganglionic muscarinic activity, slowing the heart rate. Atropine (0.04 mg/kg IV) should be given immediately before neostigmine. 17. d These drugs are classified as " z-adrenergic agonists. lB. b "z.agonists cause second -degree ~trioventricular block and bradycardia, reSUlting III decreased cardiac output. Hyperglycemia, increased urine output, and increased intrauterine pressure also occur. Respiratory function is depressed because of sedation. 19. c Intravenous atropine rapidly antagonizes the xylazine-induced bradycardia. An " z-adrenergic antagonist, such as yohimbine, would only partially antagonize the bradycardia and decrease the sedative-analgesic (desirable) effects of xylazine. 20. c Pure opioid agonists exert their effects via agonism of fJ.-opiate receptors. 21. d Assuming the potency of morphine (mg/kg basis) is 1, the potency offentanyl is 100 x, oxymorphone 10 x , butorphanol 2 x , and meperidine O.S X to O.2S x. 22. b Naloxone (Narcan), a pure opioid antagonist, has no narcotic/ agonistic effects of its own. 23. c Opioid fJ.-agonists generally cause respiratory depression, especially after intravenous or repeated intramuscular administration. 24. b Opiates alter the perception of pain by the central nervous system. Human patients may still be aware of the pain without being in pain. 2S. b In dogs either oxymorphone or fentanyl is commonly given to allow intubation. The drug is usually administered in combination with diazepam. The induction is slow (2 to S minutes) and causes respiratory depression. Therefore it should be preceded by S minutes of preoxygenation via face mask. 26. d Apart from bradycardia, there is minimal cardiac depression from intravenous oxymorphone and fentanyl.

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27. a Nalorphine and naloxone are opioid antagonists and butorphanol is a partial antagonist; therefore, all would combat the bradycardia. Atropine would also combat bradycardia without antagonizing the desirable sedative or analgesic/ properties of fentanyl. 28. c Butorphanol is a mixed (K) agonist and ("') antagonist and so is associated with less respiratory depression. 29. c Opioids can cause central nervous system stimulation in horses, especially if administered intravenously and without other tranquilizers/ sedatives. 30. b Naloxone is a ",-receptor antagonist that can reverse respiratory depression. 31. c In healthy dogs there is a high incidence (up to 40% of cases) of transient ventricular arrhythmias following anesthetic induction with intravenous thiobarbiturates. Thls does not usually cause clinical problems in healthy patients. 32. b Thiobarbiturates owe their short duration of action to almost immediate distribution from the plasma to well-perfused tissue, and then to fat depots. Therefore there is rapid recovery of consciousness after a single anesthetic dose. 33. a Thiobarbiturates can produce prolonged recovery because of saturation of muscle and fat storage depots and their subsequent release and slow metabolism and elimination. Hypoproteinemia, dehydration, acidosis and hypothermia all exacerbate this problem. 34. d Thiobarbiturates decrease intracranial and intraocular pressure and usually cause no change or an increased heart rate. 35. d Apnea is commonly seen following thiopental induction of anesthesia, especially with a hlgh inspired oxygen level. Giving 2 or 3 normal breaths per minute ensures that the patient remains oxygenated and receives some halothane; it also allows the arterial carbon dioxide to rise to a level sufficient to stimulate spontaneous ventilation. If no halothane were administered, this dog would be awake in 10 to 15 minutes. Propofol also causes postinduction apnea. 36. e Thiobarbiturates cause tissue irritation and sloughing after perivascular injection and are associated with prolonged recovery in dehydrated, emaciated, hypoproteinemic animals. They produce relatively good muscle relaxation at anesthetic doses.

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37. d Similar to thiobarbiturates, propofol depresses seizure activity, decreases intraocular pressure, and causes muscle relaxation. 38. c Hypotension can be observed following administration of propofol in healthy patients. This effect is exacerbated by dehydration. Propofol does not directly alter the heart rate or myocardial contractility. 39. a Typically, propofol does not cause excitement in recovery. Patients are quickly ambulatory and not ataxic. In part, recovery is due to rapid metaboHsm. 40. c In the commercially available product, propofol is dissolved in a nonirritant milky oil emulsion and can be given intramuscularly (requires large volume) as well as intravenously. It is stable at room temperature but contains no preservative agents. ' 41. d Ketamine can be administered intra- • muscularly, although this causes pain. 42. a Ketamine stimulates the cardiovascular system, increasing myocardial oxygen consumption, and also increases intraocular and intracranial pressures. 43. d Rapid induction of anesthesia and maintenance of laryngeal function are desirable in brachycephalic dogs. In addition, rapid recovery is desirable. Although not producing the fastest induction and smoothest recovery (thiopental or propofol would be better), ketamine would be acceptable. 44. c Ketamine is a dissociative agent. 45. d Sympathomimetics (e.g., dopamine, dobutamine) are usually administered to stimulate cardiovascular function. 46. b Hypnotic agents include pentobarbital, thiopental, thiamylal, propofol, and chloral hydrate. Tiletamine is the dissociative agent in Telazol (tiletamine-zolazepam). 47. e A neuroleptanalgesic combination usually consists of a sedative/tranquilizer (e.g., acepromazine) and an opioid analgesic (e.g., fentanyl). 48. a Ketamine produces mild visceral analgesia in people. 49. e The kidney is the major excretory organ for almost all sedative and hypnotic drugs. Because they have high lipid solubility and are poorly ionized, they are metabolized by the liver before excretion. Ketamine is excreted without metabolism via the kidney in dogs and cats.

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Anesthesiology

50. c The epidural space is located immediately outside the dura mater. 51. b An appropriate dose of epidural local anesthetic produces excellent analgesia and hind limb muscle paralysislrelaxation. 52. a Bupivacaine produces both sensory and motor blockade of 2 to 3 times longer duration than lidocaine or mepivacaine. 53. d Epidural anesthetics should not be administered when there is trauma, bleeding, or infection at the injection site. 54. a Preganglionic sympathetic blockade causes vasodilation in the anesthetized region. 55. e Local anesthetic analgesia persists approximately as long as muscle paralysis/relaxation. The longest duration of effect is from bupivacaine, whlch lasts 4 to 6 hours. 56. b Bupivacaine has the lowest placental transfer of any of the commonly used local anesthetic agents. This is because ofits high protein binding in maternal blood. 57. d If the same dose as required for epidural anesthesia is administered into the cerebrospinal fluid, the anesthetic moves far cranially and could cause respiratory muscle paralysis. 58. a In spinal anesthesia the anesthetic agent is administered into the cerebrospinal fluid, whlch circulates in the subarachnoid space. 59. b Giving the same dose as a spinal injection that was calculated for epidural administration would produce excellent analgesia and incur no more risk of adverse effects (as compared with epidural administration). This is not the situation for local anesthetics administered into the cerebrospinal fluid. 60. e Epidural drugs are also occasionally administered into the cerebrospinal fluid and so should be preservative free. Although the volume of drug administered epidurally is important (hence the different concentrations), this is not the only reason that the solution is packaged in a vial. 61. b Epidural morphine reduces the anesthetic requirement to produce analgesia in the hind limbs, and also to a lesser extent in the forelimbs. 62. a Isoflurane causes respiratory depression in dogs and horses, is relatively less arrhythmogenic, and is excreted virtually unchanged. It is one sixth as potent as methoxyflurane and two thirds as potent as halothane.

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63. d The anesthetic requirement is reduced by increasing age, hypothermia, concurrent use of other central nervous system depressants and pregnancy. 64. d MAC values for these anesthetics in dogs are 0.9 vol % for halothane, 215 vol % for nitrous oxide, and 1.4 vol % for isoflurane, versus 0.23 vol % for methoxyflurane. Propofol is not an inhalation agent. 65. c Mask inductions are slow (undesirable if rapid airway control is desirable) , with speed of induction dependent on drug solubility (insoluble agents produce faster induction) and ventilation (hyperventilation produces faster induction). Mask induction can be expensive, especially with isoflurane (about $5 for induction in a dog) . 66. d Highly soluble agents (e.g., methoxyflurane) have slow equilibration times and therefore slow induction and recovery times. 67. c About 50% of an inhaled dose of methoxyflurane ' and 25% of a dose of halothane are metabolized. Other agents have minimal metaboHsm. 68. d In decreasing order of the likelihood of arrhythmogenesis: halothane> methoxyflurane > isoflurane, desflurane, and nitrous oxide. 69. c Dose-dependent ventilatory and cardiovascular depression occurs. Respiratory depression increases arterial carbon dioxide tension. 70. c The MAC of nitrous oxide in dogs is approximately 215 vol %, so under normal conditions (1 atmosphere of pressure), it cannot alone produce anesthesia. 71. b Nitrous oxide is the most insoluble of the commonly used inhalation agents. 72. d 1.3 to 1.5 times the MAC (0.23 vol %) produces a surgical plane of anesthesia. 73. c Fluoride ions produced by metabolism of methoxyflurane are nephrotoxic. 74. c When nitrous oxide is given with halothane, the peak blood concentration of halothane is attained more rapidly than if halothane were used alone. Concurrent use of nitrous oxide causes halothane to be taken up at an accelerated rate, known as the second-gas effect. Answer b describes diffusion hypoxia.

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SECTION 1

75. c The greater an agent's alveolar concentration, the more rapid is its absorption. Uptake also depends on blood solubility. An anesthetic that is very soluble is rapidly taken up by the blood. Cardiac output determines the blood flow through the lungs and therefore the quantity absorbed. The correct ratio of inspired air to lung perfusion (ventilation/perfusion ratio) ensures optimal anesthetic uptake. 76. c The ideal agent, producing rapid induction and recovery, would have low blood solubility and low lipid solubility, rapidly achieving equilibrium (partial pressure) among gas, blood and tissue phases/compartments. Solubility is an index of the capacity of the blood or tissue to retain anesthetic. 77. b A small amount of vapor entering tissue in which the agent is not soluble causes a high vapor tension. Therefore during anesthetic recovery, arterial and brain concentrations drop to negligible levels within minutes and the patient awakens rapidly. 78. b The duration of anesthesia determines the saturation level of body tissues. Anesthetics that are highly soluble in fatty tissues take longer to be expelled from the tissues. If pulmonary blood flow or ventilation is inadequate, inhalation agents cannot be cleared through the lungs and recovery is delayed. Hthe agent is highly soluble in the blood, it is not removed quickly. An example is methoxyflurane, which is highly soluble in blood and has a long recovery period. 79. d Up to 20% of the inhaled dose of halothane is metabolized. Isoflurane causes more respiratory depression in dogs and horses. Methoxyflurane and isoflurane are arrhythmogenic, although significantly less so than halothane. Halothane is by far the cheapest commonly used inhalation agent. 80. a Painful stimulation of lightly anesthetized patients causes catecholamine release, which can lead to ventricular arrhythmias in halothane-anesthetized patients. Increasing the anesthetic depth can eliminate these arrhythmias. 81. b Halothane, 5 ml/500 ml O2 (per minute) =1% Vaporizer setting; 5 ml/120 ml O2 (per minute) = 4.2% Vaporizer setting. Each setting would result in a similar anesthetic depth. This illustrates the importance of fresh gas flow in determining anesthetic delivery to the circuit.

