Compendium | September 2009 by davidpsu

VOLUME 31 NUMBER 9 SEPTEMBER 2009

Compendium CompendiumVet.com | Peer Reviewed | Listed in MEDLINE

9 CE Contact Hours

Liver Enzyme Elevations in Dogs

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Refereed Peer Review

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September 2009 Vol 31(9) CompendiumVet.com | Peer Reviewed | Listed in MEDLINE

EDITORIAL BOARD Anesthesia Nora S. Matthews, DVM, DACVA Texas A&M University

Internal Medicine Dana G. Allen, DVM, MSc, DACVIM Ontario Veterinary College

Cardiology Bruce Keene, DVM, MSc, DACVIM North Carolina State University

Internal Medicine and Emergency/ Critical Care Alison R. Gaynor, DVM, DACVIM (Internal Medicine), DACVECC North Grafton, Massachusetts

Clinical Chemistry, Hematology, and Urinalysis Betsy Welles, DVM, PhD, DACVP Auburn University

EDITOR IN CHIEF Douglass K. Macintire, DVM, MS, DACVIM, DACVECC

Department of Clinical Sciences College of Veterinary Medicine Auburn University, AL 36849

Dentistry Gary B. Beard, DVM, DAVDC Auburn University R. Michael Peak, DVM, DAVDC The Pet Dentist—Tampa Bay Veterinary Dentistry Largo, Florida Emergency/Critical Care and Respiratory Medicine Lesley King, MVB, MRCVS, DACVECC, DACVIM University of Pennsylvania Endocrinology and Metabolic Disorders Marie E. Kerl, DVM, DACVIM, DACVECC University of Missouri-Columbia

EXECUTIVE ADVISORY BOARD MEMBERS Behavior Sharon L. Crowell-Davis, DVM, PhD, DACVB The University of Georgia Dermatology Craig E. Grifﬁn, DVM, DACVD Animal Dermatology Clinic San Diego, California Wayne S. Rosenkrantz, DVM, DACVD Animal Dermatology Clinic Tustin, California Nutrition Kathryn E. Michel, DVM, MS, DACVN University of Pennsylvania Surgery Elizabeth M. Hardie, DVM, PhD, DACVS North Carolina State University

394

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Epidemiology Philip H. Kass, DVM, MPVM, MS, PhD, DACVPM University of California, Davis Exotics Avian Thomas N. Tully, Jr, DVM, MS, DABVP (Avian), ECAMS Louisiana State University Reptiles Douglas R. Mader, MS, DVM, DABVP (DC) Marathon Veterinary Hospital Marathon, Florida Small Mammals Karen Rosenthal, DVM, MS, DABVP (Avian) University of Pennsylvania Feline Medicine Michael R. Lappin, DVM, PhD, DACVIM (Internal Medicine) Colorado State University Margie Scherk, DVM, DABVP (Feline Medicine) Cats Only Veterinary Clinic Vancouver, British Columbia Gastroenterology Debra L. Zoran, DVM, MS, PhD, DACVIM (Internal Medicine) Texas A&M University Infectious Disease Derek P. Burney, DVM, PhD, DACVIM Gulf Coast Veterinary Specialists Houston, Texas

Nephrology Catherine E. Langston, DVM, DACVIM Animal Medical Center New York, New York Neurology Curtis W. Dewey, DVM, MS, DACVIM (Neurology), DACVS Cornell University Hospital for Animals Oncology Ann E. Hohenhaus, DVM, DACVIM (Oncology and Internal Medicine) Animal Medical Center New York, New York Gregory K. Ogilvie, DVM, DACVIM (Internal Medicine, Oncology), DECVIM-CA (Oncology) CVS Angel Care Cancer Center and Special Care Foundation for Companion Animals Carlsbad, California Ophthalmology David A. Wilkie, DVM, MS, DACVO The Ohio State University Parasitology Byron L. Blagburn, MS, PhD Auburn University David S. Lindsay, PhD Virginia Polytechnic Institute and State University Pharmacology Katrina L. Mealey, DVM, PhD, DACVIM, DACVCP Washington State University Rehabilitation and Physical Therapy Darryl Millis, MS, DVM, DACVS University of Tennessee Surgery Philipp Mayhew, BVM&S, MRCVS, DACVS Columbia River Veterinary Specialists Vancouver, Washington C. Thomas Nelson, DVM Animal Medical Center Anniston, Alabama Toxicology Tina Wismer, DVM, DABVT, DABT ASPCA National Animal Poison Control Center Urbana, Illinois

AMERICAN BOARD OF VETERINARY PRACTITIONERS (ABVP) REVIEW BOARD Kurt Blaicher, DVM, DABVP (Canine/Feline) Plainﬁeld Animal Hospital Plainﬁeld, New Jersey Canine and Feline Medicine Eric Chafetz, DVM, DABVP (Canine/Feline) Vienna Animal Hospital Vienna, Virginia Canine and Feline Medicine Henry E. Childers, DVM, DABVP (Canine/Feline) Cranston Animal Hospital Cranston, Rhode Island Canine and Feline Medicine David E. Harling, DVM, DABVP (Canine/Feline), DACVO Reidsville Veterinary Hospital Reidsville, North Carolina Canine and Feline Medicine, Ophthalmology Jeffrey Katuna, DVM, DABVP Wellesley-Natick Veterinary Hospital Natick, Massachusetts Canine and Feline Medicine Robert J. Neunzig, DVM, DABVP (Canine/Feline) The Pet Hospital Bessemer City, North Carolina Canine and Feline Medicine

Compendium is a refereed journal. Articles published herein have been reviewed by at least two academic experts on the respective topic and by an ABVP practitioner. Any statements, claims, or product endorsements made in Compendium are solely the opinions of our authors and advertisers and do not necessarily reﬂect the views of the Publisher or Editorial Board.

Canadian News

Coming Events October 2009 Toronto Academy of Veterinary Medicine: Early Resuscitation and Stabilization of the Emergency Patient—October 13, Dave and Buster’s, Toronto, Ontario. This seminar will focus on practical emergency management by using case examples. It will offer 5.5 CE credits. For more information, call 800-670-1702 or visit tavm.org.

Lifelearn Inc. Continuing Education: Small Animal Cruciate Surgery—October 17, Lifetime Learning Center, Ontario Veterinary College, University of Guelph, Ontario. This seminar will offer 6 hours of CE credit. It is designed to provide practitioners with an overview of cruciate rupture diagnosis and treatment. For further information, call 800-375-7994 or visit www.lifelearn.com.

November 2009 2009 Veterinary Continuing Education Series: Feline Medicine—November 3, David Lam Campus, Douglas College, Coquitlam, British Columbia. This free program will focus on some of the basics of feline medicine. It will be hosted by Dr. Margie Scherk and offers 1.5 CE credits. For more information, e-mail lisa.timmons@ purina.nestle.com or visit www.bcvma.org.

OVC Health Sciences Centre Appoints Associate Dean T he Ontario Veterinary College (OVC) has announced the appointment of Dr. Sherri L. Cox as associate dean, administration, and chief operating ofﬁcer of the OVC Health Sciences Centre. According to Dean Elizabeth A. Stone, chairperson of the search committee, “Dr. Cox was instrumental in taking the primary healthcare initiative from vision to reality. With this continuing level of professionalism and expertise, I am conﬁdent that she will work enthusiastically and collaboratively with OVC faculty, staff, and students to ensure that all facets of our OVC Health Sciences Centre are successful.”

Dr. Cox is a recent DVM graduate from OVC and also has an MBA from the College of Management and Economics at the University of Guelph. She will use her 20 years of organizational experience to focus on strategic and immediate operational needs for the OVC Health Sciences Centre. The Health Sciences Centre’s goal is to integrate animal, human, and ecosystem health. Dr. Cox believes that, “together, we can build an exciting future for the OVC Health Sciences Centre. We will all share in the success as we create a global model for the improvement of health for animals, people, and the environment.”

Calgary Academy of Veterinary Medicine: Radiology—November 4, Clara Christie Theatre, Health Sciences, University of Calgary, Alberta. This seminar will offer 1.5 hours of scientiﬁc CE and will be presented by Dr. Tim Spotswood. For additional information, call 403-863-7160, e-mail info@cavm.ab.ca, or visit cavm.ab.ca/ ce_calendar.html.

Toronto Academy of Veterinary Medicine: Practice Management—November 10, Dave and Buster’s, Toronto, Ontario. This seminar will focus on different aspects of practice management and be hosted by Shawn McVey, MA, MSW. It will offer 5.5 CE credits. For more information, call 800-6701702 or visit tavm.org.

Lifelearn Inc. Continuing Education: Small Animal Laser Surgery—November 13–14, Ontario Veterinary College, University of Guelph, Ontario. This seminar will offer 14 hours of CE credit. It is designed to provide practitioners with an introduction to the uses of CO2 lasers in veterinary surgery. For further information, call 800-375-7994 or visit www.lifelearn.com.

December 2009 Calgary Academy of Veterinary Medicine: Hematology—December 6, Clara Christie Theatre, Health Sciences, University of Calgary, Alberta. This seminar will offer 6 hours of scientiﬁc CE and will be presented by Dr. Marjorie Brooks. For additional information, call 403-863-7160, e-mail info@cavm.ab.ca, or visit cavm.ab.ca/ ce_calendar.html.

Canadian Veterinary Medical Association Releases Code of Practice for Canadian Cattery Operations

ollowing in the footsteps of its Code of Practice for Canadian Kennel Operations, the Canadian Veterinary Medical Association (CVMA) has released its Code of Practice for Canadian Cattery Operations. Similar to other codes of practice, it is voluntary and can be used as an educational tool by cat breeders, current and prospective cat owners, and animal welfare groups. It can also be used as a practical standard by those interested in the promotion of sound care, management, and welfare practices related to the care and breeding of cats. The code of practice covers many topics, including the selection of a cat, housing and accommodation, care and supervision, behavioural needs, transportation, education, emergencies and unforeseen problems, and euthanasia. The guide is a result of the work of professionals in the ﬁeld and is

available from the CVMA’s Web site at canadianveterinarians.net. SPREAD YOUR GOOD NEWS Have any interesting news to share? Send it in! We would like to provide more recognition of veterinarians doing great things in their professional or personal lives. If you have news about yourself or a colleague or about some other newsworthy topic that would be of interest to others in the profession, send it (along with a picture if you have one) to: Canadian News c/o Veterinary Learning Systems 780 Township Line Road Yardley, PA 19067, USA E-MAIL editor@CompendiumVet.com FAX 800-556-3288 WEB CompendiumVet.com

CompendiumVet.com | September 2009 | Compendium: Continuing Education for Veterinarians®

395

Editorial ❯❯ Dana Gray Allen, DVM, MSc, DACVIM (Small Animal Internal Medicine) Ontario Veterinary College

Mandatory Continuing Education—Is It Necessary?

he reasons for promoting continuing educa- also varies by state or province, as does how often tion (CE) in any field are clear. CE provides credits are reviewed (annually or biannually). The the opportunity for lifelong development of weight placed on the various categories that are skills and knowledge and contributes to profes- approved for credit also differs: scientific or medisional competence. If a person wishes to deliver cal credits tend to be granted greater weight than the best possible service to his or her client, that self-study credits.3 Examples of self-study activities include reading journal articles, listening to person must keep abreast of current trends. The case for mandatory continuing education audiotapes, watching videotapes, and completing (MCE) is not as clear, and the reasons for support- Web-based educational material. Writing scientific ing MCE vary. It is in our own best interest as vet- articles and delivering lectures or consultation erinarians to protect the public and our patients by with veterinary specialists about patients under ensuring that we are being exposed to the most their care are also deemed acceptable for credit by current information available. However, a number some licensing boards.3 Generally, new graduates of studies in the health care professions, including are exempt for 1 or 2 years after graduation but human medicine, dentistry, nursing, and physical must show evidence of completion of CE credits therapy, have failed to demonstrate obvious ben- for relicensing after this initial grace period. The literature clearly indicates that MCE has efits of MCE to the delivery of medicine.1,2 MCE for veterinary relicensing was first introduced increased the number and variety of CE venues and in Florida, Kansas, and Tennessee in 1969. Since that has contributed to better distribution and improved time, many other states, as well as Canadian prov- quality of the programs offered. What has yet to inces, have adopted the concept. However, how CE be demonstrated is how effective MCE is in changis delivered, what counts as credit for CE, and how ing behavior to benefit the public, patients, or the the outcome of CE is evaluated among states and environment.1–3 Studies completed before the impleprovinces differ widely. Acceptable CE courses come mentation of MCE for nurses revealed a lack of enthuin a variety of formats: classroom lectures, extension siasm for the relicensure process. A follow-up study 2 studies, academic studies, conferences, seminars, years after the implementation of MCE indicated that workshops, wet labs, locally approved veterinary MCE was viewed in a much more positive light. The medical association events, distance education, study most influential criterion to this positive change was over the Internet, and self-study. Some states or prov- the availability of topics of special interest. MCE was inces accept only credits from courses approved by a also preferred over periodic reexamination. However, licensing authority (e.g., the American Association of other studies in human medicine have shown MCE Veterinary State Boards; AAVSB). The AAVSB Registry to have little effect on the long-term quality of of Approved Continuing Education (RACE) is a North patient care.1 One study demonstrated that mandatAmerican organization for the approval of CE providing programs had an adverse effect on participants’ ers and their programs.a Providers voluntarily apply perceived outcomes and on the likelihood of their a to RACE and agree to abide by RACE standards.3 All RACE-approved providers and programs are listed at aavsb.org/RACE. The number of credits required for relicensing

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Compendium: Continuing Education for Veterinarians® | September 2009 | CompendiumVet.com

Cat owners listen to their cats. Listen to your cat owners. Cats and their owners agree: a topical dewormer beats a pill any day. In fact, nearly 90% of cat owners prefer topical drops to pills or tablets.* So listen to your cat owners. Choose the only feline dewormer that treats and controls roundworms, hookworms and tapeworms with the ease and convenience of a topical application: ProfenderÂŽ Topical Solution. *From a survey of 736 cat owners. Data on file.

Federal (U.S.A.) law restricts this drug to use by or on the order of a licensed veterinarian. Children should not contact application site for twenty-four (24) hours. See Page 398 for Product Information Summary

P08711n

Editorial voluntary participation in future programs, meaning that MCE has the potential to create unwilling learners who, if given a choice, may not participate in future CE programs. Support for MCE, therefore, remains controversial. On the one hand, MCE is a measure of professional accountability. In human medicine, it has been shown that the level of current knowledge progressively declines after more than 10 years in practice and that errors in diagnosis and treatment are reduced by frequent and recent attendance at CE events.2 Advocates for veterinary MCE claim there is a need to ensure that veterinarians are compelled to routinely complete some form of CE to protect the public and their patients and to maintain the credibility of the profession.4 On the other side, MCE takes time away from practice and negatively affects income. A study conducted among nurses in Iowa revealed that the three most cited reasons for opposing MCE were program cost, need to travel, and lack of cooperation from employers to grant time off. Physical therapists argue that MCE would contribute to an increase in license fees in addition to the personal costs of tuition, travel, and hotel accommodation. To offset these costs, an increase in patient fees may be required. Those opposed to MCE point out that while attendance can be mandated, motivation, change in professional behavior, and the application of new knowledge are not being measured.1,2,4 It is the outcome, not the process, that governs the success of any MCE program. Therefore, the best method of measuring whether MCE leads to a positive change in practice may be a self-reporting scheme.2,4 Neil Donen2 suggests that requiring each physician to maintain a personal portfolio that documents his or her completed CE, the effect of CE on clinical practice, and the results of regular self-audits of the outcomes associated with application of knowledge gained during CE events may be a better measure of the success or limitations of MCE. Such portfolio programs have as their basis the promotion of reďŹ&#x201A;ective practice. These records might also help in defending complaints regarding professional misconduct and provide a basis for the planning and monitoring of personal growth in stated areas of practice. Donen proposes that licensing bodies should deďŹ ne the expected standards of care and mandate which areas of core knowledge or clinical practice must be included in MCE requirements. (CONTINUES ON PAGE 425)

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EEach CE article is accredited for 3 contact hours by Auburn University College of Veterinary Medicine. A

September 2009 Vol 31(9)

Features CompendiumVet.com | Peer Reviewed | Listed in MEDLINE

402 Feline Focus 2008 AAFP Senior Care Guidelines In December 2008, the American Association of Feline Practitioners issued its revised Senior Care Guidelines. This article gives some of the highlights of the guidelines in an easy-to-read format.

408

❯❯ Sharon L. Crowell-Davis Pets with generalized anxiety disorder (GAD) may present for an apparent speciﬁc phobia. Learn the signs that distinguish GAD from other demonstrations of fear.

Analgesia for Small Animal Thoracic Surgery

Liver Enzyme Elevations in Dogs: Diagnostic Approach

FREE

❯❯ Lucia Alvarez and Jacqueline C. Whittemore ore

Generalized Anxiety Disorder

432

FREE

❯❯ Lucia Alvarez and Jacqueline C. Whittemore ore

416 427 Understanding Behavior

Liver Enzyme Elevations in Dogs: Physiology and Pathophysiology

Increased liver enzyme activities are common ﬁndings with several diseases. In two articles, Drs. Alvarez and Whittemore describe the different patterns of liver enzyme elevations and how they can be used in conjunction with signalment and clinical status as part of a systematic diagnostic workup.

FREE

❯❯ Kyriaki Pavlidou, Lysimachos G. Papazoglou, Ioannis Savvas, and Georgios Kazakos The authors present an overview of pain management protocols for patients that have undergone thoracic surgery and suggest surgical techniques that may reduce postoperative pain.

Departments 396 Editorial: Mandatory Continuing Education— Is It Necessary? ❯❯ Dana Gray Allen 400 CompendiumVet.com 407 Research Recap Selected abstract from Veterinary Therapeutics 425 Index to Advertisers 426 Reading Room: First Steps With Puppies and Kittens: A Practice-Team Approach to Behavior 431 Letters 437 Product Forum 438 Market Showcase 438 Classiﬁed Advertising 439 Client Handout: Feline Senior Wellness

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September 2009 Vol 31(9)

WEB EXCLUSIVES

CE ARTICLES

❯❯ The Principles of Surgical Oncology: Diagnosis and Staging ❯❯ Julius M. Liptak The surgical treatment of neoplasms is one of the most common procedures performed in small animal practice. The proper approach to surgical oncology requires a knowledge of tumor types and their biologic behavior, different treatment modalities, and prognosis. Various imaging modalities can be used for clinical staging to determine the location, size, and extent of a local tumor. Biopsy of the tumor is often necessary to identify tumor type.

