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 15 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, such as Cialis, the brand name for tadalafil, and Levitra, the brand name for vardenafil, have since been approved. Cialis is effective for longer periods, up to 36 hours, compared with Viagra and Levitra, which are effective for up to 4 hours.

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.

Avian Flu

Avian Flu, also known as bird flu, an infectious disease of wild and domestic birds, caused by a range of viruses known as Type A influenza viruses. Variants of avian influenza viruses have also infected humans and a number of other mammals.

Avian influenza viruses exist in wild populations of seabirds, shorebirds, and other wildfowl, but do not usually cause illness in wild bird species. When wild birds contaminate ponds and fields with fecal droppings containing the virus, however, domesticated birds such as chickens, turkeys, and ducks can be infected. For these species, avian influenza is often fatal, afflicting the respiratory system and nervous system, and opening the way for dangerous bacterial infections. With their nasal and fecal secretions, sick individuals can rapidly spread illness to other poultry in the close confines of a farm enclosure or live animal market.

Avian influenza was not known to directly infect humans until 1997, when an outbreak in Hong Kong, China, caused by infected poultry, sickened 18 people, killing 6 of them. Death was caused by pneumonia or other respiratory ailments, kidney failure, or related complications. Symptoms of avian flu resemble those of other influenzas: fever, cough, sore throat, and muscle aches. Although humans have a degree of immunity to the influenza subtypes that circulate during the winter flu season, the human immune system is unaccustomed to recognizing and fighting off avian influenza. This makes the avian viral strains all the more dangerous. After the 1997 Hong Kong episode, other outbreaks of avian influenza followed.

Further confirmation that avian influenza can directly infect humans came in 2005 when scientists succeeded in reconstructing the infamous 1918 influenza virus, known as the Spanish flu, that killed from 20 million to 50 million people worldwide in the worst-known influenza pandemic. Two teams of United States government and university scientists succeeded in assembling the entire genetic code of the 1918 virus after discovering viral samples in the tissues of three victims of the disease, including a woman buried in Alaska’s permafrost whose body remained frozen. The scientists injected the reconstructed virus into fertilized bird eggs. The eggs died, confirming that the virus had an avian rather than human origin because a human influenza virus will not kill bird eggs.

Scientists identify the various strains of avian flu and other varieties of Type A influenza by categorizing them according to the differences in two key proteins found on the surface of the virus. The two proteins are Hemagglutinin (H) and Neuraminidase (N). There are 15 major subtypes of H and 9 major subtypes of N. The virus that caused the 1997 Hong Kong outbreak was designated H5N1 because the key proteins on the surface of the virus were subtype H5 and subtype N1. Tests determined that strains related to H5N1 were behind the deadly Asian outbreak that began in 2003. Some poultry farms in Europe and the eastern United States, meanwhile, suffered outbreaks in 2003 and 2004 of subtypes of H7, an avian strain that is currently believed to be less dangerous to humans.

Avian influenza appears to spread from birds to humans through direct, close contact with sick birds or with fecal-contaminated surfaces. As yet there is no confirmed evidence that current avian influenza viruses spread from person to person. Influenza viruses, however, mutate (change) easily. Scientists and public health experts fear that an avian flu strain might strike a person who is already infected with a human variant of influenza. The two variants could swap, or combine, their viral components in the infected person before spreading to other people. This combination of virus components could even take place in a susceptible mammal, such as a pig.

The result could be a novel virus strain completely unknown to the human immune system. It could be especially virulent and cause death in a high percentage of infected individuals, passing easily from person to person. Such a virus could touch off a global epidemic, or pandemic, of influenza that could kill millions of people. The grim benchmark for such a catastrophe is the “Spanish flu” outbreak of 1918.

Currently, the most effective means of fighting avian influenza is the destruction of infected birds or those at risk of infection, often millions at a time when outbreaks occur. In August 2005 the U.S. National Institutes of Health reported that the first trials of an avian flu vaccine were effective in humans. However, public health officials expressed concern that the vaccine did not exist in sufficient amounts to respond to a pandemic. Drugs, such as Tamiflu, can be used to treat avian flu, but some studies suggest that Tamiflu may not be fully effective against the H5N1 virus. Public health officials say there is no danger to the public from eating poultry or eggs as long as they are well cooked.
© 2008-2009 Pshycopymedia All rights reserved. Autism Avian Flu Health Insurance Impotence Type Stomach Cancer Tumor Suppressor GenesInsurance Costs and Quality of Health

Pshycopymedia by: skebber