Erectile Dysfunction



  • Erectile dysfunction (ED): the consistent or recurrent inability to acquire and/or sustain an erection of sufficient rigidity and duration for sexual intercourse
  • In the past, ED was assumed to be a symptom of the aging process in men. It is more often the result of concurrent medical conditions of the patient or from medications that patients may be taking to treat those conditions.
  • Sexual problems are frequent among older men and have a detrimental effect on their quality of life but are infrequently discussed with their physicians.
  • Synonym(s): impotence


>600,000 new cases of ED diagnosed annually in the United States; ED is vastly underreported.

Overall prevalence for some degree of ED:

  • 52% in men aged 40 to 70 years
  • Age-related increase ranging from 12.4% in men aged 40 to 49 years up to 46.6% in men aged 50 to 69 years

Etiology and Pathophysiology

  • Erections are neurovascular events.
    • With stimulation, there is a release of nitrous oxide, which increases production of cyclic guanosine 3′,5′-monophosphate (cGMP).
    • This leads to relaxation of cavernous smooth muscle, leading to increased blood flow to penis.
    • As cavernosal sinusoids distend with blood, there is passive compression of subtunical veins, which decreases venous outflow, and this leads to an erection.
  • Alterations in any of these events lead to ED.
  • ED may result from problems with systems required for normal penile erection.
  • Vascular: diseases that compromise blood flow (peripheral vascular disease, diabetes, arteriosclerosis, essential hypertension, and some medications that treat hypertension)
  • Neurologic: diseases that impair nerve conduction to brain or penile vasculature (spinal cord injury, stroke, diabetes)
  • Endocrine: diseases associated with changes in testosterone, luteinizing hormone, prolactin levels
  • Structural: phimosis, lichen sclerosis, congenital curvature
  • Psychological: patients suffering from depression, performance anxiety, premature ejaculation
  • Smoking or excessive alcohol intake
  • Medications
  • Prostate cancer treatment
  • Structural injury or trauma (bicycling accident)

Risk Factors

  • Advancing age
  • Cardiovascular disease (CVD)
  • Diabetes mellitus
  • Metabolic syndrome
  • Sedentary lifestyle
  • Cigarette smoking
  • Pelvic surgery, radiation, trauma/injury to pelvic area or spinal cord
  • Medications that induce ED: SSRIs, β-blockers, clonidine, digoxin, spironolactone, antiandrogens, corticosteroids, H2 blockers, anticonvulsants
  • Central neurologic and endocrinologic conditions
  • Substance abuse (alcohol, cocaine, opioids, marijuana)
  • Psychological conditions: stress, anxiety or depression, sexual abuse, relationship problems

General Prevention

  • Healthy lifestyle: exercise, limiting alcohol, not smoking
  • Treating existing health problems: diabetes, heart disease, etc.
Aging alone is not a cause.

Commonly Associated Conditions

  • CVD:
    • There is a documented two-way relationship between ED and CVD, and ED has been identified as an independent risk marker for CVD with ED found to confer a 25% increased 10-year risk of CVD in the QRISK model (1). Men with ED have a greater likelihood of having angina, myocardial infarction, stroke, transient ischemic attack, congestive heart failure, or cardiac arrhythmia compared to men without ED.
  • Diabetes
  • Neurologic and psychiatric conditions
  • Metabolic syndrome

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