Benign ureteral obstruction in cats: Outcome with medical management.

BACKGROUND: Limited information is available regarding the outcome of medical management (MM) of benign ureteral obstruction in cats (BUO). HYPOTHESIS: Describe clinical characteristics and outcome of MM of BUO. ANIMALS: Seventy-two client-owned cats with 103 obstructed kidneys. METHODS: Medical records of cats diagnosed with BUO between 2010 and 2021 that received >72 hours of MM were retrospectively reviewed. Clinical data, treatment, and outcome were reviewed. Outcome was classified as success, partial success, or failure based on ultrasound findings. Factors associated with outcome were assessed. RESULTS: Seventy-two cats with 103 obstructed kidneys were enrolled. The causes of obstruction were uroliths in 73% (75/103), strictures in 13.5% (14/103), and pyonephrosis in 13.5% (14/103) of affected kidneys. Median serum creatinine concentration at presentation was 4.01 mg/dL (range, 1.30-21.3 mg/dL). Outcome after MM was considered a success in 30% (31/103), partial success in 13% (13/103), and failure in 57% (59/103) of kidneys. Success was reported in 23% (17/75) of kidneys with uroliths, 50% (7/14) with pyonephrosis, and 50% (7/14) with strictures. Median time to a successful outcome was 16 days (range, 3-115 days). Distal and smaller uroliths (median length, 1.85 mm) were significantly associated with success (P = .05 and P = .01, respectively). Median survival times were 1188 days (range, 60-1700 days), 518 days (range, 7-1812 days), and 234 days (range, 4-3494 days) for success, partial success, and failure, respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: We found a higher success rate for MM of BUO than previously reported. Smaller distal uroliths (<1-2 mm) were more likely to pass.

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.

Perioperative Occlusion of a Subcutaneous Ureteral Bypass Secondary to a Severe Pyonephrosis in a Birman Cat.

A subcutaneous ureteral bypass (SUB) was placed in a 10-year-old Birman cat for management of unilateral ureterolithiasis. Perioperative occlusion of the nephrostomy tube of the SUB device happened secondary to a severe pyonephrosis. Flushing of the system throught the subcutaneous shunting port was made with saline solution after clamping the urinary bladder catheter. Repetitive flushing of the device was performed daily for 3 days to be sure of the remanent patency of the catheter. Repetitive flushing of the SUB device is a successful renal-sparing treatment for pyonephrosis in a cat and may be considered as an effective treatment option for this condition.

Emphysematous pyonephrosis associated with extrahepatic portosystemic shunt in a dog.

A 16-month-old intact female Maltese dog was referred for examination of depression and vomiting. Ultrasonography revealed dilated right renal pelvis containing echogenic fluid with free gas. A hyperechoic material suspected of urolith was identified in the right ureter. Computed tomography revealed emphysematous change of the right kidney associated with ureteral obstruction and extrahepatic portosystemic shunt (EHPSS). Ureteronephrectomy and surgical correction were performed for the EHPSS. Escherichia coli was isolated from pus from the right kidney. Quantitative analysis revealed that the urolith was an ammonium urate stone. After 5 months follow-up, no complication was observed. This is the first report of emphysematous pyonephrosis associated with EHPSS in a dog.

Double pigtail ureteral stenting and renal pelvic lavage for renal-sparing treatment of obstructive pyonephrosis in dogs: 13 cases (2008-2012).

OBJECTIVE: To describe the technical aspects and clinical outcome of endoscopic- and fluoroscopic-guided ureteropelvic lavage and ureteral stent placement for treatment of obstructive pyonephrosis in dogs. DESIGN: Retrospective case series. ANIMALS: 13 client-owned dogs (14 obstructed ureters). PROCEDURES: All patients with obstructive pyonephrosis were treated with a ureteral stent. Medical records were reviewed for history, clinical signs, pre- and postprocedural clinical and imaging data, and short- and long-term outcomes. RESULTS: 13 dogs (14 ureters) had unilateral or bilateral ureteral obstructions and pyonephrosis due to ureterolithiasis (n = 13) or a suspected ureteral stricture (1). Eleven dogs had positive results of bacteriologic culture of urine obtained from the bladder, renal pelvis, or both. Ten were thrombocytopenic, and 8 were azotemic. Stents were placed fluoroscopically with endoscopic (n = 11) or surgical (3) assistance. Median hospitalization time was 48 hours (range, 6 to 260 hours). Median follow-up time was 480 days (range, 2 to 1,460 days). Intraoperative complications occurred in 2 patients (stent occlusion from shearing of a guide wire, and wire penetration of the ureter at the location of a stone). Short-term complications included a bladder hematoma (n = 1) and transient dysuria (1). Long-term complications included stent encrustation (n = 1), stent migration (1), and tissue proliferation at the ureterovesicular junction (5), which had no clinical implications. Recurrent urinary tract infections were documented in 7 dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Ureteral stenting was a successful renal-sparing treatment for obstructive pyonephrosis in dogs and could often be performed in a minimally invasive manner. There were few major complications. This technique may be considered as an effective treatment option for this condition in dogs.

[Pyonephrosis due to xanthine stones in a bitch treated with allopurinol]. / Pyonephrose durch Xanthinsteine bei einer mit Allopurinol behandelten Hündin.

A 2-year-old, neutered, crossbreed bitch was presented as an emergency with painful abdomen, fever and vomiting. The cause of the acute abdomen was a pyonephrosis of the left kidney, caused by four xanthine stones, which had blocked the ureter. After surgical removal of the heavily altered left kidney, the bitch recovered rapidly. Because of a leishmaniasis the bitch had been treated with allopurinol over an extended period, the xanthine stone formation is likely to have resulted from allopurinol usage. Because there were additionally small concrements in the right kidney, the medication was stopped. Subsequently, the dog has received a low purine diet, and the leishmaniasis titer and renal function have been monitored regularly.

Ultrasonographic features of pyonephrosis in dogs.

Pyonephrosis refers an infected hydronephrotic kidney which arise from pyelonephritis followed by exudate accumulation in a dilated renal pelvis or hydronephrosis followed by ascending infection. Pyonephrosis may cause serious systemic complications, making prompt and reliable diagnosis critical. Clinical and ultrasonographic findings are used for the diagnosis of pyonephrosis in humans, but these findings have not been investigated in dogs. We reviewed ultrasonographic features in pyonephrosis in 18 dogs. Ten dogs with hydronephrosis were also evaluated to compare with the pyonephrosis patients. In most dogs with pyonephrosis, hyperechoic contents completely filled the dilated renal pelvis (n = 8) or a fluid-debris level was observed (n = 8). Hyperechoic contents were dispersed in renal pelvis in only two of the 18 dogs. Hyperechoic, edematous mesentery, and peritoneal and retroperitoneal effusion, which represented peritoneal and retroperitoneal inflammation, were observed in the perinephric region in 11 dogs. Compared with pyonephrosis, and as expected, hydronephrosis was characterized by anechoic contents within the urine-filled collecting system and there were no definitive findings to suspect peritonitis. Thus, there is a distinct difference in the sonographic appearance of pyonephrosis vs. hydronephrosis in dogs.