Composition of lower urinary tract stones in canines in Mexico City

Effective long-term management of urolithiasis depends on identification and manipulation of factors contributing to initial stone formation; identification of these factors depends on accurate identification of the mineral composition of the urolith involved. The purpose of this study was to determine the chemical composition of uroliths obtained from the low urinary tract of dogs in Mexico City. One hundred and five cases of urolithiasis were studied in which stones were surgically obtained from the low urinary tracts of dogs treated in different hospitals. The chemical composition of the uroliths was quantitatively and qualitatively determined by stereoscopic microscopy, IR-spectroscopy, scanning electron microscopy and X-ray microanalysis. Age of animals ranged from 4 months to 14 years, with a median of 5 years. Composition and distribution of the uroliths were struvite 38.1%, calcium oxalate 26.7%, silica 13.3%, urate 7.6%, mixed 11.4%, compounds 1.9%, and cystine 1%. Most uroliths were found in pure breed dogs (75.2%); 23 different breeds were identified, and more than half of the submissions were from breeds of small size. In our study, the frequency of struvite, calcium oxalate, cystine, urates, mixed and compounds stones are in agreement with papers that report on dog populations in America and Europe, but a higher frequency of silica uroliths was observed in Mexico City dogs.