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  1. 1. Compendium CompendiumVet.com | Peer Reviewed | Listed in MEDLINE Vol 31(5) May 2009 6 CE Contact Hours CONTI N U I NG EDUCATION FOR VETERI NARIANS ® NEW SERIES A Applied Dermatology Flea Allergy Dermatitis FREE CE Laryngeal Paralysis FREE CE Pneumothorax Clinical Snapshot al y rn lit * ou a s! Ve e ium yJ u ar l Q m O nd rin l te ra pe al v m # om ni n C lA i al 1 rS d fo te Ra
  2. 2. With Hill’s PetFitness VetSync, ® he’s losing weight and gaining health Discover the NEW tool that’s revolutionizing weight management. VetSync is a free interactive web-based program to help you boost your patients’ weight loss success. And by helping pets lose weight with VetSync your team can earn exciting rewards, including a digital camera and a Nintendo® Wii™ and Wii Fit. ™ FREE! ™ * Visit HillsVet.ca and get a Klean Kanteen, just for inquiring about VetSync. *One water bottle per clinic. ©2009 Hill’s Pet Nutrition Canada, Inc. ®/™ Hill’s is a trademark owned by Hill’s Pet Nutrition, Inc. Nintendo, VetSync is an ongoing program. Hill’s has Wii, and Wii Fit are trademarks of Nintendo Company, Ltd. Klean Kanteen is a trademark owned by Klean Kanteen. the right to change this program any time.
  3. 3. May 2009 Vol 31(5) CompendiumVet.com | Peer Reviewed | Listed in MEDLINE EXECUTIVE EDITOR Tracey L. Giannouris, MA 800-426-9119, ext 52447 | tgiannouris@vetlearn.com MANAGING EDITOR Kirk McKay 800-426-9119, ext 52434 | kmckay@vetlearn.com Subscription inquiries: PUBLISHED BY SENIOR EDITOR 800-426-9119, option 2. Robin A. Henry Subscription rate: $79 for 1 year; $143 for 2 years; $217 800-426-9119, ext 52412 | rhenry@vetlearn.com for 3 years. Canadian and Mexican subscriptions (sur- ASSOCIATE EDITOR face mail): $95 for 1 year; Chris Reilly $169 for 2 years; $270 for 3 800-426-9119, ext 52483 | creilly@vetlearn.com years. Foreign subscriptions (surface mail): $175 for 1 ASSISTANT EDITOR Published monthly by Veteri- year; $275 for 2 years; $425 Benjamin Hollis nary Learning Systems, a for 3 years. Payments by 800-426-9119, ext 52489 | bhollis@vetlearn.com division of MediMedia, check must be in U.S. funds 780 Township Line Road, drawn on a U.S. branch of a VETERINARY ADVISER Yardley, PA 19067. Copyright U.S. bank only; credit cards Dorothy Normile, VMD, Chief Medical Officer © 2009 Veterinary Learning are also accepted. Change 800-426-9119, ext 52442 | dnormile@vetlearn.com Systems. All rights reserved. of Address: Please notify Printed in the USA. No part of the Circulation Department SENIOR ART DIRECTOR this issue may be reproduced 45 days before the change in any form by any means Michelle Taylor is to be effective. Send your without prior written permis- 267-685-2474 | mtaylor@vetlearn.com new address and enclose an sion of the publisher. address label from a recent ART DIRECTOR issue. Selected back issues Printed on acid-free paper, David Beagin effective with volume 29, are available for $15 (United 267-685-2461 | dbeagin@vetlearn.com issue 5, 2007. States and Canada) and $17 (foreign) each (plus postage). OPERATIONS Periodicals postage paid at Marissa DiCindio, Director of Operations Morrisville, PA, and at addi- Indexing: Compendium: Con- tinuing Education for Veteri- 267-685-2405 | mdicindio@vetlearn.com tional mailing offices. narians® is included in the Elizabeth Ward, Production Manager Postmaster: Send address international indexing cover- age of Current Contents/ 267-685-2458 | eward@vetlearn.com changes to Compendium: Agriculture, Biology and Continuing Education for Environmental Sciences (ISI); SALES & MARKETING Veterinarians®, 780 Township SciSearch (ISI); Research Joanne Carson, National Account Manager Line Road, Yardley, PA 19067. Alert (ISI); Focus On: Veteri- 267-685-2410 | Cell 609-238-6147 | jcarson@vetlearn.com Canada Post international nary Science and Medicine publications mail product (ISI); Index Veterinarius Boyd Shearon, Account Manager (Canadian distribution) sales (CAB International, CAB 913-322-1643 | Cell 215-287-7871 | bshearon@vetlearn.com agreement no. 40014103. Abstracts, CAB Health); and Return undeliverable Canadian Agricola (Library of Congress). Lisa Siebert, Account Manager addresses to MediMedia, Article retrieval systems 913-422-3974 | Cell 215-589-9457 | lsiebert@vetlearn.com PO Box 7224, Windsor, ON include The Genuine Article N9A 0B1. Printed in USA. (ISI), The Copyright Clear- CLASSIFIED ADVERTISING ance Center, Inc., University Liese Dixon, Classified Advertising Specialist Compendium: Continuing Education for Veterinarians® Microfilms International, and 800-920-1695 | classifieds@vetlearn.com | www.vetclassifieds.com Source One (Knight-Ridder (ISSN 1940-8307) Information, Inc.). Yearly EXECUTIVE OFFICER author and subject indexes Derrick Kraemer, President for Compendium are pub- lished each December. CUSTOMER SERVICE 800-426-9119, option 2 | info.vls@medimedia.com CompendiumVet.com 201
  4. 4. May 2009 Vol 31(5) CompendiumVet.com | Peer Reviewed | Listed in MEDLINE EDITORIAL BOARD Anesthesia Internal Medicine Nora S. Matthews, DVM, DACVA Dana G. Allen, DVM, MSc, DACVIM AMERICAN Texas A&M University Ontario Veterinary College BOARD OF Cardiology Internal Medicine and Emergency/ VETERINARY Bruce Keene, DVM, MSc, DACVIM Critical Care PRACTITIONERS North Carolina State University Alison R. Gaynor, DVM, DACVIM (Internal Medicine), DACVECC (ABVP) REVIEW Clinical Chemistry, Hematology, North Grafton, Massachusetts BOARD and Urinalysis Betsy Welles, DVM, PhD, DACVP Nephrology Kurt Blaicher, DVM, DABVP Auburn University Catherine E. Langston, DVM, ACVIM (Canine/Feline) Dentistry Animal Medical Center Plainfield Animal Hospital Gary B. Beard, DVM, DAVDC New York, New York Plainfield, New Jersey Auburn University Neurology Canine and Feline Medicine EDITOR IN CHIEF R. Michael Peak, DVM, DAVDC Curtis W. Dewey, DVM, MS, DACVIM The Pet Dentist—Tampa Bay Veterinary (Neurology), DACVS Eric Chafetz, DVM, DABVP Douglass K. Macintire, Cornell University Hospital for Animals Dentistry (Canine/Feline) DVM, MS, DACVIM, DACVECC Largo, Florida Vienna Animal Hospital Oncology Department of Clinical Sciences Emergency/Critical Care and Ann E. Hohenhaus, DVM, DACVIM Vienna, Virginia College of Veterinary Medicine Respiratory Medicine (Oncology and Internal Medicine) Canine and Feline Medicine Auburn University, AL 36849 Lesley King, MVB, MRCVS, DACVECC, Animal Medical Center DACVIM New York, New York Henry E. Childers, DVM, University of Pennsylvania DABVP (Canine/Feline) Gregory K. Ogilvie, DVM, DACVIM Endocrinology and Metabolic Disorders (Internal Medicine, Oncology), Cranston Animal Hospital Marie E. Kerl, DVM, ACVIM, ACVECC DECVIM-CA (Oncology) Cranston, Rhode Island University of