❯❯ The Principles of Surgical Oncology: Surgery and Multimodality Therapy ❯❯ Julius M. Liptak The ﬁrst surgery provides the best chance for a cure in an animal with a tumor. It is important to identify potential intraoperative risk factors, such as blood loss and hypotension, and be prepared to address these complications. Types of surgical procedures used in oncology include preventive, palliative, and second-look procedures, as well as minimally invasive laparoscopy and thoracoscopy to assess treatment efﬁcacy.

WEB-EXCLUSIVE ARTICLE

❯❯ Fluid Choice for Resuscitation and Perioperative Administration ❯❯ William Muir The administration of large volumes of crystalloid solutions has become standard in the perioperative setting and for the treatment of hypotension and hypovolemia. However, any ﬂuid therapy strategy should be well thought out before administration. WEB-EXCLUSIVE VIDEO

❯❯ Collagen Injection Videos The Surgical Views article in the August 2009 issue, “Surgical Treatment of Urethral Sphincter Mechanism Incompetence in Female Dogs,” by Drs. Mary A. McLoughlin and Dennis J. Chew, describes the many surgical approaches to treating this common condition of older, spayed dogs. A video contributed by Dr. McLoughlin describes collagen injection as a treatment for urethral sphincter mechanism incompetence.

E-NEWSLETTER ❯❯ COMPENDIUM EXTRA, a monthly e-newsletter, provides Web-exclusive articles and news as well as a preview of this month’s journal. Sign up at CompendiumVet.com.

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Doesn’t wash off

2008 AAFP Senior Care Guidelines* Panelists ❯❯ Jeanne Pittari, DVM, DABVP (Feline Practice),

Co-Chair Memorial Cat Hospital, Houston, Texas ❯❯ Ilona Rodan, DVM, DABVP (Feline Practice),

Co-Chair Cat Care Clinic, Madison, Wisconsin ❯❯ Gerard Beekman, DVM Coastal Cats Feline Health Care, York, Maine ❯❯ Danièlle Gunn-Moore, BVM&S, PhD, MACVSc,

MRCVS, RCVS Specialist in Feline Medicine University of Edinburgh, Scotland ❯❯ David Polzin, DVM, PhD, DACVIM-SAIM University of Minnesota ❯❯ Joseph Taboada, DVM, DACVIM-SAIM Louisiana State University ❯❯ Helen Tuzio, DVM, DABVP (Feline Practice) Catnap Feline Veterinary Relief Services, Rego Park, New York ❯❯ Debra Zoran, DVM, PhD, DACVIM-SAIM Texas A&M University

At a Glance The Senior Cat Wellness Visit Page 402

Minimum Database in Senior Cats Page 403

Monitoring and Managing Disease Page 404

Quality of Life

ats are the most popular pet in the United States and much of northern Europe.1 Although 78% of owners consider their cats to be family members,2 many cats, particularly seniors, do not receive appropriate preventive care.3,4 With good care, many cats live into their late teens and some into their twenties; the percentage of older cats is increasing.5,6 Older cats can be classiﬁed as mature or middle-aged (7 to 10 years), senior (11 to 14 years), or geriatric (15+ years). In this article, as elsewhere, the word senior is used as a broad category for all older cats, unless otherwise noted. The goals of the American Association of Feline Practitioners (AAFP) Senior Care Guidelines are to assist veterinarians to deliver consistent high-quality care to senior cats, promote feline longevity, and improve the quality of life of senior cats.

The Senior Cat Wellness Visit Use open-ended questions (e.g., “What behavior changes have you noticed in the last few weeks?”) to obtain a comprehensive medical and behavioral history. Issues identiﬁed with such questions can raise the index of suspicion for early disease. The frequency of behavior problems increases with age. Perform a thorough physical examination to enable detection of problems that may not be obvious to owners or discovered with laboratory testing. Make weight and body condition score (BCS) comparisons at each visit.

About These Guidelines This report represents a consensus of current information compiled by the researchers and practitioners on the panel. These guidelines are based on the best research data, clinical experience, and technical judgments available at the time of preparation. While the guidelines are as accurate and comprehensive as possible, they are subject to change should new insights become available from additional research or technological updates. The American Association of Feline Practitioners is a professional organization of practitioners and board-certiﬁed specialists who seek to raise the standards of feline medicine and surgery among practitioners.

Page 406

*This is an abbreviated version of the senior care guidelines, the full text of which can be found at catvets. com/professionals/guidelines/publications/?Id=398 and in the September 2009 issue of the Journal of Feline Medicine and Surgery Clinical Practice. The guidelines are in memory of the late Dr. James R. Richards, who coauthored the initial senior guidelines in 1998 and who loved to say, “Cats are masters at hiding illness.”

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Compendium grants permission to reproduce this article for educational purposes. A downloadable version of this article is available on CompendiumVet.com.

Contributed by

AMERICAN ASSOCIATION OF

FELINE PRACTITIONERS

About AAFP

Examine apparently healthy senior cats every 6 months. More frequent evaluations may be needed once evidence of an age-related disease process is discovered. Obtain a minimum database (MDB; TABLE 1) at least annually starting at age 7 to 10 years. Increase the frequency of the MDB as a cat ages. Rely on clinical judgment and discussions with the owner to determine the speciﬁc age and frequency of testing for each individual cat. Trends in the MDB can be signiﬁcant, allowing detection of disease earlier than interpretation of a single sample.

Interpretation of the Urinalysis Interpretation of the urinalysis, particularly the urine specific gravity and protein, is of particular importance in senior cats. Assess proteinuria in the absence of urinary tract infection or gross hematuria. Dipstick protein measurement is inaccurate; the microalbuminuria test or urine protein:creatinine (UPC) ratio may be indicated for confirmation of proteinuria when the dipstick is positive or when the dipstick is negative and the cat has a disease known to promote proteinuria. If the urine specific gravity is <1.035, repeat the measurement on a subsequent sample to evaluate persistence. Conduct urine culture and sensitivity testing in patients with chronic kidney disease (CKD), diabetes mellitus, and hyperthyroidism. Bacterial infection can be present in the absence of an inflammatory sediment, particu-

larly in patients with these conditions,7 or when the urine is sufﬁciently dilute to potentially cause misinterpretation of the urine sediment.8

Blood Pressure Monitoring and Hypertension Measure blood pressure at least annually in cats in the senior and geriatric age groups. Some also recommend routine blood pressure monitoring in mature cats to provide baseline measurements for future comparison. ❯ Most hypertensive cats have an identiﬁable cause for their elevated blood pressure, but idiopathic increases in blood pressure may occur in a substantial subpopulation of older cats.9 ❯ Obtaining an accurate blood pressure requires a consistent approach with attention to detail.10 Measure blood pressure with the owner present in a quiet room. Allowing the cat to acclimate to the room for 5 to 10 minutes can decrease anxiety-associated hypertension by up to 20 mm Hg.

The American Association of Feline Practitioners improves the health and well-being of cats by supporting high standards of practice, continuing education, and scientiﬁc investigation. Feline practitioners are veterinary professionals who belong to this association because they are “passionate about the care of cats”! American Association of Feline Practitioners 203 Towne Centre Drive Hillsborough, NJ 08844-4693 phone: 800-874-0498 phone: 908-359-9351 fax: 908-292-1188 e-mail: info@catvets.com Media contact: Valerie Creighton, DVM, DABVP

Nutrition and Body Condition Individualize diet recommendations depending on the BCS. Increase water intake by offering canned food and multiple water dishes. Feeding small meals frequently increases nutrient availability. Measure serum cobalamin (vitamin B12) concentration in any cat with weight loss, diarrhea, or poor appetite that may have gastrointestinal disease. Deﬁciencies in essential B vitamins can occur with poor intake or intestinal disease.

TABLE 1

Minimum Database in Senior Cats Mature Cats (age 7–10 years)

Test/Panel

Senior/Geriatric Cats (age >10 years)

Complete blood count (hematocrit, red blood cell count, white blood cell count and differential, cytology, platelets)

All patients

Chemistry screen (total protein, albumin, globulin, ALP, ALT, glucose, blood urea nitrogen, creatinine, potassium, phosphorus, sodium, calcium)

All patients

Urinalysis (speciﬁc gravity, sediment, glucose, ketones, bilirubin, protein)

All patients

Thyroxine

Depends on patient

All patients

Blood pressure

Depends on patient

All patients

Disclaimer These guidelines are not exclusive. Other techniques and procedures may be available. The AAFP expressly disclaims any warranties or guarantees, express or implied, and shall not be liable for any damages of any kind in connection with the material, information, techniques, or procedures set forth in these guidelines.

ALP = alkaline phosphatase, ALT = alanine aminotransferase

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Design or maintain a weight loss plan for obese cats. Obesity is a metabolic disease with hormonal, metabolic, and inﬂammatory changes; it is a risk factor for diabetes, osteoarthritis, respiratory distress, lower urinary tract diseases, and early mortality.11 When possible, identify and correct the underlying health problem in cats with unexplained weight loss. Cats in the senior and geriatric age groups often become underweight, resulting in a low BCS.

Dental Care

QuickNotes With good care, many cats live into their late teens and some into their twenties.

404

Interpret free T4 in conjunction with total T4 and clinical signs in cats with normal total T4 and suspected of having hyperthyroidism. The free T4 level can be elevated in cats with nonthyroidal illness.17 Monitor affected cats for kidney disease and hypertension. ❯ Hypertension may persist or develop after treatment. ❯ Even cats with a urine speciﬁc gravity >1.035 may have kidney disease that is unmasked after treatment of hyperthyroidism.18

Oral cavity disease is an often-overlooked Diabetes Mellitus cause of morbidity in older cats and can con- Although most cats are insulin dependent at tribute to a general decline in attitude and the time of diagnosis, early glycemic control overall health.12 Age should not exclude the may lead to clinical remission. Of particular treatment of dental disease. importance for senior cats is the effect of concurrent disease, such as chronic pancreatitis, Anesthesia on their health status. Provide intravenous fluids and thermal support; monitor blood pressure and body Inflammatory Bowel Disease and temperature. Older cats require particu- Associated Disease larly attentive care and monitoring to prevent Inflammatory bowel disease, pancreatitis, and cholangiohepatitis may occur separately or together. hypoxia, hypotension, and hypothermia. Attend to comfort and handle gently, parRule out disorders causing digestion/ ticularly for cats with osteoarthritis or muscle absorption problems in euthyroid, nondiawasting. betic cats with unexplained weight loss, vomiting, diarrhea, and increased appetite and thirst. Monitoring and Managing Disease Include measurement of feline pancreatic Chronic Kidney Disease lipase immunoreactivity (fPLI), feline trypsinStage and manage CKD patients using the like immunoreactivity (fTLI), cobalamin International Renal Interest Society (IRIS) (vitamin B ), and folate concentration in the 12 guidelines.13 The IRIS stage is assigned based evaluation.19–22 on the serum creatinine concentration, UPC ratio, and blood pressure. Cancer Monitor blood pressure. CKD is the leading Weight loss in the absence of other identifiable cause of secondary hypertension. causes is a common sign of cancer. Pursuing Evaluate for proteinuria. A UPC ratio >0.4 a diagnosis before the cat’s body condition warrants consideration of treatment. deteriorates may affect the outcome.23 Critical Recommend feeding a “renal” prescription components of cancer therapy include pain diet. Use of such diets has been shown to management, antinausea medication, and nutrireduce uremic episodes, decrease phospho- tional support. rus retention, prevent muscle wasting, and Osteoarthritis increase survival times.14–16 Osteoarthritis is a common but underrecognized condition in senior cats. Signs are often Hyperthyroidism The total thyroxine (T4) level is the appropri- subtle behavioral and lifestyle changes that ate screening test. However, the total T4 level are mistaken for “old age.”24 Management is may be equivocal or normal in cats with a ideally holistic in scope, attending to both the concurrent illness.17 cat and its environment.25

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BRIEF SUMMARY (For Full Prescribing Information, see package insert.) CAUTION: Federal (USA) law restricts this drug to use by or on the order of a licensed veterinarian. DESCRIPTION: VETORYL is an orally active synthetic steroid analogue that blocks production of hormones produced in the adrenal cortex of dogs. INDICATIONS: VETORYL Capsules are indicatedfor the treatment of pituitary-dependent hyperadrenocorticism in dogs. VETORYL Capsules are indicated for the treatment of hyperadrenocorticism due to adrenocortical tumor in dogs. CONTRAINDICATIONS: The use of VETORYL Capsules is contraindicated in dogs that have demonstrated hypersensitivity to trilostane. Do not use VETORYL Capsules in animals with primary hepatic disease or renal insufficiency. Do not use in pregnant dogs. Studies conducted with trilostane in laboratory animals have shown teratogenic effects and early pregnancy loss. WARNINGS: In case of overdosage, symptomatic treatment of hypoadrenocorticism with corticosteroids, mineralocorticoids and intravenous fluids may be required. Angiotensinconverting enzyme (ACE) inhibitors should be used with caution with VETORYL Capsules, as both drugs have aldosterone-lowering effects which may be additive, impairing the patient’s ability to maintain normal electrolytes, blood volume and renal perfusion. Potassium-sparing diuretics (e.g., spironolactone) should not be used with VETORYL Capsules as both drugs have the potential to inhibit aldosterone, increasing the likelihood of hyperkalemia. HUMAN WARNINGS: Keep out of reach of children. Not for human use. Wash hands after use. Do not empty capsule contents and do not attempt to divide the capsules. Do not handle the capsules if pregnant or if trying to conceive. Trilostane is associated with teratogenic effects and early pregnancy loss in laboratory animals. In the event of accidental ingestion/overdose, seek medical advice immediately and take the labeled container with you. PRECAUTIONS: Hypoadrenocorticism can develop at any dose of VETORYL Capsules. A small percentage of dogs may develop corticosteroid withdrawal syndrome within 10 days of starting treatment. Mitotane (o,p’-DDD) treatment will reduce adrenal function. Experience in foreign markets suggests that when mitotane therapy is stopped, an interval of at least one month should elapse before the introduction of VETORYL Capsules. The use of VETORYL Capsules will not affect the adrenal tumor itself. Adrenalectomy should be considered as an option for cases that are good surgical candidates. ADVERSE REACTIONS: The most common adverse reactions reported are poor/reduced appetite, vomiting, lethargy/dullness, diarrhea, and weakness. Occasionally, more serious reactions including severe depression, hemorrhagic diarrhea, collapse, hypoadrenocortical crisis, or adrenal necrosis/rupture may occur, and may result in death.

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Cognitive Disorders Cognitive changes may result from systemic illness, organic brain disease, true behavioral problems, or cognitive dysfunction syndrome, a neurodegenerative disorder. Rule out all medical illnesses to diagnose a primary cognitive disorder.

Complex Disease Management

comes the responsibility to control pain and distress, assess quality of life, and provide guidance to the owner in end-of-life decisions. The veterinarian must act as a patient advocate when counseling clients about decisions regarding use or continuation of treatment.26 Hospice care patients and their owners beneﬁt from examination every 2 to 4 weeks or as deemed necessary to assess comfort, quality of life, and quality of the relationship. Quality-of-life scales can aid tremendously in end-of-life decision making.

Search for additional disease processes when expected therapeutic results are not obtained. The likelihood of developing more than one disease increases with age. Be aware of issues surrounding Acknowledgments: The American multiple diseases in senior cats: ❯ Diagnosing one disease while Association of Feline missing another, or assuming a sin- Practitioners wishes to gle disease is severe when signs are thank Nestlé Purina, Merial due to multiple diseases (e.g., con- Ltd., IDEXX Laboratocurrent hyperthyroidism and CKD), ries, Inc., Nutramax Laboratories, Inc., is common. ❯ Treatment of some diseases may and Abbott Laboaffect concurrent diseases (e.g., hyper- ratories for their support of these thyroidism and diabetes mellitus).

guidelines.

