Physical causes of erectile dysfunction
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 in - 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 a subsequent response in the muscles, fibrous tissues, veins and arteries in and near the corpora cavernosa.
Often a breakdown in the sequence affects the arteries, muscles and surrounding tissues of the penis, and 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 it difficult to achieve an erection. Between 35% and 50% of men with diabetes experience ED, according to research. It has been estimated that up to 75% of men with diabetes will experience at least some degree of ED during their lifetime, and the risk increases with age.
- Kidney disease: Kidney disease can cause chemical changes to occur in the body, affecting hormones, circulation, nerve function and energy level. Often these changes will lower a person’s libido (sex drive) or sexual ability. Medicines used to treat kidney disease may also cause ED.
- Neurological (nerve and brain) diseases: The nervous system (the body’s system of nerves) plays a vital part in achieving and maintaining an erection and it is common for men with spinal-cord injuries and diseases such as stroke, multiple sclerosis (MS), Alzheimer’s disease and Parkinson’s disease 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. They include atherosclerosis (narrowing of the arteries), hypertension and high cholesterol. These diseases, which account for 70% of physically related causes of ED, all restrict blood flow to the heart, the brain and, in the case of ED, the penis.
- Prostate cancer: Prostate cancer doesn’t cause ED directly, but treatment (radiotherapy, hormonal manipulation or 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 requires the removal of nerves and tissues round the affected area, which can lead to ED. Some surgery will result in temporary problems (lasting six to 18 months), but some can result in permanent damage to the nerves and tissue round the penis. In this case, treatment will be required in order for an erection to be achieved.
- Injury: Injuries to the pelvis, bladder, spinal cord and penis that require surgery also commonly cause ED.
- Hormonal imbalances: Imbalances of hormones, such as thyroid hormones, prolactin and testosterone, can affect a man’s response to sexual stimulation. These imbalances can be the result of a tumour of the pituitary gland, kidney disease, liver disease, or hormonal treatment of prostate cancer.
- 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 substances can damage 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 atherosclerosis.
- Prescription medicines: There are more than 200 types of prescription medicines that may cause ED.
- Prostate enlargement: Bladder neck obstruction due to prostate enlargement has been implicated in being associated with varying degrees of ED.