Benign prostatic hyperplasia (benign prostatic hypertrophy) is a noncancerous (benign) enlargement of the prostate gland that can make urination difficult.
Benign prostatic hyperplasia (BPH) becomes increasingly common as men age, especially after age 50. The precise cause is not known but probably involves changes induced by hormones, especially testosterone.
As the prostate enlarges, it gradually compresses the urethra and blocks the flow of urine (urinary obstruction). When men with BPH urinate, the bladder may not empty completely. Consequently, urine stagnates in the bladder, making men susceptible to urinary tract infections and bladder stones. Prolonged obstruction can damage the kidneys.
Drugs such as over-the-counter antihistamines and nasal decongestants can increase resistance to the flow of urine or reduce the bladder's ability to contract, causing temporary blockage of urine flow out of the bladder in men with BPH.
BPH first causes symptoms when the enlarged prostate begins to block the flow of urine. At first, men may have difficulty starting urination. Urination may also feel incomplete. Because the bladder does not empty completely, men have to urinate more frequently, often at night (nocturia). Also, the need to urinate may become more urgent. The volume and force of the urinary flow may diminish noticeably, and urine may dribble at the end of urination.
Other problems can develop, but these problems affect only a small number of men with BPH. Obstruction of urine flow with retention of some urine in the bladder may increase the pressure in the bladder and limit the flow of urine from the kidneys, putting increased stress on the kidneys. This increased pressure may impede kidney function, although the effect is usually temporary if the obstruction is relieved early. If obstruction is prolonged, the bladder may overstretch, causing overflow incontinence (see Disorders of Urination: Urinary Incontinence in Adults). As the bladder stretches, small veins in the bladder and urethra also stretch. These veins sometimes burst when men strain to urinate, causing blood to enter the urine.
Complete blockage of urine flow out of the bladder (urinary retention) can develop (see Disorders of Urination: Urinary Retention), making urination impossible and usually leading to a full feeling and severe pain in the lower abdomen. However, occasionally urinary retention can occur with few or even no symptoms until retention is very severe. Urinary retention can be triggered by the following conditions:
By feeling the prostate during a rectal examination, doctors can usually determine if it is enlarged. Doctors insert a gloved and lubricated finger into the rectum. The prostate can be felt just in front of the rectum. A prostate affected by BPH feels enlarged, symmetrical, and smooth but is not painful to the touch.
A urine sample should be examined to make sure there is no infection or bleeding. Doctors usually also do a test to measure the level of prostate-specific antigen (PSA) in the blood in men who have an enlarged prostate on examination or who have symptoms of urine blockage. The PSA level can be elevated in men with BPH and also in men with prostate cancer. If the PSA level is elevated or the prostate is hard or lumpy to the touch, other tests may then be required to diagnose cancer (see Prostate Disorders: Prostate Cancer).
Men who have symptoms of urine blockage may be asked to void into a device that measures the volume and rate of urine flow (a test called uroflowmetry). Immediately after the uroflowmetry, doctors do a bladder ultrasound examination to determine how completely the bladder has emptied. Both these tests help diagnose the presence and severity of urine blockage.
Treatment is not necessary unless BPH causes especially bothersome symptoms or complications (such as urinary tract infections, impaired kidney function, blood in the urine, stones, or urinary retention). Drugs that can worsen symptoms, such as opioids and drugs with anticholinergic effects (for example, many antihistamines and some antidepressants), should be stopped when possible.
Drugs are usually tried first. Alpha-adrenergic blockers (such as terazosin, doxazosin, tamsulosin, or alfuzosin) relax certain muscles of the prostate and bladder and may improve the flow of urine. Some drugs (such as finasteride and dutasteride) may block the effects of the male hormones responsible for the prostate's growth, shrinking the prostate and preventing or delaying the need for surgery or other treatments. However, finasteride and dutasteride may need to be taken for 3 months or more before symptoms are relieved. Also, some men who take finasteride or dutasteride never experience relief of their symptoms. Men who have more severe symptoms may be treated with an alpha-adrenergic blocker plus either finasteride or dutasteride.
If drugs are ineffective, surgery can be done. Surgery offers the greatest relief of symptoms but may cause complications. The most common surgical procedure is transurethral resection of the prostate (TURP), in which a doctor passes an endoscope (a viewing tube) up the urethra. Attached to the endoscope is a surgical instrument that is used to remove part of the prostate. The procedure spares men from an incision of the skin. Men who undergo TURP are usually given spinal anesthesia.
TURP can lead to such complications as infection and bleeding. Also, permanent incontinence develops in about 1 to 3% of men. The procedure also can cause permanent erectile dysfunction (impotence). How often erectile dysfunction occurs is not known. Some experts estimate as many as 35% of men who undergo TURP develop erectile dysfunction, but most estimates are lower (5 to 10%). About 10% of men undergoing TURP need the procedure repeated within 10 years, because the prostate continues to grow. If the prostate is very large, TURP may not be possible, and doctors may need to do a more invasive surgical procedure through an incision in the abdomen.
Various alternative surgical treatments offer less symptom relief than TURP. However, the risk of complications is lower with these treatments. Most of these procedures are done with instruments inserted through the urethra. These treatments destroy prostate tissue with microwave heat (transurethral microwave thermotherapy or hyperthermia), a needle (transurethral needle ablation), radiofrequency waves (radiofrequency vaporization), ultrasound (high intensity focused ultrasound), electric vaporization (transurethral electrovaporization), or lasers (laser therapy). Sometimes a channel can be inserted through the penis to widen the opening of the urethra (intraurethral stent).
Problems resulting from urine blockage may need treatment before BPH is definitively treated. Urinary retention can be treated by draining the bladder by means of a catheter inserted through the urethra. Infections can be treated with antibiotics.
Last full review/revision October 2008 by Gerald L. Andriole, MD