Canine and Feline Nephrology and Urology, Second Edition

533 Pages·2010·25.85 MB·English

by  Dennis J. Chew DVM DACVIM

Canine
Feline
d
n
a
Nephrology
dUrology
n
a
Second Edition
DENNIS J. CHEW, DVM, DACVIM
Professor of Veterinary Clinical Sciences
College of Veterinary Medicine
The Ohio State University
Columbus, Ohio 
STEPHEN P. DIBARTOLA, DVM, DACVIM
Professor of Medicine
Associate Dean for Administration and Curriculum
Department of Veterinary Clinical Sciences and Veterinary Administration
College of Veterinary Medicine
The Ohio State University
Columbus, Ohio
PATRICIA A. SCHENCK, DVM, PHD
Endocrine Section
Diagnostic Center for Population and Animal Health
Michigan State University
Lansing, Michigan
3251 Riverport Lane
St. Louis, Missouri 63043   
CANINE AND FELINE NEPHROLOGY AND UROLOGY, SECOND EDITION  ISBN: 978-0-7216-8178-8
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Preface
Canine and Feline Nephrology and Urology is intended to be used by veterinary students, recent 
graduates, and seasoned veterinarians who want to review disorders of the urinary system.  
Although this manual may have value for specialists and residents training in internal medi-
cine, it was not written specifically for that audience. We have worked together and developed our 
approach to dogs and cats with diseases of the urinary tract over the past 30 years at The Ohio State 
University Veterinary Teaching Hospital. This book reflects our experience and opinions.  Dr. Patricia 
Schenck of Michigan State University has brought her organizational skills and generalist’s viewpoint 
to the final development of the book. 
We have taken care to ensure that treatment approaches are reasonable and that drug dosages are 
correct. Ultimately, each practicing veterinarian must decide if these approaches to diagnosis and treat-
ment are consistent with his or her own philosophy of practice before implementing specific manage-
ment plans.  Drug dosages should always be double-checked and verified. We would like to hear your 
opinions about the approaches we have recommended in this manual. Every book contains errors, so 
please make us aware of any you discover. 
The second edition includes five new sections that appear at the end of each chapter. We have 
enjoyed putting them together and hope that you find them interesting and helpful. These sections are 
entitled, What Do We Do?, Thoughts for the Future, Common Misconceptions, Summary Tips, and Frequently
Asked Questions. Thoughts for the Future sections briefly discuss what lies ahead in the areas of urinary 
tract research and therapeutics.  The other sections, are composed of personal experiences from within 
our practices and our interactions with students and fellow veterinarians to present real-life scenarios 
to you and to answer the questions we most commonly encounter. The material in this manual is not 
extensively referenced, but a suggested reading list is provided for each chapter.
Dennis J. Chew
Stephen P. DiBartola
v
Acknowledgments
The wisdom of the original giants of veterinary nephrology and urology is reflected in this 
manual.  We specifically acknowledge the pioneering work of Drs. Ken Bovee, Del Finco, Gerry 
Ling, Don Low, and Carl Osborne. Likewise, we have been influenced by many contemporary 
colleagues such as Larry Adams, Tim Allen, Susi Arnold, Jeanne Barsanti, Joe Bartges, Scott Brown, 
Tony Buffington, Larry Cowgill, Jonathan Elliott, Greg Grauer, Jeff Klausner, John Kruger, Cathy 
Langston, George Lees, Meryl Littman, Jody Lulich, Dave Polzin, Linda Ross, Mike Schaer, Dave 
Senior, and Shelly Vaden. We also have learned much from several generations of veterinary students, 
interns, and internal medicine residents who have trained in OSU’s Veterinary Teaching Hospital. 
Helio deMorais, Bernie Hansen, and Jodi Westropp are previous residents we are happy to have seen 
adopt our enthusiasm for veterinary nephrology and urology. We hope the subjects discussed in this 
manual will prompt another generation of veterinary internists to explore and teach nephrology and 
urology. Replacements for our generation are sorely needed. 
Special thanks to Ray Kersey who had the original vision for this manual many years ago. After 
Ray’s retirement, Tony Winkel inherited the project at Elsevier and pushed us to keep the project going. 
Heidi Pohlman, Shelly Stringer, and Mary Pohlman have been the most recent project managers, and 
we appreciate their efforts to see the project through to completion. Dr. Amanda Owen deserves credit 
for organizational writing of the chapters on feline interstitial cystitis and urinary neoplasia. Finally, 
we appreciate the excellent artwork of Mr. Tim Vojt who has been our colleague all of these years.
