Hereditary xanthinuria and urolithiasis in a domestic shorthair cat

Abstract A 2-year-old domestic shorthair cat was presented with a history of hematuria, stranguria, and intermittent urethral obstruction. Urine sedimentation showed hematuria, pyuria, and yellow-brown, amorphous, and spherical crystals. Upon surgical correction of the obstructed urethra by perineal urethrostomy, many dark yellow to grey, irregular, gravel-like to millet grain-sized uroliths were found. These uroliths were shown to consist of 100 % xanthine by crystallography. The urinary xanthine concentration was high. The cat subsequently developed bilateral nephroliths, recurrent urinary tract infections, and chronic kidney failure. Dietary management with a low-purine diet failed in part due to poor compliance, and the cat was euthanized at 6 years of age. Xanthinuria is a rare inborn error of metabolism in cats and some other species but should be considered as a differential diagnosis in cases of feline urolithiasis. No associated molecular genetic defect has been elucidated, and management of these cases is difficult. In the absence of calculi for analysis, measuring urinary xanthine concentration can help in diagnosing this metabolic defect.
Source: Comparative Clinical Pathology - Category: Pathology Source Type: research