Missouri-Columbia CVS Angel Care Cancer Center Canine and Feline Medicine EXECUTIVE Epidemiology and Special Care Foundation for Companion Animals ADVISORY Philip H. Kass, DVM, MPVM, MS, PhD, Carlsbad, California David E. Harling, DVM, BOARD DACVPM DABVP (Canine/Feline), University of California, Davis Ophthalmology DACVO MEMBERS David A. Wilkie, DVM, MS, DACVO Reidsville Veterinary Hospital Exotics Avian The Ohio State University Reidsville, North Carolina Behavior Canine and Feline Medicine, Thomas N. Tully, Jr, DVM, MS, DABVP Parasitology Sharon L. Crowell-Davis, (Avian), ECAMS Ophthalmology Byron L. Blagburn, MS, PhD DVM, PhD, DACVB Louisiana State University Auburn University The University of Georgia Jeffrey Katuna, DVM, DABVP Reptiles David S. Lindsay, PhD Douglas R. Mader, MS, DVM, DABVP (DC) Wellesley-Natick Veterinary Virginia Polytechnic Institute Hospital Dermatology Marathon Veterinary Hospital and State University Craig E. Griffin, DVM, Marathon, Florida Natick, Massachusetts DACVD Pharmacology Canine and Feline Medicine Small Mammals Animal Dermatology Clinic Katrina L. Mealey, DVM, PhD, DACVIM, Karen Rosenthal, DVM, MS, DABVP DACVCP Robert J. Neunzig, DVM, San Diego, California (Avian) Washington State University University of Pennsylvania DABVP (Canine/Feline) Rehabilitation and Physical Therapy The Pet Hospital Wayne S. Rosenkrantz, Feline Medicine Bessemer City, North Carolina Darryl Millis, MS, DVM, DACVS DVM, DACVD Michael R. Lappin, DVM, PhD, University of Tennessee Canine and Feline Medicine Animal Dermatology Clinic DACVIM (Internal Medicine) Colorado State University Tustin, California Surgery Compendium is a Margie Scherk, DVM, DABVP Philipp Mayhew, BVM&S, MRCVS, (Feline Medicine) DACVS refereed journal. Articles Nutrition Cats Only Veterinary Clinic Columbia River Veterinary Specialists published herein have Kathryn E. Michel, DVM, Vancouver, British Columbia Vancouver, Washington MS, DACVN been reviewed by at least University of Pennsylvania Gastroenterology C. Thomas Nelson, DVM two academic experts on Debra L. Zoran, DVM, MS, PhD, Animal Medical Center the respective topic and DACVIM (Internal Medicine) Anniston, Alabama Surgery Texas A&M University by an ABVP practitioner. Elizabeth M. Hardie, Toxicology Infectious Disease Tina Wismer, DVM, DABVT, DABT Any statements, claims, or product DVM, PhD, DACVS Derek P. Burney, PhD, DVM ASPCA National Animal Poison Control endorsements made in Compendium North Carolina State Gulf Coast Veterinary Specialists Center are solely the opinions of our authors and advertisers and do not necessarily University Houston, Texas Urbana, Illinois reflect the views of the Publisher or Editorial Board. 202 CompendiumVet.com m
  5. 5. The secret to a longer life in dogs with heart failure. The QUEST study provides new evidence that Vetmedin® (pimobendan) extends life for dogs with congestive heart failure (CHF). In a study of unprecedented magnitude, dogs with CHF due to mitral valve disease who were treated with VETMEDIN* lived virtually twice as long as those on an ACE inhibitor.1 This hard evidence from the QUEST study supports using VETMEDIN as first-line therapy in all dogs with symptomatic CHF. News like this should make your clients jump for joy as well. *The study used VETMEDIN Capsules. In the US, only chewable tablets are licensed. Both capsules and chewable tablets contain the same pharmaceutical ingredient, pimobendan, and are considered equivalent for clinical use. Bioequivalence, however, has not been established. Visit www.questtrial.com for additional study details, and visit www.vetmedin-us.com for more information about VETMEDIN. Important safety information: VETMEDIN should not be given in case of hypertrophic cardiomyopathy, aortic stenosis, or any other clinical condition where an augmentation of cardiac output is inappropriate for functional or anatomical reasons. The safety of VETMEDIN has not been established in dogs with asymptomatic heart disease or in heart failure caused by other etiologies other than atrioventricular valvular insufficiency or dilated cardiomyopathy. Use only in dogs with clinical evidence of heart failure. The most common side effects reported in field studies were poor appetite, lethargy, diarrhea, dyspnea, azotemia, weakness, and ataxia. If side effects should occur, pet owners should contact their veterinarian. Please refer to the package insert for complete product information or visit www.vetmedin-us.com. Reference: 1. Häggström J et al. Effect of pimobendan or benazepril hydrochloride on survival times in dogs with congestive heart failure caused by naturally occurring myxomatous mitral valve disease: The QUEST study. J Vet Intern Med. 2008;22:1124–1135. VETMEDIN is a registered trademark of Boehringer Ingelheim Vetmedica GmbH, licensed to Boehringer Ingelheim Vetmedica, Inc. © 2009 Boehringer Ingelheim Vetmedica, Inc. VET0209003 See Page 204 for Product Information Summary
  6. 6. higher in the active control group (4%) compared to mg/kg orally. The effect was still present 8 hours the average voluntary consumption was 84.2%. the Vetmedin group (1%). after dosing. There was a delay between peak blood levels of pimobendan and active metabolite and the Animal Safety: In a laboratory study, Vetmedin Adverse reactions/new clinical findings were seen in maximum physiologic response (peak LV dP/dtmax). chewable tablets were administered to 6 healthy NADA 141-273, Approved by FDA both treatment groups and were potentially related Blood levels of pimobendan and active metabolite Beagles per treatment group at 0 (control), 1, 3, and to CHF, the therapy of CHF, or both. The following began to drop before maximum contractility was seen. 5 times the recommended dosage for 6 months. See Vetmedin ® adverse reactions/new clinical findings are listed according to body system and are not in order of Repeated oral administration of pimobendan did not result in evidence of tachyphylaxis (decreased positive Table 3 for cardiac pathology results. The cardiac pathology/histopathology noted in the 3X and 5X dose (pimobendan) Chewable Tablets prevalence: CHF death, sudden death, chordae groups is typical of positive inotropic and vasodilator inotropic effect) or drug accumulation (increased Cardiac drug for oral use in dogs only tendineae rupture, left atrial tear, arrhythmias overall, positive inotropic effect). Laboratory studies indicate drug toxicity in normal dog hearts, and is associated tachycardia, syncope, weak pulses, irregular pulses, that the positive inotropic effect of pimobendan may with exaggerated hemodynamic responses to these Caution: Federal law restricts this drug to use by increased pulmonary edema, dyspnea, increased drugs. None of the dogs developed