Dennis J. Chew, DVM
Stephen P. DiBartola, DVM
Columbus, Ohio
vi
Acknowledgments    vii
I am particularly grateful to Drs. Arthur Lage and Richard Scott who have had a great influence 
on my early training in nephrology and urology. Dr. Richard Scott’s unique thinking and deci-
sion making influence me to this day. “Scotty” always emphasized the importance of examining 
fresh urinary sediment and passed this practice on to a generation of veterinarians at the Animal  
Medical Center in the 1970s. He was decades ahead of the veterinary profession in his approach 
to what we now consider standard practice.  He is more recognized today for his development of 
guidelines for supplementation of parenteral fluids with potassium (called “Scott’s Sliding Scale”). 
Two colleagues at our university who consistently think “outside of the box” deserve special men-
tion. Dr. Larry Nagode’s passion for understanding the relationships between parathyroid hormone, 
calcitriol, and renal patholophysiology has had a major impact on me and has positively affected 
delivery of advanced patient care.  Dr. Tony Buffington deserves tremendous credit for shifting the 
paradigm of idiopathic/interstitial cystitis of cats from that of a nutritional disease to one of com-
plex neurological, endocrine, and environmental effects.  The late Dr. Charles Capen inspired me to 
advance my understanding of  disorders of calcium homeostasis, an area of great interest in nephrol-
ogy. Dr. Mary McLoughlin deserves recognition as a gifted soft tissue surgeon who has worked 
extensively to develop surgical procedures for the urinary tract, especially management of ectopic 
ureters. We shared great excitement for development of diagnositic uroendoscopy and during our 
work on ectopic ureters.   
I am especially thankful that Dr. Stephen P. DiBartola and I were able to develop our thinking in 
 veterinary nephrology and urology together during the past 30 years at The Ohio State University 
College of Veterinary Medicine.  We have had quite a ride together teaching and practicing veteri-
nary urology–vive les néphronauts!  We have had a lot of fun (and very few disagreements) in the  
process–seeing cases, researching projects, writing papers and books, and sharing in the teaching of 
more than 3500 veterinary students.  We both love the pathophysiology of fluid, electrolyte, and acid-
base derangements and have been able to be sounding boards for each other on difficult and interesting 
cases. I feel blessed to have been his colleague, but our relationship extends beyond that of colleagues. 
Most who meet us think we are very different, but we are surprisingly similar in our approach to life 
and work. I am thankful for Steve’s support and friendship during both the good and difficult times.  
Dr. Patricia Schenck also has been a great colleague and special friend along my journey. 
Dennis J. Chew, DVM
Columbus, Ohio
I echo all of Dennis’ comments about the past 30 years of working together. Dennis was the first 
person I met when I arrived as an internal medicine resident at the College of Veterinary Medicine at 
the Ohio State University in 1977 and it was his genuine love of nephrology as well as fluid, electrolyte, 
and acid-base balance that captured my interest and sparked my enthusiasm. Everyone who meets 
Dennis likes him instantly and instinctively, and I was no exception. However, unlike many others, I 
was fortunate enough to make a career out of my association with Dennis. In addition, I want to thank 
my wife Dr. Maxey Wellman for standing by me for more than 30 years despite my quirks and imper-
fections, and my children, Matthew, Michael, Alex, and Stephanie, for all they have taught me about 
the most important job in the world–being a parent.
Stephen P. DiBartola, DVM
Columbus, Ohio
viii    Acknowledgments
I came to The Ohio State University in 1992 with a background in lipid and nutrition research. 
There I met Dr. Dennis Chew, and I became rapidly drawn into the world of calcium and renal disease. 
Several positions and many years later, I’m still involved in calcium research with both Drs. Chew 
and DiBartola. I would like to thank all the four-legged critters in my life that helped me choose the 
veterinary profession. I am also thankful to all the veterinary students and veterinarians that I interact 
with and continue to learn from every day. Music is an integral part of my being, and I’m thankful for 
the musicians that surround me and fill that part of my soul. Special thanks to Dennis Chew who has 
been my friend for so many years—what a long, strange trip it’s been, and I hope there are many more 
years in the journey! Finally, I am grateful to my parents for their love and support. 
Patricia A. Schenck, DVM, PhD
Lansing, MI
This book is dedicated to
the memories of Neil Presnell
and Paul Dunkle.
CHAPTER
1
Urinalysis
INTRODUCTION
A. Routine urinalysis is simple and inexpensive.
B. Urinalysis not only is helpful in evaluation of patients with urinary tract disease but also in
those with systemic disease affecting many other body systems.
