Case Study

Left ureteral obstruction and left hydronephrosis in an 8 year old MN Himalayan mix

An 8-year-old MN Himalayan mix was presented for anorexia, vomiting, lethargy, and lack of defecation for two days. Mucous membranes were tacky, heart and lungs clear, and there was a palpable bladder with discomfort in the cranial abdomen on physical examination. Urinalysis showed 4+ proteinuria and hematuria, but urine culture yielded no growth. Abnormalities on CBC and blood chemistry included neutrophilia, lymphopenia, monocytosis, eosinopenia, hypoproteinemia, azotemia, hyperkalemia, and a low Na/K ratio. T4 was subnormal. On survey abdominal radiographs, cystic calculi and mineralization or possible bilateral ureteral calculi were noted. The patient was treated with fluids (initial IV then subcutaneous fluids), dissolution diet, famotidine, and Buprenex. Two weeks later on physical examination the patient was slightly thin, and the abdomen was perceived to be distended. Survey radiographs confirmed no change in the size of the uroliths. Blood pressure measurements were within normal limits.

DX

Ureterolith causing obstruction at urinary bladder trigone, moderate left kidney hydronephrosis

Sonographic Differential Diagnosis

Chronic dystrophic and fibrotic changes with infarction in the right kidney. Moderate left kidney hydronephrosis with obstructed left ureter at urinary bladder trigone due to grouping of small calculi. IBD GI pattern. Possible emerging lymphoma not overtly suspected

Image Interpretation

The right kidney presented severe chronic degenerative changes with cortical infarctions and minimal power flow Doppler signal. The function is likely minimal in this kidney. The ureter is not visible and assumed to be normal. The left kidney presented moderate hydronephrosis with dilation of the renal pelvis at 2 x 2cm. Mild hydroureter was noted throughout the left ureter, which was dilated to 0.75cm. There was thickening of the ureteral wall just caudal to the trigone of the urinary bladder. The ureter was tortuous, and abrupt dilation was noted with an approximately 1cm grouping of small cystic calculi prior to entry into the urinary bladder. The tortuous left ureter is superimposed over the cystourethral junction. No evidence of rupture was noted. The thickening of the ureteral wall suggests chronic obstruction and scarring. Power Doppler signal was significant in this patient on the left kidney suggestive of good residual function, however function is likely compromised by the ureteral obstruction and hydronephrosis. The urinary bladder was largely unremarkable other than a minor amount of urinary bladder calculi that was not overtly shadowing at this point. The urethra was free of evident pathology.