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Erectile Dysfunction

Erectile Dysfunction

Erectile dysfunction (ED), also known as impotence, is the inability to achieve or sustain an erection for satisfactory sexual activity. Erectile dysfunction is different from other conditions that interfere with male sexual intercourse, such as lack of sexual desire (decreased libido) and problems with ejaculation and orgasm (ejaculatory dysfunction). This article focuses on the evaluation and treatment of erectile dysfunction.

 

Erectile dysfunction (ED, impotence) varies in severity; some men have a total inability to achieve an erection, others have an inconsistent ability to achieve an erection, and still others can sustain only brief erections. The variations in severity of erectile dysfunction make estimating its frequency difficult. 

 

Many men also are reluctant to discuss erectile dysfunction with their doctors due to embarrassment, and thus the condition is underdiagnosed. Nevertheless, experts have estimated that erectile dysfunction affects 30 million men in the United States.

 

While erectile dysfunction can occur at any age, it is uncommon among young men and more common in the elderly. By age 45, most men have experienced erectile dysfunction at least some of the time. According to the Massachusetts Male Aging Study, complete impotence increases from 5% among men 40 years of age to 15% among men 70 years and older. 

 

Population studies conducted in the Netherlands found that some degree of erectile dysfunction occurred in 20% of men between ages 50-54, and in 50% of men between ages 70-78. In 1999, the National Ambulatory Medical Care Survey counted 1,520,000 doctor-office visits for erectile dysfunction. Other studies have noted that approximately 35% of men 40-70 years of age suffer from moderate to severe ED, and an additional 15% may have milder forms.

Symptoms

Erectile dysfunction is the inability to maintain an erection firm enough for sex, on an ongoing basis.

 

Symptoms related to erectile dysfunction may include:

 

  • Trouble getting an erection.
  • Trouble keeping an erection.
  • Reduced sexual desire.

Causes

The ability to achieve and sustain erections requires a healthy nervous system that conducts nerve impulses in the brain, spinal column, and penis, healthy arteries in and near the corpora cavernosa, healthy smooth muscles and fibrous tissues within the corpora cavernosa, adequate levels of nitric oxide in the penis.

 

Erectile dysfunction can occur if one or more of these requirements are not met.

 

The following are causes of erectile dysfunction:

 

Aging:

There are two reasons why older men are more likely to experience erectile dysfunction than younger men. First, older men are more likely to develop diseases (such as heart attacks, angina, cardiovascular disease, strokes, diabetes mellitus, and high blood pressure) that are associated with erectile dysfunction.

 

Second, the aging process alone can cause erectile dysfunction in some men, primarily by decreasing the compliance of the tissues in the corpora cavernosa, although it has been suggested, but not proven, that there is also decreased production of nitric oxide in the nerves that innervate the corporal smooth muscle within the penis.

 

Diabetes mellitus:

Erectile dysfunction tends to develop 10-15 years earlier in diabetic men than among nondiabetic men. In a population study of men with type I diabetes for more than 10 years, erectile dysfunction was reported by 55% of men 50-60 years of age.

 

The increased risk of erectile dysfunction among men with diabetes mellitus may be due to the earlier onset and greater severity of atherosclerosis that narrows the arteries and thereby reduces the delivery of blood to the penis. When insufficient blood is delivered to the penis, it is not possible to achieve an erection.

 

Diabetes mellitus also causes erectile dysfunction by damaging both sensory and autonomic nerves, a condition called diabetic neuropathy.

 

Smoking cigarettes, obesity, poor control of blood glucose levels, and having diabetes mellitus for a long time further increase the risk of erectile dysfunction in diabetes. In addition to atherosclerosis and/or neuropathy causing ED in diabetes, many men with diabetes also develop a myopathy (muscle disease) as their cause of ED in which the compliance of the muscles in the corpora cavernosa is decreased, and clinically this presents as an inability to maintain the erection.

 

Hypertension (high blood pressure):

People with essential hypertension or arteriosclerosis have an increased risk of developing erectile dysfunction. Essential hypertension is the most common form of hypertension; it is called essential hypertension because it is not caused by another disease (for example, by kidney disease).

 

It is not clearly known how essential hypertension causes erectile dysfunction; however, those with essential hypertension have been found to have low production of nitric oxide by the arteries of the body, including the arteries in the penis. High blood pressure also accelerates the progression of atherosclerosis, which in turn can contribute to erectile dysfunction. Scientists now suspect that the decreased levels of nitric oxide in patients with essential hypertension may contribute to erectile dysfunction.

 

Cardiovascular diseases:

The most common cause of cardiovascular diseases in the United States is atherosclerosis, the narrowing and hardening of arteries that reduces blood flow. Atherosclerosis typically affects arteries throughout the body and is aggravated by hypertension, high blood cholesterol levels, cigarette smoking, and diabetes mellitus. When coronary arteries (arteries that supply blood to the heart muscle) are narrowed by atherosclerosis, heart attacks and angina occur.

