The nonsurgical approach to unilateral ureteral obstruction due to impaction of a blood clot is described. A patient with the nephrotic syndrome secondary to minimal change disease had gross hemturia and acute renal failure following percutaneous renal biopsy. After he responded to prednisone therapy, clot obstruction developed at the site of the percutaneous biopsied kidney, which was treated with intracaliceal infusion of streptokinase via a ureteral catheter. Complete resolution of the clot and the urinary tract obstruction was accomplished within 3 days. This approach appears to be the treatment of choice in upper urinary tract obstruction secondary to blood clots when simple ureteral catheter drainage is ineffective.
