If this process were bilateral, then the problem would originate in the bladder trigone or urethra (or the prostate around the urethra) or some process (such as a large neoplasm) that could impinge on both ureters.

• 如果病变是双侧的，原因可能是膀胱三角或尿道前列腺部的病变；或是其它能侵犯两侧输尿管的病变（如大的肿瘤块）。