Physical Causes

Other Common Medical Conditions That Contribute to Erectile Dysfunction

Parkinson's Disease. As a risk factor for impotence, Parkinson's disease (PD) is an under-appreciated problem. It is estimated that about a third of men with PD experience impotence. The physical cause of PD-related impotence is most likely an impaired nervous system. Depression and lowered self-esteem also contribute to erectile dysfunction in these patients.

Multiple Sclerosis. Multiple sclerosis (MS), which affects the central nervous system, also precipitates sexual dysfunction in as many as 78% of male patients. (Corticosteroids, which are common treatments for MS, may improve sexual function.)

Other Common Medical Conditions. Other medical conditions that have been associated with erectile dysfunction include allergies, thyroid problems, lung disease, and epilepsy.

Prostate Cancer and Its Treatments

Advanced prostate cancer can damage nerves needed for erectile function. Prostate surgery and surgical and radiation treatments for prostate cancer can also cause impotence. A number of treatments for sexual dysfunction are available that may help some men. [For more information, see In-Depth Report #33: Prostate cancer.]

Prostate Cancer Surgery (Radical Prostatectomy). The first nationally representative study to evaluate long-term outcomes after radical prostatectomy concluded that impotence occurs far more frequently than previously reported. Those who have so-called nerve-sparing surgeries have better results than those whose surgeries affect the nerves around the prostate. Some evidence also suggests that sexual function rates might improve if the nerve-sparing prostate surgeries also spare the ducts that carry semen.

Some studies suggest that impotence after prostate surgery may in part be due to injury to the smooth muscles in the blood vessels. Early treatments to maintain penile blood flow, particularly alprostadil injections, may helpful in restoring erectile function. In one study, men administered injections every other night for 6 months. They then started taking sildenafil (Viagra) 3 months after surgery. At 6 months, 82% of these men achieved penetration compared to 52% of men who took Viagra only. The vacuum pump may serve a similar purpose as the injections.