What is Erectile Dysfunction?

The first step in treating Erectile Dysfunction is that the individual understands the psychology, physiology and anatomy responsible for the ability to achieve and maintain an erection.  If we can comprehend these events than we can better understand the factors that are responsible for ED and address the questions concerning treatment.

What is Normal Erectile Function?

For something that appears so natural, an erection is a rather complicated process involving the coordination of the psychological, neurological and cardiovascular systems.  The penis becomes erect following a series of events.  First, the nerves are stimulated, a sensation known as arousal.  No matter what the nature of the stimulus, visual, mental or physical the brain coordinates the following series of events:

Nerve impulses transverse the length of the spinal cord to the pudendal nerve and on to the penis.  Smooth muscle within the walls of the penile arteries respond by relaxing.

Subsequently, the penile arteries dilate allowing up to eight times more blood to flow into the corpora cavernosum, (two parallel cylinders that transverse the length of the penis).

The cavernosum become engorged with blood expanding and lengthening the penis.

The expanding tissue then exerts a positive pressure compressing the veins that normally empty the blood from the penis, maintaining the blood in the penile tissue.

When ejaculation occurs or when arousal is discontinued the penis returns to its non-erect state.

What are the causes of Erectile Dysfunction?

Historically, when an individual consulted his physician concerning ED he was usually informed there were no known physiological answers concerning his condition.  Today, a generation of research has resulted in significant advances in both the diagnosis and treatment of ED. Physicians now understand that approximately eighty-five percent of ED is attributable to physical/organic conditions while only fifteen percent is due to psychological or mixed origin (both psychological and organic).  Some important causes of physiological ED are as follows:

Vascular Disease is the leading cause of ED. Vascular disorders including arteriosclerosis (hardening of the arteries), hypertension, hypercholestremia and other conditions which interfere with the blood flow to the penis.  Additionally, "venous leakage" also contributes to poor erections.  This condition occurs when the penile veins are unable to constrict efficiently during an erection.  When these veins "leak" blood escapes to the periphery resulting in a poor erection

Diabetes is another common cause of ED. Approximately fifty percent of men with diabetes (insulin dependent) experience some degree of ED after the age of fifty-five.  Diabetes results in poor circulation and/or peripheral neuropathy.  When the nerves are involved sexual stimuli are not transmitted appropriately to or from the brain and ED develops.

Prescription medications often cause ED as a side effect.  Some two hundred known medications fall into this category including:

Substance Abuse can also negatively effect male potency.  The chronic use of cocaine, marijuana, alcohol, steroids etc. often results in ED, as well as a decrease in desire.  Excessive tobacco use can also attribute to ED by accentuating the effects of other risk factor such as vascular disease or hypertension.

Radical Pelvic Surgery also result in ED. Surgical procedures involving the prostate gland, bladder or colon may interfere with the nerves involved in the erectile response.  Radiation therapy for cancer may also effect the erectile process.

Neurological diseases such as multiple sclerosis, Parkinson's disease, spinal cord injuries, long term effects of diabetes can also result in the disruption of the normal sequence of events necessary for an erection to occur. 

Deficiencies in the Endocrine System are another source of ED. Low levels of testosterone or thyroid hormone can interfere with the stimulation process necessary in the erection sequence.  Excessive production of prolactin by the pituitary gland may contribute to decreased levels of testosterone resulting in a lack of desire.  Diabetes once again enters the scenario as it is classified as an endocrine disorder.

Psychological ED is usually diagnosed when no physical causes can be defined.  Pure psychological ED usually occurs suddenly without warning as opposed to physical ED that may gradually develop over years.  Some common causes of psychological ED are as follows:

• Performance anxiety is one of the most common causes of psychological ED.  When a man feels pressured to achieve or maintain an erection, he will commonly become anxious and nervous when in a sexually demanding situation.  Stress increases the body's production of catecholamines such as adrenaline and nor- adrenaline, which act as erection inhibitors.  The release of these inhibitors further contributes to failure resulting in more anxiety.  Therefore, the cycle begins, increased stress resulting in increased catecholomines that further inhibits the erectile process.
• Depression is another cause of psychogenic ED.  Unfortunately, many of the popular antidepressant medications (for a list see prescription medications in the next section) have side effects which include erectile failure.

Anatomical Deviation of the Penis, Peyronies Disease, may also cause ED.  This condition usually develops from an inflammatory process and results in fibrous scaring of the penis.  (The cause of this process is not yet understood)  However, when an erection does occur, there is a bending of the penis secondary to the scar tissue.  This curvature may interfere with erectile capacity and/or ejaculation.