Secondary ureteral stenosis is commonly observed with ureteroliths and following ureterectomy, accidental trauma to the ureter during routine ovariohysterectomy or following renal transplantation.
This condition may occur either unilaterally or, more commonly, bilaterally. In congenital cases, they are frequently located at the uretopelvic junction of each ureter.
Blood tests are usually unremarkable in dogs with chronic stenosis unless significant hydronephrosis has occurred, in which cases, uremia may be evident in blood tests, with azotemia and hyperkalemia commonly observed.
Diagnosis may be attempted by excretory urography but in severely stenotic ureters, a retrograde ureteropyelography might be required.
A differential diagnosis would include pyelonephritis, urothelial carcinoma, ureteroliths, circumcaval ureter associated with portosystemic shunt, ureteral atresia, ureteral duplication and ectopic ureter.
Unilateral cases may be treated with unilateral nephrectomy and ureterectomy. Bilateral cases are more challenging and may require ureteral stents, which is often successful, providing the cases is diagnosed early and renal hydronephrosis has not resulted in extensive nephron loss.
In severely affected dogs, euthanasia may be a viable option.
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