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Medical Specializations

Urology => Impotence


Impotence or Erectile Dysfunction, in medicine, condition in which a man is unable to attain an erect penis that is rigid enough for sexual penetration or sexual satisfaction. Impotence should not be confused with premature ejaculation, loss of libido, or absence of orgasm; in all of these cases, satisfactory erection may be obtained.

Impotence is a common problem; in the United States between 10 and 20 million men suffer from severe erectile dysfunction. The incidence of this problem increases with age. Less than 1 percent of the male population under 30 years of age is affected, 3 percent under 45 years, 7 percent between 45 and 55 years, 25 percent at age 65, and up to 75 percent in men 80 years old. Impotence appears to be on the rise, but this may be due to increasing life span.

Impotence is classified as either primary or secondary. Primary impotence is expressed early in adolescence as a fundamental inability to achieve erection; secondary impotence is more common and consists of an onset of erectile inability during adulthood, after a period of normal erectile ability.

Normally, when a man becomes sexually aroused, his penis increases in size, becoming erect and rigid, enabling sexual penetration. An average penis is between 7 cm (about 3 in) and 10 cm (about 4 in) long; when it is erect it increases in length to between 13 cm (about 5 in) and 18 cm (about 7 in). An erection occurs when the penis fills with blood. An erect penis contains six or seven times the blood volume of a flaccid penis. During erection, the rate of blood flow into the penis is greater than the rate at which the blood drains out, which leads to an accumulation of blood within the corpus cavernosum (cavernous spaces) of the organ. The process of erection is controlled by the autonomic nervous system.

There are various causes of impotence. In primary anatomic impotence the genitals themselves may be faulty. In secondary impotence, functional causes such as psychological problems and side effects of drugs taken for other disorders account for the greatest number of cases.

The most common psychological factors contributing to impotence are stress in a man's life or difficulties in his sexual relationships. For example, if a man has suddenly lost his job, his feeling of failure may lead to temporary impotence. It is possible to tell if the cause of a man's impotence is solely psychological; if he still experiences normal erections during rapid eye movement (REM) sleep, there is unlikely to be any physical reason for his impotence when conscious. However, in some cases a physical condition that is not severe enough to produce impotence on its own may make a man more likely to develop impotence if minor psychological factors are also present.
Many drugs can contribute to impotence. Diuretics, tricyclic antidepressants, H2 blockers, beta-blockers, and hormones are among the most common; once the drug treatment is halted, normal erections typically resume (unless psychological problems have developed in the meantime).

Other causes of impotence have to do with physical conditions, disease, or trauma. Among these, diabetes mellitus accounts for 40 percent of the cases in the United States; vascular diseases, 30 percent; surgery on the pelvis or penis, 13 percent; spinal cord injury, 8 percent; endocrine (glandular) problems, 6 percent, and multiple sclerosis, 3 percent.

Treatments for impotence were described in the literature of the Ancient Egyptians, Greeks, and Romans. Modern treatment of impotence takes into account both the physical and psychological causes of the condition. Many impotent men have been affected originally by a purely physical problem, but by the time they seek treatment, their condition is complicated by psychological factors.

There are several types of physical treatment for impotence. Since the early 1980s, it has been possible for affected men to inject a drug in the corpus cavernosum of their penis (intracorporeal pharmotherapy). This affects the smooth muscle tone in the blood vessels, producing an erection that lasts for about an hour. If this treatment is used over a long period of time, however, problems with scarring may occur. The most common drug used in this manner is Prostaglandin E1. Less commonly used drugs are papaverine and phentolamine or combinations of these three drugs.

A prosthesis may be inserted into the penis under anesthetic. This may be a semirigid rod that makes the penis permanently erect. Some newer devices enable the patient to control an inflatable rod. Technology in this area is still developing and a wide range of plastic or silicone prostheses are available. The implant may function for several years. The most common complication is infection due to the implant surgery.
There are several gadgets on the market, known as vacuum constriction devices, that draw blood into the corpus cavernosum, causing the penis to become erect. An elastic ring is placed around the penis in order to maintain the erection.

A number of drugs taken orally or applied topically are known to affect erectile ability, including those affecting nerve transmission, muscle relaxation, and hormones. Some traditional drugs known to have aphrodisiac properties are among these. They are seldom prescribed by physicians because their functions, side effects, and interactions with other drugs are not well known. In 1998, the Food and Drug Administration approved the use of sildenafil, a drug marketed under the brand name Viagra, for use in treating impotence. Viagra, which works by slowing the rate of blood flow out of the penis, is taken orally in tablet form. A number of other drugs to treat impotence are under investigation.

Treatments based on various forms of psychotherapy are also widely used. In 1970 the team of William Masters and Virginia Johnson proposed a program of behavioral therapy for an affected man and his partner. This method has been widely accepted and involves abstinence from intercourse for several weeks while the couple develops other aspects of their physical relationship. Only when the man is able to have an erection and sustain it on several occasions should the couple attempt intercourse.



Autonomic Nervous System
Diabetes Mellitus
Multiple Sclerosis
Spinal Cord