Overview
Erectile dysfunction (ED) is the inability of a man to achieve or maintain an erection sufficient for his or his partner's sexual needs. Most men experience this at some point in their lives, usually by the age of 40, and are not psychologically affected by it.
Causes
Since an erection requires a precise sequence of events, ED can occur when any of the events of the sequence is disrupted. The sequence includes nerve impulses in the brain, spinal column, and area around the penis; and response in muscles, fibrous tissues, blood vesselsin and near corpora cavernosa.
Damage to nerves, arteries, smooth muscles, and fibrous tissuesas a result of disease is the most common cause of ED. Diseasessuch as diabetes, kidney disease, chronic alcoholism, multiple sclerosis, atherosclerosis, vascular disease, and neurologic diseaseaccount for about 70 % of ED cases. Between 35- 50 % of men with diabetes experience ED. Lifestyle choices that contribute to heart diseases and vascular problems also raise the risk of ED. Smoking, overweight and avoiding exercise are possible causes of ED.
Also, surgery (especially radical prostate and bladder surgery for cancer) can injure the nerves and blood vessels near the penis, causing ED. Injury to the penis, spinal cord, prostate, bladder, or pelvis can lead to ED by harming the nerves, smooth muscles, arteries, and fibrous tissues of the corpora cavernosa.
In addition, many common medicines likeblood pressure drugs, antihistamines, antidepressants, tranquilizers, appetite suppressants, and cimetidine ( ulcer drug)can produce ED as a side effect.
Experts believe that psychological factors such as stress, anxiety, guilt, depression, low self-esteem, and fear of sexual failure cause 10-20 % of ED cases. Men with physical cause for ED frequently experience same sort of psychological reactions (stress, anxiety, guilt, depression). Other possible causes are smoking, which affects blood flow in blood vessels, and hormonal abnormalities, such as low testosterone.
Diagnosis
Patient History
Medical and sexual history helps to define the degree and nature of ED. Medical history can disclose the diseases that lead to ED, while a simple recounting of sexual activity might distinguish among the problems with sexual desire, erection, ejaculation, or orgasm. Using certain prescription or illegal drugs can suggest a chemical cause, since drug effects account for 25% of ED cases. Cutting back on or substituting certain medications can often reduce the problem.
Physical Examination
Physical examination can give clues towards systemic problems. For example, if the penis is not sensitive to touch, a problem in the nervous system may be the cause. Abnormal secondary sex characteristics such as hair pattern or breast enlargement can point to hormonal problems, which would mean that the endocrine system is involved. The examiner might discover circulatory problem by observing decreased pulse in wrist or ankle. Unusual characteristics of the penis itself could suggest the source of the problem- for example, penis that bends or curves when erect could be due to Peyronie's disease.
Laboratory Tests
Several laboratory tests can help diagnose ED. Tests for systemic diseases include blood count, urinalysis, lipid profile, and measurements of creatinine and liver enzymes. Measuring the amount of free testosterone in the blood can yield information about problems with the endocrine system and is indicated especially in patients with decreased sexual desire.
Other Tests
Monitoring the erections that occur during sleep (nocturnal penile tumescence) 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 psychological cause. Tests of nocturnal erections are not completely reliable, however scientists have not standardized such tests and have not determined when they should be applied for best results.
Psychosocial Examination
Psychosocial examination comprising of an interview and a questionnaire reveals psychological factors. Patient's sexual partner may also be interviewed to determine expectations and perceptions during sexual intercourse.
Treatment
Most physicians suggest that treatments proceed from least to most invasive. For some men, making a few healthy lifestyle changes may solve the problem. Quitting smoking, losing excess weight, and increasing physical activity may help some men regain their sexual function. Cutting back on the drugs having harmful side effects is considered the next step. For example, drugs for high blood pressure work in different ways. If you think a particular drug is causing problems with erection, tell your doctor and ask whether you 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, vaccum devices and surgically implanted devices. In rare cases, surgery involving blood vessels may be considered.
Psychotherapy
Experts often treat psychological ED using techniques that decrease anxiety associated with intercourse. Patient's partner can help with the techniques, which include gradual development of intimacy and stimulation. Such techniques can also help to relieve anxiety when ED from physical cause is being treated.
