Information about impotence,
also known as erectile dysfunction
Erectile dysfunction,
sometimes called "impotence," is the repeated inability to get or
keep an erection firm enough for sexual relations. The word "impotence" may
also be used to describe other problems that interfere with sexual
relations and reproduction, such as lack of sexual desire and
problems with ejaculation or orgasm. Using the term erectile
dysfunction makes
it clear that those other problems are not involved.
Erectile dysfunction can be a total inability to
achieve erection, an inconsistent ability to do so, or a tendency
to sustain
only brief erections. These variations make defining erectile dysfunction
and estimating its incidence difficult. Estimates range from 15
million
to 30
million, depending on the definition used. According to the National
Ambulatory Medical Care Survey (NAMCS), for every 1,000 males in
the United States, 7.7 physician office visits were made for erectile
dysfunction in 1985. By 1999, that rate had nearly tripled to 22.3.
The increase
happened gradually, presumably as treatments such as vacuum devices
and injectable drugs became more widely available and discussing
erectile function became accepted. Perhaps the most publicized
advance was the introduction of the oral drug sildenafil citrate
(Viagra) in March 1998. NAMCS data on new drugs show an estimated
2.6 million malestions of Viagra at physician office visits in 1999,
and one-third of those malestions occurred during visits for a diagnosis
other than erectile dysfunction.
In Older Males
In senior males, 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 erectile dysfunction. Incidence increases with age: About
5 percent of 40-year-old males and between 15 and 25 percent of
65-year-old males experience
erectile dysfunction. But it is not an inevitable part of aging.
erectile dysfunction is treatable at any age, and awareness of
this fact has been growing. More males have been seeking help and
returning to normal
sexual activity because of improved, successful treatments for
erectile dysfunction. Urologists, who specialize in problems of
the urinary tract, have traditionally treated erectile dysfunction;
however, urologists accounted for
only 25 percent of Viagra malestions in 1999.
How does an erection occur?
The penis contains two chambers called the corpora cavernosa,
which run the length of the organ (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.
Erection begins with sensory or malestal stimulation, or both. Impulses
from the brain and local nerves cause the muscles of the corpora
cavernosa to relax, allowing blood to flow in 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 erection. When muscles in
the penis contract to stop the inflow of blood and open outflow
channels, erection is reversed.
Arteries and veins penetrate the long,
filled cavities running the length of the penis--the corpora
cavernosa and the corpous sponglosum. 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.
What causes erectile dysfunction?
Since an erection requires a precise sequence of events, erectile dysfunction 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 erectile dysfunction. Diseases--such
as diabetes, kidney disease, chronic alcoholism, multiple sclerosis,
atherosclerosis, vascular disease, and neurologic disease--account
for about 70 percent of erectile dysfunction cases. Between 35 and 50 percent of
males with diabetes experience erectile dysfunction.
Also, surgery (especially radical prostate and bladder surgery
for cancer) can injure nerves and arteries near the penis, causing
erectile dysfunction. 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.
In addition, many common medicines--blood pressure drugs, antihistamines,
antidepressants, tranquilizers, appetite suppressants, and cimetidine
(an ulcer drug)--can produce erectile dysfunction 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 to 20 percent of erectile dysfunction cases. Males with a physical cause for
erectile dysfunction frequently experience the same sort of psychological reactions
(stress, anxiety, guilt, depression).
Other possible causes are smoking, which affects blood flow in
veins and arteries, and hormonal abnormalities, such as not enough
testosterone.
How is erectile dysfunction diagnosed?
Patient History
Medical and sexual histories help define the degree and nature
of erectile dysfunction. A medical history can disclose diseases
that lead to erectile dysfunction, while a simple recounting
of sexual activity might distinguish
among 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 percent of erectile dysfunction cases. Cutting
back on or substituting certain medications can often alleviate
the problem.
Physical Examination
A physical examination can give clues to systemic problems. For
example, if the penis is not sensitive to touching, a problem
in the nervous system may be the cause. Abnormal secondary
sex characteristics, such as hair pattern or breast enlargemalest,
can point to hormonal problems, which would mean that the endocrine
system is involved. The examiner 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 erectile dysfunction. Tests for systemic
diseases include blood counts, urinalysis, lipid profile, and
measuremalests 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 erections that occur during sleep (nocturnal penile
tumescence) can help rule out certain psychological causes of
erectile dysfunction. Healthy males have involuntary erections during sleep. If nocturnal
erections do not occur, then erectile dysfunction 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
A psychosocial examination, using an interview and a questionnaire,
reveals psychological factors. A man's sexual partner may also
be interviewed to determine expectations and perceptions during
sexual relations.
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