Erectile Dysfunction

The mechanisms for erection are fairly complex: A sensory stimulus triggers the brain to send nerve impulses down through the spinal cord. These signals trigger the release of a chemical messenger that causes the vessels supplying blood to the penis to dilate. The rod-shaped spongy tissues (corpora cavernosa) in the penis then fill with blood and expand, pressing against the veins that normally allow blood to drain from the penis, thus producing an erection. Interference with any part of this process – whether psychological or physiological – may cause erectile dysfunction.

Although an occasional inability to achieve or maintain an erection is common and not a sign of a chronic problem, a doctor should be consulted if erectile dysfunction persists. Treatment depends upon the underlying cause of erectile dysfunction.

• Emotional and psychological difficulties such as guilt or anxiety (especially performance anxiety, in which fear of not having an erection becomes so distracting that it becomes a self-fulfilling prophecy).
• Conditions that affect the brain and decrease the libido (sex drive), including depression or schizophrenia; use of drugs that act on the central nervous system (sedatives, antidepressants, some antihypertensive, antipsychotic, and alcohol); and chronic illnesses such as heart, lung, kidney, or liver disease, and certain types of cancer.
• Hormonal disturbances that decrease the libido, including diminished testosterone levels, elevated prolactin (due to a pituitary tumor) and hyper- or hypothyroidism.
• Brain disorders (that do not affect libido but have neurological consequences that affect sexual functioning), including brain tumor and stroke.
• Spinal cord disorders, such as multiple sclerosis or spinal cord trauma.
• Damage to the peripheral nerves due to diabetes mellitus or pelvic surgery for disorders such as prostate cancer or rectal cancer.
• Medications that can sometimes cause sexual dysfunction, including anticholinergics, antihistamines, beta-blockers (and other kinds of antihypertensives), and long-term use of nicotine.
• Peripheral vascular disease (impaired blood flow to the extremities and the penis).
• Fatigue.
• Advancing age.

Inability to achieve or maintain an erection sufficient for satisfactory sexual performance.