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Wednesday, December 5, 2012

Erectile Dysfunction

Erectile dysfunction (ED) is the inability to get or keep an erection firm enough for sexual intercourse. ED can be a total inability to achieve an erection, an inconsistent ability to do so, or a tendency to sustain only brief erections. ED is sometimes called impotence, but that word is being used less often so that it will not be confused with other, nonmedical meanings of the term.

The National Institutes of Health estimates that erectile dysfunction affects as many as 30 million men in the United States.[1] Incidence increases with age: About 4 percent of men in their 50s and nearly 17 percent of men in their 60s experience a total inability to achieve an erection. The incidence jumps to 47 percent for men older than 75.[2] But ED is not an inevitable part of aging. ED is treatable at any age.

How Does an Erection Occur?

Two chambers called the corpora cavernosa run the length of the penis (see Figure 1). A spongy tissue fills the chambers. The corpora cavernosa are surrounded by a membrane, called the tunica albuginea. The spongy tissue contains smooth muscles, fibrous tissues, spaces, veins, and arteries. The urethra, which is the channel for urine and ejaculate, runs along the underside of the corpora cavernosa and is surrounded by the corpus spongiosum.

Figure 1. Arteries and veins of the penis. Arteries (top) and veins (bottom) penetrate the corpora cavernosa and the corpus spongiosum. An erection occurs when relaxed muscles allow the corpora cavernosa to fill with excess blood fed by the arteries, while drainage of blood through the veins is blocked by the tunica albuginea.

An erection begins with sensory or mental stimulation, or both. Impulses from the brain and local nerves cause the muscles of the corpora cavernosa to relax, allowing blood to flow in through the arteries and fill the spaces. The blood creates pressure in the corpora cavernosa, making the penis expand. The tunica albuginea helps trap the blood in the corpora cavernosa, thereby sustaining the erection. The erection ends when muscles in the penis contract to stop the inflow of blood and open the veins for blood outflow.


Causes of Erectile Dysfunction

Erectile dysfunction usually has a physical cause, such as disease, injury, or side effects of drugs. Any disorder that causes injury to the nerves or impairs blood flow in the penis has the potential to cause ED.

Because an erection requires a precise sequence of events, ED can occur when any of the events is disrupted. The sequence includes nerve impulses in the brain, spinal column, and area around the penis, and response in muscles, fibrous tissues, veins, and arteries in and near the corpora cavernosa.

Damage to nerves, arteries, smooth muscles, and fibrous tissues, often as a result of disease, is the most common cause of ED. Diseases-such as diabetes, high blood pressure, nerve disease or nerve damage, multiple sclerosis, atherosclerosis, and heart disease account for the majority of erectile dysfunction cases. Patients should be thoroughly evaluated for these conditions before they begin any form of treatment for ED.

Lifestyle choices that contribute to heart disease and vascular problems also raise the risk of erectile dysfunction. Smoking, drinking alcohol excessively, being overweight, and not exercising are possible causes of ED.

Surgery, especially radical prostate and bladder surgery for cancer, can also injure nerves and arteries near the penis, causing erectile dysfunction. Injury to the penis, spinal cord, prostate, bladder, and pelvis can lead to ED by harming nerves, smooth muscles, arteries, and the fibrous tissues of the corpora cavernosa.

In addition, erectile dysfunction can be a side effect of many common medicines such as blood pressure drugs, antihistamines, antidepressants, tranquilizers, appetite suppressants, and Cimetidine®, a drug used to reduce excess stomach acid.

Psychological factors such as stress, anxiety, guilt, depression, low self-esteem, and fear of sexual failure can also cause ED. Even when ED has a physical cause, psychological factors may make the condition worse.

Hormonal abnormalities, such as low levels of testosterone, are a less frequent cause of erectile dysfunction.

Diagnoses

Patient History
A person's medical and sexual histories help define the degree and nature of ED. The medical history can disclose diseases that lead to ED, and a simple recounting of sexual activity might identify problems with sexual desire, erection, ejaculation, or orgasm.

Use of certain prescription or illegal drugs can suggest a chemical cause because drug effects are a frequent cause of erectile dysfunction.