signs of heart or on the order of a licensed veterinarian. be attenuated by the concurrent use of a ß-adrenergic respiratory rate, coughing, gagging, pleural effusion, blocker or a calcium channel blocker. failure and there was no mortality. Description: Vetmedin (pimobendan) is supplied as ascites, hepatic congestion, decreased appetite, vomiting, diarrhea, melena, weight loss, lethargy, Effectiveness: In a double-masked, multi-site, 56-day Table 3: Incidence of Cardiac Pathology/ oblong half-scored chewable tablets containing 1.25, Histopathology in the Six-month Safety Study 2.5 or 5 mg pimobendan per tablet. Pimobendan, depression, weakness, collapse, shaking, trembling, field study, 355 dogs with modified NYHA Class II, a benzimidazole-pyridazinone derivative, is a non- ataxia, seizures, restlessness, agitation, pruritus, III, or IV CHF due to AVVI or DCM were randomly increased water consumption, increased urination, assigned to either the active control (enalapril maleate) Severe left ventricular One 3X and sympathomimetic, non-glycoside inotropic drug hypertrophy with two 5X dogsa with vasodilatative properties. Pimobendan exerts urinary accidents, azotemia, dehydration, abnormal or the Vetmedin (pimobendan) treatment group. Of multifocal subendocardial a stimulatory myocardial effect by a dual mechanism serum electrolyte, protein, and glucose values, mild the 355 dogs, 52% were male and 48% were female; ischemic lesions of action consisting of an increase in calcium increases in serum hepatic enzyme levels, and mildly 72% were diagnosed with AVVI and 28% were sensitivity of cardiac myofilaments and inhibition of decreased platelet counts. diagnosed with DCM; 34% had Class II, 47% had Moderate to marked Three 5X dogs phosphodiesterase (Type III). Pimobendan exhibits Class III, and 19% had Class IV CHF. Dogs ranged myxomatous thickening See Table 1 for mortality due to CHF (including in age and weight from 1 to 17 years and 3.3 to of the mitral valves vasodilating activity by inhibiting phosphodiesterase euthanasia, natural death, and sudden death) and for III activity. The chemical name of pimobendan 191 lb, respectively. The most common breeds were the development of new arrhythmias (not present in a mixed breed, Doberman Pinscher, Cocker Spaniel, Myxomatous thickening One 3X and is 4,5-dihydro-6-[2-(4-methoxyphenyl)-1H- dog prior to beginning study treatments) by treatment of the chordae tendineae two 5X dogs benzimidazole-5-yl]-5-methyl-3(2H)-pyridazinone. Miniature/Toy Poodle, Maltese, Chihuahua, Miniature group and type of heart disease (AVVI or DCM) in the Schnauzer, Dachshund, and Cavalier King Charles The structural formula of pimobendan is: 56-day field study. Spaniel. The 180 dogs (130 AVVI, 50 DCM) in the Endocardial thickening One 1X, two 3X, of the left ventricular and two 5X dogs Table 1: CHF Death and New Arrhythmias in the active control group received enalapril maleate outflow tract 56-Day Field Study (0.5 mg/kg once or twice daily), and all but 2 received furosemide. Per protocol, all dogs with DCM in the Left atrial endocardial One 3X and Vetmedin® Active Control active control group received digoxin. The 175 dogs thickening (jet lesions) one 5X dog Group Group (126 AVVI, 49 DCM) in the Vetmedin group received in 2 of the dogs that pimobendan (0.5 mg/kg/day divided into 2 portions developed murmurs of that were not necessarily equal, and the portions were mitral valve insufficiency 14.3% 14.4% Indications: Vetmedin (pimobendan) is indicated for n=175 n=180 administered approximately 12 hours apart), and all the management of the signs of mild, moderate, or but 4 received furosemide. Digoxin was optional for Granulomatous One 3X dog severe (modified NYHA Class IIa, IIIb, or IV c) congestive 9 of 126 dogs 16 of 130 treating supraventricular tachyarrhythmia in either inflammatory lesion in the heart failure in dogs due to atrioventricular valvular Dogs that died right atrial myocardium with AVVI dogs with treatment group, as was the addition of a ß-adrenergic insufficiency (AVVI) or dilated cardiomyopathy (DCM). due to CHF AVVI blocker if digoxin was ineffective in controlling heart a Vetmedin is indicated for use with concurrent therapy Most of the gross and histopathologic findings rate. After initial treatment at the clinic on Day 1, dog occurred in these three dogs for congestive heart failure (e.g., furosemide, etc.) as 16 of 49 dogs 10 of 50 dogs owners were to administer the assigned product and appropriate on a case-by-case basis. with DCM with DCM concurrent medications for up to 56±4 days. Murmurs of mitral valve insufficiency were detected in a A dog with modified New York Heart Association one 3X (Day 65) and two 5X dogs (Days 135 and 163). 39.4% 45.0% The determination of effectiveness (treatment success) These murmurs (grades II-III of VI) were not associated (NYHA) Class II heart failure has fatigue, shortness n=175 n=180 for each case was based on improvement in at of breath, coughing, etc. apparent when ordinary with clinical signs. least 2 of the 3 following primary variables: modified exercise is exceeded. Dogs that 45 of 126 59 of 130 NYHA classification, pulmonary edema score by a Indirect blood pressure was unaffected by Vetmedin b developed new dogs with dogs with masked veterinary radiologist, and the investigator’s at the label dose (1X). Mean diastolic blood pressure A dog with modified NYHA Class III heart failure is arrhythmiasa AVVI AVVI comfortable at rest, but exercise capacity is minimal. overall clinical effectiveness score (based on physical was decreased in the 3X group (74 mmHg) compared examination, radiography, electrocardiography, and to the control group (82 mmHg). Mean systolic blood c A dog with modified NYHA Class IV heart failure has 24 of 49 dogs 22 of 50 dogs with DCM with DCM clinical pathology). Attitude, pleural effusion, coughing, pressure was decreased in the 5X group (117 mmHg) no capacity for exercise and disabling clinical signs activity level, furosemide dosage change, cardiac compared to the control group (124 mmHg). None of are present even at rest. a size, body weight, survival, and owner observations the dogs had clinical signs of hypotension. New arrhythmias included supraventricular Dosage and Administration: Vetmedin should be were secondary evaluations contributing information On 24-hour Holter monitoring, mean heart rate premature beats and tachycardia, atrial fibrillation, administered orally at a total daily dose of 0.23 mg/lb supportive to product effectiveness and safety. Based was increased in the 5X group (101 beats/min) atrioventricular block, sinus bradycardia, ventricular (0.5 mg/kg) body weight, using a suitable combination on protocol compliance and individual