|
Impotence
Impotence can be defined as the failure to achieve erection, ejaculation, or both. A variety of endocrine, vascular, neurologic, and psychiatric diseases can disrupt normal sexual and reproductive function in men. Sexual dysfunction can also be the presenting symptom of systemic disease. Penile erection is normally initiated by neuropsychologic stimuli that ultimately produce vasodilation of the sinusoidal spaces and arteries within the penis. Important regulatory control is provided at the brain, spinal cord level, and through actions of the autonomic nervous system. Men with sexual dysfunction present with a variety of complaints, either singly or in combination: loss of libido, inability to initiate or maintain an erection, or inability to achieve orgasm. Sexual dysfunction can be secondary to systemic disease processes (diabetes) or their treatments (drugs), specific disorders of the genitals, endocrine system, or to psychiatric disturbances.
It used to be thought that the majority of men with sexual dysfunction had a underlying psychological cause for their dysfunction. It is now believed that the majority of impotent men have a component of underlying organic disease. There are several key factors that contribute to impotency:
1. Loss of desire: A decrease in desire or libido may be due to a deficiency of the male sex hormone, testosterone. Other causes include psychological factors and habitually abused drugs (heroin, alcohol, cocaine).
2. Failure of erection: The organic causes of erectile impotence can be found in the following group:
ENDOCRINE causes (testicular failure, hyperprolactinemia)
DRUGS (cimetidine, spironolactone, ketoconazole, clonidine, methyldopa, beta-blockers, thiazide diuretics, anticholinergics, antidepressants, sedatives, barbiturates, Mao inhibitors, benzodiazepines, antipsychotics and other abused drugs (alcohol, methadone, cocaine, heroin).
PENILE DISEASES (Peyronie's disease, previous priapism, penile trauma)
Neurologic diseases (spinal cord disease, anterior temporal lobe lesions, tabes dorsalis, post-surgical nerve damage, diabetic neuropathy)
Vascular disease (aortic occlusion, atherosclerosis)
Disease of the sinusoidal spaces (inside the penis)
3. Premature ejaculation: This problem seldom has an organic cause. It is usually related to anxiety in a sexual situation, unreasonable expectations about performance, or emotional disorder.
4. Absence of emission: This symptom may be secondary to (1) retrograde ejaculation, (2) sympathetic denervation after surgery, (3) testosterone deficiency, (4) drug effects (e.g. guanethidine, phenoxybenzamine). Retrograde ejaculation can occur following surgery on the neck of the bladder or develop spontaneously in diabetic men. Demonstration of sperm in the urinalysis (after intercourse) establishes this diagnosis.
5. Absence of orgasm: If libido and erectile function are normal, the absence of orgasm is almost always due to a psychiatric disorder. Evaluation of impotence will require the physician to separate those instances due to psychological factors and those due to organic causes. Often this differentiation can be made on the basis of the medical history alone. Penile erections occur on a normal basis during REM stage sleep. This is known as nocturnal penile tumescence (NPT). The total time of NPT averages 100 minutes per night. Consequently, if the impotent man gives a history for erections under any other circumstances (upon wakening in the morning) then physiologic function is intact and the impotence is likely to be secondary to psychiatric causes. NPT can be assessed with the use of a specially adapted strain gauge (attached to the penis) that will record penile erection. Other key points of the evaluation will involve physical examination and neurologic assessment. A thorough drug history is necessary to uncover a potential pharmacological cause. Treatment for organic impotence is difficult and many times unsuccessful. Medical therapy with male sex hormones offer little more than placebo benefit. Psychiatric counseling is beneficial for both the organic and psychological causes of impotence.
Penile prostheses are the most common therapeutic alternative in impotent patients who fail to respond to other forms of therapy. Malleable silastic rode implanted into the penis provide the simplest system and lowest complication rates. The hydraulically operated prostheses offer the advantage of more physiologic erection and greater increase in penile diameter. The Urologist is the expert in the evaluation and treatment of this complex disorder.
|
