Erectile dysfunction (ED) is the inability to get or keep an erection firm enough for sexual intercourse. ED can be a total inability to achieve an erection, an inconsistent ability to do so, or a tendency to sustain only brief erections.

ED is sometimes called impotence, but that word is being used less often so that it will not be confused with other, nonmedical meanings of the term.

The National Institutes of Health estimates that ED affects as many as 30 million men in the United States. Incidence increases with age: About 4 percent of men in their 50s and nearly 17 percent of men in their 60s experience a total inability to achieve an erection. The incidence jumps to 47 percent for men older than 75.2 But ED is not an inevitable part of aging. ED is treatable at any age.

The main symptom of erectile dysfunction is the regular or repeated inability to obtain or maintain an erection. 

This can be a total inability to achieve an erection, an inconsistent ability to do so, or a tendency to sustain only brief erections.

A number of factors are involved in an erectile dysfunction diagnosis.

Patient History

A person's medical and sexual histories help define the degree and nature of ED. The medical history can disclose diseases that lead to ED, and a simple recounting of sexual activity might identify problems with sexual desire, erection, ejaculation, or orgasm. Use of certain prescription or illegal drugs can suggest a chemical cause because drug effects are a frequent cause of ED.

Physical Examination

A physical examination can give clues to systemic problems. For example, if the penis is not sensitive to physical touch, a problem in the nervous system may be the cause. Abnormal secondary sex characteristics, such as unusual hair pattern or breast enlargement, can point to hormonal problems, which would mean the endocrine system is involved. The doctor might discover a circulatory problem by observing decreased pulses in the wrist or ankles. And unusual characteristics of the penis itself could suggest the source of the problem-for example, a penis that bends or curves when erect could be the result of Peyronie’s disease.

Laboratory Tests

Several laboratory tests can help diagnose ED. Tests for systemic diseases include blood counts, urinalysis, lipid profile, and measurements of creatinine and liver enzymes. Measuring the amount of available testosterone in the blood can yield information about problems with the endocrine system and may explain why a patient has decreased sexual desire.

Other Tests

Monitoring erections that occur during sleep-nocturnal erections-can help rule out certain psychological causes of ED. Healthy men have involuntary erections during sleep. If nocturnal erections do not occur, then ED is likely to have a physical rather than a psychological cause. Tests for nocturnal erections are not completely reliable, however. Scientists have not standardized such tests and have not determined when they should be conducted for best results.

Psychosocial Examination

A psychosocial examination, using an interview and a questionnaire, can reveal psychological factors. A man's sexual partner may also be interviewed to determine expectations and perceptions during sexual intercourse.

Most doctors suggest that treatments proceed from least to most invasive. Making a few healthy lifestyle changes may solve the problem. Quitting smoking, reducing alcohol consumption, losing excess weight, and increasing physical activity may help some men regain sexual function.

Cutting back on or replacing medicines that could be causing ED is considered next. For example, if a patient thinks a particular blood pressure medicine is causing problems with erection, he should tell his doctor and ask whether he can try a different class of blood pressure medicine.

Psychotherapy and behavior modifications in selected patients are considered next if indicated, followed by oral or locally injected drugs, vacuum devices, and surgically implanted devices. In rare cases, surgery involving veins or arteries may be considered.

ED usually has a physical cause, such as disease, injury, or side effects of drugs. Any disorder that causes injury to the nerves or impairs blood flow in the penis has the potential to cause ED.

Because an erection requires a precise sequence of events, ED can occur when any of the events is disrupted. The sequence includes nerve impulses in the brain, spinal column, and area around the penis, and response in muscles, fibrous tissues, veins, and arteries in and near the corpora cavernosa.

Damage to nerves, arteries, smooth muscles, and fibrous tissues, often as a result of disease, is the most common cause of ED. Diseases-such as diabetes, high blood pressure, nerve disease or nerve damage, multiple sclerosis, atherosclerosis, and heart disease-account for the majority of ED cases. Patients should be thoroughly evaluated for these conditions before they begin any form of treatment for ED.

Lifestyle choices that contribute to heart disease and vascular problems also raise the risk of ED. Smoking, drinking alcohol excessively, being overweight, and not exercising are possible causes of ED.

Surgery-especially radical prostate and bladder surgery for cancer-can also injure nerves and arteries near the penis, causing ED. Injury to the penis, spinal cord, prostate, bladder, and pelvis can lead to ED by harming nerves, smooth muscles, arteries, and the fibrous tissues of the corpora cavernosa.

In addition, ED can be a side effect of many common medicines such as blood pressure drugs, antihistamines, antidepressants, tranquilizers, appetite suppressants, and cimetidine, an ulcer drug.

Psychological factors such as stress, anxiety, guilt, depression, low self-esteem, and fear of sexual failure can also cause ED. Even when ED has a physical cause, psychological factors may make the condition worse.

Hormonal abnormalities, such as low levels of testosterone, are a less frequent cause of ED.

It is always important to speak with your doctor about ED. Your doctor will be able to discuss your treatment options and make recommendations on ways to control your ED. 

For more information, contact the following organizations.

  • American Urological Association
  • American Diabetes Association
  • American Association of Sexuality Educators, Counselors, and Therapists
     

Advances in suppositories, injectable medications, implants, and vacuum devices have expanded the options for men seeking treatment for ED. These advances have also helped increase the number of men seeking treatment. Gene therapy for ED is now being tested in several centers and may offer a long-lasting therapeutic approach for ED.

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) sponsors programs aimed at understanding and treating ED. The NIDDK's Division of Kidney, Urologic, and Hematologic Diseases supported the researchers who developed Viagra and continue to support basic research into the mechanisms of an erection and the diseases that impair normal function at the cellular and molecular levels, including diabetes and high blood pressure.

Participants in clinical trials can play a more active role in their own health care, gain access to new research treatments before they are widely available, and help others by contributing to medical research.

ED is usually associated with a medical condition such as diabetes, high blood pressure, nerve disease or nerve damage, multiple sclerosis, atherosclerosis, and heart disease. Patients should be thoroughly evaluated for these conditions before they begin any form of treatment for ED.

Lifestyle choices that contribute to heart disease and vascular problems also raise the risk of ED. Smoking, drinking alcohol excessively, being overweight, and not exercising are possible causes of ED.

Your doctor can offer several ED treatments. For many men, the answer is as simple as taking a pill. Other men have to try two or three options before they find a treatment that works for them. Don't give up if the first treatment doesn't work. Finding the right treatment can take time.

Review Date: 
May 16, 2012
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