Objective—To determine hospital proportional morbidity
rates (HPMR) for urethral obstructions, urethral
plugs or urethroliths, and urethrostomies in cats in
veterinary teaching hospitals (VTH) in Canada and the
United States between 1980 and 1999.
Animals—305,672 cats evaluated at VTH.
Procedures—Yearly HPMR were determined for cats
with urethral obstructions, urethral plugs or urethroliths,
or urethrostomies from data compiled by
the Purdue Veterinary Medical Database. The test for
a linear trend in proportions was used.
Results—Urethral obstructions were reported in 4,683
cats. Yearly HPMR for urethral obstructions declined
from 19 cases/1,000 feline evaluations in 1980 to 7
cases/1,000 feline evaluations in 1999. Urethral plugs
or urethroliths affected 1,460 cats. Yearly HPMR for
urethral plugs or urethroliths decreased from 10
cases/1,000 feline evaluations in 1980 to 2 cases/1,000
feline evaluations in 1999. A total of 2,359 urethrostomies
were performed. Yearly HPMR for urethrostomies
decreased from 13 cases/1,000 feline evaluations
in 1980 to 4 cases/1,000 feline evaluations in
Conclusions and Clinical Relevance—Frequency of
feline urethrostomies performed at VTH in Canada and
the United States declined during the past 20 years
and paralleled a similar decline in frequency of urethral
obstructions and urethral plugs or urethroliths. These
trends coincide with widespread use of diets to minimize
struvite crystalluria in cats, which is important
because struvite has consistently been the predominant
mineral in feline urethral plugs during this period.
(J Am Vet Med Assoc 2002;221:502–505)
Objective—To evaluate the reproducibility and accuracy of 4 portable pH meters, a reagent strip, and pH paper for measuring urine pH in dogs.
Design—Prospective masked randomized study.
Sample Population—201 free-catch urine samples from 114 hospitalized dogs.
Procedures—Urine samples were divided into 2-mL aliquots. Measurements of urine pH were obtained by use of a laboratory benchtop pH meter, 4 portable pH meters, a urine reagent strip, and pH paper. The pH of each aliquot was measured within 4 hours of collection by an evaluator unaware of the aliquot's origin.To assess reproducibility, the coefficient of variation for each pH measurement device was calculated. To determine which device was most accurate, the degree of agreement among the different devices was assessed in comparison with the benchtop pH meter, which was considered the reference method.
Results—3 of the 4 portable pH meters had nearly perfect agreement with the reference method. The reagent strip and pH paper had moderate to poor agreement with the reference method.
Conclusions and Clinical Relevance—Urine pH measurements should be made by use of a portable or benchtop pH meter when accurate measurements are crucial for diagnosis or treatment. Reagent strips and pH papers are useful in obtaining pH approximations but are not recommended when accurate measurements of urine pH are required.
Objective—To evaluate the effect of dietary supplementation
with sodium chloride (NaCl) on urinary calcium
excretion, urine calcium concentration, and urinary
relative supersaturation (RSS) with calcium
Animals—6 adult female healthy Beagles.
Procedure—By use of a crossover study design, a
canned diet designed to decrease CaOx urolith recurrence
with and without supplemental NaCl (ie, 1.2%
and 0.24% sodium on a dry-matter basis, respectively)
was fed to dogs for 6 weeks. Every 14 days, 24-
hour urine samples were collected. Concentrations of
lithogenic substances and urine pH were used to calculate
values of urinary RSS with CaOx.
Results—When dogs consumed a diet supplemented
with NaCl, 24-hour urine volume and 24-hour urine
calcium excretion increased. Dietary supplementation
with NaCl was not associated with a change in urine
calcium concentration. However, urine oxalate acid
concentrations and values of urinary RSS with CaOx
were significantly lower after feeding the NaCl-supplemented
diet for 28 days.
Conclusions and Clinical Relevance—Dietary supplementation
with NaCl in a urolith-prevention diet
decreased the propensity for CaOx crystallization in
the urine of healthy adult Beagles. However, until
long-term studies evaluating the efficacy and safety of
dietary supplementation with NaCl in dogs with CaOx
urolithiasis are preformed, we suggest that dietary
supplementation with NaCl be used cautiously. (Am J
Vet Res 2005;66:319–324)