Appoximately 15 milion men in America have some degree of erectile dysfunction. Up to eight percent of cases is caused by biologic factors. Psychogenic factors are also important.

Erectile dysfunction is inability to attain or mantain penile erection sufficient for sexual intercourse. In the sacral cord (S2-S4), there are parasympathetic nerves. These nerves participate in erection. The sympathetic nerves arise from cells in T11-T12 levels of the spinal cord through the hypogastric plexus. These nerves are important in ejaculation. The parasympathetic activity release nitric oxide (local tissue mediators) and cGMP that contributing to sustained erection.

Etiology

Multifactorial can cause sexual dysfunction

1. Neurogenic.
   include myelopathy, neuropathy, cauda equina lesions, CNS dsyfunction.
2. Endocrine disorders.
   such as hypothyroidism, hypogonadism, hyperprolactinemia
3. Cronic illness.
4. Psychogenic illness.
5. Drugs.
   such as antihypertensive, anticholinergic, antidepressants, narcotics, and sedatives.
6. Metabolic and toxic disorders.
   such as liver disease, alcohol abuse, and renal failure.
7. Other causes.
   include vascular disease and pelvic trauma.

Diagnostic.

The doctor should evaluate patient with erectile dysfunction by asking complete history and doing physical exam;

1. Neurologic examination, may provide evidence of cerebral, spinal cord or peripheral nerve dysfunction.
2. Evaluation of laboratory, an endocrine panel with level of testosteron, prolactin and gonadotropins.
3. Sleep studies, erection usually occurs with each episode of rapid-eye-movement sleep.
4. EMG and somatosensory evoked potential, these are useful in case peripheral nerve disease and myelopathy.
5. Vascular studies ( by using papaverine -vasoactive agent), these studies evaluate the response of the penis to injection of papaverine.

Treatment.

The therapy of erectile dysfunction is based on the etiology. Metabolic, endocrine, vascular and psychogenic causes must be treated when present. If the cause are drugs, changes in medication may be beneficial. Selective inhibitors of cGMP specific phosphodiesterases; sildenafil (Viagra) and vardenafil (Levitra), intraurethral suppositories, and intracavernosal injections of alprostadil (Caverject) are therapy of pharmacologic for erectile dysfunction. (by doctor rend-sand)