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82. d With in-circuit vaporizers, output depends on ventilation (increases with increasing ventilation). In-circuit vaporizers are of simple "flow over liquid" design and generally use less anesthetic than out -of- circuit (precision) vaporizers. The vapor pressure of halothane at 20· C is 243 mrn Hg. At sea level (760 mni Hg), 243/760 = 32%, which means a 32% concentration of halothane can be achieved. There is a similar situation for isoflurane. Out -of-circuit precision vaporizers only deliver a 5% maximum for these agents. 83. d Uptake of anesthetic is improved with increased ventilation. The "centralized" circulation of neonates ensures rapid delivery of anesthetic to the brain. 84. d Halothane markedly lowers the arrhythmogenic dose of epinephrine in dogs. 85. e Nitrous oxide is a liquid when stored' under pressure at room temperature. Halotl'lane is a vapor, not a gas, and therefore is not stored under pressure. Gases that can be liquefied at room temperature are purchased by weight. Pressure is an accurate index of quantity for nonliquefiable compressed gases. 86. c The pressure in the cylinder begins to drop when all the liquid nitrous oxide has been vaporized and the gas loses pressure. Cylinders must be watched thereafter for rapid emptying. Another cause of decreased pressure is chilling of the cylinder. 87. a All except oxygen are liquefied at room temperature under pressure. As such, they are safely handled as liquids in cylinders. 88. c Gas cylinders for various agents are identified by a unique color, thread size, and thread diameter. E cylinders also have a pin index combination. 89. a The emergency oxygen flush valve bypasses the vaporizer to deliver only oxygen to the circuit. It should be used to fill the circuit as part of the preanesthetic "pressure check" before all anesthetic procedures. 90. a Increased ventilation increases the anesthetic concentration within the circuit. 91. e With in-circuit vaporizers, increasing fresh gas flow "washes" anesthetic out through the pop-off valve, decreasing the concentration within the circuit. 92. e Both one-way valves must be patent to ensure unidirectional gas flow.

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Anesthesiology

93. c The oxygen flush valve is located between the ~ource of compressed oxygen and the fresh gas inlet of the circuit. 94. c Without a patent inspiratory valve, exhaled gas would move into the inspiratory side of the rebreathing hose, so the patient would inspire gas containing carbon dioxide. 95. b If the one-way valves are patent, there is unidirectional gas flow from the Ypiece connector. 96. d Soda lime granules become harder when they are exhausted. 97. d Hypercapnia results in sympathetic nervous system stimulation. 98. b Occlusion of the tubing from the pop-off valve to the scavenger would cause pressure in the breathing circuit to increase. 99. d To check the circuit for leaks, it should be pressurized to 20 to 30 cm H20, and the manometer should be observed for 1 minute for pressure change. A pressure decrease indicates a leak. 100. b If the pop-off valve were closed, pressure would increase. It is possible to close the popoff valve in a low-flow system where the oxygen flow equals the patient's oxygen consumption (a closed circuit). 10 1. e Theoretically, the volume of the soda lime container should be at least twice the patient's tidal volume. 102. b The reservoir bag is the compliant (collapsible) part of the circuit and usually should have a volume of about 5 times the patient's tidal volume (approximately the functional residual capacity). 103. a These circuits require high fresh gas flows and so are not economical for larger patients. 104. b B?th are examples ofnonrebreathing circuits, so hIgh fresh gas flow is necessary to prevent rebreathing of expired carbon dioxide. 105. c Fresh gas flow rates of approximately 200 ml/kg/min are necessary to prevent rebreathing of carbon dioxide. 106. d With nonrebreathing circuits, there is no drop in anesthetic concentration from the vaporizer to the patient. 107. e For semiclosed circuits, oxygen flow is usually 30 ml/kg/min. However, for closed or low-flow circuits, the fresh oxygen flow can be as low as 4 to 6 ml/kg/min for dogs. 108. d This is approximately 4 to 6 ml/kg/min in dogs.

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109. a For closed-circuit anesthesia the system must incorporate a soda lime carbon dioxide absorber. 1l0. c The other answers are all advantages of closed-circuitllow-flow systems. The closed system permits inhalation of warm gases, maintenance of a constant anesthetic level, economical use of volatile agents, and maintenance of high humidity of inspired gases. 111. d An endotracheal tube extending well beyond the animal's nose increases dead space. 112. e With this maneuver, stomach inflation/ deflation can be mistaken for chest excursion. 113. a Early in anesthesia, the patient removes most of the anesthetic from the inspired gas and exhales gas with a low anesthetic concentration. This gas goes back around the circuit and dilutes the concentration of gas coming from the vaporizer. 114. d Tissue oxygen saturation (Sao2, measured with pulse oximetry) will not change perceptibly unless there is a marked change in tissue perfusion or hemoglobin saturation with oxygen. Neither will change enough within the range of clinical anesthetic levels to change Sa0 2, especially if the animal is breathing a high inspired concentration of oxygen. 115. a A corneal reflex can persist even at deep levels of anesthesia. Loss of the corneal reflex is a sign of very deep anesthesia. Repeated testing of the corneal reflex can damage the cornea. 116. c The esophageal stethoscope should be positioned in the esophagus at the level where heart and lung sounds are best heard. These sounds allow evaluation of heart and respiratory rates, neither of which alone is a useful guide to anesthetic depth. 117. b The bradycardia is most likely the result of excessive vagal tone and could be treated with intravenous atropine. It should also respond to cessation of the noxious stimulus (i.e., release of traction on the ovary). 118. c "'2-adrenergic agonists cause marked bradycardia. In dogs and cats, they should be used after premedication with an anticholinergic drug, such as atropine. 119. b A high blood carbon dioxide level causes cardiovascular stimulation, mediated via the sympathetic nervous system.

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SECTION 1

120. d Assessment of pulse quality does not enable you to estimate systolic or diastolic pressure. 121. d Arterial pressure =Cardiac output x Peripheral resistance. Cardiac output = Heart rate X Stroke volume. 122. a The response time of pulse oximeters is currently not fast enough to enable them to be used with a pneumatic cuff to detect blood pressure. 123. e Currently available indirect methods all have inaccuracies associated with cuff size, limb size, the amount of hair covering the site, and the animal's position. Some of these effects can be standardized for more repeatable measurements. In general, indirect methods most reliably determine systolic arterial pressure. 124. cAn overly wide cuff yields spuriously low readings. An overly narrow cuff and a loose cuff yield spuriously high readings. 125. e As the pressure wave travels distally, impedance causes the systolic pressure to increase, although mean arterial pressure tends to decrease. 126. a Hydrostatic force (gravity) causes a false elevation in pressure, proportional to the height difference (1.36 mm Hg/cm difference). 127. b Mean arterial pressure is the mean perfusion pressure (not blood flow) . It is the area under the pressure waveform. About one third of the cardiac cycle is systole, two thirds is diastole. Therefore, to calculate mean arterial pressure, systolic and diastolic pressure must be weighted. 128. e Hypotension is usually defined as a systolic pressure below 80 to 90 mrn Hg, which would generally result in a mean arterial pressure below 60 to 65 mrn Hg. 129. d Doxapram increases the metabolic rate of the brain and may stimulate ventilation. It does not directly improve cardiovascular function unless its administration has caused or follows hypoxemia. 130. e Cardiac output = Heart rate X Stroke volume. 131. d Phenylephrine and methoxamine are regarded as pure alpha -adrenergic stimulators. Isoproterenol has powerful positive inotropic and chronotropic myocardial effects, causing increased cardiac output. Peripheral vascular dilation and reduced resistance are other prominent effects of this beta-adrenergic stimulant. Ephedrine causes central nervous system-mediated release of norepinephrine; therefore, its effects are similar to those caused

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by norepinephrine administration, including increased stroke volume, presumably from increased contractility. 132. a At a dosage of 1 to 3 f.l.g/kg/minute, dopamine increases renal output by increasing glomerular filtration via dilation of the afferent arterioles. 133. a Phenylephrine may be given in reasonable doses without fear of ventricular irritability. However, epinephrine is likely to cause premature ventricular contractions. 134. c We assume that a hypotensive patient has poor tissue perfusion (not always a true assumption) . The objective of therapy is to improve tissue perfusion with oxygenated blood. 135. c Anatomic dead space comprises the area of the respiratory tract not involved in gas exchange, including the oronasal cavity and conducting airways. In healthy unanesthetized animals, it is equal to about one third of the tidal volume but increases during anesthesia, particularly as a result of atelectasis. 136. e The minute volume depends on both tidal volume and respiratory rate (Vt x Respiratory rate). 137. b An average range is 10 to 15 ml/kg/breath. 138. c Minute ventilation and arterial carbon dioxide levels are equivalent measures of the effectiveness of ventilation. 139. e Increased arterial carbon dioxide levels increase the depth and usually the rate of ventilation; increase heart rate, cardiac output, and blood pressure; and cause injection of the mucous membranes. 140. d Compliance is a measure of static pressurevolume relationships (Llcm) , whereas resistance is a measure of dynamic pressure flows (Llcm H,O/sec). 141. b Carbon dioxide causes cardiac epinephrine to be released from the sympathetic nerve endings, resulting in increased cardiac output. 142. d In general, anesthetic drugs cause dosedependent respiratory depression. 143. b Paco, is used to assess ventilation, whereas Pao, is used to assess oxygenation. 144. e CO, + H,O ... H,C0 3 ... H+ + HC03 • Large changes in blood bicarbonate levels produce only small changes in blood pH. Changes in hydrogen ion concentration have a direct effect on blood pH.

