Erectile dysfunction

Erectile dysfunction

Alternative names
Impotence; ed
Erectile dysfunction

Erectile dysfunction (ed), formerly called impotence, can affect men of all ages although it is much more common among older men. It is normal for healthy men of all ages to occasionally experience erectile dysfunction. However, if the problem becomes chronic, it can have adverse effects on relationships, emotional health, and self-esteem. Erectile dysfunction may also be a symptom of an underlying health condition. If erectile dysfunction becomes an on-going problem, it is important to talk to your doctor.

Causes of erectile dysfunction

Physical causes are the main reasons for erectile dysfunction. They include heart disease, high blood pressure, diabetes, neurological disease, medication side effects, and other health conditions.
Psychological causes of erectile dysfunction include anxiety, depression, stress, and problems in relationships.
Lifestyle factors that increase the risk for erectile dysfunction include smoking, alcohol use, and other substance abuse.
Introduction

Erectile dysfunction (formerly called impotence) is the inability to achieve or maintain an erection sufficiently rigid for sexual intercourse. Sexual drive and the ability to have an orgasm are not necessarily affected. Because all men have erection problems from time to time, doctors diagnose erectile dysfunction if a man fails to maintain an erection satisfactory for intercourse on at least 25% of attempts.

Erectile dysfunction is not new in either medicine or human experience, but it is not easily or openly discussed. Cultural expectations of male sexuality inhibit many men from seeking help for a disorder that can usually benefit from medical treatment.

The penis and erectile function

The structure of the penis. The penis is composed of the following structures:

Two parallel columns of spongy tissue called the corpus cavernosa, or erectile bodies.
A central spongy chamber called the corpus spongiosum, which contains the urethra, the tube that carries urine from the bladder through the penis.
These structures are made up of erectile tissue. Erectile tissue is rich in tiny pools of blood vessels called cavernous sinuses. Each of these vessels is surrounded by smooth muscles and supported by elastic fibrous tissue composed of a protein called collagen.

Erectile function and nitric oxide. The penis is either flaccid or erect depending on the state of arousal. In the flaccid, or unerect, penis, the following normally occurs:

Small arteries leading to the cavernous sinuses contract, reducing the inflow of blood.
The smooth muscles regulating the many tiny blood vessels also stay contracted, limiting the amount of blood that can collect in the penis.
During arousal, the following occurs:

The man's central nervous system stimulates the release of a number of chemicals, including nitric oxide, which is essential for producing and maintaining an erection.
Nitric oxide stimulates the production of cyclic GMP, a chemical that relaxes the smooth muscles in the penis. This allows blood to flow into the tiny pool-like cavernous sinuses, flooding the penis.
This increased blood flow nearly doubles the diameter of the spongy chambers.
The veins surrounding the chambers are squeezed almost completely shut by this pressure.
The veins are unable to drain blood out of the penis and so the penis becomes rigid and erect.
After ejaculation or climax, cyclic GMP is broken down by an enzyme called phosphodiesterase-5 (pde5), causing the penis to become flaccid (unerect) again.
Important substances for erectile health

A proper balance of certain chemicals, gases, and other substances is critical for erectile health.

Collagen. The protein collagen is the major component in structural tissue in the body, including in the penis. Excessive amounts, however, form scar tissue, which can impair erectile function.

Oxygen. Oxygen-rich blood is one of the most important components for erectile health. Oxygen levels vary widely from reduced levels in the flaccid state to very high in the erect state. During sleep, a man can normally have three to five erections per night, bringing oxygen-rich blood to the penis. The primary cause of oxygen deprivation is ischemia -- the blockage of blood vessels. The same blood flow-reducing conditions that lead to heart disease, such as atherosclerosis, may also contribute to erectile dysfunction.

Testosterone and other hormones. Normal levels of hormones, especially testosterone, are essential for erectile function, though their exact role is not clear.