 

When cerebral arteries (arteries that supply blood to the brain) are narrowed by atherosclerosis, strokes occur. Similarly, when arteries to the penis and the pelvic organs are narrowed by atherosclerosis, insufficient blood is delivered to the penis to achieve an erection. There is a close correlation between the severity of atherosclerosis in the coronary arteries and erectile dysfunction.

 

For example, men with more severe coronary artery atherosclerosis also tend to have more erectile dysfunction than men with mild or no coronary artery atherosclerosis. Some doctors suggest that men with new onset erectile dysfunction should be evaluated for silent coronary artery diseases (advanced coronary artery atherosclerosis that has not yet caused angina or heart attacks).

 

Cigarette smoking:

Cigarette smoking aggravates atherosclerosis and thereby increases the risk for erectile dysfunction.

 

Nerve or spinal cord damage:  

Damage to the spinal cord and nerves in the pelvis can cause erectile dysfunction. Nerve damage can be due to disease, trauma, or surgical procedures. Examples include injury to the spinal cord from automobile accidents, injury to the pelvic nerves from prostate surgery for prostate cancer (prostatectomy), radiation to the prostate, surgery for benign prostatic enlargement, multiple sclerosis (a neurological disease with the potential to cause widespread damage to nerves), and long-term diabetes mellitus.

 

Substance abuse:  

Marijuana, heroin, cocaine, methamphetamines, crystal meth, and alcohol abuse contribute to erectile dysfunction. Alcoholism, in addition to causing nerve damage, can lead to atrophy (shrinking) of the testicles and lower testosterone levels.

 

Low testosterone levels:

Testosterone (the primary sex hormone in men) is not only necessary for sex drive (libido) but also is necessary to maintain nitric oxide levels in the penis. Therefore, men withhypogonadism (diminished function of the testes resulting in low testosterone production) can have low sex drive and erectile dysfunction.

 

Medications:

Many common medicines produce erectile dysfunction as a side effect. Medicines that can cause erectile dysfunction include many used to treat high blood pressure, antihistamines, antidepressants, tranquilizers, and appetite suppressants.

 

Examples of common medicines that can cause erectile dysfunction includepropranolol (Inderal) or other beta-blockers, hydrochlorothiazide, digoxin (Lanoxin), amitriptyline (Elavil), famotidine (Pepcid), cimetidine (Tagamet), metoclopramide (Reglan), indomethacin (Indocin), lithium (Eskalith, Lithobid), verapamil (Calan, Verelan, Isoptin), phenytoin (Dilantin), and gemfibrozil (Lopid).

 

Depression and anxiety:

Psychological factors may be responsible for erectile dysfunction. These factors include stress, anxiety, guilt, depression, widower syndrome, low self-esteem, posttraumatic stress disorder, and fear of sexual failure (performance anxiety). It is also worth noting that many medications used for treatment of depression and other psychiatric disorders may cause erectile dysfunction or ejaculatory problems.

Treatment

The following are treatments for erectile dysfunction:

 

  • Working with doctors to select medications that do not impair erectile function.
  • Making life style improvements (for example, quitting smoking and exercising more).
  • Taking drugs to treat ED such assildenafil (Viagra), vardenafil (Levitra) or tadalafil (Cialis).
  • Inserting medications into the urethra (intraurethral suppositories).
  • Injecting medications into the corpora cavernosae (intracavernosal injections).
  • Vacuum constrictive devices for the penis.
  • Penile prostheses.
  • Psychotherapy.
  • Adjusting medications.

 

Many common medications for treating hypertension, depression, and high blood lipids can contribute to erectile dysfunction (see above). Treatment of hypertension is an example. There are many different types (classes) of anti-hypertensive medications (medications that lower blood pressure); these include beta-blockers, calcium channel blockers, diuretics (medications that increase urine volume), angiotensin converting enzyme inhibitors (ACE inhibitors), and angiotensin receptor blockers (ARBs).

 

Anti-hypertensives may be used alone or in combination to control blood pressure. Different classes of anti-hypertensives have different effects on erectile function. Inderal (a beta blocker) and hydrochlorothiazide (a diuretic) are known to cause erectile dysfunction, while calcium channel blockers and ACE inhibitors do not seem to affect erectile function.

 

On the other hand, angiotensin receptor blockers (ARBs) such as losartan (Cozaar) and valsartan (Diovan) may actually increase sexual appetite, improve sexual performance, and decrease erectile dysfunction. Therefore, choosing an optimal anti-hypertensive combination is an important part of treating erectile dysfunction.

 

Lifestyle improvements

 

Quitting smoking, exercising regularly, losing excess weight, curtailing excessive alcohol consumption, controlling hypertension, and optimizing blood glucose levels in patients with diabetes are not only important for maintaining good health but also may improve or even prevent erectile function. Some studies suggest that men who have made lifestyle improvements experience increased rates of success with oral medications.

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