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Anesthesiology

31

145. c Oxygen delivery is related to cardiac output, of this, the anesthetic effect produced by NO, hemoglobin concentration, and the percent has a relatively rapid onset of action. saturation with oxygen. 155. b A canister containing activated charcoal will 146. b Shifting of the oxyhemoglobin curve to the left absorb halogenated anesthetic agents. increases the affinity of oxygen for hemoglobin, However, canister use must be monitored to reducing tissue oxygen availability. As blood pH prevent overuse (exhaustion of the activated decreases, the oxygen dissociation curve shifts to carbon), resulting in reduced scavenging and the right. Carbon dioxide and lactic acid pollution. Recommended governmental levels liberated during metabolism cause this of exposure to the halogenated hydrocarbons is phenomenon (the Bohr effect). increasing body no greater than 2 ppm for volatile agents and 25 temperature above normal, an increased organic ppm for nitrous oxide. Nitrous oxide is not phosphate level (2,3-diphosphoglycerate and absorbed by activated charcoal and must be adenosine triphosphate), and an acidic pH all vented to the outside. cause a shift to the right. 156. c Propofol is a sedative-hypnotic and is 147. e When the Pao, is above 100 mm Hg, all the unrelated to other anesthetic agents. Because hemoglobin (which carries over 97% of the propofol has minimal analgesic properties, oxygen) is saturated. analgesics should be administered concurrently 148. c Reducing the Paco, by 5 mm Hg would only for painful procedures. raise the Pao, by about 5 mm Hg. Answers b, d, 157. a Slow administration ofpropofol requires a and e would raise cardiac output, which would lesser amount of drug necessary to induce improve ventilation/perfusion in the lung. general anesthesia and reduces the degree of 149. c This dog is likely cyanotic and, if not hypotension and apnea that commonly occur anesthetized, may be unconscious because of on induction. Opiate premedication tends to hypoxemia. increase the likelihood of apnea on induction 150. e Cerebral blood flow and pressure are with propofol, but is not of consequence as long as ventilation is possible. enhanced by increasing Paco, or decreased by decreasing Paco,. Brain volume increases as 158. d The duration of analgesia produced by more blood flows into the closed cranial cavity, morphine administered epidurally is much which also increases cerebrospinal fluid longer than from other routes of pressure. Carbon dioxide is an anesthetic at administration. higher concentrations (e.g., 30%), although it 159. d Analgesia produced by morphine becomes causes marked cardiovascular responses. apparent approximately 1 hour after epidural 151. a These are the anatomic landmarks for administration. The delay in onset of effect is identifying the epidural space in dogs. Answer e related to its relatively lipophobic nature. It is states the landmarks to identify the epidural slowly absorbed into the spinal cord. space in horses. 160. d The blood/gas partition coefficient indicates 152. a The dose oflocal anesthetic should be that desflurane is the least soluble in blood of reduced by approximately half (1 ml reduced to those listed. This solubility reflects the time 0.5 ml per 4.5 kg) to prevent a higher level of necessary for the drug to exert its effect. The anesthetic block than is desired. By decreasing less soluble the drug, the more rapid the onset the dose, the incidence of "total spinal of effect. The order of onset of effect for this anesthesia" is reduced, decreasing the possibility group of drugs would be as follows: desflurane of respiratory and cardiovascular collapse. > sevoflurane > isoflurane > halothane> methoxyflurane. 153. b There is no possibility of "total spinal anesthesia" when an opioid is administered 161. e The lower the MAC, the more potent the into the subarachnoid space. There are drug. MAC reflects the potency of inhalant currently no documented problems from anesthetic agents. administration of the entire dose into the 162. c Methoxyflurane may be administered using a subarachnoid space in dogs. nonprecision vaporizer, such as the Ohio #8 154. d NO, is a relatively insoluble agent, with a vaporizer. blood:gas partition coefficient of 0.47. Because

32

SECTION 1

163. d The copper kettle vaporizer must be manually adjusted to compensate for changes in temperature and fresh gas flow to deliver the desired amount of anesthetic vapor. These units are still available for use in veterinary hospitals. The Ohio #8 is a nonprecision vaporizer and has no means to compensate for temperature and changes in fresh gas flow. The Vapor (North American Drager) is a precision vaporizer that is flow compensated, but manual adjustments must be made to correct for temperature changes. The newer precision vaporizers are both temperature and flow compensated. Examples of these are the "Tec" and "Matic" types of vaporizers, which automatically compensate for changes in temperature and fresh gas flows within flow ranges normally used in veterinary anesthesia. 164. e The appropriate volume per breath can be determined by simple observation of rise of the patient's chest wall when squeezing the rebreathing bag to inflate the lungs. If a pressure manometer is located in the airway circuit, a peak airway pressure approximating 15 to 20 cm of water pressure indicates adequate lung expansion. 165. c Wright's respirometer is used to measure tidal and minute volumes in small animals. It is commonly inserted into the breathing circuit of the anesthetic machine for these measurements. 166. d The pulse oximeter measures hemoglobin's saturation with oxygen. With 90% saturation (P90), the partial pressure of oxygen is approximately 60 rnrn Hg in dogs. 167. b Butorphanol is an opioid agonist; yohimbine is an ",, -antagonist. Yohimbine does not antagonize the effects ofbutorphanol. 168. c Butorphanol has antagonistic activity at the fL-receptor and has agonistic activity at K- and 0-- receptors. When butorphanol is given to an animal that has received morphine (a fLagonist), morphine's effects at this receptor are antagonized. However, the agonistic action of butorphanol at the K-receptor produces analgesia; therefore butorphanol can be administered to partially antagonize morphine's effects. 169. d Swine are the least susceptible of all species to the effects of xylazine. It is usually used in combination with other anesthetic agents to produce the desired effect in pigs. For sedation, pigs require 20 to 30 times the low dosage used in ruminants (0.1 mglkg 1M).

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170. e Cattle are most susceptible to the effects of xylazine. Sheep and goats are also very sensitive to xylazine. 171. e This is calculated using the equation [(% oxygen inspired) x (Barometric pressure Water vapor pressure)] - Respiratory quotient. 20.9% x (760 - 47) - 40/0.8 =99 mm Hg. 172. c This is calculated using the equation [(% oxygen inspired) x (Barometric pressure Water vapor pressure)] - Respiratory quotient. 100% x (760 - 47) - 40/0.8 = 663 mm Hg. 173. c Hemoglobin content is approximately one third the packed cell volume. 174. b A packed cell volume of21% would indicate a hemoglobin content of approximately 7 gl dl, which is the lowest acceptable hemoglobin content necessary for adequate oxygen content. 175. e Intermittent positive-pressure ventilation may decrease cardiac output. All the other answers are potential treatments. Usually treatment progresses as follows if the above measures have not corrected the situation: decrease the percent of inhalation anesthetic administered, administer a fluid bolus, administer ephedrine, and, last, administer a more potent inotrope, such as dobutamine. 176. d Succinylcholine interacts with the nicotinic receptor, just as acetylcholine does, and stimulates muscle depolarization. Because succinylcholine is not rapidly metabolized, the duration of receptor occupation is longer than acetylcholine and muscle stimulation (fasciculation) is followed by flaccidity. 177. d SUCcinylcholine is hydrolyzed by cholinesterases. It must be metabolized to end its effects. 178. a A full E cylinder contains approximately 700 L, with a service pressure of approximately 2000 to 2200 psi. The pressure is proportional to the gas volume (L) in the cylinder. 179. c The pin index safety system is used to prevent inadvertent interchange of nitrous oxide and oxygen on the hanger yoke of the anesthetic machine. It consists of two pins and a nipple, with spacing specific for each anesthetic gas. 180. d Tranquilizers administered as preanesthetics help to decrease the amount of anesthetic induction agent necessary. 181. a It is only administered intravenously to induce anesthesia.

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Anesthesiology

182. e Hypercapnia may increase intracranial pressure by causing vasodilation of cerebral blood vessels, resulting in increased blood flow and leading to possible brain herniation if a mass is present. Inappropriately managed anesthesia could result in this. Also see answer 185. 183. d Because the dog is very depressed, it is probably best not to administer any of the premedicants listed. Oxyrnorphone is a potent oplOld and depresses respiration; atracurium is a neuromuscular relaxant and should not be given as a premedicant (it is administered to anesthetized patients); ketarnine increases cerebral blood flow and could further increase intracranial pressure and may induce seizure activity; acepromazine can induce seizures. 184. d Isoflurane in oxygen is the most appropriate choice in this case. Also see answer 185. 185. a Intermittent positive-pressure ventilation is used to prevent accumulation of carbon dioxide which could increase intracranial pressure. ' When controlled ventilation and isoflurane are used in cases such as this, an increase in cerebral blood flow, resulting in increased intracranial pressure, is minimized. If halothane were administered instead, even with intermittent positive-pressure ventilation, cerebral blood flow is less well controlled and there is potential for increased intracranial pressure. 186. e Capnometry allows measurement of end tidal carbon dioxide. This estimates the arterial carbon dioxide partial pressure. End tidal carbon dioxide pressure is approximately 5 mm of Hg less than the arterial value. End tidal carbon dioxide pressure should be maintained in the range of 25 to 30 mm Hg. 187. c Local anesthetics produce their effects through interaction with the sodium channel of cells. They are thought to prevent action potential generation by obstructing the sodium c~annel from inside the membrane or by dlsruptmg electrical activity by lodging within the lipid membrane of the axon. 188. b Lidocaine, mepivacaine, and bupivacaine are all amide types of local anesthetics. Procaine and chloroprocaine are ester types of local anesthetics.

33

189. e Bupivacaine has an intermediate onset of action (20 to 30 minutes) and lasts approximately 4 to 6 hours. 190. a Pr?caine produces no effect following topical appitcatlOn. 191. a Mean arterial pressure is calculated using the equation [(Systolic blood pressure - Diastolic blood pressure)/3] + Diastolic blood pressure. [(100 - 551 3) + 55] = 70 mm Hg. 192. c A mean arterial pressure less than 60 mm of Hg of pressure indicates the potential for inadequate perfusion of the vital organs, such as the heart, liver, and kidneys. 193. d Using the equation cited in answer 191, [(70 - 30) 13] + 30 = 43 mm Hg. 194. b The blood volume of dogs is approximately 7.5:ro to 9% of body weight (in kilograms). A safe estimate for general use is 8%. To estimate blood volume, multiply the body weight (in kilograms) by 80 ml/kg. 40 x 80 =3200 mi. 195. e A packed cell volume of 25% indicates a hemog!obin content of approximately 8 gl dl. At thiS pomt, more hemoglobin (in the form ofred blood cells in whole blood) is needed. 196. d The dog initially has 1440 mI of red blood cells (Blood volume x Packed cell volume = Red blood cells [mill. When the packed cell volume falls to 25%, there is 800 mI of red blood cells. Therefore the dog has lost 640 mI of red blood cells (1440 - 800 = 640). 197. c The total plasma protein concentration is low and would result in hypovolemia because of inadequate protein to maintain intravascular osmotic pressure and retain fluids in the vascular compartment. 198. c HypertOnic (7%) saline can be rapidly infused N and should be followed by slower infusion of isotonic fluids (e.g., 0.9% saline). Hypertonic salme IS generally infused over approximately 10 minutes. 199. a Midazolam is a water-soluble benzodiazepine in the same class as diazepam. 200. d M~detomidine is an ",,-agonist approved for vetennary use in 19?6. It is the most potent "', agent currently available.

