23-06: Male Erectile Dysfunction & Sexual Dysfunction

GENERAL CONSIDERATIONS

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 and severity increase with age. 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 cavernosal arteries, and smooth and striated musculature of the corpora cavernosa and pelvic floor. Erection is initiated by stimulation of the pelvic nerve plexus leading to release of nitric oxide with resultant increased arterial flow, active relaxation of corpora cavernosal smooth muscle, and increased venous resistance. Contraction of the ischiocavernosus muscle causes further rigidity of the penis with intracavernosal pressures exceeding systolic blood pressure.

Male sexual dysfunction is manifested in a variety of ways, and patient history is critical to the proper classification and treatment. Erectile dysfunction may result from neurogenic, arterial, venous, hormonal, or psychogenic causes. Concurrent medical problems may damage one or more of the mechanisms. 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.

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 develops in approximately 5–10% of men and is more common with increased age. While 10% of men improve spontaneously, 50% will stabilize and the remainder will progress if left untreated. Penile deformity can impair normal sexual function and impact self-esteem. Peyronie disease is most commonly resultant from minor, buckling penile trauma followed by inflammation in the circular or longitudinal layers of the corpora cavernosa with the subsequent, disordered deposition of collagen. Familial disease patterns and the strong association between Peyronie disease and Dupuytren contracture suggests a genetic component in some cases. Modulators of Peyronie disease include erectile dysfunction, vascular disease, and hypogonadism.

Priapism is the occurrence of penile erection lasting longer than 4 hours resulting in ischemic injury of the corpora cavernosa from venous congestion and cessation of arterial inflow (low flow or “ischemic” priapism). Ischemic priapism is a medical emergency requiring immediate medical or surgical intervention to avoid irreversible penile damage. Ischemic priapism may be caused by red blood cell dyscrasias, drug use, and any of the treatments for erectile dysfunction. High-flow priapism, caused by unregulated high blood flow due to arteriovenous ...