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

BOO; Lower urinary tract obstruction; Prostatism

Bladder outlet obstruction (BOO) can have many different causes, including:

• Benign prostatic hyperplasia (BPH), or enlarged prostate
• Bladder stones
• Bladder tumors (cancer)
• Pelvic tumors (cervix, prostate, uterus, rectum)
• Urethral stricture (scar tissue)

Less common causes include:

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

This condition is most common in aging men. It 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.

See also:

• Benign prostatic hypertrophy
• Bladder stones
• Obstructive nephropathy
• Reflux nephropathy

Images

Kidney anatomy

Kidney - blood and urine flow

Female urinary tract

Male urinary tract

Review Date: 06/17/2010
Reviewed By: Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine; Scott Miller, MD, Urologist in private practice in Atlanta, Georgia. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)