34

SECTI ON 1

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SECTION

2

NOTES ,

,

Clinical Pathology C.B. Grindem, B.T. Mitzner, R.E. Raskin

Recommended Reading Cowell RL, 'lYler RD: Cytology and hematology of the horse, St Louis, 1992, Mosby. Cowell RL, 'lYler RD: Diagnostic cytology of the dog and cat, ed 2, St Louis, 1997, Mosby. Duncan JR et al: Veterinary laboratory medicine, ed 3, Ames, Iowa, 1994, Iowa State University Press. Eades SC, Bounous Dr: Laboratory profiles of equine diseases, ed 2, St Louis, 1997, Mosby. Jain NC: Essentials of veterinary hematology, Baltimore, 1993, Williams & Wilkins. Meyer DJ et al: Veterinary laboratory medicine: interpretation and diagnosis, ed 2, Philadelphia, 1997, WB Saunders. SodikoffCH: Laboratory profiles of small animal diseases, ed 2, St Louis, 1996, Mosby. Willard MD et al: Small animal clinical diagnosis by laboratory methods, ed 2, Philadelphia, 1994, WB Saunders.

Questions C.B. Grindem 1. The anemia of chronic inflammatory disease is caused by:

c. deficiency of erythropoietin d. deficiency of transferrin e. ineffective use of stored iron

a. chronic blood loss b. deficiency of iron

Questions 2 and 3 Equine patient's sample Red blood cells (RBC) ( x 1()6/!1L) Hemoglobin (Hb) (g/rll) Packed cell volume (PCV) (%) Mean corpuscular volume (MCV) (tI) Mean corpuscular hemoglobin concentration (MCHC) (gl rIl) Total protein (gl rIl)

2.70 5.5 13

B.B

Reference range 6.0-10.43 10.1-16.1 27-43 37-49 35.3-39.3 6.0-B.5

Heinz bodies seen on blood smear

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Correct answers are on pages 55-62.

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SECTION 2

36

2. How is the anemia in this horse most accurately described?

a. b. c. d. e.

normocytic, hyperchromic normocytic, normochromic macrocytic, hyperchromic macrocytic, hypochromic microcytic, hypochromic

3. What is the most likely cause of the anemia?

a. b. c. d. e.

equine infectious anemia lead poisoning red maple poisoning bracken fern poisoning blister beetle poisoning

4. Which of the following causes extravascular hemolytic anemia? .

a. b. c. d. e.

babesiosis anaplasmosis leptospirosis copper toxicity hypophosphatemia

5. Neutrophils remain in the peripheral circulation for approximately:

a. b. c. d. e.

2 days 14 days 120 days 10 hours 30 minutes

8. If the automated white blood cell (WBC) count in a cat is 30,OOO/II'.L and 200 nucleated RBCsllOO WBCs were observed on the blood smear, the corrected WBC count would be:

a. b. c. d. e.

1000/fJ.L 1500/fJ.L 7500/fJ.L

10,OOO/fJ.L 15,0001 fJ.L

9. An 8-year-old dog has a fever, weight loss, and oculonasal discharge. Vaccinations are current (given 6 months ago). The WBC count is 20,OOO/fJ.L, with 50% lymphocytes that are morphologically normal. The platelet count is decreased, and plasma globulin levels are increased. What is the most likely cause of these findings?

a. b. c. d. e.

ehrlichiosis trypanosomiasis physiologic lymphocytosis acute lymphoblastic leukemia postvaccinationallymphocytosis

10. What is the best test to differentiate iron deficiency of chronic blood loss from relative iron deficiency of chronic inflammatory disease?

6. Neutrophil functional defects have been reported with all of the following except:

a. b. c. d. e.

c. in vivo hemolysis d. in vitro hemolysis e. extreme overanticoagulation with EDTA

estrogen toxicity after vaccination diabetes mellitus selenium deficiency bovine neutrophil CDllb/CDI8 surface marker deficiency

7. Causes of erroneous refractive index-derived total plasma protein values include all the following except:

a. b. c. d. e.

serum iron red cell indexes transferrin saturation bone marrow iron stores total iron-binding capacity

11. A dog has a PCVof 78% and normal blood urea nitrogen (BUN), total plasma protein, and erythropoietin levels. What is the most likely cause of these findings?

a. b. c. d. e.

hypoxia dehydration renal disease splenic contraction polycythemia rubra vera

d. transfusion oftype-DEA 1.1 blood into a dog with type-DEA 7 (tr) blood e. transfusion of the dam's RBCs into a foal

12. A false-negative Coombs' test can occur with any of the following except:

a. b. c. d.

glucocorticoid therapy improper antigenl antibody ratio insufficient quantity of antibody on RBCs testing an unseparated, refrigerated serum sample e. not performing the test at various temperatures

15. What is the best test to confirm failure of passive transfer of maternal immunoglobulins in a foal?

a. b. c. d. e.

13. What is the preferred test to confirm a diagnosis of systemic lupus erythematosus?

a. b. c. d. e.

37

Clinical Pathology

Coombs' test rheumatoid factor test antinuclear antibody test lupus erythematosus cell test direct immunofluorescence test

serum IgG levels serum IgM levels serum gamma glutamyltransferase (GGT) levels serum total protein serum albumin levels

16. Neonatal isoerythrolysis in foals is best diagnosed by:

a. cross matching the foal's RBCs and the mare's serum b. cross matching the mare's RBCs and the foal's serum c. blood typing the mare for Aa and Qa RBC antigens d. crossmatching the stallion's RBCs and the foal's serum e. crossmatching the mare's colostrum against the stallion's RBCs

14. Which patient is most likely to develop an immediate transfusion reaction?

a. transfusion of type-A blood into a cat with type-B blood b. transfusion of type-B blood into a cat with type-A blood c. transfusion oftype-DEA 1.2 blood into a dog with type-DEA 1.1 blood

For Questions 17 through 21, match the most likely cause with the following five canine hemograms. Test

WBCs (per ILL) PCV(%) MCV(fI) MCHC (g/dl) Platelets (x 103 ILL) Reticulocytes (%) Total plasma protein (gl dl)

a

b

c

d

e

2000 10 70 36 50 0 7.0

25,000 28 64 34 600 0 8.5

20,000 15 74 42 150 15 8

12,000 58 70 36 300 0 8.5

20,000 20 74 33 450 5 5.0

17. Acute blood loss anemia persisting for more than 3 days

19. Anemia of chronic inflammatory disease 20. Relative polycythemia

18. Hemolytic anemia 21. Aplasticanemia

a. lipemia b. Heinz bodies

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Reference range 5000-18,000 33-56 63-73 34-38 200-500 renal cortex and liver> renal medulla. In comparing echogenicities of two tissues, the sonographer must e nsure that the tissues are at the sam e depth (to avoid artifaci'caused by depth gain compensation), that the probe frequency is the same for each organ, and that structures are not present that might alter the echogenicity of one of the tissues (e.g., if fluid is superficial to the imaged tissue, echogenicity of the tissue is increased).

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Diagnostic Imaging and Recordings

104. c The capsule is a bright linear echo when the ultrasound beam is perpendicular to the kidney. The cortex and medulla are both hypoechoic, but the cortex is always more echogenic than the medulla. Echogenicity of the renal cortex should be approximately the same as that of the liver and less than that of the spleen. The renal pelvis is hyperechoic unless distended. Diverticula are hyperechoic. 105. e The renal cortex is more echogenic than the renal medulla. Echogenicity of the renal cortex should be apprOximately the same as that of the liver and less than that of the spleen. The renal cortex of obese cats has increased echogenicity because offal in the renal tubules. 106. b Small bright dots a t the corticomedullary junction represent a rcuate arteries. 107. e Acoustic shadowing occurs when a ll or most oCthe ultrasound beam is attenuated (reflected, absorbed, or scattered) by a structure so that no ultrasound is reflected by deeper structures. 108. d The spleen has smooth borders and a welldefined capsule that appears as a fine echogenic line when imaged at right angles to the probe. TIle spleen has a finer and more hyperechoic echo pattern than the liver. Intrapare nchymal splenic venous branches are hypo echoic to anechoic when viewed at a n oblique angle to the ultrasound beam but the walls may appear hyperechoic when imaged at right angles to the probe. Echogenic flow is a normal finding in larger vessels and does not indicate pathologic changes. Splenic arteries are not visible within the parenchyma, although arterial rami may uncommonly be found at the hilus. Splenic veins are visible. 109. a The gastrointestinal tract has five layers, \'lith altemating hyperechoic and hypoechoic echoes. From th e lumen to the external serosa, the layers are as follows: mucosal surface (hyperechoic), mucosa (hypoechoic), submucosa Olyperechoic), muscularis propria (hypoechoic), and serosa (hyperechoic and includes the subserosa). 110. e Mucus and gas are both hyperechoic, but mucus allows visualization of the far wall of the intestine, whereas gas exhibits distal or deep acoustic shadowing. Reverberations between the transducer and gas appear as artifactual lines \'Iithin the shadow; acoustic shado\'ling associated with gas has been called '·dirty." Intraluminal fluid is anechoic and (like mucus)

95

allows visualization of the far wall. Mucus and gas have echogenicity s imilar to that of the mucosal layer (all are hyperechoic). so that the interface between the mucosal s urface and either gas or mucus cannot be dis tinguished. Because fluid is anechoic, the mucosal surfaces are clearly seen as a separate layer. Ill. e From the lumen to the external serosal layers, the four wall layers are as follows; a hypoechoic mucosal layer; an irregular, discontinuous echogenic lamina propria submucosa parallel to the mucosa (lamina epithelialis); slightly heterogeneous, hypoechoic smooth muscle; and a hyperechoic serosa/perivesicular fat interface. All four layers may be visible when the bladder is collapsed, but imaging is suboptimal because the wall is artificially thickened. When the bladder is viewed with a high-frequency transducer (7.5 MHz or higher), v.rith slight to moderate distention, three layers are seen: a hype rechoic inner layer representing the submucosa/ mucosallumen interface; a slightly heterogeneous or hypoechoic middle layer representing the smooth muscle layers; and a hyperechoic outer laye r representing the serosa/ perivesicular fat inte rface. Stretching the bladder wall by maximal distention can mask even severe bladder wall thickening. Acoustic enhancement enol shadowing) occurs deep to the urinary bladder because there is minimal anenuation of ultrasound as it passes through a cystic structure. The cranial border (apex) of the bladder is poorly imaged by many ultrasound probes because of ultrasound refraction in this area. This area can be seen in a cystogram. 112. e The canine prostate gland is a bilobed structure surround ing the proximal urethra at the neck of the bladder. The normal prostate gla nd has a uniform, somewhat coarse echogenicity similar in brightness to that of the spleen. The urethra is a linear structure located between the lobes and has been described variously as hyperechoic or hypoechoic. The description of a hypoechoic oval \'lith a hyperechoic line located centrally \'Iithin the lobe would better apply to the testicle. The testicle is a smooth, homogeneous, elliptic organ, \'lith the rete (mediastinum) testis appearing as a central hyperechoic line in longitudinal images and a hypcrechoic dot in transverse images.

