What is erectile dysfunction (ED)?

Erectile dysfunction is defined as the persistent inability to achieve or maintain penile erection sufficient for satisfactory sexual performance. The Massachusetts Male Aging Study surveyed 1,709 men aged 40–70 years between 1987 and 1989 and found there was a total prevalence of erectile dysfunction of 52 percent. It was estimated that, in 1995, over 152 million men worldwide experienced ED. For 2025, the prevalence of ED is predicted to be approximately 322 million worldwide.

In the past, erectile dysfunction was commonly believed to be caused by psychological problems. It is now known that, for most men, erectile dysfunction 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 NIH, erectile dysfunction is also a symptom that accompanies 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)

• Chronic sleep disorders (obstructive sleep apnea, insomnia)

• Drugs

• Neurogenic disorders

• Peyronie's disease (distortion or curvature of the penis)

• Priapism (inflammation of the penis)

• Depression

• Alcohol use

• Lack of sexual knowledge

• Poor sexual techniques

• Inadequate interpersonal relationships

• Many chronic diseases, especially renal failure and dialysis

• Smoking, which exacerbates 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.

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 erectile dysfunction:

Organic Erectile Dysfunction

Organic ED involves abnormalities the penile arteries, veins, or both and is the most common cause of ED, 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 atrophy, a partial or complete wasting away of tissue, and fibrosis, the growth of excess tissue, of the smooth muscle tissue in the body of the penis (cavernous smooth muscle) triggers problems with being able to maintain a firm erection. Poor ability to maintain an erection is often an early symptom of erectile dysfunction. Although the condition is called venous leak, the real problem is not with the veins but malfunction of the smooth muscle that surrounds the veins. The end result is difficulty with maintain a firm erection (losing an erection too quickly) that is now believe to be an early manifestation of atherosclerosis and vascular disease.

• Diabetes. Erectile Dysfunction is common in people with diabetes. An estimated 10.9 million adult men in the U.S. have diabetes, and 35 to 50 percent of these men are impotent. The process involves premature and unusually severe hardening of the arteries. Peripheral neuropathy, with involvement of the nerves controlling erections, is commonly seen in people with diabetes.

• Depression. Depression is another cause of ED and is closely related to erectile dysfunction. Because there is a triad relationship between depression, ED and cardiovascular disease, men with depression should be fully evaluated for medical illness as well as psychological factors. Some antidepressant medications cause erectile failure.

• Neurologic causes. There are many neurological (nerve problems) causes of ED. 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 ED. A great variety of prescription drugs, such as blood pressure medications, antianxiety and antidepressant medications, glaucoma eye drops, and cancer chemotherapy agents are just some of the many medications associated with ED.

• Hormone-induced ED. Hormonal abnormalities, such as increased prolactin (a hormone produced by the anterior pituitary gland), steroid abuse by bodybuilders, too much or too little thyroid hormone, and hormones administered for prostate cancer may cause ED. Low testosterone can contribute to ED but is rarely the sole factor responsible for ED.

Premature Ejaculation (PE)

Premature ejaculation is a male sexual dysfunction characterized by:

• Ejaculation which always or nearly always occurs prior to or within about one minute of vaginal penetration.

• Inability to delay ejaculation on all or nearly all vaginal penetrations; and, negative personal consequences, such as distress, bother, frustration, and/or the avoidance of sexual intimacy.

Premature ejaculation is divided into lifelong and acquired categories:

• Lifelong premature ejaculation. With lifelong premature ejaculation, the patient has experienced premature ejaculation since first beginning coitus.

• Acquired premature ejaculation. With acquired premature ejaculation, the patient previously had successful coital relationships and only now has developed premature ejaculation.

• Performance anxiety. Performance anxiety is a form of psychogenic ED, usually caused by stress. 

How is ED diagnosed?

Diagnostic procedures for ED may include the following:

• Patient medical or sexual history. This may reveal conditions or diseases that lead to impotence and help 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 involve 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. These can include blood counts, urinalysis, lipid profile, and measurements of creatinine and liver enzymes. Measurement of testosterone in the blood is often done in men with ED, especially with a history of decreased libido or diabetes.

• Psychosocial examination. This is done to help reveal psychological factors that may be affecting performance. The sexual partner may also be interviewed to determine expectations and perceptions encountered during sexual intercourse.

What is the treatment for ED?

Specific treatment for erectile dysfunction will be determined by your doctor 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:

Medical treatments:

• Sildenafil. A prescription medication taken orally for the treatment of ED. This drug works best when taken on an empty stomach and many men can get an erection 30 to 60 minutes after taking the medication. Sexual stimulation is required for sildenafil citrate to have the best efficacy. 

• Vardenafil. This drug has a similar chemical structure to sildenafil citrate and works in a similar manner.

• Tadalafil. Studies have indicated that tadalafil citrate stays in the body longer than other medications in its class. Most men who take this medication find that an erection occurs within 4 to 5 hours after taking the pill (slow absorption) and the effects of the medication may last up to 24 to 36 hours.

• Avanafil

The FDA recommends that men follow general precautions before taking a medication for ED. Men who are taking medications that contain nitrates, such as nitroglycerin, should NOT use these medications. Taking nitrates with one of these medications can lower blood pressure too much. In addition, men who take tadalafil or vardenfil should use alpha blockers with care and only as instructed by their physician, as they could result in hypotension (abnormally low blood pressure). Experts recommend that men have a complete medical history and physical examination to determine the cause of ED. Men should tell their doctor about all the medications they are taking, including over-the-counter medications.

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 benefit from these medications. Also, men with liver diseases or a disease of the retina, such as macular degeneration or retinitis pigmentosa, may not be able to take these medications, or may need to take the lowest dosage.

These medical treatments should NOT be used by women or children. Elderly men are especially sensitive to the effects of these medical treatments, which may increase their chance of having side effects.

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 as a cream or gel, topical solution, skin patch, injectable form and pellet form placed under the skin.

Penile implants

Two types of implants are used to treat ED, including:

• Inflatable Penile Prosthesis (3-piece 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. 

• Semi-rigid Penile 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.

Infection is the most common cause of penile implant failure and occurs less that 2 percent of the time. Implants are usually not considered until other methods of treatment have been tried but they have a very high patient satisfaction rate and are an excellent treatment choice in the appropriate patient.

How do couples cope with ED?

Erectile dysfunction can cause strain on a couple. Many times, men will avoid sexual situations due to the 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.

Feeling embarrassed about sexual health problems may prevent many men from seeking the medical attention they need, which can delay diagnosis and treatment of more serious underlying conditions. Erectile Dysfunction itself is often related to an underlying problem, such as heart disease, diabetes, liver disease, or other medical conditions.

Since ED can be a forewarning symptom of progressive coronary disease, doctors should be more direct when questioning patients about their health. By asking patients more directly about their sexual function through conversation or a questionnaire during a checkup, doctors may be able to detect more serious health conditions sooner.

#TomorrowsDiscoveries: Testosterone Therapy –Adrian Dobs, M.D., M.P.H.

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Dr. Adrian Dobs and her team are interested in finding out whether men could benefit from testosterone replacement therapy as they age.