Benign prostatic hypertrophy (BPH)
BENIGN PROSTATIC HYPERTROPHY
BENIGN PROSTATIC HYPERTROPHY DEFINITION
A common, noncancerous enlargement of the prostate gland. The enlarged prostate may compress the urinary tube (urethra), which courses through the center of the prostate, impeding the flow of urine from the bladder through the urethra to the outside. Abbreviated BPH. If BPH is severe enough, complete blockage can occur. BPH generally begins after age 30, evolves slowly, and causes symptoms only after age 50. Half of men over age 50 develop symptoms of BPH, but only a minority need medical or surgical intervention. Medical therapy includes drugs such as finasteride and terazosin. Prostate surgery has traditionally been seen as offering the most benefits’and the most risks’for BPH. BPH is not a sign of prostate cancer. Also known as benign prostatic hypertrophy and nodular hyperplasia of the prostate.
BENIGN PROSTATIC HYPERTROPHY CAUSES
The prostate gland is located beneath your bladder. The tube that transports urine from the bladder out of your penis (urethra) passes through the center of the prostate. When the prostate enlarges, it begins to block urine flow.
Most men have continued prostate growth throughout life. In many men, this continued growth enlarges the prostate enough to cause urinary symptoms or to significantly block urine flow.
It isn’t entirely clear what causes the prostate to enlarge. However, it might be due to changes in the balance of sex hormones as men grow older.
BENIGN PROSTATIC HYPERTROPHY PATHOPHYSIOLOGY
Prostatic enlargement depends on the potent androgen dihydrotestosterone (DHT). In the prostate gland, type II 5-alpha-reductase metabolizes circulating testosterone into DHT, which works locally, not systemically. DHT binds to androgen receptors in the cell nuclei, potentially resulting in BPH.
In vitro studies have shown that large numbers of alpha-1-adrenergic receptors are located in the smooth muscle of the stroma and capsule of the prostate, as well as in the bladder neck. Stimulation of these receptors causes an increase in smooth-muscle tone, which can worsen LUTS. Conversely, blockade of these receptors (see Treatment and Management) can reversibly relax these muscles, with subsequent relief of LUTS.
Microscopically, BPH is characterized as a hyperplastic process. The hyperplasia results in enlargement of the prostate that may restrict the flow of urine from the bladder, resulting in clinical manifestations of BPH. The prostate enlarges with age in a hormonally dependent manner. Notably, castrated males (ie, who are unable to make testosterone) do not develop BPH.
The traditional theory behind BPH is that, as the prostate enlarges, the surrounding capsule prevents it from radially expanding, potentially resulting in urethral compression. However, obstruction-induced bladder dysfunction contributes significantly to LUTS. The bladder wall becomes thickened, trabeculated, and irritable when it is forced to hypertrophy and increase its own contractile force.
This increased sensitivity (detrusor overactivity [DO]), even with small volumes of urine in the bladder, is believed to contribute to urinary frequency and LUTS. The bladder may gradually weaken and lose the ability to empty completely, leading to increased residual urine volume and, possibly, acute or chronic urinary retention.
In the bladder, obstruction leads to smooth-muscle-cell hypertrophy. Biopsy specimens of trabeculated bladders demonstrate evidence of scarce smooth-muscle fibers with an increase in collagen. The collagen fibers limit compliance, leading to higher bladder pressures upon filling. In addition, their presence limits shortening of adjacent smooth muscle cells, leading to impaired emptying and the development of residual urine.
The main function of the prostate gland is to secrete an alkaline fluid that comprises approximately 70% of the seminal volume. The secretions produce lubrication and nutrition for the sperm. The alkaline fluid in the ejaculate results in liquefaction of the seminal plug and helps to neutralize the acidic vaginal environment.
The prostatic urethra is a conduit for semen and prevents retrograde ejaculation (ie, ejaculation resulting in semen being forced backwards into the bladder) by closing off the bladder neck during sexual climax. Ejaculation involves a coordinated contraction of many different components, including the smooth muscles of the seminal vesicles, vasa deferentia, ejaculatory ducts, and the ischiocavernosus and bulbocavernosus muscles.
