A physiological approach to the investigation of chronic urinary retention.

Twenty-six male patients with chronic urinary retention were investigated by self filling cystometry, followed by fast filling cystometry. Fast filling cystometry tended to increase the end filling pressure and to indicate a smaller bladder capacity than did self filling cystometry. Inadequate filling of the bladder may lead to an unrepresentative detrusor voiding contraction and an incorrect diagnosis of detrusor failure. Fast filling cystometry masks detrusor instability, which may be a factor producing upper tract dilatation and renal impairment. It is suggested that chronic retention of urine should be investigated by self filling cystometry.