Hasan Albasan

Melamine and Cyanuric Acid-Induced Crystalluria, Uroliths, and Nephrotoxicity in Dogs and Cats

This article discusses the 2007 recall of canned pet food because of concerns about adverse effects on kidney function of cats and dogs. The discovery of melamine and cyanuric acid in the foods is detailed. Case studies, including clinical, pathology, histology, and toxicology findings, are presented. An attempt is being made to identify the minerals in the uroliths and kidney tissues of affected animals.

Quantitative Analysis of 4468 Uroliths Retrieved from Farm Animals, Exotic Species, and Wildlife Submitted to the Minnesota Urolith Center: 1981 to 2007

Knowledge of the mineral composition of uroliths in various species of animals can help veterinarians predict the mineral composition of stones in vivo. This information is important because dissolution of existing uroliths, or minimizing further growth of uroliths in situ, is dependent on knowledge of the mineral composition of uroliths. With this objective in mind, this report summarizes the results of quantitative mineral analysis of uroliths retrieved from 4468 animals sent to the Minnesota Urolith Center. It also encompasses the most extensive database about uroliths from animals other than domesticated dogs and cats found in the literature.

Trends in the Frequency of Calcium Oxalate Uroliths in the Upper Urinary Tract of Cats

Medical records from cats diagnosed with uroliths at nine United States veterinary teaching hospitals from 1980 to 1999, and records of cats with uroliths submitted for analyses to the Minnesota Urolith Center from 1981 to 2000, were evaluated. A 10-fold increase in frequency of upper tract uroliths occurred in cats during the 20-year interval at the nine veterinary teaching hospitals. Calcium oxalate emerged as the predominant mineral type in upper tract uroliths, having increased more than 50-fold during the study period. These results emphasize the need for increased awareness of the occurrence of upper urinary tract uroliths in cats.

Comparison of laser lithotripsy and cystotomy for the management of dogs with urolithiasis

OBJECTIVE To compare efficacy, required resources, and perioperative complications between laser lithotripsy and cystotomy for urolith (ie, urocystoliths and urethroliths) removal in dogs. DESIGN Retrospective case-control study. ANIMALS 66 dogs with urolithiasis treated by laser lithotripsy (case dogs) and 66 dogs with urolithiasis treated by cystotomy (control dogs). PROCEDURES Medical records were reviewed. Complete urolith removal rate, resources (ie, duration of hospitalization, procedure time, anesthesia time, procedure cost, and anesthesia cost), and complications (ie, hypotension, hypothermia, incomplete urolith removal, and requirement of an ancillary procedure) were compared between cystotomy group dogs and lithotripsy group dogs. RESULTS Duration of hospitalization was significantly shorter for lithotripsy group dogs, compared with cystotomy group dogs. Procedure time was significantly shorter for cystotomy group dogs, compared with lithotripsy group dogs. Cost of anesthesia was significantly less for cystotomy group dogs, compared with lithotripsy group dogs. No significant differences were found between cystotomy group dogs and lithotripsy group dogs with regard to urolith removal rate, procedure cost, anesthesia time, or any of the evaluated complications. CONCLUSIONS AND CLINICAL RELEVANCE Laser lithotripsy is a minimally invasive procedure that has been shown to be safe and effective in the removal of urocystoliths and urethroliths in dogs. No significant differences were found in the required resources or complications associated with laser lithotripsy, compared with cystotomy, for removal of uroliths from the lower portions of the urinary tract of dogs. Laser lithotripsy is a suitable, minimally invasive alternative to surgical removal of urethroliths and urocystoliths in dogs.

Efficacy and safety of laser lithotripsy in fragmentation of urocystoliths and urethroliths for removal in dogs

OBJECTIVE To characterize the efficacy and safety of laser lithotripsy in the fragmentation of urocystoliths and urethroliths for removal in dogs. DESIGN Prospective case series. ANIMALS 100 dogs with naturally occurring urocystoliths and urethroliths. PROCEDURES Via cystoscopy, laser lithotripsy was performed to fragment uroliths. Basket retrieval and voiding urohydropropulsion were used to remove fragments. Postprocedural contrast cystography was performed to assess efficacy and safety. In 40 dogs, midstream urine samples were collected just prior to laser lithotripsy (day 0) and on days 1, 3, and 11 after laser lithotripsy to assess inflammation. RESULTS Urolith removal was complete in 82% of dogs (52/66 with only urocystoliths, 17/17 with only urethroliths, and 13/17 with urocystoliths and urethroliths). Urolith removal was incomplete in 18 dogs; of these dogs, 9, 6, and 3 had urolith fragments >or= 3 mm, 1 to < 3 mm, and < 1 mm in diameter, respectively. Sex (female) was the most significant predictor for success. Median procedure time was 72 minutes. Two dogs developed urinary tract obstruction following laser lithotripsy. Hematuria was detected in 53% of dogs on day 0 and in 84%, 13%, and 3% of dogs on days 1, 3, and 11, respectively. Leukocyturia was detected in 13% of dogs on day 0 and in 47%, 0%, and 3% of dogs on days 1, 3, and 11, respectively. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that use of laser lithotripsy was a safe and effective alternative to surgical removal of urocystoliths and urethroliths in dogs.

