Erectile dysfunction (ED), also known as male impotence, is the inability to get or maintain an erection long enough to finish having sex.
An estimated 18 to 30 million men in the U.S. are affected by ED, with 15 percent between the ages of 40 and 70 suffering from complete ED. Men are more likely to develop the condition as they age:Forty percent of 40-year olds are affected bysome level of ED, and that figure increases to 68 percent by age 70.
Understanding Erections
Three components of the body are involved in an erection:
- Heart and circulatory system - Good blood flow to the penis is vital for an erection.
- Nervous system - Healthy nerves allow full sensation and the regulation of regulates the flow of blood the penis needs for an erection. Nervous system disorders can impact these functions.
- Hormones - Male hormones, such as testosterone, control sex drive and if too low can decrease a man’s interest in sex.
When the brain senses sexual stimulation (such as touch, thoughts, or something a man sees or hears), it sends nerve impulses to the penis. This causes the organ's muscles to relax, letting blood into its spongy tissue. As blood collects here, the penis grows larger and harder. At the same time, the veins get smaller to keep blood from leaving.
After an orgasm, other nerve signals cause the veins to become wider again, allowing blood to leave and the penis to grow soft.
Erectile Dysfunction Causes
Anything that interferes with the blood vessels or nerves of the penis, or the hormones involved in stimulating sex drive, can interfere with a man’s ability to have an erection. This makes ED difficult to diagnose because it can be caused by many underlying conditions. In general, these are divided into physical and psychological causes and either or both can be involved.
Almost half of the ED cases in men over the age of 50 are caused by conditions affecting the heart and blood vessels. Heart disease, high blood pressure, and radiation therapy all interfere with bloodflow to the penis.
Other factors that can cause ED include:
- Diabetes - The disorder can affect the nerves and blood flow to the penis.
- Injury to the groin or pelvis - Any kind of injury or stress, such as riding a bicycle for extended periods of time, can compress the nerves that run to the penis.
- Surgery - Any procedure in the groin or pelvic area, such as surgery for an enlarged prostate or prostate cancer, can affect the nerves and blood vessels.
- Medications - Those that can effect ED include psychotropic drugs and some blood pressure medications.
- Lifestyle choices - Everything from smoking and alcohol consumption to being overweight and not getting enough exercise can contribute to ED.
Erectile Dysfunction Symptoms
The main symptom of ED is the inability to achieve or keep an erection. If the cause of erectile dysfunction is psychological, a man may also suffer from anxiety, mood swings, insomnia, or depression.
When the cause of ED is physical, symptoms of the underlying condition may also be present, such as poor circulation in the legs, pain in the chest, or shortness of breath while exercising.
Erectile Dysfunction Diagnosis
To diagnose ED, a physician gathers information about:
- Sexual history: firmness or duration of a patient's erections (during sex, masturbation, and while sleeping)
- Medical history: conditions such as heart disease or diabetes, past surgeries, injuries, and medications
- Psychological history: anxiety, stress, and depression
The physician will also perform a physical exam to look for conditions that might affect the circulatory, reproductive, urinary, or nervous systems. This includes checking a patient's blood pressure, prostate, testicles, and penis, as well as the pulse in his limbs.
Laboratory tests may not be necessary, but can be done to analyze blood levels, hormone levels, and urine.
In some cases, the doctor may inject drugs that cause the blood vessels to widen—prostaglandin E1, papaverine, and phentolamine, either alone or in combination—into the penis to see if an erection occurs. Nerve conduction studies may be done in patients who have nervous system problems, diabetes, or previous limb numbness.
Imaging tests can be used for men who have had a previous injury or surgery in the groin area. For example, an ultrasound can provide information about the blood flow in the penis, as well as check for abnormalities in the testicles or prostate.
Erectile Dysfunction Treatment
Erectile dysfunction treatment will depend on the seriousness of the symptoms and the underlying cause. Treatment options for ED range from medication to surgery.
References
Coburn, M. (2013). Urologic Surgery. Sabiston Textbook of Surgery, 19th ed.
What I need to know about Erection Problems. (2010). National Kidney and Urologic Diseases Information Clearinghouse (NKUDIC). NIH Publication No. 09-5483
Sadeghi-Nejad H, Brison D, & Dogra V. (2007). Male erectile dysfunction. Ultrasound Clin. 2:57–71
Feldman HA, Goldstein I, Hatzichristou DG, et al. (1994). Impotence and its medical and psychosocial correlates: Results of the Massachusetts male aging study. J Urol. 151:54–61.