case integrity, compared to the control group (94 beats/min). Not premature beats and tachycardia, and bundle of whole or half tablets. The total daily dose should 265 cases (134 Vetmedin, 131 active control) were counting escape beats, the 3X and 5X groups had branch block be divided into 2 portions that are not necessarily evaluated for treatment success on Day 29. See Table slightly higher numbers of isolated ventricular ectopic equal, and the portions should be administered Following the 56-day masked field study, 137 dogs 2 for effectiveness results. complexes (VEs). The maximum number of non- approximately 12 hours apart (i.e., morning and in the Vetmedin group were allowed to continue on Table 2: Effectiveness Results for the escape VEs recorded either at baseline or in a control evening). The tablets are scored and the calculated Vetmedin in an open-label extended-use study without 56-Day Field Study group dog was 4 VEs/24 hours. At either Week 4 or dosage should be provided to the nearest half tablet restrictions on concurrent therapy. The adverse Week 20, three 3X group dogs had maximums of 33, increment. reactions/new clinical findings in the extended-use Active Control 13, and 10 VEs/24 hours, and two 5X group dogs had Vetmedin® Contraindications: Vetmedin should not be given in study were consistent with those reported in the Group Group maximums of 22 and 9 VEs/24 hours. One 1X group cases of hypertrophic cardiomyopathy, aortic stenosis, 56-day study, with the following exception: One dog with no VEs at baseline had 6 VEs/24 hours or any other clinical condition where an augmentation dog in the extended-use study developed acute 80.7% 76.3% at Week 4 and again at Week 20. Second-degree of cardiac output is inappropriate for functional or cholestatic liver failure after 140 days on Vetmedin n=134 n=131 atrioventricular heart block was recorded in one 3X anatomical reasons. and furosemide. group dog at Weeks 4 and 20, and in one dog from Treatment 88 of 101 77 of 100 each of the 1X and 5X groups at Week 20. None of Warnings: Only for use in dogs with clinical evidence In foreign post-approval drug experience reporting, the Success on dogs with dogs with the dogs had clinical signs associated with these of heart failure. At 3 and 5 times the recommended following additional suspected adverse reactions were Day 29 AVVI AVVI electrocardiogram changes. dosage, administered over a 6-month period of time, reported in dogs treated with a capsule formulation pimobendan caused an exaggerated hemodynamic of pimobendan: hemorrhage, petechia, anemia, 20 of 33 dogs 23 of 31 dogs Treatment was associated with small differences response in the normal dog heart, which was hyperactivity, excited behavior, erythema, rash, with DCM with DCM in mean platelet counts (decreased in the 3X and associated with cardiac pathology (See Animal drooling, constipation, and diabetes mellitus. 1X groups), potassium (increased in the 5X group), 71.1% 67.2% glucose (decreased in the 1X and 3X groups), and Safety). To report suspected adverse reactions, to obtain a n=113 n=110 maximum blood glucose in glucose curves (increased Human Warnings: Not for use in humans. Keep this Material Safety Data Sheet, or for technical assistance in the 5X group). All individual values for these call 1-866-638-2226. Treatment and all medications out of reach of children. Consult a 66 of 85 dogs 56 of 85 dogs variables were within the normal range. Three 1X and Success on with AVVI with AVVI physician in case of accidental ingestion by humans. Clinical Pharmacology: Pimobendan is oxidatively Day 56 one 5X group dogs had mild elevations of alkaline demethylated to a pharmacologically active metabolite 13 of 28 dogs 17 of 25 dogs phosphatase (less than two times normal). Loose Precautions: The safety of Vetmedin has not been stools and vomiting were infrequent and self-limiting. established in dogs with asymptomatic heart disease which is then conjugated with sulfate or glucuronic with DCM with DCM or in heart failure caused by etiologies other than acid and excreted mainly via feces. The mean extent Storage Information: Store at controlled room AVVI or DCM. The safe use of Vetmedin has not been of protein binding of pimobendan and the active No increase in temperature 59-86°F (15-30°C). evaluated in dogs younger than 6 months of age, metabolite in dog plasma is >90%. Following a single furosemide 78.3% 68.6% oral administration of 0.25 mg/kg Vetmedin tablets dose between How Supplied: dogs with congenital heart defects, dogs with diabetes n=130 n=126 the maximal mean (± 1 SD) plasma concentrations Day 1 and Vetmedin® (pimobendan) Chewable Tablets: mellitus or other serious metabolic diseases, dogs Day 29 used for breeding, or pregnant or lactating bitches. (Cmax) of pimobendan and the active metabolite were Available at 1.25, 2.5 or 5 mg oblong half-scored 3.09 (0.76) ng/mL and 3.66 (1.21) ng/mL, respectively. At the end of the 56-day study, dogs in the Vetmedin chewable tablets – 50 tablets per bottle. Adverse Reactions: Clinical findings/adverse Individual dog Cmax values for pimobendan and the group were enrolled in an unmasked field study reactions were recorded in a 56-day field study of active metabolite were observed 1 to 4 hours post- Manufactured by: to monitor safety under extended use, without MEDA Manufacturing GmbH dogs with congestive heart failure (CHF) due to AVVI dose (mean: 2 and 3 hours, respectively). The total restrictions on concurrent medications. (256 dogs) or DCM (99 dogs). Dogs were treated body clearance of pimobendan was approximately Cologne, Germany with either Vetmedin (175 dogs) or the active control 90 mL/min/kg, and the terminal elimination half-lives Vetmedin was used safely in dogs concurrently Manufactured for: enalapril maleate (180 dogs). Dogs in both treatment of pimobendan and the active metabolite were receiving furosemide, digoxin, enalapril, atenolol, Boehringer Ingelheim Vetmedica, Inc. groups received additional background cardiac approximately 0.5 hours and 2 hours, respectively. spironolactone, nitroglycerin, hydralazine, diltiazem, St. Joseph, MO 64506 U.S.A. therapy (See Effectiveness for details and the Plasma levels of pimobendan and active metabolite antiparasitic products (including heartworm 1-866-638-2226 difference in digoxin administration between treatment were below quantifiable levels by 4 and 8 hours after prevention), antibiotics (metronidazole, cephalexin, groups). oral administration, respectively. The steady-state amoxicillin-clavulanate, fluoroquinolones), topical VETMEDIN is a registered trademark of volume of distribution of pimobendan is 2.6 L/kg ophthalmic and otic products, famotidine, theophylline, Boehringer Ingelheim