ERECTILE DYSFUNCTION
Ghasoub Harb, MD, FACS
What is erectile dysfunction (ED), or impotence?
Erectile dysfunction (ED) is described simply as the inability to achieve or maintain an erection suitable for sexual intercourse. Impotence affects 30 million American men, or about 10% of the entire male population, and 35% of the men over the age of 40. In a national survey conducted for AARP of 639 men age 45 years and older, only 10% of the respondents reported seeking or receiving treatment to improve sexual function. Only half of the men (5%) who had sought treatment had tried or were using Viagra.
How does an erection occur?
An erection is created when a man is sexually aroused. The penis fills with blood much like a tire fills with air. The blood is pumped into the penis and not allowed out, and the more blood that is pumped in, the firmer the erection. The reasons for lack of erections are either the lack of appropriate filling of the penis or inappropriate emptying. Because the nervous system controls the arteries and veins, psychological problems can cause emptying of the penis at unwanted times. It once was felt that psychological causes were the most important causes, but we have come to realize that they are in a significant minority. The major causes of impotence today are diabetes, atherosclerosis (or hardening of the arteries), and impotence following radical pelvic surgery. Other causes include spinal cord injuries, hormonal problems, and multiple sclerosis.The abuse of drugs, alcoholism, and smoking can interfere with normal erections, and more than 200 different prescription medications can cause impotence as a side effect.
How do physicians make the diagnosis of ED?
Any physician can make the diagnosis of impotence. Despite the fact that more than 80% of patients expect their doctors to "ask the question," unfortunately,only 23% of doctors do. A complete history and physical along with some psychological screening and, occasionally, an evaluation of the hormone levels are important. Other tests may include blood tests to check the kidney function, prostatic specific antigen (PSA) to check for prostate cancer,and fasting blood sugar to check for diabetes. Additional studies include evaluation of nerve function and blood flow measurements to the penis using Doppler ultrasound. Some additional tests are invasive and expensive. While the results are often enlightening, they rarely change the options for treatment.
Does smoking increase the risk for developing ED?
A study by McVary and colleagues found that there is an association between smoking and ED. According to the analysis, the risk of moderate or complete ED was increased 2-fold by cigarette smoking.
What about other risk factors for developing ED?
Table 1. Other risk factors for developing ED
| Severe depression |
90% |
| Cardiovascular disease |
70% |
| Multiple sclerosis |
71% |
| Diabetes |
30–60% |
| Hepatic failure |
25–70% |
| Chronic renal failure |
40% |
| Radical prostatectomy (RRP) |
57% |
| Radiation therapy |
40% |
| RRP with bilateral nerve sparing |
20% |
| Medications side effects |
15–20% |
Table 2. Chronic disease states that are major risk factors for ED
| Chronic Disease |
Fold Increase ED Risk |
| Diabetes |
x 4.1 fold increase ED risk |
| Prostate disease |
x 2.9 fold increase ED risk |
| Peripheral vascular disease |
x 2.6 fold increase ED risk |
| Cardiac problems |
x 1.8 fold increase ED risk |
| Hyperlipidemia |
x 1.7 fold increase ED risk |
| Hypertension |
x 1.6 fold increase ED risk |
