The process of achieving an erection is complex, and problems may occur for a variety of reasons. These problems can be psychological, physical or a combination of the two.
Physical causes of ED are related to a breakdown or damage to the sequence of events that leads to an erection. This sequence involves nerve impulses in the brain, spine and penis as well as the subsequent response in the muscles, fibrous tissues, veins and arteries in and near the corpora cavernosa.
In some cases, the breakdown or damage in the sequence of events affects the arteries, muscles and surrounding tissues of the penis. This breakdown is most commonly the result of a disease. Diseases that commonly cause ED include:
Diabetes
Diabetes can cause nerve and artery damage that can make achieving an erection difficult. Between 35% and 50% of men with diabetes experience ED.
Kidney disease
Kidney disease can cause chemical changes that affect hormones, circulation, nerve function and energy level. These changes can lower libido (sex drive) or sexual ability. Drugs used to treat kidney disease may also cause ED.
Neurological (nerve and brain) diseases
The nervous system plays a vital part in achieving and maintaining an erection. It is common for men with conditions such as stroke, multiple sclerosis (MS), Alzheimer’s disease, Parkinson’s disease and spinal cord injuries to experience ED. This is due to an interruption in the transmission of nerve impulses between the brain and the penis.
Vascular disease
Vascular diseases are those that affect the blood vessels. These diseases include atherosclerosis (hardening of the arteries), hypertension and high cholesterol. These diseases, which account for 70% of physical-related causes of ED, restrict blood flow to the heart, the brain and--in the case of ED-- to the penis. Atherosclerosis alone accounts for 50%-60% of ED cases in men over age 60.
Prostate cancer
Prostate cancer doesn’t cause ED on its own, but surgery to remove the cancer can lead to erectile problems.
The physical causes of ED are not only disease-related. There are many other potential causes, including:
Surgery
Surgery performed to treat diseases such as prostate cancer and bladder cancer often require the removal of nerves and tissues around the affected area. Some of these surgeries result in only temporary problems (lasting 6-18 months), while others result in permanent damage to nerves and tissue.
Injury
Injuries to the pelvis, bladder, spinal cord and penis that require surgery also commonly cause ED.
Hormonal imbalances
Hormonal causes of ED account for only 5% of all cases of ED. Imbalances of hormones such as thyroid, prolactin and testosterone, can affect a man’s response to sexual stimulation. These imbalances can be the result of a tumor on the pituitary gland, kidney disease or liver disease.
Venous leak
If the veins in the penis cannot prevent blood from leaving the penis during an erection, an erection cannot be maintained. This is known as a venous leak, and can be a result of injury or disease.
Tobacco, alcohol or drug use
All three of these substance can damage a person’s blood vessels and/or restrict blood flow to the penis, causing ED. Smoking in particular plays a large role in causing ED in people with arteriosclerosis.
Prescription drugs
There are over 200 types of prescription drugs that may cause ED.
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 9/11/2006