BENIGN PROSTATIC HYPERTROPHY SYMPTOMS
The severity of symptoms in people who have prostate gland enlargement varies, but symptoms tend to gradually worsen over time. Common signs and symptoms of BPH include:
- Frequent or urgent need to urinate
- Increased frequency of urination at night (nocturia)
- Difficulty starting urination
- Weak urine stream or a stream that stops and starts
- Dribbling at the end of urination
- Straining while urinating
- Inability to completely empty the bladder
Less common signs and symptoms include:
- Urinary tract infection
- Inability to urinate
- Blood in the urine
The size of your prostate doesn’t necessarily mean your symptoms will be worse. Some men with only slightly enlarged prostates can have significant symptoms, while other men with very enlarged prostates can have only minor urinary symptoms.
In some men, symptoms eventually stabilize and might even improve over time.
Other possible causes of urinary symptoms
Conditions that can lead to symptoms similar to those caused by enlarged prostate include:
- Urinary tract infection
- Inflammation of the prostate (prostatitis)
- Narrowing of the urethra (urethral stricture)
- Scarring in the bladder neck as a result of previous surgery
- Bladder or kidney stones
- Problems with nerves that control the bladder
- Cancer of the prostate or bladder
BENIGN PROSTATIC HYPERTROPHY DIAGNOSIS
Your doctor will first want to make sure that your urination problem is caused by benign prostatic hyperplasia (BPH) and not by something else. This can usually be determined from your medical history, aphysical exam that focuses on the urinary tract, a urinalysis, and ablood test. A neurological exam should also be done to determine whether your symptoms are related to a problem with the nerves to the bladder. A questionnaire such as the American Urological Association (AUA) symptom index may be used to evaluate how bothersome your symptoms are. It is not used to diagnose BPH.
Tests that are often done
- A digital rectal exam checks the size and firmness of the prostate. But the size of the prostate does not always determine the severity of the symptoms.
- A urinalysis and urine culture check for a urinary tract infection that might be the cause of the symptoms.
- A prostate-specific antigen (PSA) test helps check for prostate cancer, which can cause the same symptoms as BPH.
Tests that are used as needed
- If your symptoms are moderate to severe, additional tests, called urodynamic studies, may be done.
- A blood creatinine test checks how well your kidneys are working.
- Post-void residual urine test (PVR) measures the amount of urine left in the bladder after urination. This test is done using ultrasoundor a small tube (catheter) put into the bladder through the urethra.
- Pressure flow studies measure pressure in the bladder while urinating. They may help distinguish between urinary symptoms caused by obstruction, such as BPH, and those caused by a problem affecting the bladder muscles or nerves.
- Cystometrogram measures the bladder’s pressure, compliance, and capacity during urinary storage. This may include auroflowmetry test, which measures how fast the urine flows out of the bladder.
Tests that may be done
- The following tests may be done if you have complications of BPH or if there is a need to look for other causes of the symptoms.
- Ultrasound uses sound waves to check the size and structure of thekidneys, bladder, and prostate. A small device called a transducer is inserted into the rectum (transrectal ultrasound) to evaluate the prostate.
- Cystoscopy allows the doctor to look inside the urethra and bladder. This may allow the doctor to find out how much an enlarged prostate is blocking the urethra.
- Intravenous pyelogram (IVP) uses X-rays to show the function of the kidneys and the flow of urine from the kidneys to the bladder.
- Spiral (helical) computed tomography (CT) scan uses X-rays to make detailed pictures of structures inside the body. These scanners can check for an enlarged prostate gland, blockage, and urine flow from the kidneys.
BENIGN PROSTATIC HYPERTROPHY TREATMENT
A wide variety of treatments are available for enlarged prostate, including medication, minimally invasive therapies and surgery. The best treatment choice for you depends on several factors, including:
- The size of your prostate
- Your age
- Your overall health
- The amount of discomfort or bother you are experiencing
If your symptoms are tolerable, you might decide to postpone treatment and simply monitor your symptoms. For some men, symptoms can ease without treatment.
Medication is the most common treatment for mild to moderate symptoms of prostate enlargement. The options include:
- Alpha blockers. These medications relax bladder neck muscles and muscle fibers in the prostate, making urination easier. Alpha blockers — which include alfuzosin (Uroxatral), doxazosin (Cardura), tamsulosin (Flomax), and silodosin (Rapaflo) — usually work quickly in men with relatively small prostates. Side effects might include dizziness and a harmless condition in which semen goes back into the bladder instead of out the tip of the penis (retrograde ejaculation).
- 5-alpha reductase inhibitors. These medications shrink your prostate by preventing hormonal changes that cause prostate growth. These medications — which include finasteride (Proscar) and dutasteride (Avodart) — might take up to six months to be effective. Side effects include retrograde ejaculation.
