Erectile Dysfunction is sometimes called “impotence”. It is the repeated inability to get or keep an erection firm enough for sexual intercourse. The word “impotence” may also be used to describe other problems that interfere with sexual intercourse and reproduction, such as lack of sexual desire and problems with ejaculation or orgasm. Using the term erectile dysfunction makes it clear that those other problems are not involved.
Erectile dysfunction, or ED, can be a total inability to achieve erection, an inconsistent ability to do so, or a tendency to sustain only brief erections. These variations make defining ED and estimating its incidence difficult. Estimates range from about 15 million to 30 million, depending on the definition used. According to the National Ambulatory Medical Care Survey (NAMCS), for every 1,000 men in America there were 7.7 office visits for ED in 1985. By 1999, that rate had increased to 22.3. The increase happened gradually, perhaps as a result of increased availability of treatment options. Perhaps the most widely publicized advance was the introduction of Viagra (sildenafil citrate) in March 1998. NAMCS data show an estimated 2.6 million of Viagra during physician office visits during 1999.
Although ED is not an inevitable part of aging, the incidence does increase with age. Between 15 and 25 percent of men experience ED by the age of 65. In older men ED usually has a physical cause such as disease, injury, or the side effects of medications.
How Does an Erection Occur?
The penis contains two chambers called the corpora cavernosa, which run the length of the organ. A spongy tissue fills the chambers. The corpora cavernosa are surrounded by a membrane called teh tunica albuginea. The spongy tissue contains smooth muscles, fibrous tissues, spaces, veins, and arteries. The urethra, which is the channel for urine and ejaculate, runs along the underside of the corpora cavernosa. Erection begins with sensory or mental stimulation, or both. Impulses from the brain and local nerves cause the muscles of the corpora cavernosa to relax, allowing blood to flow in and fill the spaces. The blood creates pressure in the corpora cavernosa, making the penis expand. The tunica albuginea helps trap the blood in the corpora cavernosa and helps sustain the erection. When muscles in the penis contract to stop the inflow of blood and open outflow chanels, erection is reversed.
What Causes ED?
Since an erection requires a precise sequence of events, ED can occur when any of the events is dusrupted. The sequence includes nerve impulses in the brain, spinal column, and area around the penis, and response in muscles, firous tissues, veins, and arteries in and near the corpora cavernosa.
The most common cause of ED (about 70%) is damage to the nerves, arteries, smooth muscles, and fibrous tissues, often from diseases such as diabetes, kidney disease, chronic alcoholism, vascular disease, and neurologic disease. Between 35 and 50 percent of men with diabetes experience erectile dysfunction.
Surgery, especially radical prostate surgery for cancer, can also cause ED by damaging the nerves, blood supply, and tissues required for erection. Injuries are another cause of ED when they damage these structures.
Many common medications such as blood pressure drugs, antihistamines, antidepressants, ranquilizers, appetite suppressants, and cimetidine (Tagamet) can produce erectile dysfunction as a side effect. Experts believe that only about 10 – 20 percent of ED cases are the result of purely psychological factors such as stress, anxiety, guilt, depression, and low self esteem.
Diagnosis and Treatment
Since ED can be caused by or associated with many diseases, drugs, or psychological problems, it is essential that a thorough history and physical examination be performed. This should include appropriate laboratory tests and a review of all current prescription (and illegal) drugs. Most physicians suggest that treatments proceed from the least invasive to the more invasive. Adjusting medications or substituting drugs with fewer sexual side effects may be considered first. Other treatments may include oral or injectable medications, vacuum devices, or surgically implanted devices.
Drug Therapy includes oral medication such as Viagra, Levitra, or Cialis as well as smooth muscle relaxants that are injected into the penis such as alprostadil (Caverject) and papaverine. A system for inserting a pellet of alprostadil into the urethra is marketed as Muse. Men who use nitrate based heart medication such as nitroglycerin must not use medication such as Viagra, since the combination may cause a fatal collapse in blood pressure. The injectable drugs may produce side effects ranging from soreness and aching in the penis and testes to erections lasting greater that 4 hours which can cause damage to the penis. Therefore, all of these medications must be used under the supervision of a physician knowledgeable in their use.
Vacuum devices produce erections by creating a partial vacuum which draws blood into the penis. A constricting ring is then placed around the penis to prevent the blood from flowing back into the body. These devices are inexpensive and tolerated well by some men, however other men have significant pain and bruising which limits their use.
Surgery usually has one of three goals:
- To implant a device that can cause the penis to become erect
- To reconstruct arteries to increase blood flow to the penis
- To block off veins that allow blood to leak from penile tissues
Implanted devices, known as prostheses, can restore erection in many men with ED. Recent improvements have reduced the problems of infection and mechanical malfunction. Implants may be malleable consisting of a pair of rods which the user adjusts to the proper position or inflatable devices. The latter use a reservoir and pump system to allow the man to inflate or deflate the penis.