Definition

An inability to obtain or maintain an erection adequate for penetrative intercourse.

Incidence/age

Mild erectile dysfunction (ED) is extremely common affecting up to 50% of men. Complete ED affects approximately 5% of men at the age of 40 rising to 15% by the age of 70.

Causes

ED has many possible causes including psychological problems, vascular disease, neurological disease, hormonal disorders, drugs and previous surgery or radiotherapy to the pelvis. Smoking may also be an important factor. ED associated with diabetes is often due to a combination of vascular, neurological and psychological disorders.

Signs and symptoms

There may be a history of vascular disease e.g. previous myocardial infarction, angina, claudication or hypertension, diabetes or thyroid abnormalities. A detailed record of all drugs the patient is taking is important as is the smoking and drinking habits. Examination will look for signs of all the above conditions.

Tests

It is important to check the urine for evidence of diabetes and that may be the only test that is required if there is a clear history of a condition known to be associated with erectile dysfunction. In some cases a hormone profile or ultrasound scan of the penis may also be required.

Treatment

Medical Treatment will depend on the underlying cause but may include psychosexual counselling, alterations in lifestyle (reducing nicotine and alcohol intake), oral medication, transurethral agents, intracavernosal agents, vacuum devices and penile implants. The best tolerated and most effective oral agent is Viagra (sildenafil). It has been shown to be effective in 50% of diabetics with organic i.e. non-psychological impotence.

Most patients receive 50 or 100mg tablets. Side effects include facial flushing, headaches and a blue discolouration of vision. Viagra should not be taken by men with history of cardiac problems or those taking nitrates.The medicated urethral system for erection (MUSE) uses an applicator to place a small pellet of a prostaglandin, PGE1, into the urethra in the tip of the penis. A response rate of 65% has been reported.

The pellet can cause penile pain in a small proportion of men. Persistent erection (priapism), is a rare complication. Agents can also be injected directly into the shaft of the penis using a fine needle. The first agents to be used were papaverine and phenoxybenzamine but PGE1 is a newer agent with less risk of priapism. Other complications of injectables include penile pain and fibrosis leading to penile curvature. Vacuum devices use a suction pump and constriction ring to produce an erection.

Although these devices tend to be relatively free of complications the erection they produce is venous rather than arterial and hence tends to colder than normal.

Surgical For men who have not responded to medical treatment a final option is a penile implant. Silicone implants which may be semi rigid or inflatable are inserted into the penis under general anaesthetic.