SECTION 3

96

11 3. d The uterus is hypoechoic, not hyperechoic. During estrus the lumen may not be visible or a small amount orfluid may be presenl. The uterus may be differentiated from the aorta and caudal vena cava because these vessels bifurcate caudally, whereas the uterus bifurcates cranially. (Also, the vessels are uSlImly anechoic with a proper gain selling.) In contrast to the gastrointestinal tract, the uterine wall in anestrus does not exhibit layers. Also, hypcrechoic gas or ingesta in the ilHcstinal lumen and peristalsis are generally apparent. Immediately postpartum, the endometrium and myometrium can be distinguished. Three layers may be visible in the myometrium: an inne r hypoechoic circular muscle layer; a central hyperechoic fibrovascular layer; and an oLlter h ypoechoic longitudinal muscle layer. The waU of the small intestine has five layers. Pregnancy can be diagnosed in dogs by ultrasonographic visualization of the chorionic cavity at 17to 20 days after the luteinizing hormone peak. The chorionic cavity appears as a 1- to 2- mm spheric vesicle. 114. b The normal pancreas is difficult to image because it is thin, has an echogenicity similar to tha t of adjacent m esentery, and is proximal (cranial) lO gas in the bowel. II has a homogeneous echogenic texture that is isoechoic to slightly hyperecho ic to live r and hypoechoic to spleen. The right extremity is dorsomedial to the duodenum, the body is associated \vith the cranial duodenal flexure, and the left extremity is found in lile region bordered by the stomach, spleen, and transverse colon. The phrenicoabdominal vein serves as a vascular landmark for the adrenal glands. The pancreaticod uodenal vein may be seen centrally in the pancreas. In acute pancreatitis the pancreas becomes thicker and more hypoechoic. Pancreatic pseudocysls may be seen as anechoic areas lilal can become q uite large. Hyperechoic areas may be seen with chronic pancreatitis. 115. b The normal gallbladder is teardrop shaped, with a smooth, uniform wall less than 2 to 3 mm wide. The wall is isoechoic to norma1liver and is therefore difficu lt to see and measure. The gallbladder lumen is rare ly empty and usually contains anechoic bile. The common bile duct is less than 2 mm wide and is difficult to follow to the duodenum.

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11 6. d Artifacts are frequently seen when imaging the liver and ga1lbladder. Mirror-image artifact occurs when sound is repeatedly reflected between the lung/diaphragm interface and the hepatic parenchyma. Black streaks originating fTom the curved surfaces of the gallbladder and extending into the hepatic parenchyma deep to the gallbladder are caused by refraction of sound from a curved object. Distal acoustic enhancement ("through transmission~) often causes an artifactual increase in echogenicity of the live r deep to the gallbladder. 117. d Echocardiographic findings in hypertrophic cardiomyopathy include left ventricular hypertrophy, either symmetric or asymmetric, behveen the left ventricular wall and septum. Left ventricular chamber size is reduced and the wall is noncompliant, preventing diastolic filling and causing elevated pressures at the end of diastole. The high e nd-diastolic pressure, along with distortion of the mitral valve apparatus, results in mitral regurgitation and left atrial dilation. These changes are aggravated by ventricular hypercontractility, which increases cardiac workload and tachycardia, decreasing the diastolic time available to fill the ventricle. In this patient, narrowing of the left ventricular outflow tract created by disproportional septal hypertrophy is creating functional obstruction to outflow. resulting in high-velocity turbulent flow; this further distorts the mitral valve and increases afterload o n the ventricle. 118. e p-blockers slow the h eart rate, which would decrease cardiac workload and allow for inc reased diastolic filling of lile ventricle. This increases cardiac output and decreases cardiac muscle hypoxia. Calcium-channel blockers slow the heart rate and increase ventricular re laxation, which assists diastolic filling and decreases the workload of the ventricles.

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Diagnostic Imagitlg and Recordings

119. b The su perficial digital extensor tendon originates on the media1 epicondyle of the humerus and inserts d istally on the phaJanges. (An accessory ligament originates on the distal radius.) Deep to the superficial digital extensor tendon is the deep digital flexor tendon, which originates on the d istal hwnerus, proximal olecranon, and mid-radius/ulna. The inferior check ligament continues as the palmar carpal ligament, travels deep to the deep digital flexor tendon, and joins the deep digital flexor tendon in the mid-metacarpal region. The interosseous (suspensory) ligament originates on the palmar surface of the third metacarpal bone and lies deep to the flexor tendons and inferior check ligament. It bifurcates at the level of the junction of the middle and distal thirds of the metacarpus. 120. c Severe retinal detachment appears as Vshaped echogenic lines with points of attachment at the optic disk or ora serrata. The lens is anechoic, whereas the anterior and posterior lens capsules are hyperechoic linear structUres. The anterior, posterior (when seen), and vitreous chambers are anechoic. The optic nerve is hypoechoic, whereas the optic disk is hyperec hoic. The iris a nd ciliary body are seen as short echogenic lines on each side of the lens. 121. a Acoustic impedance for a given material (tissue) is defined as the sound wave velocity multiplied by the density of the material. As the difference in acoustic impedance between £\VO adjacent tissues inc reases, the proportion of sound waves reflected at the interface of the tissues increases. Increased reflection of sound waves results in a brighter image at the point of reflection. 122. c Both the axial resolution and lateral resolution of an image are improved by increasing the transducer frequency. 123. a Axial resolution improves with increasing transducer frequency and with fewer cycles per pulse. 124. e Production of an ultrasound image reHes on the transducers receiving sound waves reflected from tissue interfaces at various distances. The time for a given pulse to be emitted, reflected at an interface, and return to the transducer dete rmines the distance of the interface from the transducer. The intensity of reflected waves returning to the transducer determines the brightness of the ultrasound

97

image at the point of reflection . A constant sound wave velocity through soft tissues is assumed even though slight variations in propagation speed occur. 125. b Pulsed Doppler is a method for determining the velocity of moving structures, such as flowing blood. The technique relics on changes in the frequency of ultrasound waves reflected from objects moving toward or away from the transducer. In the example of flowing blood, ultrasound waves reflected off blood cells moving toward the transducer have a higher frequency than the original emitted sound wave frequency, whereas sound waves reflec ting off cells moving away from the transducer have a lower frequency. 126. c The power control on an ultrasou nd machine determines the amplitude or intensity of the sound waves produced. As power is inc reased, the brighlness of the image is increased because more sound waves are reflected back to the transducer. 127. a The gain control o n an ultrasound machine is used to electronically amplify the signal produced by reflected ultrasound waves returning 10 the transducer. Amplifying the signal increases the brightness of Ule ultrasound image. Most machines have a gain control that uniformly modifies the sound wave amplification. 128. e Time-gain compensation controls are used to e lectronically amplify reflected waves from deeper structures. Because sound waves emitted from a transducer are auenuated and reflected by superficial structures, deeper structures receive comparatively fewer waves. The time-gain compensation control compensates for this nonuniform Signal generated for image formation. 129. dB-mode, or brightness mode, is the standard for nvo-dimensional image generation. The brightness of a particular point in an image depends on the intensity of reflected echoes returning to the transducer from the point of reflection. 130. b A IO-MHz linear-array transducer is the best choice. High-frequency transducers provide better spatial resolution (better image detail) than low-frequency transducers. linear-array transducers, which produce a rectangular image, provide better image quality in the near field (superficially) than do sector-scanning transducers. which produce a wedge-shaped image.

98

SECTION 3

131. a A urinary bladder calculus would be most

likely to produce a shadowing a rtifact because of reflection or refraction of almost all ultrasound waves by the calculus. Because very few waves penetrate deep to the calculus, virtually no signal is generat ed in this region and an anechoic shadow is produced.

132. e Because cystic snuctures are fluid fill ed, sound waves penetrate these structures to a greater degree than for soft tissues. This results in morc sound waves reaching tissues deep to the cyst As a result, there is a comparatively greater reflection of sound waves in these deeper structures. producing a brighter image deep to the cyst. 133.

134. 135.

136.

137. 138.

139:

140.

a Mirror-image artifacts result from reflected sound waves traveling by multiple paths back to the transducer. This can delay arrival of some of the reflected waves at the transducer. Because the ultrasound image is prod uced by mapping structures based on time of travel of reflected sound waves, a delay results in apparent pOSitioning of the structure deeper than its actual location. c Spleen is most echogenic, and the renal medulla is least echogenic. b Animals with hepatic lipidosis have a generalized incrcase in hepatic parcnchymal echogenicity. e Animals with acute ethylene glycol intoxication have a marked increase in renal cortical echogenicity. The change in echogenicity is proba bly the resuJt of accumulation of calcium oxalate crystals in the re nal tubules. b Portal veins have tltis appearance on sonograms. c Lym ph nodes are generally uniformly hypoechoic and produce less distal enhancement than cystic structures. a Left ventricular failure resulting in pulmonary edema would be difficult or impossible to diagnose us ing cardiac ultrasound alone. Diagnosis of pulmonary edema would require thoracic radiographs. Echocardiographic findin gs of the othe r conditions are well described. b On sonograms of unsedated dogs, the left ventricular shortening fraction averages approximately 35%.