Quality of Life Hand in hand with the management of chronic illness in senior patients

References 1. American Veterinary Medical Association. U.S. Pet Ownership and Demographic Sourcebook. Schaumburg, IL: American Veterinary Medical Association; 2007. 2. Pew Research Center Publications. Gauging family intimacy: dogs edge cats (dads trail both). March 7, 2006. Accessed July 2009 at http://pewresearch.org/ pubs/303/gauging-familyintimacy. 3. Cohen SP. Can pets function as family members? Western J Nurs Res 2002;24(6):621-638. 4. Adams CL, Bonnett BN, Meek AH. Predictors of owner response to companion animal death in 177 clients from 14 practices in Ontario. JAVMA 2000;217(9):1303-1309. 5. Broussard JD, Peterson ME, Fox PR. Changes in clinical and laboratory ﬁndings in cats with hyperthyroidism from 1983 to 1993. JAVMA 1995;206(3):302305. 6. Wolf A. Proceedings of the BSAVA Pedigree Pet Foods Lecture Tour. 2005. 7. Mayer-Roenne BM, Goldstein RE, Erb HN. Urinary tract infections in cats with hyperthyroidism, diabe-

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tes mellitus, and chronic kidney disease. J Feline Med Surg 2007;9(2):124-132. 8. Chew J, DiBartola S. Recent concepts in feline lower urinary tract disease. Vet Clin North Am Small Anim Pract 2005;35:147-170. 9. Maggio F, DeFrancesco TC, Atkins CE, et al. Ocular lesions associated with systemic hypertension in cats: 69 cases (1985-1998). JAVMA 2000;217(5):695-702. 10. Brown S, Atkins C, Bagley R, et al. Guidelines for the identiﬁcation, evaluation, and management of systemic hypertension in dogs and cats. ACVIM Consensus Statement. J Vet Intern Med 2007;21(3):542-558. 11. Lund EM, Armstrong PJ, Kirk CA, Klausner JS. Prevalence and risk factors for obesity in adult cats from private US veterinary practices. J Applied Res Vet Med 2005;3(2):88-96. 12. Richards J, Rodan I, Beekman G, et al. AAFP Senior Care Guidelines for Cats. 1998. Accessed December 2008 at www.catvets.com. 13. International Renal Interest Society (IRIS) Web site. Accessed July 2009 at www.iris-kidney.com. 14. Ross J, Osborne C, Kirk C, et al. Clinical evalua-

Compendium: Continuing Education for Veterinarians® | September 2009 | CompendiumVet.com

tion of dietary modification for treatment of spontaneous chronic kidney disease in cats. JAVMA 2006;229:949-957. 15. Plantinga EA, Everts H, Kastelein A, Beynen AC. Retrospective study of the survival of cats with acquired chronic renal insufficiency offered different commercial diets. Vet Rec 2005;157:185-187. 16. Elliott J, Rawlings JM, Markwell PJ, Barber PJ. Survival of cats with naturally occurring chronic renal failure: effect of dietary management. J Small Anim Pract 2000;41:235-242. 17. Peterson ME, Melián C, Nichols R. Measurement of serum concentrations of free thyroxine, total thyroxine, and total triiodothyronine in cats with hyperthyroidism and cats with nonthyroidal disease. JAVMA 2001;218(4):529-536. 18. Riensche MR, Graves TK, Schaeffer DJ. An investigation of predictors of renal insufficiency following treatment of hyperthyroidism in cats. J Feline Med Surg 2008;10(2):160-166. 19. Simpson KW, Fyfe J, Cornetta A, et al. Subnormal concentrations of serum cobalamin (vitamin B12) in cats with gastrointestinal disease. J Vet Intern Med 2001;15:26-32. 20. Forman A, Marks SL, de Cock HEV, et al. Evaluation of serum feline pancreatic lipase immunoreactivity and helical computed to-

mography versus conventional testing for the diagnosis of feline pancreatitis. J Vet Intern Med 2004;18:807-815. 21. Steiner JM, Williams DA. Serum feline trypsin-like immunoreactivity in cats with exocrine pancreatic insufﬁciency. J Vet Intern Med 2000;14:627-629. 22. Parent C, Washabau RJ, Williams DA. Serum trypsin-like immunoreactivity, amylase and lipase in the diagnosis of feline acute pancreatitis [abstract]. J Vet Intern Med 1995;9:194. 23. Baez JL, Michel KE, Sorenmo K, Shofer FS. A prospective investigation of the prevalence and prognostic signiﬁcance of weight loss and changes in body condition in feline cancer patients. J Feline Med Surg 2007;9:411-417. 24. Boehringer Ingelheim. New survey highlights behavioural changes are key to identifying arthritis in cats. UK Vet 2007;12(6): 26-27. 25. Godfrey DR. Osteoarthritis in cats: a retrospective radiological study. J Small Anim Pract 2005;46:425-429. 26. Rollin BE. Ethical issues in geriatric feline medicine. J Feline Med Surg 2007;9:326-334.

QuickNotes The likelihood of developing more than one disease increases with age.

Research Recap Selected abstract from Veterinary Therapeutics

Prevalence of Intestinal Parasites in Companion Animals in Ontario and Quebec, Canada, during the Winter Months* Blagburn BL, Schenker R, Gagné F, Drake J. Vet Ther 2008;9(3):169-175. Veterinarians in Ontario and Quebec, Canada, typically prescribe monthly heartworm prophylactic and anthelmintic medications for use during the warm months of the year. In many patients, the use of dewormers is discontinued during the winter because of the perception that intestinal parasite infections and shedding of nematode eggs are unlikely when the weather is cold and the ground is frozen or covered with snow. This study

TO LEARN MORE

examined fecal samples obtained from 96 shelter dogs and cats during the winter in Ontario and Quebec. Intestinal parasites were identiﬁed in 34% of submitted samples. These ﬁndings support the recommendation that veterinarians should advise pet owners to continue administration of broad-spectrum parasiticides to companion animals during the winter months.

F From th the Fall 2008 issue

For more Veterinary Therapeutics abstracts, visit the archives at

VeterinaryTherapeutics.com

*This research was sponsored by Novartis Animal Health/Novartis Santé Animale Canada, Mississauga, Ontario, Canada.

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3 CE CREDITS

CE Article 1

Liver Enzyme Elevations in Dogs: Physiology and Pathophysiology* ❯❯ Lucia Alvarez, DVM ❯❯ Jacqueline C. Whittemore, DVM, PhD, DACVIMa University of Tennessee

At a Glance Inducible Liver Enzymes Page 408

Hepatocellular Leakage Enzymes Page 410

Mixed Liver Enzyme Patterns Page 412

*A companion article, “Liver Enzyme Elevations in Dogs: Diagnostic Approach,” begins on page 416. aDr. Whittemore discloses that she has received ﬁnancial support from Heska Corporation.

408

Abstract: Increased liver enzyme activities are sensitive indicators of primary hepatic disease, but they are also associated with extrahepatic diseases. The patient’s signalment, clinical status, and pattern of liver enzyme activity can help in interpreting ﬁndings. The three basic liver enzyme patterns are (1) cholestatic, (2) hepatocellular leakage, and (3) mixed. Predominant increases in the activities of the cholestatic or inducible enzymes, alkaline phosphatase and γ-glutamyl transpeptidase, occur with endocrine disorders, cholestasis, neoplasia, benign nodular hepatic hyperplasia, and administration of certain drugs and occur idiopathically in certain breeds. Predominant increases in the activities of the hepatocellular leakage enzymes, alanine aminotransferase and aspartate aminotransferase, occur with circulatory disturbances, hepatotoxicities, infectious diseases, hepatitis, and neoplasia. A mixed pattern of increased liver enzyme activities may occur with hepatotoxicity or concurrent cholestasis and hepatocellular injury or necrosis.

rimary liver disease is often diag- the inducible liver enzymes, ALP and nosed after hepatic damage is ir- γ-glutamyl transpeptidase (GGT), and reversible. Biochemical screening the hepatocellular leakage enzymes, ALT during routine wellness visits facilitates and aspartate aminotransferase (AST). detection of hepatopathies in asymptom- Breed-specific abnormalities and underlyatic patients, when medical intervention is ing etiologies associated with cholestatic, more likely to be successful. hepatocellular leakage, and mixed patIncreased liver enzyme activities are terns of injury are presented. common in dogs. Serum biochemistry testing conducted on 1022 samples from Inducible Liver Enzymes dogs showed that 39.1% and 17.4% had The activities of ALP and GGT, the inducincreased alkaline phosphatase (ALP) and ible or cholestatic liver enzymes, increase alanine aminotransferase (ALT) activi- with a variety of conditions (BOX 1). Both ties, respectively.1 Although liver enzyme enzymes are found along the canalicular activity increases are highly sensitive bio- membrane of hepatocytes; their expresmarkers of hepatobiliary disorders, inter- sion is increased with intrahepatic or pretation of these increases is complicated extrahepatic cholestasis. Inducible ALP by the fact that breed variations and extra- isoenzymes are found in intestine, kidhepatic diseases often cause similar labora- ney, liver, and bone tissue.2 Measured tory findings. Discerning which abnormal ALP activity in serum or plasma generfindings warrant further investigation can ally comprises liver (L-ALP), bone (B-ALP), and corticosteroid (C-ALP) isoenzymes.3 be challenging. This article reviews the physiology of In healthy dogs, L-ALP accounts for the

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Liver Enzyme Elevations in Dogs: Physiology and Pathophysiology CE largest fraction of measured ALP activity. BOX 1 B-ALP activity is highest in growing animals Conditions/Factors Associated and animals with osteolytic disorders. Little With Enzyme Activity Increases or no C-ALP activity is found in normal dogs. Because corticosteroids may increase the activin Cholestatic Patterns ity of multiple ALP isoenzymes,3,4 determination of the predominant isoenzyme increase Breed rarely aids in identification of the underlying Scottish terrier pathophysiologic disorder. There are no comMiniature schnauzer Siberian husky mercially available tests for the differentiation of ALP isoenzymes.2 Drug administration GGT is a membrane-bound protein found Corticosteroids lining biliary surfaces and within periportal Phenobarbital hepatocytes. Although high concentrations are present in the kidney and pancreas, cirEndocrine disorders culating GGT activity principally originates Diabetes mellitus from liver tissue. GGT has a lower sensitivHyperadrenocorticism Hypothyroidism ity but higher specificity than ALP for primary hepatobiliary disease5 and is exquisitely sensiNeoplastic enzyme induction tive to cholestasis. The specificity of concurOsteosarcoma rent increased activities of ALP and GGT for Mammary carcinoma hepatobiliary disease is >90%, versus 51% Lymphoma for increased ALP activity alone and approxiBiliary or hepatocellular carcinoma mately 80% for GGT alone.6 Increased cholestatic enzyme activity is Intrahepatic cholestasis Portosystemic vascular anomalies, associated with a number of breeds. Marked microvascular dysplasia increases in ALP activity may occur with benign Vacuolar hepatopathya familial hyperphosphatasemia, described in Nodular hepatic hyperplasia Siberian huskies and Scottish terriers.7,8 Scottish Neoplasia terriers may have ALP activity that is five times Sepsis higher than that in other breeds; ALP activity increases with age in this breed, indepenExtrahepatic cholestasis dent of ALP-inducing disease.9 Other breed Gallbladder disease or neoplasia associations with increased ALP activity may Pancreatitis reflect underlying disease. Moderate to severe Inflammatory bowel disease hypertriglyceridemia in miniature schnauzers High intestinal obstruction has been associated with moderate increases a Sepesy L, Center SA, Randolph JF, et al. Vacuolar hepatopathy in in ALP and mild increases in ALT activity.10 It dogs: 336 cases (1993-2005). JAVMA 2006;229:246-252. is unknown whether these increases correlate with underlying primary diseases such as biliary mucoceles or secondary processes such reported with hyperadrenocorticism, diabetes as vacuolar hepatopathy. Activity increases mellitus, and hypothyroidism.12,13 Increased congreater than two times the reference inter- centrations of progesterone and 17-hydroxyproval in miniature schnauzers warrant further gesterone may cause similar enzyme changes.13 investigation.10 Shetland sheepdogs may have ALP and GGT activities increase with altered bile increased concentrations of triglycerides and flow secondary to pancreatitis, inflammatory cholesterol and increased cholestatic liver bowel disease, cholangitis, cholecystitis, and enzyme activities due to clinically silent gall- biliary obstruction. Sepsis can cause cholestasis bladder disorders.11 through multifactorial mechanisms, including Cholestatic enzyme activity may be increased altered hepatocyte function.14 Benign nodular by numerous extrahepatic conditions. Increased hepatic hyperplasia may stimulate inducible activities of ALP and GGT secondary to hepatic enzyme activity increases. Canine hepatocellipid or glycogen accumulation have been lular carcinoma cells have been demonstrated

QuickNotes An increase in the activities of ALP and GGT in tandem has greater speciﬁcity but lower sensitivity for primary hepatobiliary disease than an increase in either enzyme activity alone.

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BOX 2

Conditions Associated With Enzyme Activity Increases in Hepatocellular Injury or Necrosis Patterns Infection Canine adenovirus 1 Leptospira spp,a ascending or hematogenous bacterial infection Leishmania,b Toxoplasma, Neospora, Hepatozoon spp Histoplasma capsulatum Diroﬁlaria immitis

QuickNotes Although ALT activity increases proportionally to hepatocyte damage, a single measurement of severely increased ALT activity should not be used for prognosis because of the regenerative capacity of the liver.

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Exogenous substances may also induce cholestatic enzyme increases. Glucocorticoid administration in dogs causes moderate to marked increases in serum GGT and ALP activities and mild increases in ALT and AST activities.3 Phenobarbital can increase ALP activity without causing liver injury.18 Infrequently, phenobarbital causes idiosyncratic hepatotoxicity with attendant clinical signs.18

Hepatocellular Leakage Enzymes

ALT and AST are hepatocellular leakage enzymes. Found primarily in the cytosol of hepatocytes, ALT is released into circulation after hepatocellular membrane disruption. The magnitude of ALT activity increase Cardiovascular disturbance approximates the degree of hepatocyte damCongestive heart failure age. Because the liver has a remarkable regenAnemia erative capacity, the degree of ALT increase Shock should not be used as a prognostic indicator. In dogs, ALT generally has a circulating half-life Neoplasia of 2 to 3 days.5 Decreases in serum ALT activPrimary (hepatocellular or biliary ity of 50% every 2 to 3 days suggest that hepacarcinoma) tocyte damage is resolving.5 Normalization of Metastatic ALT activity with the concurrent appearance of biomarkers for hepatobiliary dysfunction, Hepatobiliary disease such as hypoalbuminemia, hypoglycemia, or Hepatotoxicity hypocholesterolemia, suggests loss of funcChronic hepatitis tional hepatic parenchyma. Inborn errors of metabolism (copper AST is found in the cytosol and mitochonstorage disorders) dria of hepatocytes and myocytes. Given the Amyloidosis presence of AST in myocytes, increased AST Portosystemic vascular anomalies, activity is less speciﬁc for hepatic damage than microvascular dysplasia c ALT. When increased AST activity is secondReactive hepatopathy ary to hepatic damage, it generally increases Liver lobe torsion proportionally to ALT activity. If AST activHepatic abscess ity is increased disproportionately, especially a Adamus C, Buggin-Daubie M, Izembart A, et al. Chronic hepatitis when creatine kinase (CK) activity is increased, associated with leptospiral infection in vaccinated beagles. J Comp primary muscle damage should be suspected. Pathol 1997;117:311-328. b Rallis T, Day MJ, Saridomichelakis MN, et al. Chronic hepatitis Because increased AST activity is more sensiassociated with canine leishmaniosis (Leishmania infantum): a clinicopathological study of 26 cases. J Comp Pathol tive than ALT activity for some types of liver 2005;132:145-152. damage, hepatocellular membrane disruption c Brellou GD, Kelinschmidt S, Meneses F, et al. Eosinophilic granulomatous gastroenterocolitis and hepatitis in a 1-year-old should be considered when AST activity is male Siberian husky. Vet Pathol 2006;43:1022-1025. increased and CK and ALT activities are within their reference intervals.5 to express a unique thermostable isoenzyme A variety of extrahepatic and hepatic disof ALP, resulting in increased serum ALP activ- orders can cause increased hepatocellular ity.15 Pancreatic neoplasia may also induce ALP leakage enzyme activity (BOX 2). Because the and GGT expression. Persistently increased portal circulation provides at least half of the ALP activity is a negative prognostic indica- hepatic blood ﬂow, the liver is particularly tor for dogs with osteosarcoma16 and is com- vulnerable to vascular compromise.19 Anemia, mon in dogs with mammary carcinoma17 and congestive heart failure, and shock can modlymphosarcoma. erately increase ALT and AST activities. Mild

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BOX 3

Hepatotoxins Reported in Veterinary and Human Medicine Dose-dependent Herbal supplements: Chaparral leafa, germandera, jin bu huana, kavab, pennyroyal oilc Drugs: Acetaminophenb, amiodaroneb, lomustine (CCNU)d, stanozololb Environmental: Aflatoxinse, Amanita mushroomsc, bacterial lipopolysaccharidesf, blue-green algaec, carbon tetrachloridec, cycad (sago) palmc, heavy metalsc, phosphorusg Other: Xylitolh Idiosyncratic Drugs: Azathioprinei, chloramphenicolj, clindamycinb, clopidogrelb, cyclosporinek, fluconazolea, fluoroquinolonesl, glucocorticoidsm, griseofulvinc, halothanen, ketoconazolea, mirtazapineb, mitotaneo, nitrofurantoina, NSAIDsa, phenobarbitalp, potentiated sulfonamidesq, synthetic penicillinsa, tetracyclinesq a

Pratt DS, Kaplan, MM. Evaluation of abnormal liverenzyme results in asymptomatic patients. N Engl J Med 2000;342:1266-1271. b Navarro VJ, Senior JR. Drug-related hepatotoxicity. N Engl J Med 2006;354:731-739. c Cooper JC, Webster CRL. Acute liver failure. Compend Contin Educ Pract Vet 2006;28:498-514. d Kristal O, Rassnick KM, Gliatto JM. Hepatotoxicity associated with CCNU (lomustine) chemotherapy in dogs. J Vet Intern Med 2004;18:75-80. e Dereszynski DM, Center SA, Randolph JF, et al. Clinical and clinicopathological features of dogs that consumed foodborne hepatotoxic aﬂatoxins: 72 cases (2005-2006). JAVMA 2008;6(9):1329-1337. f Barton CC, Barton EX, Ganey PE, et al. Bacterial lipopolysaccharide enhances aﬂatoxin B1 hepatotoxicity in rats by a mechanism that depends on tumor necrosis factor α. Hepatology 2001;33(1):66-73. g Zimmerman HJ. Hepatotoxicity: The Adverse Effects of Drugs and Other Chemicals on the Liver. Philadelphia: Lippincott, Williams and Wilkins;1999: 229. h Dunayer EK, Gwaltney-Brant SM. Acute hepatic failure and coagulopathy associated with xylitol ingestion in eight dogs. JAVMA 2006;229(7):1113-1117. i Favrot C, Reichmuth TO. Treatment of canine atopic

dermatitis with azathioprine: a pilot study. Vet Rec 2007;160:520-521. j Doshi B, Sarkar S. Topical administration of chloramphenicol can induce acute hepatitis. Br Med J 2009;338:b1699. k Whiting PH, Thomson AW, Simpson JG. Cyclosporine: toxicity, metabolism, and drug interactions—implications from animal studies. Transplant Proc 1985;17(4):134-144. l Regmi NL, Abd El-Aty AM, Kuroha M. Inhibitory effect of several fluoroquinolones on hepatic microsomal cytochrome P-450 1A activities in dogs. J Vet Pharmacol Ther 2005;28:553-557. m Marinó M, Morabito E, Brunetto MR, et al. Acute and severe liver damage associated with intravenous glucocorticoid pulse therapy in patients with Graves’ ophthalmopathy. Thyroid 2004;14:403-406. n Topal A, Gul N, Ilcol Y. Hepatic effects of halothane, isoflurane or sevoflurane anaesthesia in dogs. J Vet Med A 2003;50:530-533. o Webb CB, Twedt DC. Acute hepatopathy associated with mitotane administration in a dog. JAAHA 2006;42:298-301. p Gaskill CL, Hoffmann WE, Cribb AE. Serum alkaline phosphatase isoenzyme profiles in phenobarbital-treated epileptic dogs. Vet Clin Pathol 2004;33:215-222. q Thiim M, Friedman LS. Hepatotoxicity of antibiotics and antifungals. Clin Liver Dis 2003;7(2):381-399.