Physical Examination
A physical examination can give clues to systemic problems. For example, if the penis is not sensitive to physical touch, a problem in the nervous system may be the cause. Abnormal secondary sex characteristics, such as unusual hair pattern or breast enlargement, can point to hormonal problems, which would mean the endocrine system is involved. The doctor might discover a circulatory problem by observing decreased pulses in the wrist or ankles. And unusual characteristics of the penis itself could suggest the source of the problem, for example, a penis that bends or curves when erect could be the result of Peyronie’s disease.

Laboratory Tests
Several laboratory tests can help diagnose ED. Tests for systemic diseases include blood counts, urinalysis, lipid profile, and measurements of creatinine and liver enzymes. Measuring the amount of available testosterone in the blood can yield information about problems with the endocrine system and may explain why a patient has decreased sexual desire.

Other Tests
Monitoring erections that occur during sleep (nocturnal erections) 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 a psychological cause. Tests for nocturnal erections are not completely reliable, however. Scientists have not standardized such tests and have not determined when they should be conducted for best results.

Psychosocial Examination
A psychosocial examination, using an interview and a questionnaire, can reveal psychological factors. A man's sexual partner may also be interviewed to determine expectations and perceptions during sexual intercourse.

Treatment

Most doctors suggest that treatments proceed from least to most invasive. Making a few healthy lifestyle changes may solve the problem. Quitting smoking, reducing alcohol consumption, losing excess weight, and increasing physical activity may help some men regain sexual function.

Cutting back on or replacing medicines that could be causing ED is considered next. For example, if a patient thinks a particular blood pressure medicine is causing problems with erection, he should tell his doctor and ask whether he 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, vacuum devices, and surgically implanted devices. In rare cases, surgery involving veins or arteries may be considered.

Psychotherapy
Experts often treat psychologically based erectile dysfunction using techniques that decrease the anxiety associated with intercourse. The patient's partner can help with the techniques, which include gradual development of intimacy and stimulation. Such techniques also can help relieve anxiety during treatment for ED from physical causes.

Drug Therapy
Drugs for treating ED can be taken orally, injected directly into the penis, or inserted into the urethra at the tip of the penis.

Oral Medications
In March 1998, the U.S. Food and Drug Administration (FDA) approved Sildenafil® (marketed as Viagra® and Revatio®), the first pill to treat ED. Since that time, Vardenafil® (marketed as Levitra®) and Tadalafil® (marketed as Cialis®) have also been approved.[3] Additional oral medicines are being tested for safety and effectiveness.

Viagra®, Levitra®, and Cialis® all belong to a class of drugs called phosphodiesterase (PDE) inhibitors. Taken an hour before sexual activity, these drugs work by enhancing the effects of nitric oxide, a chemical that relaxes smooth muscles in the penis during sexual stimulation and allows increased blood flow.

None of these PDE inhibitors should be used more than once a day. Men who take nitrate-based drugs such as nitroglycerin pills for heart problems should not use any of the three drugs because the combination can cause a sudden drop in blood pressure. Also, men should tell their doctor if they take any drugs called alpha-blockers, which are used to treat prostate enlargement or high blood pressure. The doctor may need to adjust the ED prescription. Taking a PDE inhibitor and an alpha-blocker within 4 hours of each other can cause a sudden drop in blood pressure. A small number of men have experienced vision or hearing loss after taking a PDE inhibitor.[3] Men who experience vision or hearing loss should seek prompt medical attention.

Oral testosterone can reduce erectile dysfunction 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 drugs, including yohimbine HCI (as per the U.S. Food and Drug Administration (FDA) this drug has been voluntarily recalled by Actavis Totowa LLC, a generic drug manufacturer), dopamine and serotonin agonists, and trazodone hydrochloride®, are effective, but the results of scientific studies to substantiate these claims have been inconsistent. Improvements observed following use of these drugs may be examples of the placebo effect-that is, a change that results simply from the patient’s belief that an improvement will occur.

Injectable Medications
While oral medicines improve the response to sexual stimulation, they do not trigger an automatic erection as injections do. Many men achieve stronger erections by injecting drugs into the penis, causing it to become engorged with blood. Drugs such as papaverine hydrochloride®, phentolamine®, and alprostadil® widen blood vessels. The injectable form of alprostadil® is marketed as Caverject®. These drugs may create unwanted side effects, however, including scarring of the penis and persistent erection, known as priapism. Topical vasodilators (e.g., nitroglycerin ointment, minoxidil), medications that are rubbed directly on the penis to improve blood flow thus enhancing an erection, may also be an option, but reports of their success are mixed.