C. Results of serial urinalyses can reflect progression or resolution of disease.
D. Abnormalities on urinalysis often occur before changes occur in serum biochemistry (i.e., uri-
nalysis can be very sensitive).
E. Urine should be submitted for analysis at the same time blood is submitted for biochemical
analysis.
F. Complete urinalysis consists of three parts: Physical properties, chemical properties, and
urine sediment findings.
COLLECTION OF URINE
A. Urine collection technique influences interpretation of the results. Urine specimens should be
placed in containers that are clean and free of chemical contaminants (e.g. detergents, disin-
fectants, bleach). Ideally, collect 10 to 12 mL of urine for analysis. At a minimum, 3 mL should
be submitted.
Midstream Voided Sample
1. The goal of this approach is to allow the initial stream of urine to flush contaminants from
the urethra and genital tract.
Technique
DOGS
(1) Male dogs may be more difficult to collect due to short duration of voiding
(i.e. “marking”).
CATS
(1) Use non-resorbable cat litter.
(2) Cellophane wrap over a tilted litter pan containing a gradient of cat litter.
Advantages
a. No risk of complications for the patient.
b. Client can collect the sample.
c. Suitable for initial screening.
d. Method of choice to evaluate hematuria (other collection methods may result in addi-
tion of red blood cells [RBCs] to the urine from trauma).
Disadvantages
a. Subject to contamination by the urethra and genital tract despite precautions.
b. Subject to contamination from the environment.
1
2    CHAPTER 1 n Urinalysis
Manual Expression of Urine by Digital Palpation of the Bladder
Technique
a. Gradually increase pressure in the bladder, compressing the bladder wall by abdomi-
nal palpation until urine is expelled.
b. Many times the animal will void urine after bladder palpation failed to produce a urine
sample. Thus, the clinician should be prepared to collect a voided sample.
Advantages
a. Ease of use in anesthetized patients.
Disadvantages
a. Not recommended except in anesthetized animals.
b. Red blood cells (RBCs) and protein may enter the urine sample as a result of the force
required to expel urine.
c. Collection of urine by manual expression carries a risk of bladder rupture.
d. Infected bladder urine can reflux into the ureters during manual expression thus
increasing the risk of upper urinary tract infection (UTI).
Catheterization
Technique
a. Maintain sterile technique while using a catheter, gloves, and proper patient cleansing
and disinfection. A gentle approach is necessary to minimize trauma to the urinary
tract. The catheter should never be advanced by force, and a ruptured urethra or blad-
der can be a consequence of poor technique.
(1) Male dogs (Figure 1-1): Catheter types include polypropylene, polyvinyl, and bal-
loon-tipped ureteral catheters for use in humans. Softer catheters are chosen for
indwelling urinary catheterization. A catheter size of 3.5 to 10 French (1 French unit =
0.33 mm) is recommended, depending on the size of animal. The appropriate
length of catheter to insert is chosen by estimating the length from the external ure-
thral orifice to the bladder neck by over-laying the catheter on the animal’s body.
The patient is positioned in lateral recumbency, excessive hair near the tip of the
prepuce clipped, and the penis extruded by an assistant. The penis and external
urethral orifice are gently cleansed and rinsed with a mild disinfectant (e.g., ben-
zalkonium chloride) and sterile saline. The packaging containing the sterile cath-
eter can be cut to facilitate manipulation of the catheter without contamination.
Liberally coat the end of the catheter with sterile lubricating jelly and insert the
catheter into the external urethral orifice. The catheter should be directed parallel
to the abdominal wall to facilitate its passage. Resistance may be encountered in the
perineal region and also at the level of the ischial arch. If necessary, external peri-
neal palpation or rectal palpation can be used to redirect the catheter tip. To avoid
trauma to the bladder, the catheter is passed only as far as needed to obtain urine
drainage. In cases of obstruction the catheter may be advanced farther to allow bet-
ter drainage of urine.
(2) Female dogs (Figure 1-2): Direct visualization of the urethral orifice using a specu-
lum is preferred over a blind technique so as to avoid contamination of the urinary
tract with genital bacterial flora. A variety of types and sizes of specula are avail-
able; those with self-contained light sources are preferable. Anuscopes designed
for humans are easily adapted for use in most female dogs. Otoscopic and vaginal
specula of various sizes also can be used. Catheters described above for use in
male dogs can be used in females, as can Foley catheters and metal bitch catheters.
Stylets are necessary for polyvinyl catheters and for small-caliber polypropylene