Vetmedica GmbH, The Vetmedin group had the following prevalence indicating that the drug is readily distributed into levothyroxine sodium, diphenhydramine, hydrocodone, licensed to Boehringer Ingelheim Vetmedica, Inc. (percent of dogs with at least one occurrence) of tissues. Food decreased the bioavailability of an metoclopramide, and butorphanol, and in dogs on common adverse reactions/new clinical findings (not © 2009 Boehringer Ingelheim Vetmedica, Inc. aqueous solution of pimobendan, but the effect of sodium-restricted diets. present in a dog prior to beginning study treatments): food on the absorption of pimobendan from Vetmedin Code 448011, 448111, 448211 poor appetite (38%), lethargy (33%), diarrhea (30%), Palatability: In a laboratory study, the palatability of Revised 06/2007 tablets is unknown. dyspnea (29%), azotemia (14%), weakness and ataxia Vetmedin was evaluated in 20 adult female Beagle (13%), pleural effusion (10%), syncope (9%), cough In normal dogs instrumented with left ventricular (LV) dogs offered doses twice daily for 14 days. Ninety (7%), sudden death (6%), ascites (6%), and heart pressure transducers, pimobendan increased LV percent (18 of 20 dogs) voluntarily consumed more murmur (3%). Prevalence was similar in the active dP/dtmax (a measure of contractility of the heart) than 70% of the 28 tablets offered. Including two dogs control group. The prevalence of renal failure was in a dose dependent manner between 0.1 and 0.5 that consumed only 4 and 7% of the tablets offered,
  7. 7. E Each CE article is accredited for 3 contact hours by CE A Auburn University College of Veterinary Medicine. May 2009 Vol 31(5) Features 212 Laryngeal Paralysis in Dogs FREE CompendiumVet.com | Peer Reviewed | Listed in MEDLINE ❯❯ Ralph P. Millard and Karen M. Tobias Laryngeal paralysis can CE 220 Applied Dermatology NEW cause progressive upper SERIES airway obstruction and Overview of Flea Allergy Dermatitis ultimately death, usu- ❯❯ Andrea Lam and Anthony Yu ally in older, large-breed A new quarterly column debuts this month dogs. Videos of normal with a quick guide to the diagnosis and man- and paralyzed laryngeal agement of flea allergy dermatitis in general abduction are available at practice. An extended version of this article, CompendiumVet.com. with details of available flea-control products, is available at CompendiumVet.com. 232 Pneumothorax ❯❯ Karl C. Maritato, José A. Colón, and David H. Kergosien Pneumothorax is classified according to type and causative mechanism. Information on sig- nalment, diagnostic evaluation, and treatment is given for each type, along with the basic steps of thoracocentesis and thoracostomy tube p placement. FREE CE Departments 208 Clinical Snapshot Poor Haircoat Clinical in a Persian Snapshot ❯❯ Jeff Ruth PAGE 208 211 Editorial: Applied Dermatology Cover image © 2009 Peter Olson Photography ❯❯ Wayne S. Rosenkrantz and Craig E. Griffin 245 Product Forum On the Cover 226 CompendiumVet.com Dr. Anthony Yu performs a dermatologic 246 Index to Advertisers examination on Joey, a Parson Russell terrier 230 Abstract Thoughts ❯❯ Joseph Harari 246 Market Showcase mix, at Ontario Veterinary College in Guelph, Ontario, Canada. 243 Letters 246 Classified Advertising 244 Research Recap 248 Reading Room * 2009 PERQ/HCI FOCUS® Veterinary Study of Total Com- Selected abstract from Guidelines for Euthanasia panion Animal Veterinarians, in comparison to ratings Veterinary Therapeutics of Nondomestic Animals for each publication, by that publication’s readers. Compendium: Continuing Education for Veterinarians® 205
  8. 8. Canadian News Veterinary Cancer Centre Opens Therapy Dogs Trained T he St. John Ambulance Company T he Western Veterinary Specialist and Emergency Centre in downtown Calgary, Alberta, opened its new Can- ulated radiation therapy capabilities that allow radiation to be targeted specifically at tumor cells, sparing normal tissues. of Comox Valley, Vancouver Island, British Columbia, has 10 new therapy dog teams, bringing the total to 34 active cer Centre Tuesday, April 14. The centre, The Western Veterinary Specialist teams. The addition of these new teams which has been in development since and Emer gency Centre treats more makes the St. John Ambulance Therapy 2006, will use cutting-edge technology, than 8000 companion animal patients Dog Branch the largest on Vancouver previously unavailable in Canada, to annually at its Island. treat pets with cancer. 30,000-square- The therapy dogs serve as surro- The Cancer Centre is equipped with foot facility. gate pets for people who are no lon- a linear accelerator with intensity mod- ger able to have animals of their own. Before entering the program, the dogs are tested against national standards for OVC Pet Trust Funds $232,500 temperament and obedience for work in seniors’ facilities. Volunteers commit in Companion Animal Research to a minimum of 1 hour per week. T he donor-supported OVC Pet Trust the needs and expectations of pet own- SPREAD YOUR GOOD NEWS has funded 19 research projects at the ers whose animals are receiving cancer Canadian News Ontario Veterinary College (OVC). The care at the OVC. Another will study the c/o Veterinary Learning Systems projects were chosen in a fall 2008 com- use of laser lithotripsy (the treatment 780 Township Line Road petition. Species to be studied include of choice in humans) to pulverize kid- Yardley, PA 19067 USA , companion animals such as cats, dogs, ney and ureteral stones in vitro in dogs. E-MAIL editor@CompendiumVet.com parrots, and veiled chameleons. Other areas of research funded by the FAX 800-556-3288 The chosen projects cover a wide Pet Trust include hematology, cardiol- WEB CompendiumVet.com range of topics. One project will explore ogy, and infectious disease topics. Coming Events July 16 September 9 October 13 Ontario Veterinary Medical Association: Calgary Academy of Veterinary Medicine: Toronto Academy of Veterinary Medicine: Career Planning for Associate Ophthalmology Early Resuscitation and Stabilization of the Veterinarians & Potential Clara Christie Theatre, Health Sciences Emergency Patient Practice Owners University of Calgary, Alberta Dave and Buster’s Ontario Veterinary Medical Association This seminar will offer 1.5 hours of scientific Toronto, Ontario Milton, Ontario CE and will be presented by Dr. Cheryl Cullen. This seminar will focus on practical This course presents the benefits and Phone 403-863-7160 emergency management using case downsides of owning a practice as well as E-mail info@cavm.ab.ca examples. It will offer 5.5 CE credits. the practical aspects of practice ownership. Web www.cavm.ab.ca/ce_calendar.html Phone 800-670-1702 Web https://www.ovma.info/Meetings/ Web www.tavm.org September 15 August 8–13 Toronto Academy of Veterinary Medicine: October 18 World Association for the Advancement Update on Clinical Gastroenterology Calgary Academy of Veterinary Medicine: of Veterinary Parasitology: Dave and Buster’s Hematology 22nd International Conference Toronto, Ontario Clara Christie Theatre, Health Sciences Calgary, Alberta This seminar will provide an update on University of Calgary, Alberta This conference will discuss current issues GI disorders of cats and dogs, with an This seminar will offer 6 hours of scientific CE in parasitology, with a theme of “One emphasis on diagnosis and treatment. and will be presented by Dr. Marjorie Brooks. World One Health: Parasites in a Changing It will offer 5.5 CE credits. Phone 403-863-7160 Environment.” Phone 800-670-1702 E-mail info@cavm.ab.ca Web www.waavp2009.com Web www.tavm.org Web www.cavm.ab.ca/ce_calendar.html 206 Compendium: Continuing Education for Veterinarians® | May 2009 | CompendiumVet.com
