Page 940 - Small Animal Clinical Nutrition 5th Edition

972 Small Animal Clinical Nutrition

Endnotes
a. Prescription Diet c/d Feline, Hill’s Pet Nutrition, Inc., Topeka, KS, USA.
VetBooks.ir b. Prescription Diet x/d Feline, Hill’s Pet Nutrition, Inc., Topeka, KS, USA.
c. Iams Veterinary Formula Urinary O Moderate pH/O/Feline, P&G Pet Care, Dayton, OH, USA.
d. Prescription Diet c/d Multicare Feline, Hill’s Pet Nutrition, Inc., Topeka, KS, USA.

Bibliography
Bartges JW, Kirk CA. Nutrition and lower urinary tract disease in cats.Veterinary Clinics of North America: Small Animal Practice
2006; 36: 1361-1376.
Forrester SD,Roudebush P.Evidence-based management of feline lower urinary tract disease.Veterinary Clinics of North America:
Small Animal Practice 2007; 37: 533-558.

CASE 46-3

Struvite Urolithiasis in a Cat
S. Dru Forrester, DVM, MS, Dipl. ACVIM (Small Animal Internal Medicine)
Scientific Affairs
Hill’s Pet Nutrition, Inc.
Topeka, Kansas, USA

Jody P. Lulich, DVM, PhD, Dipl. ACVIM (Small Animal Internal Medicine)
College of Veterinary Medicine
University of Minnesota
St. Paul, Minnesota, USA

Patient Assessment
An eight-year-old, spayed female domestic shorthair cat was evaluated for pollakiuria of three days’ duration. Although the cat was
using the litter box, its caregivers suspected that it also was urinating in other locations in the house. Physical examination was unre-
markable (body condition score 3/5) and the urinary bladder was small. The cat remained in the hospital until there was sufficient
urine to collect for analysis.
Urine subsequently obtained by cystocentesis had a specific gravity of 1.043, pH of 6.5, hematuria (>200 RBCs/hpf) and stru-
vite crystalluria. Survey abdominal radiographs revealed two radiopaque uroliths in the urinary bladder (Figure 1). Subsequent aer-
obic bacterial culture of the urine sample revealed no growth. With a tentative diagnosis of struvite urolithiasis, the attending vet-
erinarian discussed treatment options with the owners including medical dissolution and surgical removal.
Assess the Food and Feeding Method
Before urolith diagnosis, the cat was fed a commercial moist food twice daily and a dry commercial maintenance food was avail-
able at all times. Water was available free choice.
Questions
1. What urolith types are most likely in cats and how does one determine their mineral composition?
2. What treatment should be recommended for cats with struvite uroliths?
3. What recommendations should be made to prevent struvite urolith recurrence?

Answers and Discussion
1. Approximately 90% of uroliths in cats are composed of either magnesium ammonium phosphate (struvite) or calcium oxalate.
Using information from the history, signalment, urinalysis and diagnostic imaging, it is possible to estimate the mineral type.The
textbook case of struvite uroliths involves a younger (<7 years), spayed female cat with slightly acidic to alkaline urine (pH >6.5),
struvite crystalluria and round or disk-shaped radiopaque uroliths. Cats with calcium oxalate uroliths usually are older (>7 years),
male, have acidic to neutral urinary pH, calcium oxalate crystalluria and radiopaque uroliths that may be small and/or have point-
ed edges. Some cats with uroliths may not have all findings (e.g., there may be no urine crystals) or there may be findings consis-