Acute flank pain in dialysed patients. Demonstration of hydronephrosis by computer tomography.

Repeated episodes of acute renal flank pain were observed in a uremic patient on maintenance hemodialysis. Computer tomography during the acute attack repeatedly showed unilateral hydronephrosis which always subsided after passage of stones. X-ray failed to visualize the non-radioopaque stones and sonography was non-contributory. The stones consisted of organic matrix and contained protein material. The present observation documents that computer tomography is valuable in establishing the diagnosis of acute ureteral obstruction resulting from non-radioopaque renal stones in dialysed patients with contracted kidneys.