Health Encyclopedia

Bladder outlet obstruction

Definition

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.

Alternative Names

BOO; Lower urinary tract obstruction; Prostatism

Causes, incidence, and risk factors

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.

Symptoms

The symptoms of bladder outlet obstruction may vary. The most common symptoms experienced include:

Slow urinary flow
Delayed onset of urination (urinary hesitancy)
Inability to urinate (acute urinary retention)
Urinary stream starts and stops (urinary intermittency)
Urinary tract infection
Abdominal pain
Pain on urination (dysuria)
Frequent urination
Continuous feeling of a full bladder

Signs and tests

If bladder outlet obstruction is suspected, your health care provider will take a thorough history of your problems and perform a physical exam. On physical exam, your provider may find one or more of the following possible causes:

Distended bladder
Enlarged prostate (men)
Cystocele (women)
Abdominal mass

In addition to a physical exam your provider may order a variety of tests which may include:

Serum chemistries to reveal kidney damage
Ultrasound to locate the blockage of urine is, and find out completely the bladder is emptied
IVP to locate the blockage is
Urinalysis to look for blood or infection
Urine culture to show an infection
Uroflow to determine how fast the urine flows out
Urodynamic testing -- a more sophisticated way of seeing how much urine flow is blocked and how well the bladder contracts
Cystoscopy and retrograde urethrogram (x-ray to look for urethral narrowing)

Treatment

Treatment of bladder outlet obstruction depends on the underlying cause of the obstruction. For most cases, a Foley catheter (a tube inserted through the urethra into the bladder) will relieve the obstruction temporarily.

Occasionally, a suprapubic catheter (a catheter through the abdomen into the bladder) is needed to drain the bladder.

Long-term treatment of bladder outlet obstruction is mostly surgical. However, medical treatment options are available for many of the diseases that cause BOO. You should have a thorough discussion of treatment options with your provider.

Expectations (prognosis)

If diagnosed early, most causes of BOO can be treated with great success. However, if diagnosis is delayed, permanent damage can result.

Complications

Complications of BOO can be devastating. Permanent damage can be done on all parts of the urinary system with long term or high-grade bladder outlet obstruction.

Complications of BOO include:

Renal failure
Recurrent urinary tract infection
Urinary incontinence
Urinary retention
Bladder and renal calculi

Calling your health care provider

If you have symptoms of bladder outlet obstruction, call your provider. Early diagnosis is important and can often lead to a simple and effective cure.

Prevention

The condition may be prevented by identifying and treating the cause of the blockage.

Review Date:6/13/2006
Reviewed By:Neil D. Sherman, MD, Urologist, Essex County, NJ. Review provided by VeriMed Healthcare Network.

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