Reproductive · Male Sexual Dysfunction
The facts most likely to be tested
The most common organic cause of erectile dysfunction is vascular disease, specifically atherosclerosis affecting the penile arteries.
Nocturnal penile tumescence testing is the gold standard to differentiate between psychogenic (present) and organic (absent) erectile dysfunction.
Phosphodiesterase-5 (PDE-5) inhibitors are the first-line pharmacologic therapy but are strictly contraindicated with nitrates due to the risk of refractory hypotension.
Diabetes mellitus is a major risk factor for erectile dysfunction due to autonomic neuropathy and endothelial dysfunction.
Peyronie disease presents with a palpable fibrous plaque and penile curvature during erection, often leading to secondary erectile dysfunction.
Medication-induced erectile dysfunction is frequently caused by thiazide diuretics, beta-blockers, and SSRIs.
Hormonal evaluation including morning serum total testosterone is indicated in patients with decreased libido, testicular atrophy, or gynecomastia.
Vignette unlocked
A 58-year-old male presents to the clinic complaining of a 6-month history of difficulty achieving and maintaining an erection. He has a history of hypertension and type 2 diabetes mellitus, for which he takes lisinopril and metformin. He reports that he still experiences morning erections occasionally, though they are less firm than in the past. Physical examination reveals decreased peripheral pulses in the lower extremities. He denies any recent changes in mood or libido.
What is the most appropriate next step in the management of this patient's condition?
Initiate a trial of a PDE-5 inhibitor (e.g., sildenafil).
The patient's history of morning erections suggests a psychogenic component or preserved vascular integrity, but his risk factors (diabetes, hypertension) point toward organic vascular disease; PDE-5 inhibitors are the first-line treatment for erectile dysfunction in the absence of nitrate use.
Full handout
High yield triage
Etiology / Epidemiology
Common in diabetes mellitus, hypertension, and atherosclerosis. Often a sentinel marker for cardiovascular disease.
Clinical Manifestations
Inability to achieve or maintain an erection. Psychogenic vs organic etiology differentiation is key.
Diagnosis
Clinical diagnosis. Nocturnal penile tumescence testing is the gold standard to differentiate psychogenic from organic causes.
Treatment
Sildenafil is first-line. Absolute contraindication: concurrent nitrates due to risk of refractory hypotension.
Prognosis
High correlation with ischemic heart disease. Lifestyle modification can reverse symptoms in 25-30% of patients.
Full handout
Epidemiology & Etiology
Prevalence increases significantly with age, affecting over 50% of men aged 40-70. Primary risk factors include metabolic syndrome, smoking, and pelvic surgery (e.g., prostatectomy). It is frequently the first clinical manifestation of systemic vascular disease.
Pertinent Anatomy
The corpora cavernosa are the primary erectile tissues. Parasympathetic innervation via the pelvic splanchnic nerves (S2-S4) triggers vasodilation. The pudendal nerve provides somatic sensory input.
Pathophysiology
Sexual stimulation triggers release of nitric oxide, which increases cGMP levels, leading to smooth muscle relaxation and arterial inflow. Phosphodiesterase-5 (PDE5) normally degrades cGMP. Pathological states disrupt this pathway, often via endothelial dysfunction or impaired nerve signaling.
Clinical Manifestations
Patients report inability to achieve or maintain erection sufficient for intercourse. Psychogenic causes often present with sudden onset and preserved morning erections. Red flags include sudden onset of severe perineal pain or trauma, suggesting Peyronie's disease or vascular injury.
Diagnosis
Diagnosis is primarily clinical via history and physical. Nocturnal penile tumescence testing is the gold standard to rule out organic causes. Labs should include fasting glucose and lipid profile to screen for underlying metabolic disease.
Treatment
Sildenafil or Tadalafil are first-line agents. Contraindicated with nitrates due to fatal hypotension. Second-line options include intracavernosal alprostadil injections or vacuum erection devices. Surgical placement of a penile prosthesis is reserved for refractory cases.
Prognosis
ED is a strong predictor of future myocardial infarction and stroke. Patients require aggressive cardiovascular risk factor modification. Failure to respond to PDE5 inhibitors warrants further workup for occult vascular disease.
Differential Diagnosis
Psychogenic ED: sudden onset, normal nocturnal erections
Peyronie's disease: palpable fibrous plaque, penile curvature
Hypogonadism: low libido, decreased morning erections
Neurologic disease: history of spinal cord injury or multiple sclerosis
Medication-induced: SSRIs or beta-blockers