Erectile dysfunction, also called sexual dysfunction or impotence, is one of the most common health problems affecting men and is more common with increasing age. It is estimated that chronic ED affects about 5% of men in their 40s and 15-25% of men by the age of 65. And about 50% of men between the ages of 40 and 70 suffer from transient ED and inadequate erection.
Erectile dysfunction is the inability to get or keep an erection suitable for sexual intercourse. ED can be a total inability to achieve erection, an inconsistent ability to do so, or a tendency to sustain only brief erections. This is not an illness of its own, but rather a result of another medical problem.
Causes & Risk factors
Although some men may think that sexual dysfunction is "all in their head", actually there are various physical and psychological factors that can provoke it.
The development of successful erection is a complex event and requires a healthy brain; healthy endocrine, vascular and circulatory systems; functional nerves, arteries, and veins; and certain hormones. Therefore, ED can be caused a by a fail in any one of these systems.
There are many underlying physical and psychological causes of erectile dysfunction. Most men with physical causes usually have an associated psychological component. Various diseases may affect erectile function by altering the nervous, vascular, or hormonal systems or by influencing the patient's psychologic mood and behavior. Reduced blood flow to the penis and nerve damage are the most common physical causes.
Problems with the nervous system can affect the transmission of signals from the brain to the blood vessels in the penis. This occurs in conditions including multiple sclerosis, spinal cord injury and Parkinson's disease. The nerves involved in sexual arousal can also be damaged in surgery to the pelvic area, such as removal of the prostate. In a small number of cases, problems with hormone levels, can also affect erection.
Trauma or injury to the penis, spinal cord, prostate, bladder, and pelvis can lead to erectile dysfunction by harming nerves, smooth muscles, arteries, and fibrous tissues of the corpora cavernosa. Injuries to the penis may also result in scar tissue formation as well as penis curvature during an erection. Bicycle riding for long periods has also been implicated as a cause of erectile dysfunction.
Some types of prostate or bladder surgery. Surgery of the colon, prostate, bladder, or rectum may damage the nerves and blood vessels involved in erection.
A great variety of medication are known to cause or contribute to erectile dysfunction:
The brain is the most sensitive "sex organ" and greatly influences the ability to get and maintain erections. Anxiety and guilt are the most common psychological causes of erectile dysfunction. Depression, worry, stress, low self-esteem, and fear of sexual failure all contribute to loss of libido and impotence. One episode of failure, regardless of cause, may propagate further psychological distress leading to further erectile failure.
Psychological factors in impotence are often secondary to physical causes, and they magnify their significance. Experts believe that psychological factors cause 10 to 20% of ED cases.
Chronic use of alcohol, tobacco, marijuana and substance abuse often causes erectile dysfunction and decreased sexual drive.
Hormone Disorders account for fewer than 5% of cases of erectile dysfunction. Hormonal abnormalities such as hyperthyroidism (overactive thyroid gland), hypothyroidism (underactive thyroid gland), hypogonadism (leads to lower testosterone levels), increased prolactin (a hormone produced by the anterior pituitary gland), steroid abuse by body-builders may cause impotence. Rarely is low testosterone alone responsible for poor erections. Testosterone stimulates desire, but is believed to have little effect on erections.
All studies demonstrate a strong association with age, even when data are adjusted for the confounding effects of other risk factors. Erection problems tend to become more common with age, but they can affect men at any age and at any time in their lives. Physical causes are more common in older men, while psychological causes are more common in younger men.
In around 95% of the cases, a suitable treatment can be found. Erectile dysfunction is treatable at any age, and awareness of this fact has been growing. More men have been seeking help and returning to normal sexual activity because of improved, successful treatments.
There are three phosphodiesterase (PDE) inhibitors approved for the treatment of erectile dysfunction: sildenafil (Viagra), vardenafil (Levitra), and tadalafil (Cialis). They vary in dosage, duration of effectiveness and possible side effects, but are generally well tolerated.
These agents block the enzyme phosphodiesterase-5 (PDE-5) which helps to maintain levels of cyclic guanosine monophosphate (GMP), a chemical produced in the penis during sexual arousal. Balanced levels of GMP causes the smooth muscles of the penis to relax and increases blood flow. This allows a natural sequence to occur - an erection in response to sexual stimulation. These medications don't automatically produce an erection. Instead they allow an erection to occur after physical and psychological stimulation.
PDE-5 inhibitors, unless contraindicated, should be offered as a first-line therapy for erectile dysfunction. They are a good choice for men at any age and in any ethnic group who are in good health and who do not have conditions that preclude taking them (such as the use of nitrates or alpha-blockers). The success rates of all three vary between 70% and 90%.
Last updated: March 2012