Drug Therapy
Drugs for treating ED can be taken orally, injected directly into the penis, or inserted into the urethra from the tip of the penis. In March 1998, the Food and Drug Administration (FDA) approved Viagra, the first pill to treat ED. Since that time, Vardenafil Hydrochloride (Levitra) and Tadalafil (Cialis) have also been approved. Additional oral medicines are being tested for safety and effectiveness. Viagra, Levitra, and Cialis all belong to the class of drugs called Phosphodiesterase (PDE) Inhibitors. Taken an hour before sexual activity, these drugs work by enhancing the effect of nitric oxide, a chemical that relaxes smooth muscles in the penis during sexual stimulation and allows increased blood flow.
While oral medicines improve the response to sexual stimulation, they do not trigger an automatic erection like injections. The recommended dose for Viagra is 50 mg, although the physician may adjust this dose even to 100 mg, depending on the patient. The recommended dose for Levitra or Cialis is 10 mg, and the physician may adjust this dose to 20 mg, if required. A lower dose of 5 mg is available for patients who take other medicines or have conditions that may decrease the ability of the body to use the drug. Levitra is also available in 2.5 mg dose.
None of these PDE inhibitors should be used more than once a day. Men who take nitratebased drugs such as Nitroglycerin for heart problems should not use either of the drug because the combination can cause a sudden drop in blood pressure. Also, tell your doctor if you take any alpha-blocker drug used to treat prostate enlargement or high blood pressure. Your doctor may then need to adjust your ED prescription. Taking a PDE inhibitor and an alpha-blocker at the same time (within 4 hours) can cause a sudden drop in the blood pressure.
Oral testosterone can reduce ED in some men with low levels of natural testosterone, but it is often ineffective and may cause liver damage. Patients also have claimed that other oral drugsincluding Yohimbine Hydrochloride, Dopamine and Serotonin agonists, and Trazodoneare effective, but the results of scientific studies to substantiate these claims have been inconsistent. Improvements observed following the use of these drugs may be examples of the placebo effect ( change that results simply from the patient's belief that improvement will occur).
Many men achieve strong erection by injecting drug into the penis causing it to become engorged with blood. Drugs such as Papaverine Hydrochloride, Phentolamine and Alprostadil (marketed as Caverject) widen the blood vessels. However, these drugs may create unwanted side effects including persistent erection (known as priapism) and scarring. Nitroglycerin, a muscle relaxant, can sometimes enhance erection when rubbed on the penis.
A system for inserting a pellet of Alprostadil into the urethra is marketed as 'Muse'. This system uses a prefilled applicator to deliver the pellet about an inch deep into the urethra. An erection begins within 8-10 minutes and may last till 30 - 60 minutes. The most common side effects are aching in the penis, testicles, and area between penis and rectum; warmth or burning sensation in urethra; redness due to increased blood flow to the penis; and minor urethral bleeding or spotting.
Research on drugs for treating ED is expanding rapidly. Patients should ask their doctor about the latest advances.
Vaccum Devices
Mechanical vaccum devices cause erection by creating a partial vacuum, which draws blood into the penis, engorging and expanding it. These devices have 3 components: plastic cylinder to place the penis, pump to draw air out of the cylinder, and an elastic band placed around the base of the penis to maintain the erection after the cylinder is removed and during intercourse by preventing blood from flowing back into the body.
Surgery
Surgery usually has 1 out of 3 goals:
- to implant a device that can make penis to become erect
- to reconstruct arteries to increase blood flow to the penis
- to block off veins that allow blood to leak from the penile tissues
Implanted devices (known as prostheses) can restore erection in many men with ED. Possible problems with implants include mechanical breakdown and infection, although mechanical problems have diminished in recent years because of technological advances. Malleable implants usually consist of paired rods, which are inserted surgically into the corpora cavernosa. The user adjusts the position of the penis manually and therefore, the rods. Adjustment does not affect the width or length of the penis.
Inflatable implants consist of paired cylinders, which are surgically inserted inside the penis and can be expanded using pressurized fluid. Tubes connect the cylinders to a fluid reservoir and a pump, which are also surgically implanted. The patient inflates the cylinders by pressing on the small pump, located under the skin in the scrotum. Inflatable implants can expand the length and width of the penis to some extent. They also leave the penis in a more natural state when not inflated.
Surgery to repair arteries can reduce ED caused by obstruction that blocks the blood flow. The best candidates for such surgery are young men with discrete blockage of an artery because of an injury to the crotch or fracture of the pelvis. The procedure is almost never successful in older men with widespread blockage.
Surgery of veins that allow blood to leave the penis usually involves an opposite procedure, intentional blockage. Blocking off the veins (ligation) can reduce the leakage of blood that diminishes the rigidity of the penis during erection. However, experts have raised questions about the long-term effectiveness of this procedure, and it is rarely done.
