Benign Prostatic Hyperplasia (BPH): Causes, Symptoms and Diagnosis

The Prostate Gland

The prostate is a walnut-sized gland that forms part of the male reproductive system. The gland is made of two lobes, or regions, enclosed by an outer layer of tissue. The prostate is located in front of the rectum and just below the bladder, where urine is stored. The prostate also surrounds the urethra, the canal through which urine passes out of the body.

Scientists do not know all the prostate's functions. One of its main roles, though, is to squeeze fluid into the urethra as sperm move through during sexual climax. This fluid, which helps make up semen, energizes the sperm and makes the vaginal canal less acidic.

BPH: A Common Part of Aging

It is common for the prostate gland to become enlarged as a man ages. Doctors call the condition benign prostatic hyperplasia (BPH), or benign prostatic hypertrophy.

As a male matures, the prostate goes through two main periods of growth. The first occurs early in puberty, when the prostate doubles in size. At around age 25, the gland begins to grow again. It is this second growth phase that often results, years later, in BPH.

Though the prostate continues to grow during most of a man's life, the enlargement doesn't usually cause problems until late in life. BPH rarely causes symptoms before age 40, but more than half of men in their sixties and as many as 90 percent in their seventies and eighties have some symptoms of BPH.

As the prostate enlarges, the surrounding capsule stops it from expanding, causing the gland to press against the urethra like a clamp on a garden hose. The bladder wall becomes thicker and irritable. The bladder begins to contract even when it contains small amounts of urine, causing more frequent urination. As the bladder weakens, it loses the ability to empty itself, and urine remains behind. This narrowing of the urethra and partial emptying of the bladder cause many of the problems associated with BPH.

Many people feel uncomfortable talking about the prostate, since the gland plays a role in both sex and urination. Still, prostate enlargement is as common a part of aging as gray hair. As life expectancy rises, so does the occurrence of BPH. In the United States alone, 350,000 operations take place each year for BPH.

It is not clear whether certain groups face a greater risk of getting BPH. Studies done over the years suggest that BPH occurs more often among married men than single men and is more common in the United States and Europe than in other parts of the world. However, these findings have been debated, and no definite information on risk factors exists.

Why BPH Occurs

The cause of BPH is not well understood. For centuries, it has been known that BPH occurs mainly in older men and that it doesn't develop in males whose testes were removed before puberty. For this reason, some researchers believe that factors related to aging and the testes may spur the development of BPH.

Throughout their lives, men produce both testosterone, an important male hormone, and small amounts of estrogen, a female hormone. As men age, the amount of active testosterone in the blood decreases, leaving a higher proportion of estrogen. Studies done with animals have suggested that BPH may occur because the higher amount of estrogen with the gland increases the activity of substances that promote cell growth.

Another theory focuses on dihydrotestosterone (DHT), a substance derived from testosterone in the prostate, which may help control its growth. Most animals lose their ability to produce DHT as they age. However, some research has indicated that even with a drop in the blood's testosterone level, older men continue to produce and accumulate high levels of DHT in the prostate. This accumulation of DHT may encourage the growth of cells. Scientists have also noted that men who do not produce DHT do not develop BPH.

Some researchers suggest that BPH may develop as a result of "instructions" given to cells early in life. According to this theory, BPH occurs because cells in one section of the gland follow these instructions and "reawaken" later in life. These "reawakened" cells then deliver signals to other cells in the gland, instructing them to grow or making them more sensitive to hormones that influence growth.

Symptoms of BPH

Many symptoms of BPH stem from obstruction of the urethra and gradual loss of bladder function, which results in incomplete emptying of the bladder. The symptoms of BPH vary, but the most common ones involve changes or problems with urination, such as:

• A hesitant, interrupted, weak stream.
• Urgency and leaking or dribbling.
• More frequent urination, especially at night.

The size of the prostate does not always determine how severe the obstruction or the symptoms will be. Some men with greatly enlarged glands have little obstruction and few symptoms while others, whose glands are less enlarged, have more blockage and greater problems.

Sometimes a man may not know he has any obstructions until he suddenly finds himself unable to urinate at all. This condition, called acute urinary retention, may be triggered by taking over-the-counter cold or allergy medicines. Such medicines contain a decongestant drug, know as a sympathomimetic, which may, as a side effect, prevent the bladder opening from relaxing and allowing urine to empty. When partial obstruction is present, urinary retention also can be brought on by alcohol, cold temperatures, or a long period of immobility.

It is important to tell your doctor about urinary problems such as those described above. In 8 out of 10 cases, these symptoms suggest BPH, but they also can signal other, more serious conditions that require prompt treatment. These conditions can be ruled out only by a doctor's exam.

Severe BPH can cause serious problems over time. Urine retention and strain on the bladder can lead to urinary tract infections, bladder or kidney damage, bladder stones, and incontinence. If the bladder is permanently damaged, treatment for BPH may be ineffective. When BPH is found in its earlier stages, there is a lower risk of developing such complications.

Diagnosis of BPH

You may first notice symptoms of BPH yourself, or your doctor may find that your prostate is enlarged during a routine checkup. When BPH is suspected, you may be referred to a urologist, a doctor who specializes in problems of the urinary tract and the male reproductive system. Several tests help the doctor identify the problem and decide whether surgery is needed. The tests vary from patient to patient, but the following are the most common:

• Rectal Exam: This exam is usually the first test done. The doctor inserts a gloved finger into the rectum and feels the part of the prostate next to the rectum. This exam gives the doctor a general idea of the size and condition of the gland.

• Ultrasound: If there is a suspicion of prostate cancer, your doctor may recommend a test with rectal ultrasound. In this procedure, a probe inserted in the rectum directs sound waves at the prostate. The echo pattern of the sound waves form an image of the prostate gland on a display screen.

• Urine Flow Study: Sometimes the doctor will ask a patient to urinate into a special device which measures how quickly the urine is flowing. A reduced flow often suggests BPH.

• Intravenous Pyelogram (IVP): IVP is an x-ray of the urinary tract. In this test, a dye is injected into a vein, and the x-ray is taken. The dye makes the urine visible on the x-ray and shows any obstruction or blockage in the urinary tract.

• Cystoscopy: In this exam, the doctor inserts a small tube through the opening of the urethra in the penis. (This procedure is done after a solution numbs the inside of the penis so all sensation is lost.) The tube, called a cystoscope, contains a lens and a light system, which helps the doctor see the inside of the urethra and the bladder. This test allows the doctor to determine the size of the gland and identify the location and degree of the obstruction.

Each year, Medical College of Wisconsin physicians care for more than 180,000 patients, representing nearly 500,000 patient visits. Medical College physicians practice at Children's Hospital of Wisconsin, Froedtert Memorial Lutheran Hospital, the Milwaukee VA Medical Center, and many other hospitals and clinics in Milwaukee and southeastern Wisconsin.