Urological Disorders

Impotence / Erectile Dysfunction

What is erectile dysfunction (ED)?

Impotence, or erectile dysfunction, is the inability to achieve or maintain an erection more than 20 percent of the time. Erectile dysfunction affects millions of men.

Although in the past it was commonly believed to be due to psychological problems, it is now known that 80 to 90 percent of impotence is caused by physical problems, usually related to the blood supply of the penis. Many advances have occurred in both diagnosis and treatment of erectile dysfunction.

What are the risk factors for erectile dysfunction?

According to the National Institutes of Health, erectile dysfunction is also a symptom in many disorders and diseases.

Direct risk factors for erectile dysfunction may include the following:

prostate problems
type 2 diabetes
hypogonadism in association with a number of endocrinologic conditions
hypertension (high blood pressure)
vascular disease and vascular surgery
high levels of blood cholesterol
low levels of HDL (high-density lipoprotein)
rugs
neurogenic disorders
Peyronie's disease (distortion or curvature of the penis)
priapism (inflammation of the penis)
depression
alcohol ingestion
lack of sexual knowledge
poor sexual techniques
inadequate interpersonal relationships
many chronic diseases, especially renal failure and dialysis
smoking, which accentuates the effects of other risk factors such as vascular disease or hypertension

Age appears to be a strong indirect risk factor in that it is associated with increased likelihood of direct risk factors, some of which are listed above.

It is estimated that nearly 5 percent of men become impotent by the age of 40, and 15 to 25 percent by the age of 65. Accurate risk factor identification and characterization are essential for prevention or treatment of erectile dysfunction.

What are the different types (and causes) of ED?

The following are some of the different types and possible causes of impotence:

premature ejaculation (PE)
Premature ejaculation is the inability to maintain an erection long enough for mutual satisfaction. Premature ejaculation is divided into primary and secondary forms:
- primary premature ejaculation
  Primary premature ejaculation is a learned behavior that begins when a male first become sexually active. Like any learned behaviors, it can be unlearned. This form of primary PE is psychogenic (as opposed to organic or physical) impotence. (Congenital venous leak is a subset of primary PE and is caused by a congenital venous leak in which the venous drainage system in the penis does not shut down properly.)

secondary premature ejaculation
Secondary premature ejaculation occurs when, after years of normal ejaculation, the duration of intercourse grows progressively shorter. Secondary PE is due to physical causes, usually involving the penile arteries, veins, or both.

performance anxiety
Performance anxiety is a form of psychogenic impotence - usually caused by stress or anxiety.

depression
Depression is another cause of psychogenic impotence. Some antidepressant medications cause erectile failure.
organic impotence
Organic impotence involves the penile arteries, veins, or both, and is the most common cause of impotence, especially in older men. When the problem is arterial, it is usually caused by arteriosclerosis, or hardening of the arteries, although trauma to the arteries may be the cause. The controllable risk factors for arteriosclerosis - being overweight, lack of exercise, high cholesterol, high blood pressure, and cigarette smoking can cause erectile failure often before progressing to affect the heart. Many experts believe that when veins are the cause, a venous leak or "cavernosal failure" is the most common vascular problem.

diabetes
Impotence is common in persons with diabetes. There are 5 million adult men in the US with diabetes, and it is estimated that half are impotent and the other half will become impotent in time. The process involves premature and unusually severe hardening of the arteries. Peripheral neuropathy, with involvement of the nerves controlling erections, is commonly seen in persons with diabetes.
neurologic causes
There are many neurological (nerve problems) causes of impotence. Diabetes, chronic alcoholism, multiple sclerosis, heavy metal poisoning, spinal cord and nerve injuries, and nerve damage from pelvic operations can cause erectile dysfunction.
drug- induced impotence
A great variety of prescription drugs, such as blood pressure medications, anti-anxiety and antidepressant medications, glaucoma eye drops, and cancer chemotherapy agents are just some of the many medications associated with impotence.
hormone- induced impotence
Hormonal abnormalities such as increased prolactin (a hormone produced by the anterior pituitary gland), steroid abuse by body-builders, too much or too little thyroid hormone, and hormones administered for prostate cancer may cause impotence. Rarely is low testosterone responsible for impotence.

