Men's Health, Age related illnesses | July 12, 2014 | Author: The Super Pharmacist
The prostate is a small gland that is part of the male reproductive system. In younger men, it is about the size of a walnut. The prostate is positioned below the bladder, in front of the rectum, and surrounds part of the urethra (the tube that carries urine from the bladder). Its primary role is to produce the fluid portion of semen (the substance that protects and transports sperm as the sperm move through the urethra during sexual climax). An enlarged prostate means the gland has grown larger.
Nonmalignant prostate enlargement happens to almost all men as they get older. An enlarged prostate is often called benign prostatic hyperplasia (BPH) or benign prostatic hypertrophy. When the prostate gland enlarges, it may constrict the urethra and interfere with urination. Although the prostate continues to grow during a man's life, the enlargement does not usually cause problems until later in life. Benign prostatic hypertrophy 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 experience symptoms of benign prostatic hypertrophy.
Testosterone, the major androgen sex hormone in men, plays a key role in the development of male reproductive tissues such as the testis and prostate. Testosterone levels begin to decline in the late third or early fourth decade and diminish at a constant rate thereafter. Approximately five percent of testosterone is normally converted to the more potent androgen, dihydrotestosterone (DHT). DHT has an essential role in the formation of the male external genitalia in the fetus, and acts as the primary androgen in the prostate during adulthood.
Despite a drop in the blood testosterone level, older men continue to produce and accumulate substantial levels of DHT in the prostate. DHT stimulates cell growth in the tissue that lines the prostate gland and is the major cause of the rapid prostate enlargement that occurs between puberty and young adulthood. DHT is the primary suspected cause of prostate enlargement in later adulthood. In addition to testosterone, men also normally produce small amounts of oestrogen, a female hormone. As men age, the amount of active testosterone in the blood decreases, leaving a higher proportion of oestrogen. Studies done on animals have suggested that benign prostatic hypertrophy may occur because the higher amounts of oestrogen within the prostate gland increases the activity of substances that promote cell growth.
The enlarged prostate gland may compress the urethra which courses through the center of the prostate. This can impede the outflow of urine from the bladder. It can cause urine to back up into the bladder (urinary retention) leading to incomplete emptying of the bladder. The symptoms of benign prostatic hypertrophy vary, but the most common involves changes or problems with urination. The symptom complex associated with benign prostatic hypertrophy is often referred to as "prostatism" and includes:
Severe benign prostatic hypertrophy can cause serious problems over time. Urine retention and strain on the bladder can lead to urinary tract infections, bladder or kidney damage, bladder/kidney stones, and incontinence.
Pharmacological treatment of benign prostatic hypertrophy is usually reserved for men who have significant lower urinary tract symptoms. Drug treatment is directed at relaxing prostatic smooth muscle, reducing prostate volume, or a combination of these effects. The most commonly used drugs are:
Alpha blockers. Alpha blockers relax the smooth muscles of the prostate, and the bladder neck, which helps to relieve urinary obstruction caused by an enlarged prostate in BPH.
Side effects can include headaches, fatigue, problems ejaculating, or lightheadedness.
Commonly used alpha blockers in BPH include: tamsulosin (Flomaxtra), alfuzosin, and older medications such as terazosin, slidosin and doxazosin.
These drugs generally will lead to improvement in symptoms within several weeks but have no effect on prostate size.6
5-Alpha reductase inhibitors. 5-Alpha reductase inhibitors block the conversion of testosterone to dihydrotestosterone (DHT). The prostate enlargement in benign prostatic hypertrophy is directly dependent on DHT, so these drugs lead to an approximate 25% reduction in prostate size over six to 12 months. For this reason, improvement in urinary symptoms most commonly takes this long to occur. Examples of 5-alpha reductase inhibitors include: finasteride (Proscar) and dutasteride (Avodart). Side effects of finasteride may include decreased libido, erectile and/or ejaculatory dysfunction.
Phosphodiesterase (PDE) -5 inhibitors. These agents mediate smooth muscle relaxation in the lower urinary tract, thus improving the symptoms of BPH. Tadalafil (Cialis) has been approved by the FDA for the treatment of BPH signs and symptoms.