to moderate increases may occur with retrievers,22 which also have an increased strenous exercise and should resolve prevalence of idiopathic chronic hepaticonsistent with their half-lives after exer- tis.23 Rarely, liver lobe torsion has been tion is discontinued. Hepatotoxicity and described in large-breed dogs presenthepatitis result in hepatocellular mem- ing with nonspecific clinical signs (vombrane disruption. Underlying etiologies iting, anorexia, lethargy) and increased for hepatitis include infectious agents, hepatocellular leakage enzyme activiinborn errors of metabolism, immune- ties.24 Hepatic abscesses and primary or mediated inflammation, and reac- metastatic neoplasia are also associated tive hepatopathies. Copper-associated with increased hepatocellular leakage hepatopathy occurs as an autosomal enzyme activities. recessive disorder in Bedlington terriers and has been described in West Mixed Liver Enzyme Patterns Highland white terriers, Skye terri- A mixed pattern of increased cholestatic ers, dalmatians, Doberman pinschers, and hepatocellular leakage enzyme and Labrador retrievers.20,21 Heritability activities suggests concurrent disorders, of copper-associated hepatopathy has hepatocellular inflammation and necrorecently been demonstrated for Labrador sis with secondary cholestasis, or drug

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Liver Enzyme Elevations in Dogs: Physiology and Pathophysiology CE induction resulting in concomitant mild cholestatic and hepatocellular leakage enzyme activity increases. Serial monitoring may aid in identiﬁcation of the primary pattern, and a comprehensive diagnostic workup is often warranted. Portosystemic vascular anomalies and microvascular dysplasia may cause hepatocellular, cholestatic, or mixed patterns of injury.25 Hepatotoxins (BOX 3) can cause hepatocellular, cholestatic, or mixed patterns of injury. Because nutrients, bacteria, drugs, and other xenobiotic agents are delivered hematogenously from the gastrointestinal tract to the liver, the liver is at higher risk than other organs for toxic insult.19 A drug may cause dose-dependent (predictable), idiosyncratic (unpredictable), or both types of toxicity. Dogs with low glutathione transferase activity or decreased inherent protective mechanisms may be predisposed to liver injury.26

Conclusion Given their high sensitivity and limited specificity for hepatic disease, liver enzyme activity increases may be difficult to interpret. The patient’s signalment, clinical status, and pattern of liver enzyme activity increase may aid practitioners in ranking diagnostic differentials. Predominant increases in ALP and GGT activities characterize a cholestatic liver enzyme pattern. Causes include breedspecific abnormalities, endocrine disorders, hepatic and posthepatic cholestasis, neoplasia, benign nodular hepatic hyperplasia, and induction by drugs. A hepatocellular leakage pattern is characterized by increases in ALT and AST activities. Etiologies include circulatory disturbances, hepatotoxins, hepatic infection and inflammation, and primary hepatic neoplasia. Mixed patterns occur with hepatotoxicity, progressive hepatic disease, and concurrent disorders.

References 1. Comazzi S, Pierlasi C, Bertazzolo W. Haematological and biochemical abnormalities in canine blood: frequency and associations in 1022 samples. J Small Anim Pract 2004;45:343-349. 2. Itoh H, Kakuta T, Genda G, et al. Canine serum alkaline phosphatase isoenzymes detected by polyacrylamide gel disk electrophoresis. J Vet Med Sci 2002;64:35-39. 3. Wiedmeyer CE, Solter PF, Hoffman WE. Kinetics of mRNA expression of alkaline phosphatase isoenzymes in hepatic tissues from glucocorticoid-treated dogs. Am J Vet Res 2002;63:10891095. 4. Wiedmeyer CE, Solter PF, Hoffman WE. Alkaline phosphatase expression in tissues from glucocorticoid-treated dogs. Am J Vet Res 2002;63:1083-1088. 5. Center SA. Interpretation of liver enzymes. Vet Clin North Am Small Anim Pract 2007;37:297-333. 6. Center SA, Slater MR, Manwarren T, et al. Diagnostic efﬁcacy of serum alkaline phosphatase and γ-glutamyltransferase in dogs with histologically conﬁrmed hepatobiliary disease: 270 cases (1980-1990). JAVMA 1992;201:1258-1264. 7. Lawler DF, Keltner DG, Hoffman WE, et al. Benign familial hyperphosphatasemia in Siberian huskies. Am J Vet Res 1996;57: 612-617. 8. Gallagher AA, Panciera DL, Panciera RJ. Hyperphosphatasemia in Scottish terriers: 7 cases. J Vet Intern Med 2006;20: 418-421. 9. Nestor D, Holan K, Johnson CA, et al. Serum alkaline phosphatase activity in Scottish terriers versus dogs of other breeds. JAVMA 2006;228:222-224. 10. Xenoulis PG, Suchodolski JS, Levinski MD, et al. Serum liver enzyme activities in healthy miniature schnauzers with and without hypertriglyceridemia. JAVMA 2008;232:63-67. 11. Aguirre AL, Center SA, Randolph JF, et al. Gallbladder disease in Shetland sheepdogs: 38 cases (1995-2005). JAVMA 2007; 231:79-88. 12. Hess RS, Saunders HM, Van Winkle TJ, et al. Concurrent disorders in dogs with diabetes mellitus: 221 cases (1993-1998). JAVMA 2000;217:1166-1173. 13. Webster CRL, Cooper JC. Diagnostic approach to hepatobil-

iary disease. In: Kirk’s Current Veterinary Therapy XIV. St. Louis: Saunders Elsevier; 2009:543-549. 14. Chand N, Sanyal AJ. Sepsis-induced cholestasis. Hepatology 2007;45:230-241. 15. Fukui Y, Sato J, Sato R, et al. Canine serum thermostable alkaline phosphatase isoenzyme from a dog with hepatocellular carcinoma. J Vet Med Sci 2006;68:1129-1132. 16. Ehrhart N, Dernell WS, Hoffmann WE, et al. Prognostic importance of alkaline phosphatase activity in serum from dogs with appendicular osteosarcoma: 75 cases (1990-1996). JAVMA 1998;213:1002-1006. 17. Karayannopoulou M, Polizopoulou ZS, Koutinas AF, et al. Serum alkaline phosphatase isoenzyme activities in canine malignant mammary neoplasms with and without osseous transformation. Vet Clin Pathol 2006;35:287-290. 18. Gaskill CL, Hoffmann WE, Cribb AE. Serum alkaline phosphatase isoenzyme proﬁles in phenobarbital-treated epileptic dogs. Vet Clin Pathol 2004;33:215-222. 19. Webster C. Hepatocyte survival signaling. 26th Proc Am College Vet Intern Med 2008;26:675-677. 20. Spee B, Arends B, van den Ingh TS, et al. Copper metabolism and oxidative stress in chronic inﬂammatory and cholestatic liver diseases in dogs. J Vet Intern Med 2006;20:1085-1092. 21. Smedley R, Mullaney T, Rumbeiha W. Copper-associated hepatitis in Labrador retrievers. Vet Pathol 2009;46:484-490. 22. Hoffmann G, Heuven HC, Leegwater PA, et al. Heritabilities of copper-accumulating traits in Labrador retrievers. Anim Genet 2008;39:454. 23. Shih JL, Keating JH, Freeman LM, et al. Chronic hepatitis in Labrador retrievers: clinical presentation and prognostic factors. J Vet Intern Med 2007;21:33-39. 24. Schwartz SG, Mitchell SL, Keating JH, et al. Liver lobe torsion in dogs: 13 cases (1995-2004). JAVMA 2006;228:242-247. 25. Simpson KW, Meyer DJ, Boswood A, et al. Iron status and erythrocyte volume in dogs with congenital portosystemic vascular anomalies. J Vet Intern Med 1997;11:14-19. 26. Watanabe T, Sugiura T, Manabe S, et al. Low glutathione Stransferase dogs. Arch Toxicol 2004;78:218-225.

QuickNotes A mixed liver enzyme pattern can be caused by simultaneous hepatocellular injury and cholestasis and often warrants a comprehensive diagnostic workup.

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3 CE CREDITS

CE TEST 1 This article qualiﬁes for 3 contact hours of

continuing education credit from the Auburn University College of Veterinary Medicine. Subscribers may take individual CE tests online and get real-time scores at CompendiumVet.com. Those who wish to apply this credit to fulﬁll state relicensure requirements should consult their respective state authorities regarding the applicability of this program. 1. Which breed has been documented to have increased ALP activity independent of underlying disease? a. Scottish terrier b. miniature schnauzer c. Siberian husky d. Shetland sheepdog

7. CK activity needs to be considered when interpreting the activities of which enzymes? a. ALP and ALT b. ALT and AST c. AST and GGT d. GGT and ALP

2. ALP isoenzymes are not found in the a. intestines. b. kidneys. c. bones. d. lungs.

8. Which statement is correct with regard to AST? a. It is more speciﬁc for liver damage than ALT. b. It is released from osteocytes and hepatocytes. c. Increases in activity occur secondary to membrane disruption. d. Its production in myocytes is induced.

3. GGT has ______ sensitivity and ______ speciﬁcity than ALP for hepatobiliary disease. a. higher; higher b. lower; lower c. higher; lower d. lower; higher 4. Which endocrine disorder has not been associated with increased cholestatic enzyme activities? a. diabetes mellitus b. hypothyroidism c. hyperadrenocorticism d. hypoadrenocorticism 5. Which type of neoplasia has not been associated with ALP induction? a. mammary carcinoma b. insulinoma c. osteosarcoma d. lymphosarcoma 6. Increase in the activity of ______ best approximates the degree of hepatocyte damage. a. ALP c. AST b. ALT d. GGT

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9. Copper-associated hepatopathy has a proven heritable basis in which breed? a. dalmatian b. Labrador retriever c. Scottish terrier d. West Highland white terrier 10. ______ does not result in a mixed liver enzyme pattern. a. The presence of concurrent cholestatic and hepatocellular disorders b. Hepatocellular damage with secondary cholestasis c. Drug induction leading to cholestasis with secondary hepatocyte damage d. Osteolytic disease and paraneoplastic expression of ALP by hepatocellular carcinoma cells

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CE Article 2

Liver Enzyme Elevations in Dogs: Diagnostic Approach* ❯❯ Lucia Alvarez, DVM ❯❯ Jacqueline C. Whittemore, DVM, PhD, DACVIMa University of Tennessee

At a Glance Signalment, History, and Physical Examination Page 416

Laboratory Screening Page 418

Additional Testing Page 420

Diagnostic Imaging Page 422

Liver Sampling Techniques Page 422

Diagnostic Sampling Page 422

*A companion article, “Liver Enzyme Elevations in Dogs: Physiology and Pathophysiology,” begins on page 408. aDr. Whittemore discloses that she has received ﬁnancial support from Heska Corporation.

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Abstract: Increased liver enzyme activities are sensitive indicators of hepatic disease, but their limited specificity can make their interpretation a challenge. A stepwise approach to diagnosing the source of increased liver enzyme activity involves characterization of the clinical picture, identification of the predominant enzyme activity pattern, elimination of common extrahepatic diseases, and a systematic diagnostic workup for hepatobiliary disease. Comprehensive hepatobiliary testing includes a complete blood count, biochemical profile, and urinalysis; coagulation and liver function tests; abdominal imaging; bile cytology and culture; and liver biopsy for histopathology, culture, and metal analysis.

lterations in circulating liver enzyme activities may present a diagnostic challenge because they are common, often nonspecific biochemical findings. A systematic approach to interpretation of increased liver enzyme activities is outlined in FIGURE 1. The first step is to develop an integrated clinical picture based on the patient’s signalment, history, clinical signs, and concurrent laboratory abnormalities. Careful evaluation of this picture aids in ranking diagnostic differentials. Increases in liver enzyme activities are categorized as cholestatic, hepatocellular leakage, or mixed. A cholestatic or inducible pattern is characterized by predominant increases in alkaline phosphatase (ALP) and γ-glutamyl transpeptidase (GGT) activities. A hepatocellular leakage pattern has predominant increases in the activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) secondary to hepatocyte injury or necrosis. A mixed pattern of liver enzyme activity increase suggests concurrent hep-

atocellular injury and cholestasis and may be caused by concurrent disease processes or progressive disorders. The magnitude and duration of increase in liver enzyme activities should be considered in addition to the pattern. Mildly increased activity of a single liver enzyme in a clinically asymptomatic dog may be spurious and should be rechecked. Lipemia and hemolysis may falsely increase activities of serum liver enzymes and should be considered when interpreting laboratory data. Because increases in hepatocellular leakage enzyme activity are proportional to the severity of damage, increases greater than twice the reference interval warrant further scrutiny. Increased activity of multiple liver enzymes, particularly if a hepatocellular or mixed pattern of injury is present, also warrants close attention because of an increased likelihood of severe disease.

Signalment, History, and Physical Examination Once spurious or self-limiting increases of liver enzyme activities have been ruled

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Liver Enzyme Elevations in Dogs: Diagnostic Approach CE FIGURE 1

Flowchart demonstrating a stepwise approach to the evaluation of increased activities of liver enzymes. Blue differentials are etiologies that may require a comprehensive hepatobiliary evaluation for diagnosis. CompendiumVet.com | September 2009 | Compendium: Continuing Education for VeterinariansÂŽ

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FREE CE Liver Enzyme Elevations in Dogs: Diagnostic Approach

BOX 1

Breeds Associated With Increased Activities of Liver Enzymesa

QuickNotes Supplements, nutraceuticals, and topical medications are easily overlooked as potential hepatotoxins.

Hepatocellular leakage pattern Idiopathic hepatitis ❯ American and English cocker spaniels ❯ Labrador retriever ❯ Standard poodle Copper-associated hepatitis ❯ Bedlington terrier ❯ Dalmatian ❯ Doberman pinscher ❯ Labrador retriever ❯ Skye terrier ❯ West Highland white terrier Amyloidosis ❯ Chinese shar-pei Cholestatic pattern Benign hyperphosphatasemia ❯ Scottish terrier ❯ Siberian husky Hyperlipidemia ❯ Miniature schnauzer Gallbladder disease ❯ Shetland sheepdog a This list does not include breeds associated with congenital

vascular abnormalities, which commonly have mixed liver enzyme activity patterns.

the onset of injury.1 Liver injury may worsen for days or weeks following withdrawal of the medication before improvement is seen. Repeat challenge with a suspected hepatotoxin may greatly exacerbate hepatotoxicosis. Alternatively, a patient may develop tolerance for a hepatotoxin and have negative challenge results. If potential hepatotoxins are identiﬁed, they should be discontinued and liver enzyme activities reassessed in 2 to 3 weeks. The patient’s vaccination history and potential exposure to infectious agents should be determined. Hepatopathies have been documented with Leptospira interrogans serovars Icterohaemorrhagiae and Pomona and Leptospira kirschneri serovar Grippotyphosa2; additional associations may be identiﬁed with increased molecular testing. Canine adenovirus 1 infection, heartworm disease, ehrlichiosis, leishmaniasis, neosporosis, toxoplasmosis, and systemic mycoses should be considered as potential causes of hepatocellular disease.3,4 In dogs, bacterial infections arise primarily from hematogenous routes and breaks in host defenses, such as periodontal disease.5 Lethargy, inappetence, vomiting, and diarrhea are common clinical signs. Icterus, ascites, acholic feces, or hepatic encephalopathy may occur with acute liver failure or progression of chronic disease. Physical examination may be unremarkable or may reveal abnormalities consistent with an extrahepatic disorder. Poor body condition, icterus, abdominal pain, hepatomegaly or microhepatia, and abdominal effusion may suggest hepatic dysfunction. The presence of clinical signs, physical examination abnormalities, or evidence of decreased liver function should prompt an expeditious workup to maximize chances of obtaining a diagnosis and successful therapeutic intervention.

out, the patient should be evaluated for breed associations (BOX 1). A careful dietary history may identify risk factors for infection (e.g., raw or undercooked meat) or intoxication (e.g., poor food storage practices, recalled diets). Depending on the geographic location, access to Amanita mushrooms and cycad palm plants should be determined. The owner should be carefully questioned about medications to which the patient may have access, including Laboratory Screening supplements, nutraceuticals, and topical gluco- A minimum database of a complete blood corticoids. Owners may not notice a pet’s con- count (CBC), biochemical profile, and urinalysumption of prescription medications or know sis should be obtained for dogs with verified that common items for human use, such as increased activities of liver enzymes. Hepatobiliary disease can be associated those containing xylitol, can be hepatotoxic. Diagnosis of drug-related hepatotoxicity with a variety of CBC abnormalities. Although can be challenging. The time between initial gastrointestinal bleeding or coagulopathy secadministration of a medication and detection ondary to hepatobiliary dysfunction may stimof hepatic injury can vary greatly, which makes ulate a regenerative anemia, the chronicity of it difficult to establish exposure preceding many hepatic diseases often leads to anemia

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FREE CE Liver Enzyme Elevations in Dogs: Diagnostic Approach

QuickNotes Coagulation testing should be conducted no more than 24 hours before liver biopsy.

