23-06: Male Erectile Dysfunction & Sexual Dysfunction

GENERAL CONSIDERATIONS

Male sexual dysfunction is manifested in a variety of ways, and patient history is critical to the proper classification and treatment. A loss of libido may indicate androgen deficiency. Erectile dysfunction is the consistent inability to attain or maintain a sufficiently rigid penile erection for sexual intercourse. More than half of men aged 40–70 years have erectile dysfunction and its incidence increases with age. Loss of erections may result from neurogenic, arterial, venous, hormonal, or psychological causes. Concurrent medical problems may damage one or more of the mechanisms. Normal male erection is a neurovascular event relying on an intact autonomic and somatic nerve supply to the penis, arterial blood flow supplied by the paired cavernosal arteries, and smooth and striated musculature of the corpora cavernosa and pelvic floor. Erection is initiated by nerve impulses in the pelvic plexus leading to an increase in arterial flow, active relaxation of the smooth muscle within the sinusoids of the corpora cavernosa, and an increase in venous resistance. Contraction of the ischiocavernosus muscle causes further rigidity of the penis with intracavernosal pressures exceeding systolic blood pressure. Nitric oxide is the key neurotransmitter that initiates and sustains erections.

The most common cause of erectile dysfunction is a decrease in arterial flow resultant from progressive vascular disease. Endothelial dysfunction results from the decreased bioavailability of nitric oxide with subsequent impairment of arterial vasodilation. Erectile dysfunction may be an early manifestation of endothelial dysfunction, which precedes more severe atherosclerotic cardiovascular disease. Many medications, especially antihypertensive, antidepressant, and opioid agents, are associated with erectile dysfunction.

Anejaculation is the loss of seminal emission and may result from androgen deficiency by decreasing prostate and seminal vesicle secretions, or by sympathetic denervation as a result of spinal cord injury, diabetes mellitus or pelvic or retroperitoneal surgery or radiation. Retrograde ejaculation may occur as a result of mechanical disruption of the bladder neck, due to congenital abnormalities, transurethral prostate surgery, pelvic radiation, sympathetic denervation, or treatment with alpha-blockers. Premature ejaculation is the distressful, recurrent ejaculation with minimal stimulation before a person desires. Primary premature ejaculation may be treated with behavioral modification, sexual health counseling, local anesthetic agents, and systemic medications used alone or in combination. Secondary premature ejaculation is due to erectile dysfunction and responds to treatment of the underlying disorder. Peyronie disease is a fibrotic disorder of the tunica albuginea of the penis resulting in varying degrees of penile pain, curvature, or deformity. Peyronie disease affects up to 10% of men and, similar to erectile dysfunction, is more common with increased age. While 10% of men ...