  9. 9. . . . trust me! . . . you’ll be fine! My patients rely on me every day. And I rely on Baytril®. Because when it comes to infections, it’s on my side – an effective partner I can count on. Federal (U.S.A.) law restricts this drug to use by or on the order of a licensed veterinarian. In animal safety studies, isolated incidences of vomition and inappetence were reported. © 2009 Bayer HealthCare LLC, Animal Health Division, Shawnee Mission, Kansas 66201. Bayer, the Bayer Cross, Baytril and Right the first time are registered trademarks of Bayer. B090123n See Page 208 for Product Information Summary
  10. 10. Clinical Snapshot Particularly intriguing or difficult cases Case Presentation #1 ❯❯ Jeff Ruth, DVM, DABVP (Canine/Feline) Bissonnet/Southampton Veterinary Clinic Houston, Texas A 3-year-old intact male Persian cat presented with chronic, greasy skin of the tail and an unkempt haircoat (A). Prior unsuccessful attempts to treat the cat included systemic antibiotics (cefpodoxime 6.25 mg/kg PO q24h for 14 days) and antibacterial shampoo (4% chlorhexidine every 14 days for 3 months). A 2 × 6–cm focal zone of seborrhea oleosa, yellow crusting, and alopecia affected the proximal third of the tail (B). Additional abnormalities included mild medial canthal entropion of the left eye and resultant obstruction of nasolacrimal tear drainage. A 1. Given the history and clinical signs, what is the most likely cause of the lesion? 2. What ancillary tests should be performed? 3. What are the recommended treat- ment and the prognosis for this cat? SEE PAGE 210 FOR ANSWERS AND EXPLANATIONS. B 208 Compendium: Continuing Education for Veterinarians® | May 2009 | CompendiumVet.com
  11. 11. Month-long flea protection in a chewable tablet Fast-acting Convenient Family-friendly Doesn’t wash off • Starts killing fleas in 30 minutes • 100% effective within 4 hours in a controlled laboratory study • Approved by the FDA and available by prescription only To learn more about Comfortis®, see your Lilly representative or distributor representative, call 1 (888) LillyPet or visit www.comfortis4dogs.com The most common adverse reaction recorded during clinical trials was vomiting. Other adverse reactions were decreased appetite, lethargy or decreased activity, diarrhea, cough, increased thirst, vocalization, increased appetite, redness of the skin, hyperactivity and excessive salivation. For product label, including important safety information, see page 210. ©2009 Eli Lilly and Company CF00305 010109
  12. 12. Clinical Snapshot Answers and Explanations Case Presentation #1 A B SEE PAGE 208 FOR CASE PRESENTATION. 1. Feline tail gland hyperplasia (FTGH). 3. Treatment goals are to minimize The tail gland, or supracaudal gland, the accumulation of seborrheic is a dense accumulation of seba- oil produced by the glands and ceous glands located on the dorsal to address secondary skin infec- surface of the tail in cats and dogs. tions. The influence of androgens Hyperplasia of the sebaceous glands is poorly understood, and cas- and resultant sebum overproduction tration is unlikely to completely induces focal clinical signs that may resolve the condition. The use of include a greasy haircoat, hyperpig- keratolytic and keratoplastic sham- mentation, furunculosis, alopecia, poos (e.g., sulfur 2% and salicylic and comedones in the region of the acid 2% q36h for 4 weeks, then tail gland. FTGH, or stud tail, is a weekly) or degreasing agents (e.g., disease of young cats of either sex, benzoyl peroxide 2.5% q36h for altered or intact. 4 weeks, then weekly) is recom- mended. Systemic antiseborrheic 2. Skin cytology should be conducted agents used in veterinary medicine to detect secondary bacterial pyo- include synthetic retinoids such as derma or Malassezia infection, isotretinoin and etretinate. While which may complicate the disease. these agents may have benefit in Dermatophyte culture and skin refractory cases, their use carries scrapings for Demodex spp are also a greater risk of adverse effects. warranted. Seborrheic dermatitis Clients should be prepared to also necessitates the identification invest time in regular grooming and strict control of fleas and other to minimize the largely cosmetic ectoparasites. clinical signs of this disease. With A variety of primary and sec- attention to routine care, the prog- ondary keratinization defects have nosis for FTGH is favorable. characteristics that can mimic FTGH. Among these are gener- alized primary seborrhea, allergic dermatitis, neoplasia (carcinoma in Recommended Reading g situ or cutaneous lymphoma), and Guaguère E, Prélaud P. A Practical zoonotic infectious disease (pythiosis, Guide to Feline Dermatology. Paris: phaeohyphomycosis). If the signs are Merial; 1999. not localized to the region of the tail Scott DW, Miller WH, Griffin CE. gland, or if the initial workup fails Keratinization defects. In: Scott DW, to elucidate a cause, biopsy for his- Miller WH, Griffin CE, eds. Muller topathology and culture is indicated. and Kirk’s Small Animal Dermatol- Histopathology in cases of FTGH ogy. 6th ed. Philadelphia: WB Saun- demonstrates the characteristic hyper- ders; 2001:1046-1048. plasia of regional sebaceous glands. 210 Compendium: Continuing Education for Veterinarians® | May 2009 | CompendiumVet.com
