Bladder outlet obstruction

Injury	Disease	Nutrition	Poison

Symptoms	Surgery	Test	Special Topic

Kidney anatomy

Female urinary tract

Male urinary tract

Kidney - blood and urine flow

Bladder outlet obstruction

Definition:

Bladder outlet obstruction occurs at the base of the bladder, and reduces or prevents the flow of urine into the urethra (the tube that carries urine out of the body).

Alternative Names:
BOO; Lower urinary tract obstruction; Prostatism
Causes, incidence, and risk factors:

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Bladder outlet obstruction can have many different causes. Some of the most common causes of BOO are:

Benign prostatic hyperplasia (BPH)
Bladder calculi (stones)
Urethral stricture (scar tissue)
Bladder tumors (cancer)
Pelvic tumors (cervix, prostate, uterus, rectal)

Less common causes of bladder outlet obstruction include:

Cystocele
Posterior urethral valves (congenital birth defect)
Foreign objects
Urethral spasms
Urethral diverticula

Bladder outlet obstruction is most common in aging men, and is often caused by BPH. Bladder stones and bladder cancer are also more commonly seen in men than women. As a man ages, the chance of developing these diseases increases dramatically. One in three American males over the age of 60 has significant symptoms of bladder outlet obstruction.