Causes

Over the past decades, the medical perspective on the causes of erectile dysfunction has shifted. Common belief used to attribute almost all cases of ed to psychological factors. Now doctors believe that up to 85% of ed cases are caused by medical or physical problems. Only 15% are completely psychologically based. Sometimes, erectile dysfunction is due to a combination of physical and psychological causes.

A number of medical conditions share a common problem with erectile dysfunction -- the impaired ability of blood vessels to open and allow normal blood flow.

Heart disease, atherosclerosis, and high blood pressure

Heart disease, atherosclerosis, high blood pressure, and high cholesterol levels are major risk factors for erectile dysfunction. In fact, erectile problems may be a warning sign of these conditions in men at risk for atherosclerosis. Men who experience ed have a greater risk for angina, heart attack, or stroke.

Erectile dysfunction is a very common problem in men with high blood pressure. Many of the drugs used to treat hypertension (such as calcium channel blockers and beta-blockers) may also cause ed.

Diabetes

Diabetes is a major risk factor for erectile dysfunction. Blood vessel and nerve damage are both common complications of diabetes. When the blood vessels or nerves of the penis are involved, erectile dysfunction can result. Diabetes is also associated with heart disease and chronic kidney disease, other risk factors for ed.

Obesity

Obesity increases the risk for diabetes, heart disease, and erectile dysfunction.

Metabolic syndrome

Metabolic syndrome -- a cluster of conditions that includes obesity and abdominal fat, unhealthy cholesterol and triglyceride levels, high blood pressure, and insulin resistance -- is also a risk factor for erectile dysfunction in men older than 50 years.

Benign prostatic hyperplasia

Although benign prostatic hyperplasia (BPH or 'enlarged prostate') does not cause erectile dysfunction, surgical and drug treatments for the condition can increase the risk for erectile dysfunction.

Neurologic conditions

Diseases that affect the central nervous system can cause erectile dysfunction. These conditions include Parkinson's disease, multiple sclerosis, and stroke.

Endocrinologic and hormonal conditions

Low levels of the male hormone testosterone can be a contributing factor to erectile dysfunction in men who have other risk factors. (low testosterone as the sole cause of erectile dysfunction affects only about 5% of men. In general, low testosterone levels are more likely to reduce sexual desire than to cause ed.) abnormalities of the pituitary gland that cause high levels of the hormone prolactin are also associated with erectile dysfunction. Other hormonal and endocrinologic causes of erectile dysfunction include thyroid and adrenal gland problems.

Physical trauma and injury

Spinal cord injury and pelvic trauma, such as a pelvic fracture, can cause nerve damage that results in ed. Other conditions that can injure the spine and cause erectile dysfunction include spinal cord tumors, spina bifida, and a history of polio.

Surgery

Surgery for prostate diseases. Radical prostatectomy for prostate cancer often causes loss of sexual function but nerve-sparing surgical procedures reduce the risk of ed. (radiation treatments for prostate cancer also cause erectile dysfunction.) surgical treatments for BPH can also cause ed, but this complication is relatively uncommon.

Surgery for colon and rectal cancers. Surgical and radiation treatments for colorectal cancers can cause ed in some patients. In general, colostomy does not usually affect sexual function. However, wide rectal surgery can cause short-term or long-term sexual dysfunction.

Fistula surgery. Surgery to repair anal fistulas can affect the muscles that control the rectum (external anal sphincter muscles), sometimes causing ed. (repair of these muscles may restore erectile function.)

Orthopedic surgery. Erectile dysfunction can sometimes result from orthopedic surgery that affects pelvic nerves.

Note: vasectomy does not cause erectile dysfunction.