The Medical Therapy of Prostatic Symptoms (MTOPS) Trial, supported by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), recently found that using finasteride and doxazosin together is more effective than using either drug alone to relieve symptoms and prevent benign prostatic hypertrophy progression. The two-drug regimen reduced the risk of benign prostatic hypertrophy progression by 67 percent, compared with 39 percent for doxazosin alone and 34 percent for finasteride alone.
Because drug treatment is not effective in all cases, researchers in recent years have developed a number of procedures that relieve benign prostatic hypertrophy symptoms but are less invasive than conventional surgery.
Most minimally invasive therapies rely on heat to destroy prostatic tissue. This heat is delivered in a limited and controlled fashion, in the hope of avoiding the complications associated with transurethral resection of the prostate (TURP). They also allow for the use of milder forms of anesthesia, which translates into less anesthetic risk for the patient. Heat may be delivered in the form of laser energy, microwaves, radiofrequency energy, high-intensity ultrasound waves, and high-voltage electrical energy.
All of these procedures are performed by passing an instrument through the opening in the penis (meatus). Anesthesia is achieved using general anesthesia, spinal or epidural anesthesia, or local anesthesia and sedation. These procedures are performed in the urologist's office or at an outpatient surgery center. Patients normally return home the same day.
Transurethral incision of the prostate (TUIP). TUIP has been in use for many years and, for a long time was the only alternative to TURP. In this procedure, the surgeon makes small surgical cuts where the prostate meets the bladder. This makes the urethra wider. TUIP is suitable for patients with small prostates and for patients unlikely to tolerate TURP well because of other medical conditions. TUIP is associated with less bleeding and a lower incidence of retrograde ejaculation and impotence than TURP.7
Transurethral microwave thermotherapy (TUMT). TUMT delivers heat using microwave pulses to destroy prostatic tissue. The microwave antenna is inserted through the urethra. A cooling system protects the urinary tract during the procedure. TUMT has not been reported to lead to erectile dysfunction or incontinence.
Transurethral needle ablation (TUNA). The TUNA system delivers low-level radiofrequency energy through twin needles to burn away a well-defined region of the enlarged prostate. Shields protect the urethra from heat damage. No incontinence or impotence has been observed.
Transurethral electroevaporation of the prostate (TUVP). In this procedure, an instrument called a resectoscope is inserted through the penis into the urethra. An electrode moves across the surface of the prostate and transmits electrical current that vaporises prostate tissue. The vaporising effect penetrates below the surface area being treated so underlying blood vessels are coagulated and sealed.
Holmium laser enucleation of prostate (HoLEP). A resectoscope is inserted through the penis into the urethra. A visual lens and laser are passed through the hollow center of the instrument. The prostate tissue is vaporized using the holium: YAG laser. There is very little bleeding and recovery time is shortened significantly.
Photoselective vaporization of the prostate (PVP). This procedure uses a high-powered laser that vaporises the obstructing prostate tissue with minimal bleeding or side effects.
High-intensity focused ultrasound (HIFU). A special ultrasound probe is placed into the rectum near the prostate. Ultrasound waves heat the prostate to very high temperatures, causing destruction of the prostate tissue. High-intensity ultrasound is considered investigational at this time and should not be offered outside of clinical trials.
Prostatic stents. Mechanical approaches are used less commonly and are usually reserved for patients who cannot have a formal surgical procedure. Mechanical approaches do not involve the use of energy to treat the prostate. Prostatic stents are flexible devices that can expand when put in place to improve the flow of urine past the prostate. Complications associated with their use include encrustation, pain, incontinence, and overgrowth of tissue through the stent, possibly making their removal quite difficult.
Transurethral resection of the prostate (TURP).
For most of the 20th century, the premier treatment for symptomatic BPH was TURP.
To this day, it remains the criterion standard therapy for obstructive prostatic hypertrophy and is both the surgical treatment of choice and the standard of care when other methods fail. In this type of surgery, no external incision is needed.
Under general anesthesia, the surgeon reaches the prostate by inserting an instrument through the urethra.
In general, TURP surgery is reserved for patients with symptomatic benign prostatic hypertrophy who have acute, recurrent, or chronic urinary retention; in whom medical management and less-invasive prostatic surgical procedures failed; who have prostates of an unusual size or shape; who have renal insufficiency (kidney damage) due to prostatic obstruction; or who have the most severe symptoms of prostatism.
Risks of the TURP procedure include urinary incontinence with a documented incidence of less than five percent and patient-reported retrograde ejaculation in 66 to 75% of patients.
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