Erectile dysfunction (ED) is a medical term that describes the inability to achieve and or maintain an erect penis adequate for sexual function. This condition is one of the most common sexual problems for men. The number of men suffering from ED increases with age. Approximately 25 million American men suffer from ED, although not all men are equally distressed by the problem.
Achieving a normal erection is a complex process involving psychological impulses from the brain, adequate levels of the male sex hormone testosterone, a functioning nervous system, and adequate and healthy vascular tissue in the penis. During erection, the sum of these processes is to cause increased blood flow into, and decreased blood flow out of, the penis. Under these conditions the specialized vascular tissue of the penis (the paired corpora cavernosa) become firm and rigid. Eventually, these conditions revert to the resting state of low blood flow into and increased blood flow out of, the penis. This process, called detumescence, leaves the penis flaccid. Any conditions that impact adversely on these event can lead to erectile dysfunction. Diabetes, in addition to damaging penile vascular tissue, causes problems with the nerves that innervate the penis (peripheral neuropathy) and can adversely affect the ability to get an erection. Finally, the medications used to treat these disorders particularly anti-hypertensives, themselves are known to contribute to ED.
There are risk factors for the development of ED. As men age, the level of circulating testosterone decreases, which may interfere with normal erection. While a low testosterone level itself is rarely the cause of ED (5 percent or less), low testosterone can be an additional contributing factor in many men who have other risk factors for ED. Low levels of sexual desire, lack of energy, mood disturbances and depression can all be symptoms of low testosterone. A simple blood test can determine if the testosterone level is abnormally low, and testosterone can be replaced using a number of different delivery systems (e.g., shots, skin patches, transdermal gels).
The most important causes of the development of ED are high blood pressure, diabetes mellitus, high cholesterol levels and cardiovascular disease. These processes, acting over time, can lead to a degeneration of the penile blood vessels, leading to restriction of blood inflow through the arteries and also leakage of blood through the veins, during erection.
Lifestyle choices can contribute to degeneration of the erectile tissue and the development of ED. Smoking, drug or alcohol abuse, particularly over a long period of time, will compromise the blood vessels and nerves of the penis. Lack of exercise and a sedentary lifestyle contribute to the development of ED. Correction of these conditions will aid to overall health and may in some individuals correct mild ED. Treatment of many medical conditions can interfere with normal erections. Patients undergoing surgery or radiation therapy for cancer of the prostate, bladder, colon or rectum are at high risk for the development of ED.
For most patients, the diagnosis will require a simple medical history, physical examination and a few routine blood tests. Most patients do not require extensive testing before beginning treatment. The choice of testing and treatment depends on the goals of the individual. If erection returns with simple treatment like oral medication and the patient is satisfied, no further diagnosis and treatment are necessary. If the initial treatment response is inadequate or the patient is not satisfied, then further steps may be taken. In general, as more invasive treatment options are chosen, testing may be more complex.
The first line of therapy for uncomplicated ED is use of oral medications known as phosphodiesterase-5 inhibitors (PDE-5) -- sildenafil, vardenafil or tadalafil. Men with ED take these pills before beginning sexual activity and the drugs boost the natural signals that are generated during sex, thereby improving and prolonging the erection itself. These medications are safe and fairly effective with improvement in erection in up to 80 percent of patients who use them. The most common side effects are headache, stuffy nose, flushing and muscle aches. In rare cases, sildenafil can cause blue-green shading of vision. This is of no long-term risk and is gone within a short time as the amount of sildenafil in the blood decreases. It is important to follow the instructions for using these medications in order to get the best results. Tests have shown that 40 percent of men who do not respond to sildenafil will respond when they receive proper instruction on medication use.
For men who do not respond to oral medications another drug, alprostadil, is approved for use in men with ED. This drug comes in two forms:
Injections that the patient places directly into the side of the penis.
A transurethral suppository. Success rates with self-injection can reach 85 percent.
For men who cannot or do not wish to use drug therapy, an external vacuum device may be implemented. This device combines a plastic cylinder or tube that slips over the penis, making a seal with the skin of the body. A pump on the opposite end of the cylinder creates a low-pressure vacuum around the erectile tissue, which results in an erection. To keep the erection once the plastic cylinder is removed a rubber constriction band goes around the base of the penis, which maintains the erection.
There are some men who have severe degeneration in the tissues of the penis, which makes them unable to respond to any of the treatments listed above. While this is a small number of men, they usually have the most severe forms of ED. Patients most likely to fall into this group are men with advanced diabetes, men who suffered from ED before undergoing surgical or radiation treatment for prostate or bladder cancer and men with deformities of the penis called Peyronie's disease. For these patients reconstructive prosthetic surgery (placement of a penile prosthesis or "implant") will restore erection, with patient satisfaction rates approaching 90 percent. Surgical prosthetic placement normally can be performed in an outpatient setting or with one night of hospital observation. Possible adverse effects include infection of the prosthesis or mechanical failure of the device.
All of the treatments above, with the exception of prosthetic reconstructive surgery, are temporary and meant for use on demand. The treatments compensate for but do not correct the underlying problem in the penis. So it is important to follow-up with your doctor and report on the success of the therapy. If your goals are not reached, if your erection is not of sufficient quality or duration and you are still distressed, you should explore the alternatives with your doctor. Because the medications used are not correcting the problems leading to ED, your response over time may not be what it once was. If such should occur again, have a repeat discussion with your physician about the remaining treatment options.