  13. 13. Editorial COLUMN EDITOR COLUMN EDITOR Craig E. Griffin, DVM, DACVD Animal Dermatology Clinic, San Diego, California COLUMN EDITOR COLUMN EDITOR Wayne S. Rosenkrantz, DVM, DACVD Animal Dermatology Clinic, Tustin, California Dr. Yu (shown here with his dogs [from left to right] Timmy, Joey, and Bitsy) is associate professor Overview of Flea Allergy Dermatitis of dermatology at The University of Guelph Ontario Veterinary College in Canada. ❯❯ Andrea Lam, DVM ❯❯ Anthony Yu, DVM, MS, DACVDa University of California Davis Veterinary Medical Teaching Hospital University of Guelph Ontario Veterinary College F lea allergy dermatitis, or flea-bite hypersensitivity, is the most common small animal dermatologic condition.1–3 In some regions of the world, it is the most commonly seen sources. The larvae feed on adult flea feces (partially digested blood) in the environment. Within 5 to 11 days, a larva undergoes two sep- arate molting stages before forming a pupa. canine disease. This disease does not exist in locations that The pupal stage is the most resilient of all are inhospitable to fleas, such as those at elevations above stages because the cocoon is highly resistant to desiccation. It also has a sticky surface that 1500 ft or with low humidity (e.g., the desert). helps to prevent premature removal from the Although there are more than 2000 docu- environment and that accumulates dust and mented species and subspecies of fleas, the other household particulates to provide pro- cat flea (Ctenocephalides felis felis) is the spe- tection. On average, the pupal stage lasts 8 to cies most frequently found infesting dogs, cats, 9 days; however, fleas can pupate for up to 6 and all caged pets in North America. months if the environmental conditions are not ideal for emergence. Only with proper environ- Flea Facts mental stimuli, such as an increase in carbon The life cycle of the flea ranges from as few dioxide, warmth, physical pressure, and vibra- as 12 to as many as 190 days, with an average tion, will an adult flea emerge from its cocoon. of 21 days. The time needed for development After emerging from the cocoon, adult fleas At a Glance depends heavily on environmental conditions, search for an appropriate host. Adult fleas are particularly temperature and humidity. The opti- attracted to light and tend to migrate upward Flea Facts Page 220 mal environment is a low-altitude geographic toward surfaces where contact with an appropri- location, a temperature of 75°F (23.8°C), and a ate host is more likely. Once a host is found, feed- Pathogenesis Page 220 relative humidity of 78%. ing and mating take place within 8 to 24 hours. An adult flea takes its first blood meal from Female fleas can consume 15 times their body Diagnosis a host within minutes of contact. Female fleas weight in blood per day. Adult fleas act as obligate, Page 222 lay their first egg 24 to 36 hours after this permanent ectoparasites, preferring to remain on Treatment blood meal. Flea eggs are smooth and slick. a host rather than in the environment. Page 223 Only 30% of eggs remain on the haircoat; the Flea Control remainder fall off the host into the environ- Pathogenesis Products ment. Hatching takes place within 1 to 10 days, Flea saliva contains histamine-like compounds, Page 224 again depending on humidity and tempera- proteolytic enzymes, and anticoagulants. These ture. A single female flea can lay 1000 eggs proteins are released into the host during within 30 days, and most average 2000 eggs feeding and can act as inflammatory or anti- ❯❯ Wayne S. Rosenkrantz, ❯❯ Craig E. Griffin, DVM, during their life. genic stimuli in sensitive animals. Various Although eggs can hatch anywhere in the immunologic responses are provoked, includ- WEB environment, development of the larvae that ing immediate and delayed hypersensitivity EXCLUSIVE a Dr. Yu discloses that he emerge from the eggs must take place off the reactions,4 late-phase IgE-mediated responses, has received financial sup- host because mammalian body temperatures and cutaneous basophil hypersensitivity reac- An extended version of port from Greer Laborato- DVM, DACVD DACVD are too high for survival. Larvae are highly sen- tions.5 Dogs with atopic dermatitis appear to this article is available on ries, Iams, Novartis Animal Health, and Pfizer Animal sitive to heat and desiccation and therefore tend be predisposed to the development of flea CompendiumVet.com. Health. to move downward and away from direct light allergy dermatitis.6,7 220 Compendium: Continuing Education for Veterinarians® | May 2009 | CompendiumVet.com CompendiumVet.com | May 2009 | Compendium: Continuing Education for Veterinarians® 221 Animal Dermatology Clinic Animal Dermatology Clinic Tustin, California San Diego, California New dermatology series begins on page 220. Applied Dermatology S kin and ear diseases are the most common be written or coauthored by diplomates or residents problems that veterinarians deal with in of the American College of Veterinary Dermatology, practice on a daily basis. Because many of who will present evidence-based approaches to these cases are secondary to genetic causes, cure common dermatologic conditions. This new col- is often not possible, and management becomes umn will appear quarterly. Occasionally, recog- the mainstay of therapy. Fortunately, many nized dermatology experts will contribute their advances in diagnostics and therapeutics have individual approaches to specific problems as been made in the field of veterinary dermatology, online supplements to this series; the first of these and pet owners are demanding a higher level articles, “A Practical Approach to Diagnosing and Managing Ear Disease in Dogs,” by Paul Bloom, The new dermatology series will provide DVM, DACVD, DABVP (Canine and Feline), will be published on CompendiumVet.com this month. practical, easy-to-use techniques for the We hope that this new column will provide valuable information on how specialists approach diagnosis and treatment of many common and manage common skin and ear diseases and canine and feline ear and skin diseases. will help keep you updated on new diagnostic and therapeutic options so you can better han- of care and are often willing to allow advanced dle these often frustrating cases in your clinical diagnostic testing and therapy. To be able to offer practice. your clients this higher quality of medicine, it is imperative to stay current on the latest options available to manage these chronic and sometimes SHARE YOUR COMMENTS frustrating cases. Have something to say about this To help you in this effort, the new Compendium editorial or topic? Let us know: dermatology series, Applied Dermatology, will pro- E-MAIL editor@CompendiumVet.com vide practical, easy-to-use techniques for the diag- nosis and treatment of many common canine and FAX 800-556-3288 feline ear and skin diseases. The articles in this new series, which debuts on page 220 of this issue, will CompendiumVet.com | May 2009 | Compendium: Continuing Education for Veterinarians® 211
