Ureteral obstruction

A partial or complete mechanical or functional blockage of urine flow within one or both ureters, leading to impaired urinary drainage from the renal pelvis to the bladder, with risk of hydronephrosis and obstructive uropathy. Possible causes are kidney stones, blood clot, stricture, tumor (BPH or prostate, colon, ovarian, cervical cancer), retroperitoneal fibrosis, pregnancy, and congenital causes (UPJ obstruction, nearby blood vessel comression).