FUNCTIONAL BLADDER NECK OBSTRUCTION - A RARE CAUSE OF RENAL-FAILURE

We studied 7 men and 6 women (average age 33 years) who presented in renal failure with obstructive voiding symptoms or retention. Of these patients 11 had a dilated upper tract and 2 had shrunken kidneys. Mean serum creatinine at presentation was 7.0 mg./dl. No abnormality was noted on cysto-panendoscopy, retrograde urethrography and voiding cystourethrography. The patients were initially treated with clean intermittent self-catheterization following 7 to 10 days of indwelling catheterization. The majority of patients had low pressure and low flow rate at initial presentation but high end filling pressure (mean 35.3 cm. water), high voiding pressure (mean 118.9 cm. water), high opening pressure (mean 95.3 cm. water) and low peak flow (mean 5.7 ml. per second) on video pressure flow electromyography. The external sphincter was relaxed during voiding but the bladder neck opened intermittently or inadequately. No proper funneling of the bladder neck was seen. Thus, functional bladder neck obstruction was considered to be responsible for obstructive voiding in these patients. Of the patients 3 void to completion with the help of alpha blockers alone, 5 underwent bladder neck incision and are voiding well, and 5 were practicing clean intermittent self-catheterization at last followup. Serum creatinine returned to near normal in 10 patients. End stage renal failure persisted in 2 patients, 1 of whom underwent renal transplantation and is voiding well but the other died without having undergone renal replacement therapy. In the remaining patient serum creatinine was stable at 3.2 mg./dl. Mean serum creatinine at 6 months of followup was 2.33 mg.%. Bladder neck obstruction is a rare cause of renal failure which can be corrected if treated appropriately.