What is it?
Impotence is the failure to achieve or maintain your erection. Some men can initially get an erection but as they try to reach climax, their erection fades. Some men's erections are not stiff enough to penetrate their partner's anus (a mouth is usually no problem because it opens wider and does not have sphincters). This is another form of impotence.

Diagnosis
Like other forms of sexual dysfunction, your doctor will not realize you have a problem unless you or your partner mentions it. Once your doctor knows, he/she will no doubt conduct a series of tests to determine the cause.

It is essential that your blood sugar, cholesterol and blood pressure be checked. Doctors also check hormone levels to be sure that they are normal, and will examine you for signs of circulation or neurologic (nerves) disorders as well as a check of your genitalia. It is also important to run through a list of all medications (and recreational drugs) you take, as many of these cause impotence. One doctor might not be aware of a medication another doctor prescribed.

If all is fine, you will most likely need to visit a urologist for the next step in your evaluation - a nocturnal penile tumescence test (NPT). And no, your urologist doesn't get into bed with you and wait for Mr. Happy to rise up and take a bow. You will be sent home with a machine that when attached to your penis, records the frequency and strength of your erections. (Normal is 3 to 5 per night). If you have normal erections, your impotence is probably caused by psychological problems. If your erections are diminished in number or weak, you probably have a physiological cause.

A good at-home test can help determine the cause of your problem. If you have that morning erection - or pee erection as some men call it, and still have problems having sex, then your impotence is probably due to a psychological problem. If your doctor determines that your impotence results from a physiological cause, a further search will be made to find exactly what is wrong.

Symptoms
Failure to achieve or maintain an erection. Your erection is not stiff enough to penetrate your partner.

How is it acquired?
Doctors used to believe that most impotence was caused by psychological problems. They now know that this is not the case, with 80 percent of impotence resulting from a physiologic abnormality and only 20 percent resulting from psychologic disturbances.

There are 4 major physiologic causes of impotence, with vascular (blood vessel) problems being the most common cause. Just as atherosclerosis (hardening of your arteries) can narrow arteries in your heart, it can also affect the arteries that bring blood to your penis. In order to get and maintain an erection, you need to increase blood flow to your penis. Narrowed arteries may bring enough blood to a flaccid penis, but they might not be able to bring enough blood to bring it to attention. High blood pressure, smoking, diabetes and high cholesterol are the most common causes of atherosclerosis and vascular impotence.

An erection not only requires more blood to reach your penis through arteries, but you must also keep the blood from getting out to sustain your erection. Blood is held in your erect penis because veins constrict and prevent it from getting out. If your veins can't constrict (a condition known as "leaky veins") your erection will not happen or not last.

Nerves play an important role in producing your erection. Signals to your arteries and veins arrive via nerves from your brain or spinal chord. If your nerves are diseased or damaged your erections will suffer. The most common neurologic causes of impotence are spinal chord injury and post surgical destruction of your nerves (most often after radical surgery or radiation treatment for cancer). Other causes include nerve damage from diabetes, Parkinson's disease, multiple schlerosis and herniated discs.

Hormone abnormalities are another common cause of impotence -- most notably in men with HIV who have low testosterone levels. Problems with your thyroid and pituitary glands also contribute to impotence. Gay men who take steroids or estrogen (looking to fill out that evening gown) also frequently become impotent because supplements destroy your natural hormonal balances.

Drugs (either prescribed or illicit) are the fourth cause of physiologic impotence. The list is long, but some of the biggest culprits are antidepressants in the Prozac family (called SSRIs), tranquilizers, heart and blood pressure medications, depressants (narcotics, babiturates, alcohol, cocaine and marijuana) and some diuretics and ulcer medications. If you can tie your impotence to the start of a new drug, chances are you've found the culprit.

Prevention
The best way to prevent impotence is to keep your blood pressure, blood sugar and cholesterol under control, and not to smoke.

Of particular concern to Men
Impotence increases dramitically with age.

Of particular concern to Immune Compromised
HIV+ men have increased rates of impotence secondary to low testosterone levels. Protease inhibitors can raise viagra levels in your blood to dangerous levels.

Sex
Anal sex requires a stiffer erection than other forms of sex. The anal sphincters contract and your penis must push through. A condom can also decrease sensation and make it more difficult to maintain an erection.

by Stephen E. Goldstone, M.D., F.A.C.S.