ABC of Urology: BLADDER OUTFLOW OBSTRUCTION

Symptoms

Bladder outflow obstruction due to benign prostatic hyperplasia is a common problem in elderly men, and by the age of 80 years most men will have developed symptoms attributable to this disorder. The symptoms may be either obstructive or irritative in type. Less common causes of bladder outflow obstruction include bladder neck obstruction and urethral stricture.

The aetiology of the irritative symptoms is poorly understood. Obstruction of the urethra by an enlarged prostate leads to a poor urinary flow. The bladder may take longer to generate a high enough pressure to start the flow of urine, and this pressure may not be sustained over the (prolonged) voiding cycle. This leads to hesitancy and intermittency. Other causes of irritative symptoms which merit attention are bladder cancer, urinary tract infection, urethral stricture, bladder diverticula, bladder calculus, and neuropathic bladder dysfunction.

Evaluation

The assessment of a patient with outflow obstruction begins with a thorough history and examination. Symptom scores such as the American Urological Association's score are seldom used except in clinical trials.

The clinical examination of a patient should focus on the urinary tract, especially the external genitalia, and should also include a digital rectal examination. A digital rectal examination is minimally invasive, allows a rough estimation of the size of the prostate, will detect locally advanced prostate cancer, and permits an assessment of rectal sphincter tone (which may be relevant to the presenting history).

A urine culture should be performed to exclude urinary infection or haematuria, and the serum electrolytes should be checked for satisfactory renal function.

Uroflometry is an important procedure that is often neglected but should be performed before surgery is considered. In some centres this …