420

of chronic disease, which is nonregenerative. Microcytosis is common with acquired or congenital portosystemic shunts.6 Thrombocytosis occurs with hyperadrenocorticism,7 chronic blood loss, and inflammatory disorders,8 and thrombocytopenia suggests ongoing vasculitis or consumptive processes. Biochemical changes may aid in the differentiation of extrahepatic and hepatobiliary disease. Concentrations of bilirubin, cholesterol, blood urea nitrogen (BUN), albumin, and glucose provide information about liver function despite low sensitivity and specificity. In the absence of hemolysis or sepsis, hyperbilirubinemia indicates cholestasis due to hepatobiliary disease or posthepatic obstruction. Cholesterol concentrations increase with cholestatic disease and decrease with endstage liver disease.9 BUN concentration may be increased secondary to gastrointestinal bleeding or decreased by shunting of portosystemic blood or decreased hepatic production.9 Creatinine concentration typically remains within the reference interval. With the loss of approximately 70% of functional hepatic parenchyma, hypoalbuminemia may occur.10 Other causes of hypoalbuminemia should be ruled out, including gastrointestinal disease, protein-losing nephropathy, hemorrhage, vasculitis, inflammation, and prolonged anorexia. Hypoglycemia may occur after loss of 75% of hepatic parenchymal function and is a poor prognostic indicator.9,11 Other causes of hypoglycemia should be excluded, including congenital portosystemic vascular anomalies, insulinoma, and sepsis.12 A variety of abnormalities may be identified on urinalysis. Hyposthenuria and isosthenuria occur frequently with extrahepatic and hepatobiliary diseases. Bilirubinuria with or without hyperbilirubinemia may be identified. A small amount of bilirubinuria can be normal, particularly in male dogs.13 The presence of urobilinogen can be normal or associated with hepatic disease, while absence may suggest biliary obstruction. Due to urobilinogen’s instability and variable excretion, this test has questionable clinical usefulness.14 Portosystemic shunting and end-stage liver disease may result in ammonium biurate crystal formation. Glucosuria and aminoaciduria, consistent with Fanconi syndrome, have been noted in dogs with copperstorage hepatopathy.15

Additional Testing Thorough evaluation of liver enzyme activity increases may require additional testing for extrahepatic and hepatobiliary diseases after integration of the minimum database with the clinical presentation. Hyperadrenocorticism and hypothyroidism should be considered in dogs with appropriate clinical findings and cholestatic enzyme activity increases. Thyroid hormone testing should be interpreted carefully because sick euthyroid syndrome is common in dogs with chronic disease. Dogs with gastrointestinal signs should be evaluated for pancreatitis and primary gastrointestinal disease. Depending on risk assessment and vaccination history, infectious disease screening may be indicated. Liver function can be evaluated in a variety of ways. Increased bile acids are extremely sensitive for detecting decreased functional hepatic mass or portosystemic shunting in nonicteric patients. Administration of ceruletide, a cholecystokinin analogue, instead of food may improve the reliability of results in anorectic patients, facilitate standardization of serum bile acid evaluation, and be more sensitive for mild hepatic dysfunction.16 Urine nonsulfated bile acids have a specificity similar to that of serum bile acids but are less sensitive.17 Increased ammonia concentration occurs with portosystemic shunting, hepatic failure, and urea cycle enzyme deficiencies and is a useful biomarker for hepatic encephalopathy.18 Protein C is a circulating anticoagulant protein that is synthesized by the liver. Decreased protein C activity may be a useful biomarker for decreased hepatic function or hepatoportal perfusion.19 Protein C activity may also be useful for therapeutic monitoring and differentiation between microvascular dysplasia and congenital portosystemic shunts.19 The liver synthesizes most clotting factors and is responsible for activation of vitamin K–dependent clotting factors. In dogs with chronic hepatitis, prolonged prothrombin time (PT) and partial thromboplastin time (PTT) have been associated with decreased survival times.20 Buccal mucosal bleeding time is used to assess risk of abnormal platelet function. Because of the fragile balance between procoagulant and anticoagulant factors,21 we recommend that PT, PTT, and buccal mucosal bleeding time tests be conducted no more than 24 hours before liver biopsy.

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FREE CE Liver Enzyme Elevations in Dogs: Diagnostic Approach

Diagnostic Imaging

QuickNotes When a liver biopsy is performed, samples should be obtained for histopathology, aerobic and anaerobic cultures, and copper and iron quantitation.

422

Survey radiography allows assessment of the size, shape, position, opacity, and margins of the liver. Mineralization of hepatic parenchyma or choleliths may be detected on survey ﬁlms. Abdominal ultrasonography allows visualization of focal, multifocal, or diffuse lesions within the hepatic parenchyma, although it cannot distinguish pathologic from benign lesions.22 Ultrasonography also allows assessment of the biliary tract and provides visualization for percutaneous cholecystocentesis, a minimally invasive method of bile collection.23,24 Gallbladder rupture and iatrogenic inoculation of bile with surface microbes are rare complications,23 but the procedure is generally regarded as safe. Normal ﬁndings on abdominal imaging do not rule out primary hepatobiliary disease.

of the time in one veterinary study.28 Accuracy may be improved by use of the largest appropriate biopsy instrument and collection of multiple samples. Keyhole surgical biopsies allow collection of large samples and good access for hemostatic control, but the surgeon’s ability to evaluate all aspects of the liver, gallbladder, and other organs is limited. Laparoscopy offers excellent visualization and sampling of the liver, gallbladder, and other abdominal organs; provides better hemostatic access than percutaneous sampling; and is less invasive than laparotomy. Widespread use of laparoscopy is limited by requirements for specialized training and equipment. Laparotomy is recommended when surgical cure may be possible and in cases for which full exploration of the abdominal cavity is desired.

Liver Sampling Techniques

Diagnostic Sampling

The optimal time for liver biopsies is early in the disease course so that they yield useful information rather than demonstrate nonspecific end-stage changes. When selecting a biopsy technique, clinicians should consider the ability to obtain adequate samples for histopathology, aerobic and anaerobic cultures, and copper and iron quantitation. Contraindications to biopsy include coagulopathy and liver failure. Ultrasound-guided fine-needle aspiration of the liver is easy to perform and minimally invasive. Unfortunately, cytology has been demonstrated to have poor agreement (29% to 66%) with primary histopathologic diagnoses,25,26 including the diagnosis of neoplasia. In data from two recent studies, 3.6% (2 of 56)26 and 3.9% (2 of 51)27 of cases were inappropriately diagnosed with neoplasia on cytology; 14% (2 of 14)26 and 50% (5 of 10)27 of cases with histologically confirmed neoplasia were identified cytologically. The poor agreement between liver cytology and histopathology and the potential ramifications of misdiagnoses should be kept in mind when considering fine-needle aspiration findings. The least invasive method of liver biopsy is percutaneous ultrasound-guided needle biopsy. One disadvantage of this technique is the inability to directly monitor the liver for hemostasis. Needle biopsy findings concurred with findings from wedge biopsies only 48%

Histopathologic evaluation of liver biopsy samples remains the gold standard for the diagnosis of hepatobiliary disease, but it can fail to provide a definitive diagnosis. Clinicians often must incorporate information regarding the extent and type (inflammatory, neoplastic, vascular, vacuolar) of pathology into the clinical picture to make a diagnosis. Quantification of iron and copper concentrations may aid in diagnosis, prognostication, and therapeutic tailoring.29,30 Abnormally high hepatic copper levels cause oxidative stress and are associated with low hepatic glutathione levels, which contribute to hepatocellular damage.29 Both inborn errors of metabolism leading to decreased copper excretion and impaired copper excretion due to chronic hepatitis and cholestatic disease may occur in dogs.29 Abnormal accumulation of iron may be due to increased intestinal absorption or abnormalities of hemoglobin metabolism and delivery of iron to the liver.31 Accumulation of iron in Kupffer cells has been correlated with inflammation and increased copper levels.30 Aerobic and anaerobic cultures of hepatic tissue and bile complete a comprehensive hepatobiliary workup. In findings from one study,32 biliary cultures were more commonly positive (30%) than hepatic cultures (7%) in dogs. It is unclear whether the biliary system is more susceptible to infection or whether it

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FREE CE Liver Enzyme Elevations in Dogs: Diagnostic Approach

is a more sensitive sampling site. Cytologic evaluation of bile may aid in identiﬁcation of infectious organisms.

Conclusion Successful interpretation of liver enzyme abnormalities requires integrated evaluation of the patient’s clinical picture and diagnostic testing. A thorough diagnostic workup for

hepatobiliary disease includes a CBC, biochemical proﬁle, and urinalysis; liver function tests, including coagulation parameters; abdominal radiography and ultrasonography; bile cytology and culture; and hepatic biopsy for histopathology, culture, and metal analysis. Employing a systematic approach facilitates diagnosis of hepatobiliary disease in a timely fashion to improve patient outcome.

References 1. Navarro VJ, Senior JR. Drug-related hepatotoxicity. N Engl J Med 2006;354:731-739. 2. Greene CE, Sykes JE, Brown CA, et al. Leptospirosis. In: Infectious Diseases of the Dog and Cat. 3rd ed. Philadelphia: WB Saunders; 2006:402-417. 3. Decaro N, Martella V, Buonavoglia C. Canine adenoviruses and herpesvirus. Vet Clin North Am Small Anim Pract 2008;38:799814. 4. Webster CRL, Cooper JC. Diagnostic approach to hepatobiliary disease. In: Kirk’s Current Veterinary Therapy XIV. St. Louis: Saunders Elsevier; 2009:543-549. 5. Pavlica Z, Petelin M, Juntes P, et al. Periodontal disease burden and pathological changes in organs of dogs. J Vet Dent 2008;25:97105. 6. Simpson KW, Meyer DJ, Boswood A, et al. Iron status and erythrocyte volume in dogs with congenital portosystemic vascular anomalies. J Vet Intern Med 1997;11:14-19. 7. Bass MC, Schultze AE. Essential thrombocythemia in a dog: case report and literature review. JAAHA 1998;34:197-203. 8. Dunn JK, Heath MF, Jeffries AR, et al. Diagnostic and hematologic features of probable essential thrombocythemia in two dogs. Vet Clin Pathol 1999;28:131-138. 9. Center SA. Acute hepatic injury: hepatic necrosis and fulminant hepatic failure. Small Animal Gastroenterology. 3rd ed. Philadelphia: WB Saunders; 1996:654-704. 10. Cooper J, Webster CRL. Acute liver failure. Compend Contin Educ Pract Vet 2006;28:498-512. 11. Poldervaart JH, Favier RP, Penning LC, et al. Primary hepatitis in dogs: a retrospective review (2002-2006). J Vet Intern Med 2009;23:72-80. 12. Holford AL, Tobias KM, Bartges JW, et al. Adrenal response to adrenocorticotropic hormone in dogs before and after surgical attenuation of a single congenital portosystemic shunt. J Vet Intern Med 2008;22:832-838. 13. Webster CRL. History, clinical signs, and physical ﬁndings in hepatobiliary disease. In: Textbook of Veterinary Internal Medicine. 6th ed. St. Louis: Elsevier; 2008:1423-1434. 14. Reine NJ, Langston CE. Urinalysis interpretation: how to squeeze out the maximum information from a small sample. Clin Tech Small Anim Pract 2005;20:2-10. 15. Appleman EH, Ciancolo R, Mosenco AS, et al. Transient acquired Fanconi syndrome associated with copper storage hepatopathy in 3 dogs. J Vet Intern Med 2008;22:1038-1042. 16. Bridger N, Glanemann, B, Neiger, R. Comparison of postprandial and ceruletide serum bile acid stimulation in dogs. J Vet Intern Med 2008;22:873-878. 17. Balkman CE, Center SA, Randolph JF, et al. Evaluation of urine sulfated and nonsulfated bile acids as a diagnostic test for liver dis-

ease in dogs. JAVMA 2003;222:1368-1375. 18. Szatmari V, Rothiuzen J, van den Ingh TS, et al. Ultrasonographic findings in dogs with hyperammonemia: 90 cases (20002002). JAVMA 2004;224:717-727. 19. Toulza O, Center SA, Brooks MB, et al. Evaluation of plasma protein C activity for detection of hepatobiliary disease and portosystemic shunting in dogs. JAVMA 2006;229:1761-1771. 20. Shih JL, Keating JH, Freeman LM, et al. Chronic hepatitis in Labrador retrievers: clinical presentation and prognostic factors. J Vet Intern Med 2007;21:33-39. 21. Senzolo M, Burra P, Cholongita E, et al. New insights into the coagulopathy of liver disease and liver transplantation. World J Gastroenterol 2006;12:7725-7736. 22. Feeney DA, Anderson KL, Ziegler LE, et al. Statistical relevance of ultrasonographic criteria in the assessment of diffuse liver disease in dogs and cats. Am J Vet Res 2008;69:212-221. 23. Vörös K, Sterczer A, Manczur F, Gaál T. Percutaneous ultrasound-guided cholecystocentesis in dogs. Acta Vet Hung 2002; 50:385-393. 24. Savary-Bataille KC, Bunch SE, Spaulding KA, et al. Percutaneous ultrasound-guided cholecystocentesis in healthy cats. J Vet Intern Med 2003;17:298-303. 25. Wang KY, Panciera DL, Al-Rukibat RK, et al. Accuracy of ultrasound-guided fine-needle aspiration of the liver and cytologic findings in dogs and cats: 97 cases (1990-2000). JAVMA 2004;224:75-78. 26. Cohen M, Bohling MW, Wright JC, et al. Evaluation of sensitivity and specificity of cytologic examination: 269 cases (1999-2000). JAVMA 2003;223:964-967. 27. Weiss DJ, Blauvelt M, Aird B. Cytologic evaluation of inflammation in canine liver aspirates. Vet Clin Pathol 2001;30:193-196. 28. Cole TL, Center SA, Flood SN, et al. Diagnostic comparison of needle and wedge biopsy specimens of the liver in dogs and cats. JAVMA 2002;220:1483-1490. 29. Spee B, Arends B, van den Ingh TS, et al. Copper metabolism and oxidative stress in chronic inflammatory and cholestatic liver diseases in dogs. J Vet Intern Med 2006;20:1085-1092. 30. Schultheiss PC, Bedwell CL, Hamar DW, et al. Canine liver iron, copper, and zinc concentrations and association with histologic lesions. J Vet Diagn Invest 2002;14:396-402. 31. Alexander J, Tung BY, Croghan A, Kowdley KV. Effect of iron depletion on serum markers of fibrogenesis, oxidative stress and serum liver enzymes in chronic hepatitis C: results of a pilot study. Liver Int 2007;27:268-273. 32. Wagner KA, Hartmann FA, Trepanier LA. Bacterial culture results from liver, gallbladder, or bile in 248 dogs and cats evaluated for hepatobiliary disease: 1998-2003. J Vet Intern Med 2007; 21:417-424.

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Liver Enzyme Elevations in Dogs: Diagnostic Approach CE

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CE TEST 2 This article qualiﬁes for 3 contact hours of continuing education credit from the Auburn University College of Veterinary Medicine. Subscribers may take individual CE tests online and get real-time scores at CompendiumVet.com. Those who wish to apply this credit to fulﬁll state relicensure requirements should consult their respective state authorities regarding the applicability of this program.

1. The ______ of liver enzyme activity increase is not a consideration when evaluating a dog with increased liver enzyme activities. a. magnitude c. pattern b. duration d. sequence 2. Which of the following may be associated with hepatotoxicosis? a. xylitol c. metaldehyde b. ethylene glycol d. cannabis 3. Which of the following regarding hepatotoxins is incorrect? a. Pet owners may not consider human foods as potential hepatotoxins. b. Nutritional and herbal supplements are often overlooked during the history. c. Plants and fungi do not contain hepatotoxins. d. Timing between ingestion of a hepatotoxin and liver injury can be highly variable. 4. ______ has/have not been associated with hepatic disease. a. Canine adenovirus 1

b. Canine parvovirus c. Leishmania infantum d. Leptospira interrogans 5. ______ is a poor prognostic indicator in patients with hepatic disease. a. Hyperbilirubinemia b. Decreased BUN concentration c. Hypercholesterolemia d. Hypoglycemia 6. ______ can be used as a biomarker of hepatic encephalopathy. a. Serum bile acids b. Urine nonsulfated bile acids c. Serum ammonia concentration d. Protein C activity 7. Which statement regarding abdominal imaging is correct? a. A lack of ultrasonographic abnormalities rules out clinically signiﬁcant hepatic disease. b. The ultrasonographic appearance of the liver can be used to distinguish benign from pathologic changes. c. Abdominal ultrasonography provides

(CONTINUED FROM PAGE 398)

A similar self-reporting practice may be adopted for veterinary medicine. It appears that this practice would not markedly increase cost or time, and it would serve to document the time and effort an individual veterinarian has spent on CE as well as to assure the public that our profession is committed to maintaining current standards of patient care. It may also serve to deﬂect issues pertaining to professional misconduct. References 1. Finley C. Mandatory continuing education—a survey of current activity. A special communication. Phys Ther 1988;68:374-377. 2. Donen N. No to mandatory continuing medical education, yes to mandatory practice auditing and professional educational development. CMAJ 1998;158(8):10441046. 3. Moore DA, Klingborg DJ, Wright T. Mandatory continuing veterinary education requirements in the United States and Canada. J Vet Med Educ 2003;30(1):19-27. 4. Caple IW. Continuing professional development for veterinarians. Aust Vet J 2005; 83:200-202.

Recommended Reading Crandall JS, Cunliff AE. Experience with mandatory continuing education in a teaching hospital. J Contin Educ Health Prof 1989;9:155-163. Frye SJ. Mandatory continuing education for professional relicensure: a comparative analysis of its impact in law and medicine. J Contin Higher Educ 1990;38:16-25. Little CD. Mandatory continuing education: a survey of the literature and a comment on the implications for physical therapy. J Contin Educ Health Prof 1993;13:159-167.

a reliable and noninvasive means to assess the gallbladder and biliary tree. d. Seeding of the gallbladder with skin bacteria is a frequent complication of ultrasound-guided cholecystocentesis. 8. Which is not a contraindication to liver biopsy? a. increased bile acids b. poor anesthetic risk c. coagulopathy d. liver failure 9. Which is not an advantage of ﬁne-needle aspiration of the liver? a. It allows reliable diagnosis of neoplasia. b. It is minimally invasive. c. The risk of hemorrhage is limited. d. It does not require anesthesia. 10. When performing a biopsy, samples of liver parenchyma should be collected for all of the following except a. histopathology. b. protein C activity. c. metal analysis. d. bacterial culture.

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425

Reading Room*

his book offers the veterinary health care team a pragmatic approach to behavior and training issues in puppies and kittens—in the author’s words, addressing “behavioral needs before they become behavior problems.” It does not cover behavior theories but rather draws on the author’s 30 years of training experience to offer practical advice and methods for achieving cooperation and harmony between owner and pet.

This practical book will help veterinarians realize the goal of a full-service practice that addresses every aspect of pet health and well-being. Title: First Steps With Puppies and Kittens: A Practice-Team Approach to Behavior Author: Linda M. White Publisher: American Animal Hospital Association Press Year: 2008 Pages: 211 ISBN: 978-1-58326-101-9

TO LEARN MORE For further information about this book or to order a copy, visit aahanet.org.