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141. d Unless the fibers are clad, light tends to leak as it traverses the fibers toward the distal tip of the endoscope. 142. a These features enhance maneuverability of the distal tip. 143. b Air should not be used because of the risk of air e mbolism. Nitrous oxide, oxygen and hydrogen can support combustion. 144. d Endoscopy can detect morphologic but not fu nctional disease. 145. c Surrounding tissues could be contaminated by leakage of ingesta during insufflation. 14 6. a It may be caused by vagovagal refl exes stimulated by overdistention of the bowel or by traction on the mesentery. 147. b Glycopyrrolate is commonly used. 148. a The endoscope should be withdrawn to the cardia and the stomach partially deflated before further attempts are made. 149. c Fasting and administration of oral electrolyte solutions help to cleanse the colonic mucosa in preparation fo r colonoscopy. 150. a Some treated cats may develop hypermagnesemia. 15 1. c The directional control knobs can be manipulated so as to view the entire ci rcumference of the colon. 152. a Gas could escape from the a bdominal cavity into the thoracic cavity, caus ing pneumotllorax. 153. c Preceding rhinoscopic examination may alter the radiographic appearance of structures. 154. e Biopsy during bronchoscopy could result in serious hemorrhage. 155. b None of the other answer choices accurately describes the endoscopic view of the right bronchial tree. 156. a This instrument can be inserted through the urethra of dogs and cats. 157. d The bladder must be kept undistended to allow the puncture sites to heal. 158. a The view caudally is obscured during swallowing. .. 159. c These openings are evident in the rostroventral portion ofche guttural pouches. 160. d The endoscope tip should be directed dorsally and to the right to view this portion of the stomach. 161. b Differences in appearance may indicate pathologic changes.

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Diagnostic Imaging and Recordings

162. d Introduction of air into the uterus produces a hyperemic response. 163. b Both cause minor pathologic changes in chondrocytcs that resolve in a few days. 164. e This preserves the anatomic position of tendons and their sheaths for accurate incision. 165. e Birds should be placed in right lateral recumbency for gender determination. 166. c The other possible choices describe electrical activity within the myocardial cell. 167. b Digitalis acts directly on the myocardium , vagus nerve, and atrioventricular junction . 168. b Us ing at least two limb leads (I, aVF) and the different angles at which they record the heart's electrical activity, one can estimate the mean electrical axis in the frontal plane. 169. a Sinus arrhythmia is represented by alternating pe riods of slower and more rapid heart rates, usually related to respiration . The heart rate increases with inspiration and decreases with expiration. 170. c Atrial depolarization and repolarization represent the P wave and subsequent T wave, whereas ventricular repolarization represents the T wave following a QRS complex. 171. d The depolarization waves spread from the sinoatrial node through the right atrium, toward the left atrium and the atrioventricular node, resulting in a P wave. This indicates depolarization. 172. e The QT interval is the summation of ventricular depolarization and repolarization. 173. d Procainamide, lidocaine, and disopyramide are ventricular antiarrhythmic agents. 174. e Sympathetic stimulation increases the si nus rate and increases tlle force of myocardial contraction. 175. c Ventricular bigeminy occurs when the rhythm alternates between a normal sinus complex and a ventricular premature complex. 176. e The othe r possible choices are not primary ventricular arrhythmias and are also arrhythmias that usually do not lead to ventricular fibrillation. 177. a One or more P waves not followed byQRS.Y complexes can be classified into two types of second-degree atrioventricular block: Mobitz type I and Mobitz type II. With Mobitz type I, the RR interval becomes progressively shorter as the PR interval becomes longer, until a P wave is blocked.

99

178. c The cardiac parasympathetic nerves form the vagus nerves, whose fibers terminate primarily in the s inoatrial node, atria, and atrioventricular node, slowing the heart rate and slowing conduction through the atrioventricular node. 179. a The normal PR interval range is 0.06 to 0. 13 seconds. 180. b A fus ion complex is simultaneous activation of the ventricles by impulses coming from the s inoatrial node and ventricular ectopic foc i. 181. d Ventricular tachycardia can be thought of as a continuous series of ventricular premature complexes resulting from stimulation of an ectopic ventricular focus. 182. b Delay in conduction of a supraventricular impulse through the atrioventricular junction is called first-degree atrioventricular block. 183. d Mobitz type-I atrioventricular block is present when the RR interval becomes progressively shorter as the PR interval becomes longer, until a P wave is blocked. 184. a Leads I, II, and III represent the s tandard bipolar leads. 185. a Electrical alternans is diagnosed when the Po QRS, or T complexes alter in configuration on every olher complex, every third complex, every fourth complex, etc., with each complex originating from the same focus. 186. c Sick sinus syndrome describes a number of electrocardiographic abnonnalities of the sinoatrial node, including severe sinus bradycardia a nd severe s inoatriaJ block andl or sinus arrest. 187. b Wolff-Parkinson-White syndrome consists of ventricular preexcitation, with episodes of paroxysmal supraventricular tachycardia associated with an accessory conduction pathway. 188. b In tlle normal canine heart, the axis lies betwee n +40 degrees and + 100 degrees, with right-axis deviation occurring when the axis is greater than +100 degrees. 189. a Atrioventricular dissociation implies that the atria and ventricles are discharged by two independent foci of impulse fonnation. 190. a Hyperkalemia is a very common cause of atrial standstill in animals with hypoadrenocorticism, kidney failure, or diabetes mellitus.

100

SECTION 3

191 . c All other choices are incomplete or ambiguous. Some of the other choices. such as

band e, are amy half-truths, because there are other ways to evaluate consciousness and epilepsy.

192. e All other answers refer to other sources of artifact, but these problems are not always present In fact, the problem of muscle spasms a nd movement is so great that many veterinary e lectroencephalographers insist that recordings be made with the patie nt under anesthesia. 193. a Although the other answers refer to other possible sources of EEG signals, these

influences are probably relatively minor. 194. e The EEG becomes activated (low voltage, fast activity) when an animal is in pain. However, it becomes Similarly activated when the animal is stimulated imensely by stimuli that a re not painful. Also, the EEG of dream sleep appears similar. 195. e Conscious awareness is e nabled by the excitatory action of the brain s tem reticular form ation upon the neocortex. Lesions or stimulation of the brain ste m produces predicta ble changes in the EEG.

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196. b Electromyography is an important adjunct to neurologic examination. By ilSelf, e lectromyography does not provide a definitive diagnosis of a nerve or muscle disease. 197. b Needle electromyographic e lectrodes cause focal muscle fiber damage, which results in release of CPK and elevation of serum CPK activities proportional to the number of needle insertions. 196. d Fibrillation potentials in canine skeletal muscles usually appear on day 5 after denervation. A direct re lations h.ip exists between size of the animal species and the time of appearance of fibrillation potentials. 199. c Fibrillation potentials appear in the denervated motor units. Motor unit potentials occur in the innervated motor units. Thus both types of potentials would be recorded from a partially innervated muscle. 200. d Demyelination of a periphe ral nerve results in conversion of conduction of impulses from a saltatory (nodal) process to continuous conduction, which is significantly slower than saltatory conduction.

SECTION

4 Hematology and Cytology R.L. Cowell,

W.I.

Dodds, B.L. Hines

Recommended Reading Cowell RI.., Tyler RD: Cytology and hematology of tile horse, St Louis, 1992. Mosby. Cowell RI.., Tyler RD, Meinkoth JH: Diagnostic cytologyoftlle dog and cat, ed 2. St Louis. 1998,

Mosby. Duncan JR et al: Veterinary labomtory medicine, ed 3. Ames, Iowa. 1994, Iowa State Uni\'ersity

Pre". fain NC: Essentials of veterinary Ilemat%gy, Baltimore, 1993. \Vllliams & Wllldns.

Meyer 0 1 el al: Vererinary laboratory medici/Ie: interpretation and d iagllosis, Philadelphia. i 992, we Saunders. Willard MO et al: Small animal clinical diagnosis by laboratory methods. ed 2, Philadelphia. 1994, WE Saunders.

NOTES

Practice answer sheetli are on pages 261-262.

Questions R.L. Cowell and B.L. Hines 1. Which anticoagulant does not act by binding calcium ?

a. I, II, V; Xl b. II, V, VII, IX

a . heparin

b. c. d. e.

sodium EDTA sodium citrate potassium EDTA potassium oxalate

c. II, IX. X. XII d. II. VII. IX, X e. III, VII, IX, X

2. Which type of red blood cell morphology is compatible with phenothiazine roxicity in horses? a. b. c. d. e. «)

1998 MoslJy-Year Book, In c. Photocopying is prohibited bylaw

target cells Heinz bodies stomatocylosis basophilic s tippling nucleated red blood ceUs

3. Which clottingfactors are affected in animals wilh dicumarol toxicosis?

4. lNhich factor in Ole clotting cascade has the shortest half-life? a. I b. III c. V d. VII

e. IX Correct aTlSUJers are on pages 124-130.

101

5. A 5-year-old St. Bernard is presenced to your

small-animal practice because of lethargy and anorexia 0[2 weeks' duration. Physical examination reveals generalized lymphadenopathy. Microscopic examination ofa fine-needle aspirate shows a monotonous population (>90%) ofround cells with a high nucleus/cytoplasm ratio and prominent nucleoli. These cells are larger than tile rare neutrophils you find. Based on this description. what is the most likely diagnosis?

a. b. c. d. e.

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SECTION 4

102

inflammation osteosarcoma lymphosarcoma benign hyperplasia immune stimulation

6. W1Jal is the predominant cell type seen in most chylous effusions?

a. mast cell b. eosinophil c. neutrophil d . lymphocyte e. macrophage 7. Wlljcll oftile following is typical offluid removed from tile peritoneal cavityofa cat with effusive feline infectious peritonitis?

a. clear. high-protein fluid containing primarily lymphocytes b. straw-colored, low-protein fluid containing primarily neutrophils c. straw-colored, high-protein flu id containing primarilyeosinophils d. straw-colored, high-protein fluid containing primarily neutrophils e. s traw-colored. high-protein fluid containing primarily lymphocytes

9. A KurfoJfbody is an eosinophilic-staining inclusion seen normally witllin the lymphocytes of

14. All exaggerated response to mild anemia, in the form of polychromasia, nucleated erythrocytes,

and basophilic stippling. is most often seen in

a. rats b. rabbits c. reptiles d. hamsters e. guinea pigs

animals wilh : a. iron toxicity b. iron deficien cy c. lead poisoning d. folate deficiency e. copper deficiency

10. Wllich of tile following is not classified as a round-cell tumor?

15. Larce '/limbers of spherocyres are characteristic of

a. histiocytoma b. mastocytoma c. osteosarcoma d. lymphosarcoma e. trans missible venereal tumor

a. anem ia of lead poisoning b. Heinz-body anemia c. iron-deficiency anemia d. anemia of chronic disease e. immune-mediated hemolytic anemia

11. Which of the following best describes the most

16. Tn dogs the normal activated clottjng rime is:

likely hematologic findings in a dog given corticosteroids 12 to 24 hours previously?

a. lymphoCYlOsis. neutropenia. monocytosis. eosinopenia b. lymphopenia, neutropenia, monocytopenia, eosinopenia c. lymphopenia, mature neutrophilia, monocytosis. eosinophilia d. lymphopenia. mature neutrophilia. monocytosis, eosinopenia e. lymphocytosis. mature neutrophilia, monocytosis, eoSinopenia 12. In horses, which of the following is the best indicator ofa bone marrow response to anemia?

a. b. c. d.

polychromasia increased reticulocyte count improved mucous membrane color increased packed cell volume on serial determinations , e. increased nucleated red blood cell count

8. Megakaryocytes are ti,e precursor cells to:

a. platelets only b. lymphocytes only c. red blood cells only d. segmented white blood cells only e. all circulating blood cells except lymphocytes

Hematology and Cytology

13. Von Wiflebrand's disease is most common in:

a. boxers b. Irish setters c. Labrador retrievers d. Doberman pinschers e. German short-haired pointers

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•.

