A 54-year-old man is evaluated for erectile dysfunction. The patient has been having problems attaining and maintaining erections during sexual activity for the past 6 months. Prior to the development of this problem, he had an active and satisfactory sex life. The patient continues to have normal early-morning penile erections. Medical history is notable for hypertension, mixed hyperlipidemia, and lumbar stenosis with a chronic right L4 radiculopathy. His current medications include ibuprofen, lisinopril, and atorvastatin. The patient smokes a pack of cigarettes daily and drinks alcohol only on social occasions. Blood pressure is 144/78 mm Hg and pulse is 80/min. BMI is 35 kg/m2. Physical examination shows normal body hair distribution and testicular size with no gynecomastia. Which of the following is the most likely cause of this patient's erectile dysfunction?
Common causes of erectile dysfunction | |
Clinical features | |
Vascular |
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Neurologic |
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Psychogenic |
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Endocrine |
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Medications |
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Hypogonadism |
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ED = erectile dysfunction; SSRIs = selective serotonin reuptake inhibitors. | |
Normal male erectile function requires interplay between psychological and physical stimulation, and vascular, neurologic, and hormonal systems. Causes of erectile dysfunction (ED) can be categorized as organic (eg, hypogonadism, diabetes, smoking) or psychogenic. Organic ED is often initially intermittent or slowly progressive and is more common with advancing age.
Psychogenic ED is typically due to interpersonal conflict, performance anxiety, or an underlying emotional disorder. Clinical factors suggesting a psychogenic etiology include sudden-onset, situational ED (eg, ED with a certain partner but normal erectile function during masturbation) and persistence of nonsexual nocturnal erections. Normal nocturnal erections indicate intact vascular and nerve function in the penis and are usually absent in patients with organic causes.
(Choice A) Antihypertensives, especially beta blockers and thiazide diuretics, are a common cause of ED. ACE inhibitors, angiotensin II receptor blockers, and calcium channel blockers are less likely to cause ED. Spironolactone and selective serotonin reuptake inhibitors are other common causes.
(Choice B) Systemic atherosclerosis is commonly associated with ED. However, although this patient has risk factors for atherosclerotic disease, vascular ED is typically chronic, insidious, and leads to loss of nonsexual erections.
(Choices C and D) Pituitary tumors can cause ED from low testosterone due to prolactin overproduction or compression of normal gonadotrophs. However, this patient has no features of hypoandrogenism or clinical features of a sellar mass. Primary hypogonadism is a common cause of ED but is usually associated with other signs (eg, weakness, loss of libido, gynecomastia, testicular atrophy).
(Choice E) Autonomic control of erectile function is mediated by lower thoracic (T11-T12) sympathetic and sacral (S2-S4) parasympathetic fibers. Reflex erection via tactile stimulation involves S2-S4 nerve roots. Disruption of lumbar nerve roots is less likely to affect erectile function.
Educational objective:
Persistence of nocturnal and early-morning penile erections helps differentiate psychogenic from organic causes of male erectile dysfunction. Normal nocturnal erections indicate intact vascular and nerve function in the penis.