Medical and sexual histories help
define the degree and nature of impotence. A medical history can
disclose diseases that lead to impotence. A simple recounting of
sexual activity might distinguish between problems with erection,
ejaculation, orgasm, or sexual desire.
A history of using certain
prescription drugs or illegal drugs can suggest a chemical cause.
Drug effects account for 25 percent of cases of impotence. Cutting
back on or substituting certain medications often can alleviate the
problem.
Physical Examination
A physical examination can give clues
for systemic problems. For example, if the penis does not respond as
expected to certain touching, a problem in the nervous system may be
a cause. Abnormal secondary sex characteristics, such as hair
pattern, can point to hormonal problems, which would mean the
endocrine system is involved.
A circulatory problem might be indicated by, for example, an
aneurysm in the abdomen. And unusual characteristics of the penis
itself could suggest the root of the impotence--for example, bending
of the penis during erection could be the result of Peyronie's
disease.
Laboratory Tests
Several laboratory tests can help
diagnose impotence. Tests for systemic diseases include blood counts,
urinalysis, lipid profile, and measurements of creatinine and liver
enzymes. For cases of low sexual desire, measurement of testosterone
in the blood can yield information about problems with the endocrine
system.
Other Tests
Monitoring erections that occur
during sleep (nocturnal penile tumescence) can help rule out certain
psychological causes of impotence. Healthy men have involuntary
erections during sleep. If nocturnal erections do not occur, then
the cause of impotence is likely to be physical rather than
psychological. 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 questionnaire, reveals psychological factors. The
man's sexual partner also may be interviewed to determine
expectations and perceptions encountered during sexual intercourse.
Since an erection requires a
sequence of events, impotence can occur when any of the events is
disrupted. The sequence includes nerve impulses in the brain, spinal
column, and area of the penis, and response in muscles, fibrous
tissues, veins, and arteries in and near the corpora cavernosa.
Damage to arteries, smooth muscles,
and fibrous tissues, often as a result of disease, is the most
common cause of impotence. Diseases--including diabetes, kidney
disease, chronic alcoholism, multiple sclerosis, atherosclerosis,
and vascular disease--account for about 70 percent of cases of
impotence. Between 35 and 50 percent of men with diabetes experience
impotence.
Surgery (for example, prostate
surgery) can injure nerves and arteries near the penis, causing
impotence. Injury to the penis, spinal cord, prostate, bladder, and
pelvis can lead to impotence by harming nerves, smooth muscles,
arteries, and fibrous tissues of the corpora cavernosa.
Also, many common medicines produce
impotence as a side effect. These include high blood pressure drugs,
antihistamines, antidepressants, tranquilizers, appetite
suppressants, and cimetidine (an ulcer drug).
Experts believe that psychological
factors cause 10 to 20 percent of cases of impotence. These factors
include stress, anxiety, guilt, depression, low self-esteem, and
fear of sexual failure. Such factors are broadly associated with
more than 80 percent of cases of impotence, usually as secondary
reactions to underlying physical causes.
Other possible causes of impotence
are smoking, which affects blood flow in veins and arteries, and
hormonal abnormalities, such as insufficient testosterone.