426

Because they know that they are the primary source of advice concerning all aspects of pet ownership, most veterinarians provide information about feeding, care, and training during the initial puppy or kitten visit. Unfortunately, owners frequently feel overwhelmed, retaining only a portion of the instructions, and many practices are too busy to implement a comprehensive, ongoing training program. This book explains how such a program can be developed. It takes the reader step by step through the process and describes how to involve every member of the health care team in the effort. It also comes with a companion CD containing forms and instructional materials that can be customized and printed out to give to owners. The book begins with a discussion of the “business side” of training, addressing ﬁnancial considerations and the roles of various members of the health care team. The author describes how the veterinary team can become “patient behavior advocates” using methods such as operant and associative conditioning and verbal, target, and clicker training. Concepts include reinforcement and punishment, extinction, cure, reward, shaping, and counterconditioning. Special emphasis is given to socialization and desensitization. This is followed by a detailed section on puppy development that

Compendium: Continuing Education for Veterinarians® | September 2009 | CompendiumVet.com

covers basic commands (e.g., come, down, sit, stay) and how to handle undesirable behaviors such as barking, biting, and “counter surfing.” The next chapter similarly covers kitten development and behavior, including common problems like scratching, biting, and litterbox issues. These chapters, which establish the fundamentals of the training program, are followed by six appendixes with samples of handouts dealing with every issue raised in the book. The material is presented in brief, discrete sections, highlighted by a wealth of useful lists. Each training exercise is broken down into specific, detailed steps tailored to the particular behavior in question. Equipment is described as well, including collars, leashes, harnesses, and training aids. This practical book will help veterinarians realize the goal of a fullservice practice that addresses every aspect of pet health and well-being. By viewing the pet and owner-family as a whole, rather than individuals, it should help veterinarians promote the human–animal bond to enable owners to work with their pets in the animals’ best interests, as well as help establish behaviors that will lead to less stressful office visits and more practice loyalty. *Written by Patricia L. Van Horn, a freelance writer in Long Branch, New Jersey.

Understanding

Generalized Anxiety Disorder ❯❯ Sharon L. Crowell-Davis, DVM, PhD, DACVBa The University of Georgia

hobias in pets are commonly assumed to be associated with speciﬁc stimuli, such as thunderstorms, loud noises, strangers, separation from an owner, or the outdoors. However, some dogs and cats chronically exhibit signs of anxiety regardless of their situation. While demonstrations of fear may intensify when these animals are exposed to certain situations or stimuli, such pets are rarely or never truly relaxed and calm. These pets may have generalized anxiety disorder (GAD).

Clinical Signs In humans, the essential feature of GAD is defined as follows: …excessive anxiety and worry (apprehensive expectation), occurring more days than not for a period of at least 6 months, about a number of events or activities […] the intensity, duration, or frequency of the anxiety and worry is far out of proportion to the actual likelihood or impact of the feared event.1 People with GAD have difficulty controlling their almost constant worrying and report a variety of symptoms, including restlessness, being easily fatigued, difficulty concentrating, irritability, muscle tension, disturbed sleep, cold or clammy hands, dry mouth, sweating, nausea or diarrhea, frequent urination, and trouble swallowing. The exact way in which GAD manifests varies depending on the affected individual’s culture. Regardless of culture, however, the anxiety, worry, and physical symptoms are significant enough to interfere with a person’s ability to function normally in a social, occupational, or other important context. Animal patients sometimes exhibit signs that are analogous to symptoms of GAD in humans. Specifically, the animal shows constant or almost constant signs of fear and anxiety, regardless of the situation it is in or the stimuli to which it is exposed. Specific behaviors, such as those listed in BOX 1, vary depending on the patient.

Behavior About This Series Behavior problems are a signiﬁcant cause of death (euthanasia) in companion animals. While most veterinary practices are necessarily geared toward the medical aspect of care, there are many opportunities to bring behavior awareness into the clinic for the beneﬁt of the pet, the owner, and ourselves. This series acknowledges the importance of behavior as part of veterinary medicine and speaks practically about using it effectively in daily practice. SERIES EDITOR Sharon L. CrowellDavis, DVM, PhD, DACVB The University of Georgia

QuickNotes Pets with generalized anxiety disorder exhibit behaviors indicative of mild to severe anxiety most or all of the time and in a wide variety of contexts.

History and Diagnosis Pets with GAD may present to the veterinary clinic for an apparent speciﬁc fear-related disorder

a Dr. Crowell-Davis discloses that she has received ﬁnancial support from CEVA Animal Health.

CompendiumVet.com

427

Understanding

Behavior

QuickNotes Pets with generalized anxiety disorder may also have speciﬁc phobias.

(e.g., separation anxiety, storm phobia, fear aggression, subSigns of Anxiety missive urination) beTrembling cause their fear—and consequent problem Persistent vocalizing behaviors—becomes Urinating more common or Defecating more intense in cerSalivating tain situations. For Pacing example, the owners of a dog with GAD Panting even when not in a hot environment may state that the dog trembles and Hiding hides under the furPersistently holding niture during storms. the ears back against If the dog’s behavior the neck in the examination Persistently holding room is also indicathe mouth in a tive of anxiety, it is submissive grin important to ask how Destructiveness the dog acts in other Freezing (not moving) situations. If the dog’s fear is context specific, the owners will describe the dog as “happy” or “relaxed” in other contexts (e.g., good weather, at home). However, it is also important to ask about specific somatic signals, such as pinning the ears against the neck or holding the lips in a submissive grin. Some owners are not sufficiently familiar with canine communication to understand that if their dog is thumping its tail while displaying a submissive grin and pinning its ears back, it is displaying some degree of arousal coupled with anxiety, not happiness. The owners should describe the pet’s BOX 1

428

specific signals in a variety of situations, especially when the pet is in its own home, the owners are present, and nothing obvious is happening to disturb the pet. If the pet is almost constantly demonstrating signals of fear and anxiety, regardless of context, and simply gets worse in particular situations, then the pet has GAD. In contrast, some owners may present their pet because they have already perceived a more general problem. They may describe the pet as seeming consistently “miserable” or “frightened.” These pets may not demonstrate exacerbated signs of fear in specific contexts. Instead, they simply exhibit low levels of behavior indicative of anxiety most of the time. The owners may make comments like, “He’s never happy.” As for pets that present because of exacerbation of specific behaviors in specific situations, it is important to ask for detailed descriptions of behaviors that cause the owner to believe the pet is unhappy, anxious, miserable, or frightened. Animals that have had prior stressful experiences (e.g., abuse, repeated homelessness) commonly display some degree of chronic, low-level anxiety when they are taken into a new home. As these animals persistently experience a loving, stable environment over a period of days or weeks, many show decreased signs of anxiety. However, if the passage of 2 to 3 months does not improve the pet’s general level of anxiety, GAD should be presumed and the pet treated accordingly.

Treatment Once a pet has been identiﬁed as being chronically anxious, medication is a critical component of treatment. A selective serotonin reuptake inhibi-

Compendium: Continuing Education for Veterinarians® | September 2009 | CompendiumVet.com

Understanding

Behavior TABLE 1

Medications That May Beneﬁt Pets With Generalized Anxiety Disordera–c Medication

Dogs

Cats

Fluoxetine

1–2 mg/kg q24h

0.5–1.5 mg/kg q24h

Paroxetine

1–1.5 mg/kg q24h

0.5–1.5 mg/kg q24h

Sertraline

0.5–4.0 mg/kg q24h

0.5–1.5 mg/kg q24h

Clomipramine

1–3 mg/kg q12h

0.24–1.3 mg/kg q24h

Buspirone

0.5–2.0 mg/kg q8–24h

0.5–1.0 mg/kg q12h

aCrowell-Davis SL, Murray T. Selective serotonin reuptake inhibitors. In: Veterinary Psychopharmacology. Ames, Iowa: Blackwell Publish-

ing; 2006:80-100. bCrowell-Davis SL, Murray T. Tricyclic antidepressants. Veterinary Psychopharmacology. Ames, Iowa: Blackwell Publishing; 2006:179-206. cCrowell-Davis SL, Murray T. Azapirones. Veterinary Psychopharmacology. Ames, Iowa: Blackwell Publishing; 2006:111-118.

tor, serotonin and norepinephrine reuptake inhibi- it engages in a desired behavior), should never be tor, or azapirone can beneﬁt most cases (TABLE 1). used when handling pets with GAD. These trainThese drugs are given daily over a period of weeks ing techniques include such common practices as to effect a long-term change in the pet’s underly- “leash correction,” in which, if the pet does not obey ing emotional state. Because of their potential for a command, the leash is jerked, snapping the coladdiction and the chronic nature of GAD, benzodi- lar against the skin covering the trachea, external azepines are not good choices for the primary treat- jugular vein, carotid artery, and vagoment of this disorder. However, if the pet shows an sympathetic nerve trunk, until the QuickNotes exacerbation of fear in particular contexts, benzo- pet does obey the command. Instead, Effective treatdiazepines can be useful supplements, especially if desired behaviors should be encourment requires the they can be given 30 to 60 minutes before an exac- aged and reinforced, and the owners erbating situation (TABLE 2). should attempt to prevent undesired use of appropriate Along with medication, all training protocols behaviors by logical management. medication. should be reviewed to identify and minimize stres- For example, if the pet chews on cersors in the pet’s life. Training techniques that involve tain objects (e.g., electronic remote control devices), aversive stimuli, such as positive punishment (an these objects should be kept out of the pet’s reach. aversive stimulus occurs when the pet engages in Otherwise, undesirable behaviors should be ignored an undesired behavior) and negative reinforcement because use of aversive stimuli will only worsen the (the pet experiences an aversive stimulus unless pet’s anxiety and potentially exacerbate the severity TABLE 2

Benzodiazepines Commonly Used in Dogs and Catsa,b Generic name

Dogs

Cats

Alprazolam

0.02–0.1 mg/kg q4h

0.0125–0.25 mg/kg q8h

Chlordiazepoxide

2.0–6.5 mg/kg q8h

0.2–1.0 mg/kg q12h

Clonazepam

0.1–0.5 mg/kg q8h

0.015–0.2 mg/kg q8h

Clorazepate dipotassium

0.5–2.0 mg/kg q4h

0.5–2.0 mg/kg q12h

Diazepam

0.5–2.0 mg/kg q4h

0.1–1.0 mg/kg q4h

Flurazepam

0.1–0.5 mg/kg q12h

0.1–0.4 mg/kg q12h

Lorazepam

0.02–0.5 mg/kg q8h

0.03–0.08 mg/kg q12h

Oxazepam

0.04–0.5 mg/kg q6h

0.2–1.0 mg/kg q12h

aCrowell-Davis SL, Murray T. Benzodiazepines. In: Veterinary Psychopharmacology. Ames, Iowa: Blackwell Publishing; 2006:34-71. bThe dose frequency is the maximum frequency that should be used. The lowest dose and frequency that alleviate the fear should be used.

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Understanding

Behavior

QuickNotes

of the clinical signs or cause the manifestation of new signs. A safe, predictable As much as possible, a stable, preenvironment with reg- dictable environment should be provided for the pet. This does not mean ular pleasant experithat the family must stick to a rigorences is required ous and specific schedule, but there for improvement. should be enough consistency in the Recovery is likely pet’s day that it can learn which events to require weeks to predict certain subsequent events and months of treatment. can expect things to happen in a certain order. Efforts by the family to elicit relaxation, play, or other “happy” behaviors can be beneficial. The most effective stimulus varies from patient to patient. Some pets respond well to delicious food treats; others are relatively uninterested in food. In severe cases, the pet may have a poor appetite due to chronic anxiety, and the use of appetite-stimulating benzodiazepines may be beneficial for the fi rst weeks of treatment. Other pets respond better to gentle petting or massage from someone they are familiar with, while others may exhibit their rare moments of “happiness” (e.g., relaxed face, ears up) when a Frisbee is thrown. Many other solutions exist, and it is important to communicate with the family about identifying and extending the situations in which their pet does seem to be relaxed or happy. Various products that provide environmental enrichment can also be useful. Regardless of the specific treatment, the owners should watch for signals of relaxation,

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alertness, and playfulness and facilitate the repetition of those signals. It is important for the family to understand the need for patience. Whether the pet has developed GAD because of genetic factors that make it overreactive to fear-inducing stimuli; a single, severe traumatic event; chronic environmental deprivation at a young age; repeated exposure to fear-inducing stimuli; or some other cause, recovery is likely to require weeks or months. Family members should endeavor to be relaxed when around their anxious pet and should not engage in excessive consoling behavior. While emotions such as fear cannot be operantly reinforced, some behaviors that are common indicators of fear can be. Thus, if a dog learns that leaning against a person’s legs and whining results in its being picked up, cuddled, talked to in a soft voice, and fed treats, it will become more likely to engage in that behavior.

Conclusion The major criterion for identifying a pet as having GAD is the persistence and frequency of behaviors indicative of anxiety, even low levels of anxiety, over long periods of time. The standard criterion in human psychiatric medicine is 6 months. In the case of adopted pets whose earlier history is not known, GAD should be assumed if chronic anxiety persists 2 to 3 months after the pet has been provided with a stable, loving, secure household free of aversive stimuli. Reference 1. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 4th ed. Washington, DC: American Psychiatric Association; 1994.

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Letters AAFP Retrovirus Guidelines I read the recent Feline Focus article (June 2009) on FeLV/FIV testing and vaccination guidelines and wanted to make a brief comment about the FIV vaccine. As the article implies, vaccination with the FIV vaccine interferes with the ability to test cats for FIV infection because vaccinated cats will have positive FIV test results. Our clinic recently referred a cat to a university hospital for kidney transplant consultation. The cat was declined because it had received the FIV vaccine and therefore tested positive for FIV. Although the university knew we had vaccinated this cat, the pet was not a candidate for kidney transplantation because immunosuppressive drugs would be used to regulate organ rejection, and if the cat was truly infected, these drugs would cause a detrimental outcome. The university’s rationale was that, at present, there is no reliable test to differentiate vaccinated from naturally infected cats. Therefore, another important, if uncommon, criterion that veterinarians need to assess before administering the FIV vaccine is whether their client would pursue kidney transplantation if their cat developed kidney disease in the future. Marguerite Hoey, DVM Kearny, New Jersey

The Editor’s Reply Thank you very much for sharing your experience. Most veterinarians would not readily think of this repercussion given that recommendations for renal transplantation are still relatively uncommon. However, it is a very real concern because of the inability to distinguish between antibodies induced by vaccination and those induced by infection.1 It is also theoretically possible for a cat to possess wild-type and vaccination antibodies from having been both infected and vaccinated because we do not conclusively know the full spectrum of serovar (serotype/strain/clade) protection afforded by the existing vaccine. Five subtypes, or clades, of FIV have been characterized and are classiﬁed by

the letters A through E. Other subtypes may exist in nature. The most common FIV subtypes in North America are A, B, and C. The current FIV vaccine contains a mix of subtype A (Petaluma strain) and subtype D (Shizuoka strain) virus. The challenge virus used in the licensing study was a subtype A virus (strain not identiﬁed). Two subsequent studies evaluated protection against infection with two different subtype B strains. In one, 100% protection was noted2; in the other, less than 100% protection was achieved.3 Another study using a subtype A strain was not protective, and 100% of the cats, both control and vaccinated, became infected when challenged.4 Many thanks for bringing this concern regarding vaccination and lack of

2008 Feline Retrovirus Management Guidelines* Members of the Advisory Panel gg Julie Levy, DVM, PhD, DACVIM, Chair gg Cynda Crawford, DVM, PhD University of Florida

gg Katrin Hartmann, Dr. Med. Vet., Dr. Habil., DECVIN-CA Ludwig Maximilian University Munich | Munich, Germany

eLV and FIV are among the most common infectious diseases of cats. Risk factors for infection include male gender, adulthood, and outdoor access, whereas indoor lifestyle and sterilization are associated with reduced infection rates.1–5 The retroviral status of all cats should be known. Cats may require retrovirus testing at different times in their lives. Here are some general principles for retrovirus testing:

A cat with a conﬁrmed-positive test result should be diagnosed as having a retroviral infection—not clinical disease. Diseases in cats infected with FeLV or FIV may not necessarily be the result of the retrovirus infection. Cats infected with FeLV or FIV may live for many years. A decision for euthanasia should never be made solely on the basis of whether the cat is infected. No test is 100% accurate at all times under all conditions. All test results should be interpreted along with the patient’s health and prior likelihood of infection. All positive results should be conﬁrmed by another test method.

gg Regina Hoffmann-Lehmann, Dr. Med. Vet., Dr. Habil, FVH University of Zurich | Zurich, Switzerland

gg Susan Little, DVM, DABVP (Feline Practice) Winn Feline Foundation | Manasquan, New Jersey

gg Eliza Sundahl, DVM, DABVP (Feline Practice)

While FeLV and FIV can be life-threatening viruses, proper management can give infected cats longer, healthier lives. The following article reﬂects the recommendations of the AAFP on managing these infections.

KC Cat Clinic | Kansas City, Missouri

gg Vicki Thayer, DVM, DABVP (Feline Practice) Purrfect Practice | Lebanon, Oregon

At a Glance Epidemiology Page 265

Preventing FeLV and FIV Infection Page 265

Limiting Transmission in the Veterinary Practice Page 268

Diagnosing FeLV and FIV Page 269

About These Guidelines This report represents a consensus of current information compiled by the researchers and practitioners on the panel. These guidelines are based on the best research data, clinical experience and technical judgments available at the time of preparation. While the guidelines are as accurate and comprehensive as possible, they are subject to change should new insights become available from additional research or technological updates. The American Association of Feline Practitioners is a professional organization of practitioners and board-certiﬁed specialists who seek to raise the standards of feline medicine and surgery among practitioners.

Managing Positive Cats Page 270

*This is an abridged version of the full guidelines (Levy JC, Crawford C, Hartmann K, et al. 2008 American Association of Feline Practitioners’ feline retrovirus management guidelines. J Feline Med Surg 2008;10[3]:300-316) available at catvets.com from the American Association of Feline Practitioners (AAFP). Adapted with permission from AAFP.

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suitability for a renal transplantation program to our attention. References 1. Levy JK, Crawford PC, Slater MR. Effect of vaccination against feline immunodeficiency virus on results of serologic testing in cats. JAVMA 2004;225:1558-1561. 2. Pu RY, Coleman J, Coisman J, et al. Dual-subtype FIV vaccine (Fel-O-Vax® FIV) protection against a heterologous subtype B FIV isolate. J Feline Med Surg 2005; 7:65-70. 3. Kusuhara H, Hohdatsu T, Okumura M, et al. Dualsubtype vaccine (Fel-O-Vax FIV) protects cats against contact challenge with heterologous subtype B FIV infected cats. Vet Microbiol 2005;108:155-165. 4. Dunham SP, Bruce J, Mackay S, et al. Limited efficacy of an inactivated feline immunodeficiency virus vaccine. Vet Rec 2006;158:561-562.