,

less than I minute b. less than 2 minutes c. less than 3 minutes d. less than 4 minutes e. less than 5 minutes

18. A 6-momll-o/d puppy has had cOllghingand all OCu/ollasai discharge for the past week. TIle puppy was vaccinated at 10 and 12 weeks a/age. A blood smear stained Wilh Diff-Quik reveals homogeneous eosinophilic-staining inciusiom ill red blood cells and nemrophils. The most likely cause ofthis puppy's illness is:

a. b. c. d. e.

a. Activated c10tfing time is normaJ in both instances. b. Platelet count is generally elevated in DIC and normal in warfarin toxicosis. c. Platelet count is generaJly elevated in Die and decreased in warfarin toxicosis. d. Concentrations of fibrin degradation products are typically increased in DIC and normal in warfarin toxicosis. e. Concentrations of fibrin degradation products are typically normaJ in DIe and increased in warfarin toxicosis.

parvovirus infection ehrlichiosis borreliosis distempet pneumonia. \vith normaJ morphologic changes seen in the blood cells of young animals

19. On an impression smear made from an ulcerated area on tile forelimb ofa cat. you find multiple. small (2 to 4 ~m). basophilic-scainingorganisms whose shape varies from round to oval to fusiform (cigar shaped). wirh a thin, clear halo. The most likely calise of the lesion in this cat is:

a. b. c. d. e.

17. Concerning differentiation of warfarin toxicosis from disseminated illtravascularcoagulation (DIC), wh ich statemetlt is most accurate?

103

leishmaniasis toxoplasmosis sporotrichosis histoplasmosis cytauxzoonosis

20. In a cat witll a packed cel/volume (PCV) of5%. an adequate regenerative response is suggested by an aggregate reticulocyte cOlmt ofat least:

a. J% b. 2% c. 5% d.10% e. 20% 21. Whicll organism commonly affects the central nervous system and might be found on cytologic evaluation ofcerebrospinal fluid?

a. Sporothrix schenckii b. CoccidiQides immitis c. Histoplasma capslliatum d . Blastomyces dermatitidis

e. Cryptococcus neoformans

Corm;t arlSwerSQn- 0" pages 124- 130.

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SECTION -4

104 22. A cow in respiratory distress has pale mucous

membranes. Evaluation ofa blood sample reveals small, round, basophilic-staining inclusions on the margins a/many red blood cells. Based on this informatioll, what is the most likely diagnosis?

26. Red blood cell Willi no central pa/lorand much smaller thall normal 27. Differentiated lymphocyte that produces immunoglobulin

a. babesiosis h. leptospirosis c. molybdenum toxicosis

28. Eosinophilic inc/usion normally found in lymphoid cells ofguinea pigs

d. anaplasmosis e. bacillary hemoglobinuria 23. Avian species are hosts to several different blood parasites, which can be idelllified 011 examination afa blood smear. W1Iich of tile following is not a blood parasite a/birds? a. Prototlleca b. Plasmodium c. TIypanosoma d. Haemoproteus e. Leukocytozoon 24. Whicilleukocyce predominates in the peripheral blood ofhamsters?

a. basophil h. eosinophil

30. ImmwlOglobulin -fiffed vacuole ill tile cytoplasm of plasma ceffs

For Questions 31 through 35, select the correct answer from the five choices below.

a. metaplasia b. dysplaSia c. crenation d. carcinoma e. sarcoma 31. Morphologic change of red blood cel~picaffy caused by dehydration and characterized by multiple indentatiollS in the cell membrane 32. Malignant neoplasm ofepithelial-cell origin

25. Which term describes the sex chromatin lobe seen as a "drumstick" on the nucleus ofa neutrophil from afemaleanimal?

a. b. c. d. e.

8arrbody Heinz body Russell body Curschmann body Pappenheimer body

For Questions 26 through 30, select the correct answer from the five choices below. a. b. c. d. e.

Kurloffbody Russell body plasma cell spherocyte schistocyte

37. The major role of VOIl Willebrand's factor in the coagulation cascade is ill:

a. b. c. d. e.

lysis of clots formation of platelets activation of factor X activation of factor XII platelet adherence to damaged tissue

38. The normal Ufe span ofa canine red blood cell is: 29. Fragment ofa red blood cell

c. monocyte d. ne utrophil e. lymphocyte

Hematology and Cytology

33. Tissue challge caused by chronic irritation and characterized byf'eplacement ofolle mature cell type willi allother mature cell type

a. b. c. d. e.

30 days 60 days 90 days 120 days JSOdays

intrinsic pathway only extrinsic pathway only common pathway only intrinsic and common pathways extrinsic and common path,vays

40. TIle activated partial thromboplastin time (APIT) is used to evaluate which aspect of the

coagulation cascade?

a. b. c. d. e.

il1(rinsic pathway only extrinsic pathway only common pathway only intrinsic and common pa£hways extrinsic and common pathways

34. Maligllant neoplasm ofmese1lchymal-cell origin 35. Nonneoplastic tissue change associated with variOlLs factors, such as inflammation, and characterized by irregular, atypical, and proliferative changes in cell populations 36. Steatitis defines:

a. inflammation or the mammary glands b. excessive lipid globules in feces, associated with enteritis c. inflammation of adipose tissue d. excessive conjugated bilirubin in the serum, associated with hepatitis e. inflammation of lymph vessels C 1998 Mosby-Year Book. Inc. Phorocopying is prohibired by law.

42. Leukocytosis is all increase in the total white blood cell count above the normal range. An increased number of which cell type most commonly characterizes leukocytosis in dogs?

a. basophil b. eosinophil c. monocyte d. neutrophil e. lymphocyte 43. YOllfind rare, smail, roulld, pale blue- to gray_ staining. mulberry-like morulae in the cytoplasm of neutrophils ofa 3-year-old English poimer with polyarthritis. The most likely cause of this finding is:

39. One-slage prothrombin rime (OSPT) is used to evaluate which aspect ofthecoaglllntioll cascade?

a. b. c. d. e.

105

41. C0 11cern ing corticosteroid-i1lduced neutrophilia, which statemelll is kastaccurate?

a. Release of mature neutrophils from bone marrow is increased. b. The peak response is seen t2 to 15 hours after corticosteroid administration. c. The magnitude of neutrophilia diminishes with long-term corticosteroid therapy. d . Leukocyte values relUm to pretreatment levels within 24 hours after a single dose of corticosteroids. e. Neutrophils remain in circulation longer because of decreased margination of cells.

a. b. c. d. e.

distemper babesiosis ehrlichiosis leptospirosis histoplasmosis

44. Wllicll of the following is least likely to cause macrocytic anemia? a. b. c. d. e.

erythremic myelosis folic acid deficiency vitamin 8 12 defiCiency iron defiCiency cobalt deficiency in ruminants

45. Which type ofanemia is most likely to be macrocytic hypochromic?

a. b. c. d. e.

regenerative anemia anemia associated \vith iron deficiency anemia associated with copper deficiency anemia associated with folic acid deficiency anemia associated with bone marrow suppression

46. In a cat with leukocytosis induced by endogenous epinephrine (physiologic leukocytosis), the leukocytosis is attributable to:

a. b. c. d. e.

neulJ'ophilia only lymphocytosis only neUlJ'ophilia and monocytosis neutrophilia and lymphocytosis monocytosis and lymphocytosis

Correct answers are 0" pages 124·130.

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106

47. Which leukocyte predominates in the peripheral blood ofnormal dogs?

a. basophil b. monocyte c. neutrophil d. eosinophil e. lymphocyte

53. Which of the following is an inherited disease causing a defect in leukocyresegme'ltatioll?

48. Wllieh leukocyte predominates in the peripheral blood ofa normal weanling pig?

a. basophil b. monocyte c. neutrophil d. eosinophil e. lymphocyte

a. b. c. d. e.

Evans' syndrome Pelger-Huet anomaly mucopolysaccharidosis CMdiak-Higashi syndrome neutTophii granulation anomaly of Birman cats

54. Which oflhe following causes microcytic hypochromic anemia?

49. Which leukocyte predominates in tile peripheral blood ofa normal adult cow?

a. basophil b. monocyte c. neutrophil d. eosinophil e. lymphocyte

a. b. c. d. e.

renal fail ure iron deficiency estrogen toxicity folic acid deficiency inflammatory disease

55. Avian tllrombocytes differ from mammalian tllrombocytes in that avian tllrombocytes:

50. Heinz bodies are most likely to be detected on a smear a/blood from healthy:

a. pigs b. cats c. dogs d. cattle e. horses

a. b. c. d. e.

are phagocytic are nucleated cells have no role in hemostasis can transport oxygen playa major role in immune responses

56. Concerning protamine sulfate, which statement is most accurate f

51. Wll ich type o[abnormaJ red blood cell indicates microangiopathic hemolysis?

a. target cell b. lep tocyte

c. schistocyte d. Slomatocyte e. Mott cell

a. It is an irreversible anticoagulant. b. It is a potentiator of sodium citrate in anticoagulation. c. It is a cause of Heinz-body anemia in cats. d. I{ is used in an early screening test for disseminated intravascular coagulation. e. II is a common cause of autoimmune hemolytic anemia in dogs. 57. Which cell type can divide by mirosis?

52. Which of the following is most difficult to d ifferentiate from an Anaplasma organism on a Romanowsky-slllined blood smear?

a. Heinz body b. Dohle body

c. Schmauch body d. Howell-Jolly body e. erythrocyte refractile body

a. b. c. d. e.

myelocyte reticulocyte metamyelocyte band neutrophil segmented neutrophil

C 1998 Mosby-Year Book, Inc. Photocopying is prohibited by law.

Hema tology and Cyto logy

58. Which type of hemorrhage is not typically seen in animals with platelet abnormalities or thrombocytopenia?

a. b. c. d. e.

epistaxis hematuria ecchymosis petechiation hemarthrosis

107

d. Kupffer cell e. T lymphocyte For Questions 63 through 67, select the correct answer from the five choices below.