Note: Men who use nitroglycerin ointment (applied directly to the penis) to treat erectile dysfunction should wear a condom during intercourse. Nitroglycerin is absorbed through the skin, including the vagina, and can cause a headache or other symptoms in your partner. Wearing a condom is always recommended if you are not involved in a long-term, monogamous relationship.

Alprostadil® is available as a suppository via the use of a prefilled applicator which delivers a pellet about an inch into the urethra. The pellet form of alprostadil® is marketed as Medicated Urethral System for Injection, or MUSE®. An erection will begin within 8 to 10 minutes and may last 30 to 60 minutes. The most common side effects are aching in the penis, testicles, and area between the penis and rectum; a warm or burning sensation in the urethra; redness from increased blood flow to the penis; and minor urethral bleeding or spotting.

Research on drugs for treating erectile dysfunction is expanding rapidly. Patients should ask their doctor about the latest advances.

Vacuum Devices
Mechanical vacuum devices cause an erection by creating a partial vacuum, which draws blood into the corpora cavernosa, engorging and expanding the penis. The devices have three components: a plastic cylinder, into which the penis is placed; a pump, which draws air out of the cylinder; and an elastic ring, which is moved from the end of the cylinder to the base of the penis as the cylinder is removed. The elastic ring maintains the erection during intercourse by preventing blood from flowing back into the body (see Figure 2). The elastic ring can remain in place up to 30 minutes. The ring should be removed after that time to restore normal circulation and to avoid skin irritation.

Figure 2. Vaccuum device. A vacuum device causes an erection by creating a partial vacuum around the penis, which draws blood into the corpora cavernosa.

Couples may find that using a vacuum device requires some practice or adjustment. An erection achieved with a vacuum device may not feel like an erection achieved naturally. The penis may feel cold or numb and have a purple color. Bruising on the shaft of the penis may occur, but the bruises are usually painless and disappear in a few days. Ejaculation may be weakened because the elastic ring blocks some of the semen from traveling through the urethra, but the pleasure of orgasm is usually not affected. 

Surgery

Surgery usually has one of three goals:
  • to implant a device that can cause the 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 erectile dysfunction.

Malleable implants usually consist of paired rods, which are inserted surgically into the corpora cavernosa. The user manually adjusts the position of the penis 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 (see Figure 3). 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. The pump causes fluid to flow from a reservoir residing in the lower pelvis to two cylinders residing in the penis. Inflatable implants can expand the length and width of the penis to some degree. They also leave the penis in a more natural state than malleable implants do when not inflated.

Figure 3. Inflatable implant. With an inflatable implant, an erection is produced by squeezing a small pump implanted in the scrotum. The cylinders expand to create the erection.

Once a man has either a malleable or inflatable implant, he must use the device to have an erection. Possible problems with implants include mechanical breakdown and infection, although mechanical problems have decreased in recent years because of technological advances.

Surgery to repair arteries can reduce erectile dysfunction caused by obstructions that block the flow of blood. The best candidates for such surgery are young men with discrete blockage of an artery because of an injury to the groin or fracture of the pelvis. The procedure is usually unsuccessful in older men with widespread blockage.

Surgery to veins that allow blood to leave the penis usually involves an opposite procedure-intentional blockage. Blocking off veins, called ligation, can reduce the leakage of blood that diminishes the rigidity of the penis during an erection. However, experts have raised questions about the long-term effectiveness of this procedure, and it is rarely done.

External Links

Erectile Dysfunction - Mayo Foundation for Medical Education and Research.
Erectile Dysfunction (ED) - American Academy of Family Physicians.

Diagnosis/Symptoms
Erectile Dysfunction - Impotence: Questions to Discuss with Your Doctor - Harvard Medical School.
Testosterone Test - American Association for Clinical Chemistry.