Margie Scherk, DVM, DABVP (Feline Medicine) Series Editor, Feline Focus

Call for Papers Are you involved in research? Veterinary Therapeutics: Research in Applied Veterinary Medicine® is a quarterly journal j l ddedicated di t d tto rapid id publication. bli ti We invite the submission of clinical and laboratory research manuscripts in small animal, large animal, and comparative medicine, including pathophysiology, diagnosis, treatment, and prognosis. Prospective, retrospective, and corroborative studies are all welcome. Submitted articles are scheduled to be published 90 to 120 days after acceptance. Contact Cheryl Hobbs, 800-426-9119, ext 52408, or e-mail chobbs@vetlearn.com.

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3 CE CREDITS

CE Article 3

Analgesia for Small Animal Thoracic Surgery ❯❯ Kyriaki Pavlidou, DVM ❯❯ Lysimachos G. Papazoglou, DVM, PhD, MRCVS ❯❯ Ioannis Savvas, DVM, PhD ❯❯ Georgios Kazakos, DVM, PhD Aristotle University of Thessaloniki Thessaloniki, Greece

At a Glance Pathophysiology of Pain in Thoracic Surgery Page 432

Effect of Surgical Technique Page 432

Pharmacologic Pain Relief After Thoracotomy Page 433

Factors Contributing to Postthoracotomy Pain Page 433

Suggested Protocols for Pain Management Page 435

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Abstract: Thoracic surgery in small animals is considered a painful procedure, resulting in alterations in pulmonary function and respiratory mechanics. Modiﬁcations in surgical approach and technique and selection of the appropriate analgesic protocol may improve outcomes in dogs and cats after thoracic surgery. Systemic administration of opioids and other agents, intercostal and intrapleural blocks, and epidural analgesia are among the most common options for pain management after thoracic surgery in small animals.

horacic surgery is associated with con- respiratory mechanics.9,10 Anesthesia and siderable postoperative pain in small thoracotomy in healthy dogs may result animals, leading to hypoventilation, in ventilation/perfusion mismatch and increased morbidity, prolonged hospital- hypoxemia, decreased lung compliance ization, and delayed recovery.1–10 Therefore, and tidal volume, and increased work of analgesia is indicated in all thoracic surgery breathing and pulmonary resistance.2,9,10 patients to provide pain relief without interfering with respiration. The choice of surgi- Effect of Surgical Technique cal technique and analgesic protocol may Access to the thoracic cavity may be affect the analgesic outcome in dogs and obtained in many ways. The choice of thocats after thoracic surgery. Preemptive and racic approach is mainly determined by the multimodal analgesia are considered to be type of intrathoracic damage or disease. among the leading analgesic strategies for Postoperative pain may be affected by the postthoracotomy pain in small animals. Most surgical approach (e.g., open thoracotomy of the information presented in this article versus thoracoscopy), the type of incision, pertains to dogs due to the lack of research and the technique of rib or sternebrae into pain associated with thoracic surgery approximation for thoracotomy closure.2,9,10–15 in cats; however, information regarding cats Median sternotomy in dogs appears to be more painful than intercostal thoracotomy.10 has been included where available. Thoracoscopic surgery for pericardiecPathophysiology of Pain in tomy in dogs has been reported to cause less postoperative pain and morbidity than Thoracic Surgery Noxious stimuli associated with thoracic intercostal thoracotomy,15 possibly due to surgery are carried via C and Aδ ﬁbers smaller incisions and reduced rib retracand transmitted to the central nervous sys- tion resulting in less surgical trauma. tem (CNS) by the intercostal, vagus, and Pain after intercostal thoracotomy is 11 phrenic nerves. Analgesic management mainly associated with intercostal nerve during and after thoracic surgery is aimed irritation.14 Muscle-sparing thoracotomy, at stopping the transmission of nocicep- which preserves the latissimus dorsi mustive stimuli between the area of incision cle, decreases morbidity without comand the CNS and prohibiting peripheral promising exposure.16 However, further and central sensitization. Severe posttho- studies regarding pain and morbidity in racotomy pain in small animals is the most small animals should be implemented to important factor responsible for alterations compare muscle-sparing intercostal thorain pulmonary function and impairment of cotomy with the traditional technique.

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Analgesia for Small Animal Thoracic Surgery CE Intense pain may develop during intercostal thoracotomy closure because the intercostal nerves are often trapped in the sutures that are placed circumcostal to the thoracotomy wound.14 Transcostal suture placement for thoracotomy closure has been reported to avoid nerve entrapment and appears to be less painful than the standard technique of circumcostal closure in dogs.14 Passage of the blunt end of the needle in close proximity to the rib during intercostal thoracotomy closure has been demonstrated to result in less nerve entrapment than other techniques.14 Suture type (wire versus polybutester) has been shown to have no effect on the degree of pain after median sternotomy closure in dogs.13 Surgical procedures and factors that contribute to pain after thoracic surgery in dogs and cats and the nerve supply involved are presented in TABLE 1.

Pharmacologic Pain Relief After Thoracotomy Regional Analgesia Intercostal Nerve Block

TABLE 1

Factors Contributing to Postthoracotomy Pain

Surgical Procedure Involved

Nerve Supply

Skin incision

Thoracic and pectoral nerves

Muscle incision in intercostal thoracotomy (division of latissimus dorsi, scalenus, external abdominal oblique, and intercostal muscles)

Pectoral, thoracodorsal, intercostal, and cervical nerves

Muscle incision in median sternotomy (division of pectoral muscles)

Pectoral, cervical, and thoracic nerves

Rib spreading or fracture

Intercostal nerves

Intercostal nerve stretching, compression by retractors, sutures, or thoracostomy tubes

Intercostal nerves

Thoracic wall excision

Intercostal and thoracic nerves

Parietal pleura incision

Intercostal nerves

Thoracostomy tube placement

Thoracic, pectoral, thoracodorsal, and intercostal nerves

Doses of Bupivacaine 0.5% for Intercostal Blocks in Dogs and Cats1,17,a TABLE 2

Selective intercostal block is employed before thoracotomy closure to alleviate pain and improve pulmonary function in small animals. Because of the overlapping nerve supply, two or three nerves on either side of the thoracotomy should be blocked.1,2–4,7,17 Selective intercostal block with a solution of 0.5% bupivacaine provides analgesia for up to 12 hours, and— compared with parenteral administration of morphine or oxymorphone—has minimal effect on postoperative blood gas values and minute ventilation in dogs undergoing intercostal thoracotomy.2,4 The bupivacaine 0.5% solution is injected caudal to the head of the rib near the insertion of the epaxial musculature and close to the intervertebral foramen.4 Doses of bupivacaine for intercostal blocks are shown in TABLE 2. The total dose of bupivacaine should not exceed 5 mg/kg.18 Intercostal nerve block has been recommended as an adjunct to systemic opioid therapy for the management of postthoracotomy pain,18 but it is not recommended for pain control after median sternotomy.

Intrapleural Analgesia Intrapleural analgesia is achieved by placing local anesthetic between the visceral and parietal pleura to produce ipsilateral somatic block of multiple thoracic dermatomes. Diffusion

Animal Size

Dose

Small dogs (<10 kg) and cats

0.25 mL/site

Medium dogs (<25 kg)

0.5 mL/site

Large dogs (>25 kg)

1 mL/site

Any size

0.3 mL/site for ﬁve sites

aModiﬁed by the authors.

of the anesthetic across the parietal pleura allows intercostal neural blockade by prohibiting the generation and conduction of nerve impulses.8 Local anesthetics can be given as a single injection, multiple injections, or a continuous infusion through an indwelling catheter placed intrapleurally. Intrapleural administration of bupivacaine is used for pain relief after intercostal thoracotomy and median sternotomy in dogs.8–10 Localization of the block over dependent areas of the rib with changes in animal position suggests an inﬂuence by gravitational pooling.19 Use of this block is gaining popularity because a larger volume of bupivacaine can be used and no spinal or central effects are seen after induction.19 Bupivacaine 0.5% (1.5 mg/kg) is instilled through a thoracostomy tube; after instillation, the tube is ﬂushed with saline solution. Because the bupivacaine is distributed by gravity, the animal is placed with the incision site down for up to 5 minutes. Intrapleural

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FREE CE Analgesia for Small Animal Thoracic Surgery

Analgesic Agents for Loading and Continuous Epidural Administration to Manage Postthoracotomy Pain in Dogs and Cats5–7,21–23 TABLE 3

Analgesic Agent(s)

Dose (mg/kg)

Bupivacaine 0.5%

Morphine

0.1–0.4

Oxymorphone

0.1

Buprenorphine

0.003–0.006

Morphine + bupivacaine

(0.1–0.4) + (0.6–2)

Morphine + fentanyl

(0.1–0.3) + (0.01–0.2)

Bupivacaine + buprenorphine

(0.06–0.7) + (0.003–0.03)

Morphine + bupivacaine + fentanyl

0.1 + (0.06–0.1) + 0.01

QuickNotes Median sternotomy appears to be more painful than intercostal thoracotomy in small animals.

bupivacaine administration provides analgesia for up to 12 hours. Analgesia produced by intrapleural bupivacaine in dogs has been reported to be similar to that from morphine given systemically or intrapleurally4,9,10 and that from selective intercostal block with bupivacaine4 and superior to that from buprenorphine given systemically.8 Intrapleural bupivacaine in dogs has been associated with fewer blood gas alterations and earlier normalization of certain pulmonary function values than morphine given systemically or intrapleurally4,9 and produces signiﬁcantly improved oxygenation compared with buprenorphine administered systemically.8 Bupivacaine administered intrapleurally at a dose of 1.5 mg/kg has been found to have minimal effects on cardiac output and to cause clinically insigniﬁcant hemodynamic alterations in dogs, and it can be used safely in healthy dogs with a previous pericardectomy.19,20

Epidural Analgesia Analgesic agents may be injected into the spinal epidural space, most commonly through the lumbosacral space and close to the site of action (e.g., spinal cord receptors, spinal nerves) to achieve regional analgesia. Epidural analgesics may be administered as a bolus or by multiple injections through an epidural catheter to provide preemptive, intraoperative, and postoperative analgesia for thoracic surgery in dogs and cats. Local anesthetics, opioids, and other agents and combinations have been employed to provide analgesia using this technique.5,7,21–23 Local anesthetics primarily block spinal

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nerve roots via a gravity effect.23 Bupivacaine is the most commonly used local anesthetic in small animals and has a longer duration of action than lidocaine or mepivacaine. Potentiation of the analgesic effect has been reported in dogs undergoing thoracotomy with combined epidural administration of bupivacaine and morphine.22 This synergy of opioids with local anesthetics may be the result of interaction with opioid receptors or diminished efferent nociceptive transmission facilitating the effect of opioids.22 Epidural morphine administered preemptively has been reported to provide long-lasting analgesia in dogs and cats6,22 and is at least as effective as intercostal bupivacaine after intercostal thoracotomy in dogs.7 Morphine administered epidurally provides better analgesia than morphine given intravenously in dogs after intercostal thoracotomy.6 Epidural oxymorphone administered intraoperatively has been reported to provide better and longerlasting analgesia in dogs than postoperative intramuscular oxymorphone.5 The increased lipid solubility of oxymorphone compared with morphine may provide more segmental analgesia for surgical procedures involving the hindlimbs and caudal abdomen; by contrast, epidural morphine—because of its more hydrophilic nature—may diffuse cranially and is more appropriate for providing analgesia for thoracic and cranial abdominal surgery.5,23 Analgesic agents and their epidural doses for the relief of postthoracotomy pain in small animals are presented in TABLE 3.

Systemic Analgesia Systemic analgesics can be adjuncts to other, more invasive analgesic strategies, especially when the latter are discontinued. Opioids administered parenterally are the primary form of systemic analgesia for thoracic surgery. Central respiratory depression is a potential adverse effect of opioid administration; however, because postthoracotomy pain may cause hypoventilation, systemic opioids may actually improve respiratory function by relieving the pain.2,4,5 Parenterally administered morphine (0.5 to 1 mg/kg SC, IM, or IV), oxymorphone (0.1 to 0.2 mg/kg IM or IV), or buprenorphine (10 μg/kg IV) can provide effective postoperative analgesia in dogs after intercostal thoracotomy or median sternotomy.2,4–6,8–10 Morphine

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Analgesia for Small Animal Thoracic Surgery CE Suggested Protocols for Pain Management in Small Animals Undergoing Intercostal Thoracotomy or Median Sternotomy2,4–10,12,21–24 TABLE 4

When to Administer Analgesics

Intercostal Thoracotomy Protocol

Median Sternotomy Protocol

Preoperatively

NSAIDs IV, SC Systemic opioids (fentanyl CRI) Ketamine IV loading dose

Systemic opioids (fentanyl CRI)

Intraoperatively

Intercostal bupivacaine block Intrapleural bupivacaine Epidural analgesia Fentanyl CRI Ketamine CRI

Intrapleural bupivacaine Epidural analgesia Fentanyl CRI Ketamine CRI

Postoperatively

Ketamine CRI NSAIDs Opioids (fentanyl CRI)

Opioids (fentanyl CRI)

CRI = constant-rate infusion

and oxymorphone administration may cause hypoventilation, respiratory acidosis, and moderate hypoxemia in dogs, which (unlike humans) are relatively insensitive to the respiratory depressant effects of opioids.2,4,5 Systemic administration of buprenorphine has shown no effect on respiratory function in dogs.8 Fentanyl administered at a loading dose (2 to 5 μg/kg IV) before surgery and followed by continuous infusion intraoperatively (20 to 80 μg/kg/hr) and postoperatively (2 to 5 μg/kg/ hr) provides adequate analgesia and allows for quick titration to increase the analgesic effect and decrease excessive hypoventilation.12,18 Low-dose ketamine infusion administered at a loading dose (0.5 mg/kg IV) before surgery and followed by continuous infusion intraoperatively (10 μg/kg/min) and postoperatively (2 μg/kg/min) has been employed as an adjunct to preanesthesia morphine (1 mg/kg SC). This protocol can also be used as an adjunct to continuous intraoperative fentanyl infusion (1 to 5 μg/kg) to augment analgesia and comfort after forelimb amputation in dogs24; it may also be used for postthoracotomy pain relief in small

animals.12 Medetomidine (10 μg/kg IM) and other α2-adrenergic agonists given postoperatively are thought to produce a better analgesic effect than buprenorphine (20 μg/kg IM) in dogs after intercostal thoracotomy.25 NSAIDs are particularly useful for pain relief after thoracic surgery because they have no respiratory depressant effects. They are employed as adjuncts to systemic opioids or as part of a multimodal approach to pain management after thoracotomy.12 Postoperative administration of magnesium sulfate is reportedly associated with reduced morphine consumption for pain after thoracotomy in human patients.26 An algorithm for postthoracotomy pain control is presented in TABLE 4.

QuickNotes Transcostal thoracotomy closure seems to result in less pain compared with circumcostal thoracotomy closure.

Conclusion Several analgesic modalities are available for use in thoracic surgery in small animals, providing a range of choices to suit practice requirements and surgeon preference. These protocols can not only increase patient comfort but also improve pulmonary function during the critical period immediately after surgery.

References 1. Gilroy BA. Effect of intercostal nerve blocks on post thoracotomy ventilation and oxygenation in the canine. J Vet Crit Care 1982;6:1-9. 2. Berg JR, Orton CE. Pulmonary function in dogs after intercostal thoracotomy: comparison of morphine, oxymorphone, and selective intercostal nerve block. Am J Vet Res 1986;47:471-474. 3. Flecknell PA, Kirk AJB, Liles JH, et al. Post-operative analgesia following thoracotomy in the dog: an evaluation of the effects of bupivacaine intercostal nerve block and nalbuphine on respiratory function. Lab Anim 1991;25:319-324.

4. Thompson SE, Johnson JM. Analgesia in dogs after intercostal thoracotomy. A comparison of morphine, selective intercostal nerve block, and intrapleural regional analgesia with bupivacaine. Vet Surg 1991;20:73-77. 5. Popilskis S, Kohn D, Sanchez JA, et al. Epidural vs. intramuscular oxymorphone analgesia after thoracotomy in dogs. Vet Surg 1991;20:462-467. 6. Popilskis S, Kohn D, Laurent L, et al. Efﬁcacy of epidural morphine versus intravenous morphine for post-thoracotomy pain in dogs. J Vet Anaesth 1993;20:21-25.

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FREE CE Analgesia for Small Animal Thoracic Surgery

7. Pascoe PJ, Dyson DH. Analgesia after lateral thoracotomy in dogs. Epidural morphine vs. intercostal bupivacaine. Vet Surg 1993;22:141-147. 8. Conzemius MG, Brockman DJ, King LG, et al. Analgesia in dogs after intercostal thoracotomy: a clinical trial comparing intravenous buprenorphine and intrapleural bupivacaine. Vet Surg 1994;23:291-298. 9. Stobie D, Caywood DD, Rozanski EA, et al. Evaluation of pulmonary function and analgesia in dogs after intercostal thoracotomy and use of morphine administered intramuscularly or intrapleurally and bupivacaine administered intrapleurally. Am J Vet Res 1995;56:1098-1109. 10. Dhokarikar P, Caywood DD, Stobie D, et al. Effects of intramuscular or intrapleural administration of morphine and intrapleural administration of bupivacaine on pulmonary function in dogs that have undergone median sternotomy. Am J Vet Res 1996;57:375-380. 11. Hughes R, Gao F. Pain control for thoracotomy. Contin Educ Anesth Crit Care Pain 2005;5:56-60. 12. Perkowski SZ. Anesthesia of the patient with respiratory disease. In: King LG, ed. Textbook of Respiratory Disease in Dogs and Cats. St. Louis: Saunders; 2004:253-261. 13. Pelsue DH, Monnet E, Gaynor JS, et al. Closure of median sternotomy in dogs: suture versus wire. JAAHA 2002;38:569-576. 14. Rooney MB, Mehl M, Monnet E. Intercostal thoracotomy closure: transcostal sutures as a less painful alternative to circumcostal suture placement. Vet Surg 2004;33:209-213. 15. Walsh PJ, Remedios AM, Ferguson JF, et al. Thoracoscopic versus open partial pericardiectomy in dogs: comparison of postoperative pain and morbidity. Vet Surg 1999;28:472479. 16. Dean PW, Pope ER. Modiﬁed intercostal thoracotomy approach. JAAHA 1992;28:87-91. 17. Scarda RT. RT Local and regional anesthetic and analgesic techniques: dogs. In: Thurmon

JC, Tranquilli WJ, Benson JG, eds. Lumb & Jones Veterinary Anesthesia, ed 3. Baltimore: Williams & Wilkins; 1996:426-447. 18. Orton CE. Thoracic wall. In: Slatter D, ed. Textbook of Small Animal Surgery, ed 3. Philadelphia: Saunders; 2003:373-387. 19. Bernard F, Kudnig ST, Monnet E. Hemodynamic effects of intrapleural lidocaine and bupivacaine combination in anesthetized dogs with and without an open pericardium. Vet Surg 2006;35:252-258. 20. Kushner LI, Trim CM, Madhusudhan S, et al. Evaluation of the hemodynamic effects of intrapleural bupivacaine in dogs. Vet Surg 1995;24:180-187. 21. Hansen BD. Epidural catheter analgesia in dogs and cats: technique and review of 182 cases (1991-1999). J Vet Emerg Crit Care 2001;11:95-103. 22. Troncy E, Junot S, Keroack S, et al. Results of preemptive epidural administration of morphine with or without bupivacaine in dogs and cats undergoing surgery: 265 cases (19971999). JAVMA 2002; 221:666-672. 23. Torske KE, Dyson DH. Epidural analgesia and anesthesia. Vet Clin North Am Small Anim Pract 2000;30:859-874. 24. Wagner AE, Walton JA, Hellyer PW, et al. Use of low doses of ketamine administered by constant rate infusion as an adjunct for postoperative analgesia in dogs. JAVMA 2002;221:7275. 25. Vainio O, Ojala M. Medetomidine, an α2-agonist, alleviates post-thoracotomy pain in dogs. Lab Anim 1994;28:369-375. 26. Ozcan PE, Tugrul S, Senturk NM, et al. Role of magnesium sulfate in postoperative pain management for patients undergoing thoracotomy. J Cardiothorac Vasc Anesth 2007;21(6):827-831.