How is ED diagnosed?

Diagnostic procedures for ED may include the following:

patient medical/sexual history - may reveal conditions or diseases that lead to impotence and helps distinguish among problems with erection, ejaculation, orgasm, or sexual desire.

physical examination - to look for evidence of systemic problems, such as the following:
- A problem in the nervous system may be involved if the penis does not respond as expected to certain touching.
- Secondary sex characteristics, such as hair pattern, can point to hormonal problems, which involves the endocrine system.
- Circulatory problems could be indicated by an aneurysm.
- Unusual characteristics of the penis itself could suggest the basis of the impotence.
laboratory tests - to help diagnose impotence include blood counts, urinalysis, lipid profile, and measurements of creatinine and liver enzymes. When low sexual desire is a symptom, measurement of testosterone in the blood can yield information about problems with the endocrine system.

psychosocial examination - to help reveal psychological factors. The sexual partner also may be interviewed to determine expectations and perceptions encountered during sexual intercourse.

Treatment for ED:
Specific treatment for erectile dysfunction will be determined by your physician based on:

your age, overall health, and medical history
extent of the disease
your tolerance for specific medications, procedures, or therapies
expectations for the course of the disease
your opinion or preference

Some of the treatments available for ED include the following:

sildenafil citrate (Viagra^TM)
Viagra^TM is a medication made by Pfizer Pharmaceuticals, and is the first approved non-surgical treatment for erectile dysfunction that does not have to be either injected or inserted directly into the penis to achieve and maintain erection. It was approved by the US Food and Drug Administration (FDA) for prescription sale at the end of March, 1998.

Viagra does not directly cause penile erection, but affects the response to sexual stimulation. The FDA recommends that men follow these general precautions before taking Viagra:

If you are taking medications that contain nitrates, such as nitroglycerin, you should not use Viagra. The two taken together can lower blood pressure too much.
Viagra should not be used by women or children.
Have a complete medical history and physical examination to determine your cause of erectile dysfunction.
Men with medical conditions that may cause a sustained erection such as sickle cell anemia, leukemia or multiple myeloma, or a man who has an abnormally shaped penis may not be able to take Viagra.
Tell your physician about all the medications you are taking - including over-the-counter ones - because there are medications known to interact with Viagra.
Viagra's use in combination with other ED treatments has not been studied, therefore, its use in combination with other treatments is not recommended.

hormone replacement therapy

Testosterone replacement therapy may improve energy, mood, and bone density, increase muscle mass and weight, and heighten sexual interest in older men who may have deficient levels of testosterone. Testosterone supplementation is not recommended for men who have normal testosterone levels for their age group due to the risk of prostate enlargement and other side effects. Testosterone replacement therapy is available in an oral form and as a skin patch.

penile implants

There are three types of implants used to treat ED, including the following:

hydraulic pump - a pump and two cylinders are placed within the erection chambers of the penis which causes an erection by releasing a saline solution; it can also remove the solution to deflate the penis.
prosthesis - two semi-rigid but bendable rods are placed within the erection chambers of the penis which allows manipulation into an erect or non-erect position.
interlocking soft plastic blocks - these are placed within the erection chambers of the penis and can be inflated or deflated using a cable that passes through them.

Infection is the most common cause of penile implant failure and is treatable with antibiotics. In some cases, the infected implant must be replaced by a new implant. Implants are usually not considered until other methods of treatment have been tried.

Coping with ED:

Erectile dysfunction can cause strain on a couple. Many times, men will avoid sexual situations due to their emotional pain associated with ED, causing their partner to feel rejected or inadequate. It is important to communicate openly with your partner. Some couples consider seeking treatment for ED together, while other men prefer to seek treatment without their partner's knowledge. A lack of communication is the primary barrier for seeking treatment, and can prolong the suffering. The loss of erectile capacity can have a profound effect on a man. The good news is that ED can usually be treated safely and effectively.

This page was last updated on: February 28, 2008.

For more information, call the University Physicians Consultation and Referral Service at 1-800-492-5538 (patients) or 1-800-373-4111 (physicians).