Bilateral ureteropelvic junction stenosis causing hydronephrosis and renal failure in an adult cat

Case Report: Imaging Features and Successful Management of Ureteral Stenosis in a Kitten With Bilateral Atypical Papillary Transitional Mucosal Hyperplasia

A 3-month-old cat weighing 2.62 kg was brought to the VIP Animal Medical Center with vomiting, diarrhea, anorexia, and depression. Laboratory findings confirmed azotemia with elevated blood urea nitrogen (BUN) (168.9 mg/dl) and creatinine (5.9 mg/dl) and symmetric dimethylarginine (SDMA) (86 μg/dl). Abdominal radiography revealed bilateral renomegaly. Ultrasonography revealed bilateral hydronephrosis and left partial and right complete ureteral obstructions with bilateral focal irregular and circumferential thickenings at ureters. Reduction of bilateral renal function was confirmed through excretory urography on computed tomography. The cat underwent subcutaneous ureteral bypass surgery on the left kidney, right nephrectomy, and bilateral ureterectomy. Histopathology of bilateral ureteral irregular and circumferential thickening revealed bilateral atypical papillary transitional mucosal hyperplasia. Three days after surgery, the left hydronephrosis resolved, and azotemia was almost resolved. This is the first report of successful management of ureteral stenosis with congenital papillary transitional mucosal hyperplasia in a kitten using multimodality imaging.

Congenital Unilateral Ureteral Stenosis With Hydronephrosis in a Kitten

A 4-month-old, intact male, domestic longhair cat was admitted with a 2-month history of abdominal distention. Physical examination revealed a mild inspiratory distress and a large palpable intraabdominal mass, in an otherwise bright and alert cat. Abdominal ultrasonography revealed a large hypoechoic cystic structure compatible with hydronephrosis or a renal cyst. On exploratory celiotomy, hydronephrosis of the right kidney was documented and ureteronephrectomy was performed. Histopathology of the excised tissues revealed severe stenosis in the proximal ureteral lumen without evidence of obstructive material, a normal ureteral epithelium and severe atrophy of the renal cortex and medulla, supporting the diagnosis of congenital unilateral ureteral stenosis. The cat recovered uneventfully and 8 months later was in excellent clinical condition. Congenital ureteral stenosis with secondary hydronephrosis may occur rarely in cats and should be included in the differential diagnosis of progressive abdominal distention in young cats.

Treatment of congenital distal ureteral orifice stenosis by endoscopic laser ablation in dogs: 16 cases (2010-2014)

OBJECTIVE To determine characteristics of and outcomes for dogs with congenital distal ureteral orifice stenosis (CDUOS) treated by cystoscopic-guided laser ablation (CLA). DESIGN Retrospective case series. ANIMALS 16 client-owned dogs with CDUOS treated by CLA at 2 veterinary hospitals between 2010 and 2014. PROCEDURES Medical records were reviewed and data collected regarding clinical findings, imaging results, surgery characteristics, treatment, and outcome. Follow-up information was collected from dog owners and referring veterinarians via standardized interview. RESULTS Dogs included 10 males and 6 females; median age was 11.5 months (range, 4 to 112 months). Labrador Retriever (n = 6; 3 males) was the most common breed. Intramural ectopic ureteral openings were identified at the site of stenosis in 15 dogs (18/20 stenotic ureteral openings). Treatment with CLA to enlarge and relocate the stenotic opening was successful in all dogs. Median duration of anesthesia and hospitalization was 105 minutes and 24 hours, respectively. No complications were noted. Fourteen dogs remained alive (2 lost to follow-up) during a median follow-up period of 14.5 months. Owners of 11 of 13 dogs reported improvement in their dog's quality of life after CLA. The treated ureteral orifice remained patent in the 2 dogs that were reimaged. CONCLUSIONS AND CLINICAL RELEVANCE CDUOS should be considered as a differential diagnosis for dogs with idiopathic distal ureteral obstruction, particularly young male Labrador Retrievers, and was most often associated with an intramural ectopic ureter in this study. Treatment with CLA was safe and effective for opening the ureteral orifice.

BILATERAL HYDRONEPHROSIS IN A SUGAR GLIDER (PETAURUS BREVICEPS)

An adult, intact male sugar glider ( Petaurus breviceps ) presented for acute caudal abdominal swelling. Treatment by the referring veterinarian included aspiration of urine from the swelling. On physical examination, mild depression, pale mucus membranes, and caudal abdominal swelling were noted. Focused ultrasonographic assessment revealed a fluid-filled caudal abdominal structure and subjective bladder wall thickening. The following day, the sugar glider was severely depressed. Hematology results included hypoglycemia, hyperkalemia, hyponatremia, and azotemia. Ultrasonography revealed bilateral hydronephrosis and hydroureter. Despite supportive care, the animal died. Postmortem examination confirmed bilateral ureteral dilation, renal petechial hemorrhage, and dilation of the right renal pelvis. Submucosal edema, hemorrhage, and lymphoplasmacytic infiltration of the urinary bladder, ureters, and renal pelvises were noted. Hyperplasia of the urinary bladder and ureteral epithelium, coupled with inflammation, may have caused functional obstruction leading to bilateral hydronephrosis and hydroureter. This is the first reported case of hydronephrosis in a marsupial.