Changing Paradigms in the Treatment of Uroliths by Lithotripsy

Surgery remains a common procedure for removal of uroliths from the lower urinary tract of dogs. Incorporation of intracorporeal laser lithotripsy and extracorporeal shock wave lithotripsy has provided impetus for a paradigm shift in the way veterinarians manage urinary stones, however. These minimally invasive techniques provide a successful alternative to surgical urolith extraction.

Recent shifts in the global proportions of canine uroliths

Epidemiological surveys are important tools to identify emerging trends in disease. The Minnesota Urolith Centre has been tracking the occurrence of uroliths for over 30 years. To evaluate global changes in the frequencies of canine uroliths, submissions to the Minnesota Urolith Centre in 1999 and 2000 (n = 39,965) were compared with submissions in 2009 and 2010 (n = 99,598). The proportion of calcium oxalate uroliths rose on every continent except in Europe. Seventy-five per cent of dogs with calcium oxalate uroliths were between 5 and 11 years old. The proportion of struvite uroliths decreased on every continent except in Australia-Oceania. Seventy-seven per cent of all struvite formers were between two and eight years old. The proportion of purine uroliths has declined slightly. Worldwide, uroliths composed of cystine, calcium phosphate, calcium phosphate carbonate and silica remain uncommon. Epidemiological studies of urolithiasis are essential for constructing effective experimental designs and selecting appropriate cases and controls to conduct clinical trials with meaningful results.

Paradigm Changes in the Role of Nutrition for the Management of Canine and Feline Urolithiasis

Results of experimental and clinical investigation have confirmed the importance of dietary modifications in medical protocols designed to promote dissolution and prevention of uroliths. The objectives of medical management of uroliths are to arrest further growth and to promote urolith dissolution by correcting or controlling underlying abnormalities. For therapy to be most effective, it must promote undersaturation of urine with lithogenic crystalloids by 1) increasing the urine solubility of crystalloids, 2) increasing the volume of urine in which crystalloids are dissolved or suspended, and 3) reducing the quantities of lithogenic crystalloids in urine. This article summarizes and applies evidence about nutritional management of urolithiasis derived from experimental and clinical studies of cats and dogs performed at the Minnesota Urolith Center.

Rate and frequency of recurrence of uroliths after an initial ammonium urate, calcium oxalate, or struvite urolith in cats.

OBJECTIVE To determine frequency of and interval until recurrence after initial ammonium urate, calcium oxalate, and struvite uroliths in cats and whether breed, age, or sex was associated with increased risk for urolith recurrence. DESIGN Case-control study. ANIMALS 4,435 cats with recurrent uroliths. PROCEDURES To identify recurrence of uroliths in cats for which uroliths were submitted for analysis at the Minnesota Urolith Center in 1998, the facilitys database was searched for urolith resubmissions from the same cats between 1998 and 2003. Risk factors and differences in mean interval until recurrence were assessed. RESULTS Of 221 cats with ammonium urate uroliths in 1998, 29 (13.1%) had a first and 9 (4.1%) had a second recurrence. Mean interval until recurrence was 22 and 43 months for the first and second recurrence, respectively. Of 2,393 cats with calcium oxalate uroliths in 1998, 169 (7.1%) had a first, 15 (0.6%) had a second, and 2 (0.1%) had a third recurrence. Mean interval until recurrence was 25, 38, and 48 months for the first, second, and third recurrence, respectively. Of 1,821 cats with struvite uroliths in 1998, 49 (2.7%) had a first and 3 (0.2%) had a second recurrence. Mean interval until recurrence was 29 months for first and 40 months for second recurrences. CONCLUSIONS AND CLINICAL RELEVANCE These results provided insights into the frequency of urolith recurrence in cats. Because some uroliths associated with recurrent episodes probably were not submitted to our facility, our data likely represented an underestimation of the actual recurrence rate.

Efficacy of two commercially available, low-magnesium, urine-acidifying dry foods for the dissolution of struvite uroliths in cats

OBJECTIVE To compare the efficacy and safety of using 2 commercially available, low-magnesium, urine-acidifying dry foods to dissolve sterile struvite uroliths in cats. DESIGN Prospective, multicenter, randomized clinical trial . SAMPLE 37 cats with presumed struvite uroliths. PROCEDURES Cats were randomly assigned to be fed 1 of 2 low-magnesium, urine-acidifying dry foods (food A or B). For each cat, physical examination, urinalysis, and abdominal radiography were performed weekly to assess treatment response. RESULTS 32 cats had complete urolith dissolution. Mean ± SD times for a 50% reduction in urolith size (0.69 ± 0.1 weeks) and complete urolith dissolution (13.0 ± 2.6 days) were significantly shorter for cats fed food A, compared with those (1.75 ± 0.27 weeks and 27.0 ± 2.6 days, respectively) for cats fed food B. At study termination, mean ± SD urine pH (6.083 ± 0.105) for cats fed food A was lower than that (6.431 ± 0.109) for cats fed food B. In 5 cats, uroliths did not dissolve and were subsequently determined to be composed of 100% ammonium urate (n = 4) or 100% calcium oxalate (1). Adverse events associated with diet were not observed in any of the cats. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that dietary dissolution is safe and effective for eradication of sterile struvite uroliths in cats. Cats fed food A had faster urolith dissolution than did cats fed food B. Lack of a reduction in urolith size at 2 weeks after diet initiation was indicative of misdiagnosis or noncompliance.