  14. 14. 3 CE CREDITS CE Article 1 Laryngeal Paralysis in Dogs ❯❯ Ralph P. Millard, DVM Abstract: Laryngeal paralysis is a common cause of upper airway obstruction in large-breed dogs. ❯❯ Karen M. Tobias, DVM, Although congenital forms have been reported, the disease is usually an acquired condition in older MS, DACVS dogs. Clinical signs include voice change, inspiratory stridor, and dyspnea. Laryngeal paralysis is ❯❯ University of Tennessee diagnosed by observing the absence of arytenoid abduction during laryngeal examination under a light plane of anesthesia. The most common method of surgical treatment is unilateral arytenoid lateralization. Most dogs experience significant improvement in respiration following surgery; however, they have an increased risk of aspiration pneumonia for the remainder of their lives. L aryngeal paralysis is a well-recog- laryngeal paralysis displayed neurogenic nized disease of large-breed dogs atrophy of the cranial tibial muscle and that results in upper airway obstruc- axonal degeneration of the peroneal nerve tion and dyspnea. The condition results in all cases, regardless of whether the from dysfunction of the caudal laryngeal dogs had signs of peripheral neuropathy.8 nerves, which are the terminations of Within 2 years after diagnosis of laryn- the recurrent laryngeal nerves. The cau- geal paralysis, clinical signs of general- dal laryngeal nerves provide innervation ized lower motor neuron disease were to all the muscles of the larynx except the cricothyroideus muscle. Dysfunction FIGURE 1 of these nerves results in the loss of arytenoid abduction by the cricoarytenoi- deus dorsalis muscle and the inability to actively constrict the glottis or relax the At a Glance vocal folds1 (FIGURES 1 AND 2). Etiology Etiology Page 212 Laryngeal paralysis can be congenital or Signalment and Clinical acquired. A hereditary form has been Signs described in Bouvier des Flandres, dal- Page 213 matians, rottweilers, and Siberian huskies Diagnosis and is usually reported in dogs younger Page 213 than 1 year.2–5 Acquired laryngeal paraly- Medical Management sis may result from trauma or iatrogenic Page 216 injury to the recurrent laryngeal nerve (e.g., during thyroidectomy) or compres- Surgical Treatment Page 217 sion of the recurrent laryngeal nerve by a cranial mediastinal or cervical mass.6 More commonly, however, laryngeal paral- ysis is classified as idiopathic in older dogs. Although the underlying etiology is Cranial view of a dissected canine unknown, idiopathic laryngeal paralysis larynx. (a) Corniculate process of arytenoid is most likely part of a generalized periph- cartilage, (b) cuneiform process of arytenoid eral neuropathy.7 In one recent study, cartilage, (c) epiglottis, (d) vocal fold, (e) laryn- muscle and peripheral nerve biopsy sam- geal ventricles, (f) cricoid cartilage, (g) muscu- ples obtained from 11 dogs with acquired lar process of arytenoid cartilage. 212 Compendium: Continuing Education for Veterinarians® | May 2009 | CompendiumVet.com
  15. 15. FREE Laryngeal Paralysis in Dogs CE present in all dogs in the study. 8 Although FIGURE 2 laryngeal paralysis has been reported in dogs with hypothyroidism, the association between the two conditions is unknown.9,10 Myasthenia gravis has also been suggested as a cause of laryngeal paralysis in dogs.11 Signalment and Clinical Signs Laryngeal paralysis is most commonly reported in older, large-breed dogs, especially Labrador retrievers.9,12–14 The average age at the time of presentation is approximately 10 years.9,12,14 Males are affected more frequently than females.12–14 Clinical signs progress as laryn- geal dysfunction becomes more severe. Early in the disease process, owners may notice a voice change, inspiratory stridor, and exercise intolerance. Owners may initially believe that Lateral view of a dissected canine larynx. (a) Thyroid cartilage, (b) cricoid the dog’s reluctance to move is simply a sign cartilage, (c) hyoid apparatus, (d) epiglottis, (e) corniculate process of arytenoid of aging. Dysphagia can also occur, possibly cartilage. in association with peripheral neuropathy.9,14 Owners may also report vomiting; however, could contribute to exercise intolerance. A they may actually be seeing regurgitation from complete neurologic examination should be concurrent esophageal disease or gagging and performed to evaluate for signs of polyneu- retching from a soft palate that has elongated ropathy, such as decreased postural reactions, as a result of inspiratory dyspnea. Once the deficits in spinal reflexes, and cranial nerve laryngeal muscles are paralyzed bilaterally, abnormalities.7 dogs may develop severe dyspnea, cyanosis, A rectal temperature should be obtained, and syncope. Exercise, obesity, excitement, and all dogs should be evaluated for sys- and increased ambient temperature can exac- temic signs of heatstroke, such as petechial QuickNotes erbate clinical signs, leading to an emergency hemorrhages associated with disseminated presentation.9 Affected dogs may develop intravascular coagulation, excessive panting, Acquired laryngeal pneumonia or pulmonary edema, which can collapse, hyperemic mucous membranes, and paralysis may be contribute to respiratory distress. Inability abnormalities in mentation, regardless of body associated with a to constrict the glottis properly during swal- temperature at time of presentation.17,18 The generalized periph- lowing, regurgitation, or vomiting increases primary means of heat loss in dogs is evapo- eral neuropathy. the risk of aspiration. Pulmonary edema can ration while panting. Dogs affected by acute develop in cases of upper airway obstruction signs of laryngeal paralysis are more suscepti- as a result of changes in intrathoracic pressure ble to hyperthermia due to a lack of heat dissi- and hypoxia, which cause increased perme- pation through an obstructed respiratory tract. ability of alveolar capillary membranes.15,16 Heatstroke from sustained hyperthermia can progress to multiorgan failure and death.17,18 Diagnosis If the body temperature is ≥106°F (41°C) or If an affected dog is stable, it should undergo systemic signs of heatstroke are evident, addi- a thorough physical examination. The thorax tional diagnostics (e.g., coagulation panels, should be auscultated for evidence of pneumo- immediate evaluation of glucose and elec- nia or pulmonary edema, such as harsh crack- trolytes) and supportive treatment should be les, wheezes, or rales, and for cardiac murmurs instituted. or arrhythmias. Arterial pulses should be pal- Complete blood count and serum biochem- pated for rate, rhythm, symmetry, and strength istry profile results are typically normal unless to assess for cardiovascular abnormalities that concurrent diseases are present. In dogs with CompendiumVet.com | May 2009 | Compendium: Continuing Education for Veterinarians® 213

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