Xanthine urolithiasis causing bilateral ureteral obstruction in a 10-month-old cat.

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Xanthine urolithiasis was diagnosed in a 10 -month -old intact female domestic shorthair cat presented with acute renal failure due to bilateral ureteral obstruction . Ultrasonography revealed the presence of multiple uroliths in both kidneys and ureters that were not detectable on previous survey radiographs . Medical management failed and ureteral obstruction persisted with no evidence of stone migration into the bladder . Bilateral ureterotomy with urolith removal was performed in order to relieve the obstruction . The cat recovered from surgery , and blood urea nitrogen and creatinine values decreased within normal limits 6 days postoperatively . Urolith analysis by infrared spectrometry determined xanthine composition , and a higher blood and urine concentration of hypoxanthine and xanthine was also found . At 1 -year follow-up , the cat was free of clinical signs . However , ultrasonography of the abdomen revealed small -size calculi in both kidneys , despite the low protein diet intake . The very young age of the animal suggests a possible congenital xanthinuria .