Medications

Many medications increase the risk for erectile dysfunction. They include:

High blood pressure medications, particularly diuretics, beta-blockers, and calcium channel blockers.
Heart or cholesterol medications such as digoxin, gemfibrozil, or clofibrate.
Finasteride (Proscar, generic) and dutasteride (Avodart), which are used to treat benign prostatic hyperplasia (BPH). A lower-dose form of finasteride (Propecia), which is used to treat male pattern baldness, may also cause ed. Erectile dysfunction may persist even after these medications are stopped.
Psychotropic medication used to treat depression and bipolar disorder such as selective serotonin-reuptake inhibitors (SSRIs), tricyclic antidepressants, monoamine oxidase inhibitors, and lithium. Certain types of antipsychotic medication, such as phenothiazines (like Compazine) and butyrophenones (like haloperidol), can also cause erectile dysfunction.
Gastroesophagelal reflux disorder (gerd) medications, used to reduce stomach acids, such as rantidine (Zantac) and cimetidine (Tagamet).
Hormone drugs such as estrogens, corticosteroids, and 5-alpha reductase inhibitors.
Chemotherapy drugs such as methotrexate.
Psychological causes

Anxiety. Anxiety has both emotional and physical consequences that can affect erectile function. It is among the most frequently cited contributors to psychological ed.

Stress. Even simple stress can affect sexual dysfunction.

Depression. Depression can reduce sexual desire and is associated with erectile dysfunction.

Relationship problems. Troubles in relationships often have a direct impact on sexual functioning.

Risk factors

Age

For most men, erectile dysfunction is primarily associated with older age. Nevertheless, ed is not inevitable with age. Severe erectile dysfunction often has more to do with age-related disease than age itself. In particular, older men are more likely to have heart disease, diabetes, and high blood pressure than younger men. Such conditions and some of their treatments are causes of erectile dysfunction.

Lifestyle factors

Smoking. Smoking contributes to the development of erectile dysfunction, mainly because it increases the effects of other blood vessel disorders, including high blood pressure and atherosclerosis.

Alcohol use. Heavy drinking can cause erectile dysfunction. Alcohol depresses the central nervous system and impairs sexual function.

Drug abuse. Illicit drugs such as heroin, cocaine, methamphetamines, and marijuana can affect sexual function.

Weight and sedentary lifestyle. Obesity is a risk factor for erectile dysfunction. Lack of exercise and a sedentary lifestyle can lead to obesity and other health problems associated with erectile dysfunction.

Diagnosis

The doctor typically interviews the patient about various physical and psychological factors and performs a physical exam.

Medical history

The doctor will ask about:

Past and present medical conditions, surgeries, and medications
Any history of psychological problems, including stress, anxiety, or depression
Lifestyle factors such as alcohol, drug, and dietary supplement use
In addition, the doctor will ask about your sexual history, which may include:

When problems with sexual function began
The frequency, quality, and duration of any erections, including erections that occur during sleep or on awakening in the morning
The specific circumstances when erectile dysfunction occurs
Details of sexual technique
Whether problems exist in the current relationship
If appropriate, the doctor may also interview the sexual partner.

Physical examination

The doctor will perform a physical exam, including examination of the genital area and a digital rectal examination (the doctor inserts a gloved and lubricated finger into the patient's rectum) to check for prostate abnormalities. It is important to check blood pressure and to evaluate circulation by checking pulses in the legs.

Laboratory tests

Because erectile dysfunction and atherosclerosis are often linked, it is important to check cholesterol levels. Similarly, the doctor may order tests for blood sugar (glucose) levels to check if diabetes is a factor. In some cases, blood tests may be used to measure testosterone levels to determine if there are hormone problems. The doctor may also screen for thyroid and adrenal gland dysfunction. For more sophisticated tests, the doctor may refer the patient to a urologist.

Treatment

Many physical and psychological situations can cause erectile dysfunction, and brief periods of ed are normal. Every man experiences erectile dysfunction from time to time. Nevertheless, if the problem is persistent, men should seek professional help, particularly since erectile dysfunction is usually treatable and may also be a symptom of an underlying health problem. It is important to treat any medical condition that may be causing erectile dysfunction.