Treatment
Erectile Dysfunction: Viagra and Other Oral Medications - Mayo Foundation for Medical Education and Research.
Kegel Exercises for Men: Understand the Benefits - Mayo Foundation for Medical Education and Research.
Non-Surgical Management of Erectile Dysfunction (ED) - Urology Care Foundation.
Penile Implants - Mayo Foundation for Medical Education and Research.
Penis Pump - Mayo Foundation for Medical Education and Research.
Surgical Management of Erectile Dysfunction - Urology Care Foundation.
Testosterone Therapy: Key to Male Vitality? - Mayo Foundation for Medical Education and Research.

Complementary and Alternative Medicine (CAM) Therapy
Erectile Dysfunction Herbs: A Natural Treatment for ED? - Mayo Foundation for Medical Education and Research.
Hidden Risks of Erectile Dysfunction "Treatments" Sold Online - U.S. Food and Drug Administration.
Yohimbe - National Center for Complementary and Alternative Medicine.

Coping
How Will Cancer Affect My Sex Life? - American Cancer Society. 

Specific Conditions
Bent Penis - Mayo Foundation for Medical Education and Research.

Related Issues
Cardiovascular Implications of Erectile Dysfunction - American Heart Association.
Erectile Dysfunction and Diabetes: Take Control Today - Mayo Foundation for Medical Education and Research.
Erectile Dysfunction: A sign of heart disease? - Mayo Foundation for Medical Education and Research.
Low Testosterone and Men's Health - Endocrine Society.
Questions and Answers about Viagra, Levitra, Cialis, and Revatio: Possible Sudden Hearing Loss - U.S. Food and Drug Administration (FDA).
Sexuality for the Man with Cancer - American Cancer Society.

Tutorials
Erectile Dysfunction - Your Choices - self-playing tutorial, MedlinePlus Patient Education Institute.

Videos
Minimally Invasive Penile Impant Surgery - OR-Live - Coral Gables Hospital, Coral Gables, FL,3/26/2007
Simultaneous Inflatable Penile Prosthesis (IPP) and Male Sling Placement: Aiding in a Faster Return to Patient Quality-of-Life - OR-Live - Washington University School of Medicine in St. Louis, St. Louis, MO, 05/11/2011

Clinical Trials
ClinicalTrials.gov: Erectile Dysfunction, Impotence, Drugs and Erectile Dysfunction, Drugs and Impotence, Yohimbe and Erectile Dysfunction - National Institutes of Health.

Research
Effect of Testosterone on Response to Sildenafil in Men with Erectile Dysfunction - American College of Physicians.

Directories
Directory of Kidney and Urologic Diseases Organizations - National Kidney and Urologic Diseases Information Clearinghouse.
Find a Urologist - Urology Care Foundation.

Organizations
American Urological Association.
American Diabetes Association.
American Association of Sexuality Educators, Counselors, and Therapists.

References
1. National Institutes of Health (NIH) Consensus Conference. NIH Consensus Development Panel on Impotence. Impotence. Journal of the American Medical Association. 1993;270:83-90.
2. Saigal CS, Wessells H, Wilt T. Predictors and prevalence of erectile dysfunction in a racially diverse population. Archives of Internal Medicine. 2006;166:207-212.
3. Information for Healthcare Professionals: Sildenafil (marketed as Viagra and Revatio), Vardenafil (marketed as Levitra), Tadalafil (marketed as Cialis). http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/ucm124841.htm. U.S. Food and Drug Administration, U.S. Department of Health & Human Services. Retrieved 5 December 2012. 



DISCLAIMER
These statements have not been approved by the U.S. Food and Drug Administration (FDA). This information is not intended to diagnose, treat, cure or prevent any disease.

Information conveyed herein is based on pharmacological and other records - both ancient and modern. No claims whatsoever can be made as to the specific benefits accruing from the use of any herb, essential oil, dietary and/or nutritional supplement, home remedy, or therapeutic regimen. Holistic Lifestyle Community Blog has provided this material for general information and education purposes only. It is not intended as a substitute for or to take the place of medical advice. If you have a medical emergency call 9-1-1. Before beginning any type of natural, integrative or conventional treatment regimen, it is advisable to seek the advice of a licensed health care professional. The mention of any product, service, or therapy is not an endorsement by Holistic Lifestyle Community Blog. Any mention in the Holistic Lifestyle Community Blog of a specific brand name is not an endorsement of the product.

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