- Combination drug therapy. Your doctor might recommend taking an alpha blocker and a 5-alpha reductase inhibitor at the same time if either medication alone isn’t effective.
- Tadalafil (Cialis). Studies suggest this medication, which is often used to treat erectile dysfunction, can also treat prostate enlargement. However, this medication is not routinely used for BPH and is generally prescribed only to men who also experience erectile dysfunction.
Minimally invasive or surgical therapy
Minimally invasive or surgical therapy might be recommended if:
- Your symptoms are moderate to severe
- Medication hasn’t relieved your symptoms
- You have a urinary tract obstruction, bladder stones, blood in your urine or kidney problems
- You prefer definitive treatment
Minimally invasive or surgical therapy might not be an option if you have:
- An untreated urinary tract infection
- Urethral stricture disease
- A history of prostate radiation therapy or urinary tract surgery
- A neurological disorder, such as Parkinson’s disease or multiple sclerosis
Any type of prostate procedure can cause side effects. Depending on the procedure you choose, complications might include:
- Semen flowing backward into the bladder instead of out through the penis during ejaculation
- Temporary difficulty with urination
- Urinary tract infection
- Erectile dysfunction
- Very rarely, loss of bladder control (incontinence)
There are several types of minimally invasive or surgical therapy.
Transurethral resection of the prostate (TURP)
A lighted scope is inserted into your urethra, and the surgeon removes all but the outer part of the prostate. TURP generally relieves symptoms quickly, and most men have a stronger urine flow soon after the procedure. After TURP you might temporarily need a catheter to drain your bladder, and you’ll be able to do only light activity until you’ve healed.
Transurethral incision of the prostate (TUIP)
A lighted scope is inserted into your urethra, and the surgeon makes one or two small cuts in the prostate gland — making it easier for urine to pass through the urethra. This surgery might be an option if you have a small or moderately enlarged prostate gland, especially if you have health problems that make other surgeries too risky.
Transurethral microwave thermotherapy (TUMT)
Your doctor inserts a special electrode through your urethra into your prostate area. Microwave energy from the electrode destroys the inner portion of the enlarged prostate gland, shrinking it and easing urine flow. This surgery is generally used only on small prostates in special circumstances because re-treatment might be necessary.
Transurethral needle ablation (TUNA)
In this outpatient procedure, a scope is passed into your urethra, allowing your doctor to place needles into your prostate gland. Radio waves pass through the needles, heating and destroying excess prostate tissue that’s blocking urine flow.
This procedure might be a good choice if you bleed easily or have certain other health problems. However, like TUMT, TUNA might only partially relieve your symptoms and it might take some time before you notice results.
A high-energy laser destroys or removes overgrown prostate tissue. Laser therapy generally relieves symptoms right away and has a lower risk of side effects than does nonlaser surgery. Laser therapy might be used in men who shouldn’t have other prostate procedures because they take blood-thinning medications.
The options for laser therapy include:
- Ablative procedures. These procedures vaporize obstructive prostate tissue to increase urine flow. Examples include photoselective vaporization of the prostate (PVP) and holmium laser ablation of the prostate (HoLAP). Ablative procedures can cause irritating urinary symptoms after surgery, so in rare situations another resection procedure might be needed at some point.
- Enucleative procedures. Enucleative procedures, such as holmium laser enucleation of the prostate (HoLEP), generally remove all the prostate tissue blocking urine flow and prevent regrowth of tissue. The removed tissue can be examined for prostate cancer and other conditions. These procedures are similar to open prostatectomy.
In this experimental transurethral procedure, special tags are used to compress the sides of the prostate to increase the flow of urine. Long-term data on the effectiveness of this procedure aren’t available.
In this experimental procedure, the blood supply to or from the prostate is selectively blocked, causing the prostate to decrease in size. Long-term data on the effectiveness of this procedure aren’t available.
Open or robot-assisted prostatectomy
The surgeon makes an incision in your lower abdomen to reach the prostate and remove tissue. Open prostatectomy is generally done if you have a very large prostate, bladder damage or other complicating factors. The surgery usually requires a short hospital stay and is associated with a higher risk of needing a blood transfusion.
Your follow-up care will depend on the specific technique used to treat your enlarged prostate.
Your doctor might recommend limiting heavy lifting and excessive exercise for seven days if you have laser ablation, transurethral needle ablation or transurethral microwave therapy. If you have open or robot-assisted prostatectomy, you might need to restrict activity for six weeks.
Whichever procedure you have, your doctor likely will suggest that you drink plenty of fluids afterward.