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1. Which statement regarding the pathophysiology of postthoracotomy pain is false? a. Intercostal, vagus, and phrenic nerves carry impulses to the CNS. b. Postthoracotomy pain may cause alterations in pulmonary function. c. Provision of analgesia is aimed at interrupting stimulus transmission to the CNS. d. The basic goal of analgesic management is peripheral and central sensitization. 2. Postthoracotomy pain may be affected by the a. surgical approach. b. technique of rib approximation. c. surgical incision (muscle-sparing versus standard thoracotomy). d. all of the above 3. Which type of suture placement for thoracotomy closure avoids nerve entrapment and causes less postoperative pain? a. transcostal c. circumcostal b. subcostal d. wire 4. Thoracotomy in dogs has been associated with a. increased lung compliance. b. increased tidal volume. c. decreased tidal volume. d. decreased pulmonary resistance.

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5. Intercostal nerve block is not recommended a. for pain control after median sternotomy. b. for pain control after intercostal thoracotomy. c. as an adjunct to opioids for the management of pain after intercostal thoracotomy. d. before thoracotomy closure. 6. Which statement concerning intrapleural bupivacaine administration in dogs is false? a. Analgesia achieved by intrapleural bupivacaine administration is similar to that produced by systemically administered morphine. b. Analgesia achieved by intrapleural bupivacaine administration is similar to that produced by intercostal bupivacaine block. c. Intrapleural administration of bupivacaine can be used safely in healthy dogs after pericardiectomy. d. Intrapleural administration of bupivacaine has been associated with more blood gas alterations than systemically administered morphine. 7. Which statement regarding epidural administration of bupivacaine for the management of postthoracotomy pain is correct? a. Bupivacaine has a shorter duration of

Compendium: Continuing Education for Veterinarians® | September 2009 | CompendiumVet.com

action than lidocaine. b. Combined administration of bupivacaine and morphine potentiates the analgesic effect. c. Combined administration of bupivacaine and morphine decreases the analgesic effect. d. Epidural bupivacaine administration has a shorter duration of action than mepivacaine. 8. In human patients, postoperative administration of magnesium sulfate has been associated with a. increased morphine consumption. b. decreased morphine consumption. c. respiratory depression. d. small-airway collapse. 9. Which opioid(s), administered systemically, showed no effect on respiratory function in dogs? a. morphine c. buprenorphine b. oxymorphone d. all of the above 10. Which statement is false with regard to the use of NSAIDs in postthoracotomy pain management? a. NSAIDs cause respiratory depression. b. NSAIDs have no effect on respiratory function. c. NSAIDs are used as adjuncts to systemic opioids. d. NSAIDs may be used as part of a multimodal approach.

Product Forum Desktop Tool

Canine Cushing’s Treatment

CareCredit, a client payment plan program, has released a new desktop tool that can instantly connect to six exclusive online resources, including payment calculator, CareCredit reports, and a resource center. With the new tool, ofﬁces can order supplies, submit applications, and process transactions quickly from a single interface. They can also show clients available payment plans and estimated monthly payments.

Vetoryl capsules, manufactured by Dechra, contain the drug trilostane, which has been demonstrated to be effective in the treatment of Cushing’s syndrome in dogs. Dechra has just received FDA approval to market 10-mg Vetoryl capsules in addition to the 30-mg and 60-mg sizes. Vetoryl is the only FDA-approved product that is indicated for use in pituitary-dependent and adrenaldependent hyperadrenocorticism in dogs. The 10-mg capsules will be available from distributors shortly.

CareCredit | 800-865-9975 | www.carecredit.com

Electrolyte Analyzer

Dechra Veterinary Products | 866-933-2472 | www.dechra-us.com

IDEXX’s new Electrolytes 8 Plus cassette for the VetStat electrolytes and blood gas analyzer combines the capabilities of the electrolytes cassette and the ﬂuid therapy/ acid–base cassette. The new cassette allows electrolyte values, acid–base disorders, and ventilation status to be assessed from a single venous whole blood sample for same price as the electrolytes cassette. Results provide in-depth information regarding the Na+, K+, Cl–, tCO2, and HCO3 – concentrations; pH; PCO2; and the anion gap. IDEXX Reference Laboratories | 888-433-9987 | www.idexx.com

Dog Sling

Touch-Up Trimmer Wahl has added a new product to its line of animal grooming instruments. The dualhead rechargeable Touch-Up Trimmer is a single trimmer with two blades. The ﬁrst blade is the standard-width blade for regular trimming; the second is a narrow detail blade for closer deﬁnition. Changing between the blades is simple with the Quick Detach Blade System. The trimmer is cordless and, with a fully charged battery, will run continuously for 40 minutes. Wahl Clipper Corporation | 800-776-9245 | www.wahl.com

A.S. slings are designed to allow owners and veterinary technicians to assist dogs in standing, walking, and performing orthopedic exercises during rehabilitation. The slings are made from durable terry cloth and are machine washable. The handles are made from long-lasting, thick poly nylon that provides a strong, comfortable grip. A.S. slings are offered in a variety of colors and can include custom embroidery of hospital name, logo, and phone number. The slings come in shorter and longer lengths for large- and small-breed dogs.

Vetericyn VF is a special veterinary formulation of the FDA-approved Vetericyn wound and infection treatment. The first nontoxic, broad-spectrum topical antimicrobial on the market, Vetericyn is scientifically designed to treat a wide variety of wounds, skin ulcers, and abrasions. It also inhibits the release of histamines, which cause chronic wound inflammation, and lessens wound odor by killing bacteria, helping to keep flies and other pests away from outdoor animals during treatment. Vetericyn also decreases healing time.

A.S. Enterprises | 714-938-4725

Vetericyn, Inc. | 866-318-3116 | www.vetericyn.com

Wound Care

Wireless Otoscope

Shampoo

The Tele-View TV-200V wireless magnifying otoscope allows veterinarians to easily magnify and display ear pathology on any television or computer. Its many features include a high-resolution sensor, improved illumination, 2× zoom capability, working channel specula, and easy computer image download. The wireless capability allows images to be displayed on monitors or televisions to be shared with clients.

Allergroom shampoo has been reformulated to include glycotechnology, a patent-pending advancement that reduces adherence of bacteria and yeast to the skin surface. The moisturizing, hypoallergenic shampoo is designed for frequent use to treat dry skin in cats, dogs, and horses. It is also emollient and antiseborrheic and contains Spherulites microspheres, an exclusive encapsulation system that allows the slow release of ingredients long after product application.

Advanced Monitors Corporation | 877-838-8367 | www.tele-view.com

Virbac Animal Health | 800-338-3659 | www.virbacvet.com

The product information presented here is provided by the manufacturers and does not reﬂect endorsement by Compendium. CompendiumVet.com | September 2009 | Compendium: Continuing Education for Veterinarians®

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CLASSIFIED C MARKET L A SSSSI F I ED SHOWCASE ADVERTISING ADV E R T ISI NG

CLASSIFIED ADVERTISING

VETERINARIANS WANTED

GLASS DOORS

Northgate Veterinary Supply, the makers of Ultra Cage and Econocage, now offers choice of glass door or rod gates. Available in standard and custom sizes. 4140 Redwood Highway San Rafael, CA 94903 1-888-DOGCAGE FAX (415) 499-5738 www.northgatevetsupply.com

Need Techs? Support Staff?

NORTH CAROLINA – Well-established, 24-hour, AAHA-accredited small animal hospital in central North Carolina needs an emergency/critical care veterinarian and an associate veterinarian. Located only hours from the mountains and coastlines, our busy, progressive, and expanding five-doctor practice is fully equipped and staffed by 25 highly motivated veterinarians, technicians, and lay staff. Established more than 27 years, our hospital has an excellent client base and strong emphasis on quality care. Work in a great practice environment with an excellent opportunity for career development. Competitive salary and benefits include 401(k), profit sharing, CE, and insurance. Experience preferred. Send resume to Dr. Karl B. Milliren, 303 National Highway, Thomasville, NC 27360; email tvh303@cs.com; fax 336-475-0140.

TEXAS Associate Veterinarian Full-time position for enthusiastic individual with excellent work ethic. Busy small animal clinic located in thriving West Texas has full diagnostic and surgical capabilities, including ultrasound, endoscopy, and neurosurgery. All interested applicants welcome. Call 432-332-5782

CONTINUING VETERINARIANS MEDICALWANTED EDUCATION

Mid-South Regional Conference November 13, 14, 15, 2009 Harrah’s Casino and Convention Center (formerly the Grand Casino and Convention Center) Tunica, Mississippi. Conference will feature topics on Ophthalmology, Dermatology, Oncology, Orthopedics, Infectious Diseases and Immunology, Spay/Neuter Techniques, Practice Management and VLE principals. Technician Track, November 14, 2009 Physical Therapy/Rehab, Emergency/Critical Care, Spay/Neuter & Shelter Med Topics, Parasitology. For more information and registration form, contact: Lee Hughes, Executive Director Memphis/Shelby County Veterinary Medical Association 901-754-1615 Lmhughes@bellsouth.net

RELIEF VETERINARY SERVICES

VIRGINIA – Small animal practice in Shenandoah

Fast. Easy. Inexpensive. WhereTechsConnect.com is your answer! Publisher’s Disclaimer: Advertising appearing in this issue does not necessarily reflect the opinions of nor constitute or imply endorsement or recommendation by the Publisher. The Publisher is not responsible for any statements or data made by the Advertiser.

Valley seeks full-time associate. Spacious, newly remodeled small animal hospital with in-house laboratory with IDEXX Vet Test and QVC machine. Emergency clinic 20 minutes away. Great location to live, beautiful country, fishing, camping, great outdoors. Seventy-five minutes from District of Columbia. Excellent compensation and benefits. Must be client-oriented; equine experience a plus. Contact Shenandoah Animal Hospital, PO Box 503, Woodstock, VA 22664; fax 540-459-4998; phone 540-459-2930, ask for Paula Cooper.

Log in at VetRelief.com Relief veterinarians: search for work dates, view job details, then bid. Hospitals: post your job openings; no charge until you hire. Contact: www.vetrelief.com info@vetrelief.com • 949-234-1960

Place Your Ad Where It Will Get Noticed: Contact Susan Deakins at comp@rja-ads.com or call 800-237-9851, ext. 258 438

Compendium: Continuing Education for Veterinarians® | September 2009 | CompendiumVet.com

CLIENT HANDOUT

What You Should Know About

Feline Senior Wellness How Old Is Old? With many cats routinely living well into their teens or even their twenties, many owners and veterinarians wonder, When is a cat truly a senior citizen? The answer is that there is no speciﬁc age at which a cat becomes “senior.” Individual pets age at different rates. As a general guide, however, the American Association of Feline Practitioners (AAFP) has suggested the following age ranges to help you assess how the aging process may be affecting your cat’s health: Mature to middle-aged: 7 to 10 years Senior: 11 to 14 years Geriatric: 15+ years Knowing the general age range of your cat can help you monitor your pet for early signs of any problems. For example, as cats grow older, their bodies

become less able to cope with physical or environmental stress. Their immune systems become weaker, and they are more prone to developing certain diseases, such as diabetes mellitus, hyperthyroidism, kidney disease, inﬂammatory bowel disease, or cancer. That’s why a senior wellness visit with your veterinarian can be so important for the longterm health of your cat.

It’s Time to See the Doctor Just as with people, it’s important for feline patients to see their doctors more frequently as they age. During a senior wellness exam, your veterinarian will screen your pet for a variety of age-related health concerns. A thorough senior wellness exam is designed to:

Clinical Conditions in Older Cats Cognitive disorders Deafness Retinal disease/ vision problems Dental disease Thyroid disease

Kidney disease Constipation

Lung disease High blood pressure Arthritis Diabetes mellitus Inﬂammatory bowel disease

Cancer

Healthy senior cats should see the veterinarian every 6 months.

Promote the longest and healthiest life possible Recognize and control known health risks for older cats Detect any signs of disease at their earliest stage, when they are the most treatable Most experts agree that healthy senior cats should see their veterinarians every 6 months. Cats age much more rapidly than people do, and health problems can occur quickly. It’s also important to realize that cats are very good at hiding signs of illness. They may appear healthy for a long time only to become suddenly ill once their ability to compensate for an underlying disease is gone.

08/09 Produced in association with Vetstreet and the American Association of Feline Practitioners. A customizable, downloadable version of this client handout is also available at CompendiumVet.com.

CLIENT HANDOUT

Feline Senior Wellness What You Need to Know About Your Senior Cat You can help your veterinarian by keeping a close eye on your cat between exams. Unexplained weight loss or weight gain is often one of the ﬁrst indicators of underlying disease. Weight management itself can also be an issue: many mature cats are obese, while senior or geriatric cats often have trouble maintaining their weight and can become too thin. Obesity itself can contribute to the development of diabetes, osteoarthritis, and other conditions. Behavior problems also become more common as pets age. One studya found that 28% of 11- to 14-year-old cats developed at least one behavior problem. This percentage jumps to 50% in cats older than 15 years. If you note any changes in your cat’s behavior (e.g., unusual cries) or regular routines, such as grooming or litterbox habits, bring your cat in for a checkup and inform your veterinarian.

The Senior Cat Wellness Visit At every visit, your veterinarian will ask you a list of questions designed to obtain a complete medical history for your cat and determine if there have been any changes in health status or behavior since the last visit. During the physical examination, your veterinarian will assess your cat’s overall appearance and body condition by listening to his or her heart; feeling for signs of pain, tumors,

How Aging Affects Your Cat Reduced skin elasticity

Decreased sense of smell

Reduced stress tolerance

Brittle nails

Changes in sleep/ wake cycles Hearing loss

Lessened lung capacity Reduced ability to digest fat

Vision loss a Moffat KS, Landsberg GM. An investigation of the prevalence of clinical signs of cognitive dysfunction syndrome (CDS) in cats. JAAHA 2003;39:512.

One study found that 28% of 11- to 14-year-old cats developed at least one behavior problem. or other unusual changes in the neck and abdomen; checking joints for signs of arthritis or muscle weakness; and examining the ears, eyes, and mouth for any signs of disease. Finally, a routine senior wellness exam should also include a panel of laboratory tests to check your cat’s blood for signs of disease and to assess your cat’s kidney and liver function. Most veterinarians recommend that this baseline laboratory testing be conducted at least once a year in cats that are 7 to 10 years old and then more frequently as the cat ages. Additional tests may be required depending on the results of these routine screening exams.

Don’t Forget the Basics! Along with paying more attention to your cat’s health as he or she ages, you should continue routine wellness care such as parasite prevention, prophylactic dental care, nutritional management, and appropriate vaccination. Maintaining proper routine care becomes even more important as your pet’s immune system ages. Also, take steps to ensure your cat’s comfort, such as making sure litterboxes and food bowls are still easily accessible to your old friend and that you give him or her plenty of attention and affection.

Tests That Senior Cats Need Which tests are necessary and how often are different for each cat, but, in general, the following tests will provide your veterinarian with a good “snapshot” of your senior cat’s health. Over time, these test results can be tracked and compared to help your veterinarian detect any developing health trends. CBC (complete blood count) CHEM screen (liver and kidney function) Urinalysis T4 (thyroid function) Blood pressure

08/09 Produced in association with Vetstreet and the American Association of Feline Practitioners. A customizable, downloadable version of this client handout is also available at CompendiumVet.com.

We believe you re too good to be micromanaged. We believe in providing more resources, not taking them away. We believe a econd opinion, or third, or fourth, can make yours even stronger. We believe in getting out of the way and letting doctors be octors. We believe you own your career. We believe you went to vet school for a very furry reason. We believe people need eterinarians as much as Pets do. We believe you’re better at your job when you’ve had some time away from it. We believe in iving you the tools you need to do your job. We believe no matter how good you are, you can always get better. We believe t xcellent doctors make excellent colleagues. We believe mentors can learn as much as mentees. We believe in saving the lives f Pets and improving the lives of vets. We believe that you should be focused on your patient, not your paperwork. We belie hat flexible hours make for refreshed doctors. We believe cats aren’t the only animals that purr. 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We believe we’re helping families along with their Pets We believe you’re too good to be micromanaged. We believe in providing more resources, not taking them away. We believe a econd opinion Visit us at banfield.net/veterinarians We believe in getting out of the way and letting doctors be doctor We believe for a very furry reason. We believe people need veterinarians as much as Pets do. We believe you’re better at your j when you’ve had some time away from it. We believe in giving you the tools you need to do your job. We believe no matter h d l b b l h ll