Treatment of pyonephrosis with a subcutaneous ureteral bypass device in four cats

CASE DESCRIPTION 4 cats were examined because of ureteral obstruction. CLINICAL FINDINGS Clinical and clinicopathologic abnormalities were nonspecific and included anorexia, lethargy, weight loss, anemia, leukocytosis, neutrophilia, lymphopenia, and azotemia. A diagnosis of pyonephrosis was made in all cats. The presence of bacteriuria was confirmed by means of urinalysis in 2 cats, bacterial culture of a urine sample obtained by means of preoperative cystocentesis in 2 cats, and bacterial culture of samples obtained from the renal pelvis intraoperatively in 3 cats. Ureteral obstruction was caused by a urolith in 3 cats; ureteral stricture associated with a circumcaval ureter was identified in 1 cat. TREATMENT AND OUTCOME All 4 cats underwent renal pelvis lavage and placement of a subcutaneous ureteral bypass (SUB) device for treatment of obstructive pyonephrosis. Postoperatively, the cystostomy tube became occluded with purulent material in 1 cat, requiring exchange. The procedure was successful in relieving the obstruction and pyonephrosis in all cats. Three of 4 cats had documented resolution of urinary tract infection. One cat had persistent bacteriuria without clinical signs 1 month after SUB device placement. CLINICAL RELEVANCE Results of this small series suggested that renal pelvis lavage with placement of an SUB device may be a treatment option for cats with obstructive pyonephrosis.