59. Which of the followillg is IlOt a hereditary

a. b. c. d. e.

basophilic stippling Heinz body rouleaux agglutination Howell-Jolly body

coagulopathy?

a. b. c. d. e.

Pelger-Huet anomaly factor X deficiency von WiUebrand's disease hemophilia A (factor VIII deficiency) hemophilia B (factor IX deficiency)

60. In which species has cytauxzoonosis not been reported or described?

a. b. c. d. e.

dogs bobcats cheetahs antelopes domestic cats

63. Random clumping oferythrocytes

64. Organized grouping of red blood cells, resembling stacked COiTlS 65. Mulear remnaflts within mature (nonnucleated) red blood cells 66. Clumps of denatured hemoglobin within red

blood cells 67. Ribosomal clumping in red blood cells tliat stains basophilic witl! Wrights stain and may appear as distinct granules or fine dots

61. Tn a blood smear from a markedly anemic cal,

youfind large nllmbers ofllucleated red blood cells in the absence of polychromasia alld reticulocytosis. The most li/cely cause of this finding is:

a. b. c. d. e.

lead poisoning erythremic myelosis Pelger-Huet anomaly lymphoblastic leukemia Chediak-Higashi syndrome

a. b. c. d. e.

siderocyte Mott cell Kupffer cell ferrocyte Downey cell

69. Which of tile following is sometimes referred to as plumbism?

62. A differentiated B lymphocyte develops into a:

a. rubricyte b. siderocyte c. plasma cell

68. A mature red blood cell containing visible iron particles (Pappenheimer bodies) is known as a:

a. b. c. d. e.

iron deficiency copper toxicity lead poisoning lymphosarcoma multiple myeloma

Correcranswers are on pages 124-130.

108 70. Tile hematologic response associated with hypothyroidism in dogs is:

a. polycythemia b. erythroleukemia c. normocytic normochrom ic anemia wim leptocytosis d. microcytic hypochromic anemia with spherocytosis e. macrocytic hypochromic anemia with reticulocytosis 71. Which pair of species can become infected with Ehrlichia?

a. dogs and pigs b. horses and pigs c. dogs and horses d. cattle and sheep e. horses and canle

astrocytes plasma cells endothelial cells precursor cells of granulocytes myelin.producing cells of the central nervous system

73. Which ofthefollowillg is not associated with Heinz -body formmio,,? a. b. c. d. e.

d. increased erythropoietin production e. splenic contraction in stressed animals 75. What is the most common cause of polycythemia ;nanimals?

a. b. c. d. e.

onions red maple bracken fern new methylene blue phenothiazine dewormers

74. Polycythemia uera is associated with:

a. pulmonary hypoxia b. reduced atmospheric oxygen c. a malignant stem·cell disorder

polycythemia vera familial erythrocytosis disorders resulting in hypoxemia abnormal erythropoietin production dehydration and splenic contraction

77. eonceming the effect ofcorticosteroids on

..

a. 11ley have no effect on granulopoiesis or lymphopoiesis. b. 11ley inhibit granulopoiesis and lymphopoiesis. c. They stimulate granulopoiesis and lymphopoiesis. d. They inhibit granulopoiesis but stimulate lymphopoiesis. , e. They stimulate granulopoiesis but inhibit lymphopoiesis. 7B. The proteins responsible for blood coagulation are

produced primarily in the:

a. b. c. d. e.

liver spleen kidney pancreas small intestine

79. In a vaginal swab from a 2·year-old intact miniature schnauzer,youfind 96% superficial celis, with small pyknotic nuclei. Thisfinding indicates that this bitch is most likely:

a. b. c. d. e.

a. b. c. d. e.

estrogens thyroxine androgens corticosteroids growth hormone

grallulopoiesisand lymphopoiesis. which sMtemeru is most accurate?

Hematology and Cytology

in estrus in diestrus in anestrus in proestrus infected with a fungus

c. leukocytosis caused by neutrophilia and lymphocytosis d. leukocytos is caused by neutrophilia and monocytosis e. leukopenia primarily caused by neutropenia

aplastic anem ia myeloid leukemia sevcre le ukopenia erythrOid le ukemia iron-deficiency anemia

a. b. c. d. e.

immune-mediated thrombocytopenia feline infectious anemia equine infectious anemia immune-mediated hemolytic anemia microangiopathic hemolytic anemia

85. WI/icll abllormality is associated Will, Willebrand's disease?

81. In a transtraclleal wash from a couglling dog. you find columnar cells, macrophages, a mixed population of bacilli alld cocci, and numerous Simonsiella organisms. The most likely cause of these findings is:

a. b. c. d.

a hypersensitivity reaction oropharyngeal contamination a mixed fungal and bacterial infection a mixed bacterial infection associated with immunosuppression e. a fungal infection associated with overuse of antibiotics

a. b. c. d. e.

VOII

thrombocytosis thrombocytopenia thrombocytopathy deficiency of factor IX deficiency of factor VI I

For Questions 86 through 90, select the correct answer from the five choices below. a. b. c. d. e.

major crossmatch minor crossmatch Russell's viper venom time (Rvvr) intravascular hemolysis extravascular hemolysis

86. Associated Willi babesiosis in cattle

82. Which cell type may occasionally be observed in syrlOllial flllid and is diagnostic of systemic lupus erythematosus?

a. b. c. d. c.

lupus erythematosus (LE) cells Mott cells giant cell leplOcytcs siderocytes

87. Test using recipient's plasma and donor's cells 88. Associated with anaplasmosis in cattle 89. Used to differentiate factor VII deficiencies from common pathway coagillopathies

83. loW/icll hematologic finding is most likely to be observed in cottle with severe, acute inflammation?

90. Test using dOllor's plasma and recipient's cells

a. leukocytosis caused by neutrophilia only b. leukocytosis caused by lymphocytosis only

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109

84. A Coombs' test is used to help diagnose:

80. Which hematologic abnormality is associated willI IOllg-term bracken-fern jngestion in cattle?

76. Which of the following does not stimulate erythropoiesis?

a. b. c. d. e.

72. From which cell rype does multiple myeloma arise?

a. b. c. d. e.

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Correcr answers are on pages 124-130.

110

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91. Theanemia seen associated with:

a. b. c. d. c.

jn

chronic Tenalfailure is

lack of e rythropoietin production hemolysis caused by electrolyte imbalances splenic removal of abnormal red blood cells loss of red blood cells in the form o f hematuria stress· induced estrogen release and resultant bone marrow suppression

92. In dogs, w/lere is erythropoietin produced?

c. meat d. eggs e. legumes 97. Mwt protein rransports iron in tile plasma?

a. b. c. d. e.

transferrin lipofuscin hemosiderin chromaffin transcobalamin

a. liver

H ematology and Cytol ogy

102. A giallC cell isformed by /iJSion of

a. heterophils

98. A Serto{j-cell OImor is most likely to occur:

93. Which organisms are referred to as marginal bodies?

a. Babesia b. Anaplasma c. Eperythrozoon d. Hem obarlollclla e. Ehrlichia

a. b. c. d. e.

in the mouth of a cat around the eye of a horse on the distal limb of a 6-month-old dog in an ovary of an 8- to 12-year-old female dog in a retained (abdominal) testicle of a 7-yearold dog

103. III w/tich type of leukocyte is ~tox;c change" most commonly seen?

a. basophils

99. Wlljc/I disorder is least likely to produce peripheral neutropenia?

a. hyperadrenocorticism

c. monocytes d. neutrophils e. lymphocytes 104. In which dog breed do eosinophilsfrequently have more vacuoles t/Jan granules?

a. b. c. d. e.

akita boxer Samoyed greyhound A1askan malamute

h. parvoviral infection

94. Which of the [oI/owing does not increase nwnbers ofcirculating platelets in animals with

immune-mediated thrombocytopenia? a. vincristine

c. rupture of the cecum d. overwhelming bacterial infection e. Salmonella- induced endotoxemia in a horse

c. tetracyclines d. corticosteroids e. cyclophosphamide 95. Which blood type is most common in cats in the United Stales?

a. F b. Tr

a. leptocytosis b. anisocytosis c. poikilocytosis d. reticulocytosis e. stomatocytosis

96. Which of the followin g is a poor source of iron?

a. fo lded in half c. variable shapes d. organized like a stack of coins e. s malle r than normal, with no cen tral pallor 106. Concemillg histiocytomas. whicll statement is most accurate?

a. They are relatively more common in beagles. h. They contain distinct spindle-shaped ceUs.

/01. A heterophil is most likely to befollnd in a:

c. B d.AB e. A

105. Mlich of fhe following best describes anisocytosis oferythrocytes? h. variable sizes

100. A general term Ilsed to describe abnormal and bizarre shapes in erythrocytes is:

h. splenectomy

a. pig h. cat c. dog d. bird e. Uama

107. In wliich ofthefollowing is a Diilile body most likely to befoulld?

eosinophil in a greyhound cytoplasm of a toxic neutrophil cytoplasm of a thrombocyte in a bird nucle us of a liver cell in a puppy with infectious canine hepatitis e. cytoplasm of a lymphocyte stimulated to produce antibodies a. b. c. d.

b. neutrophils c. hepatocytes d. lymphocytes e. macrophages

h. eosinophils

b. kidney c. spleen d. thyroid e. bone marrow

c. They tend to occur in youn g dogs.

108. In a transtracheal wash from a horse,youfind ciliated and nOllciliated columnar and cuboidal cells. alveolar macropl/ages, an occasional neutrophil. and approximately 20% of cells as eosinop/ti/s. You observe no superficial squamolJS epithelial cells or Simonsiella organisms. Which of the following is tile most appropriate cytologic interpretation?

a. This is a normal ceUpopulation. b. There is evidence of malignant neoplaSia. c. There is evidence of a hypersensitivity reaction . d. There is evidence of bacterial or fu ngal inflammation. e. There is evidence of oropharyngeal contamination. 109. Concemillg the procedure ofpercutaneous trallStracheallbronchial wash, which statement is most accurate?

a. It cannot be done without general anesthesia. h. It is preferred in frac tious animals. c. It requires use of a sterilized endotracheal tube. d. It reduces the risk of oropharyngeal contamination. e. It involves passage of a needle and catheter through the thyroid cartilage.

d. They can metastasize to the lungs. e. Azurophilic granuJation can obscure the nucleus ofhlstiocytoma cells.

a. dirt b. milk

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III

Correct answers are on pages 124-130.

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112

110. Which a/the following best characterizes a septic

exudate? a. low protein conlent (