Description

• Erectile dysfunction (ED): the consistent or recurrent inability to acquire 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, but 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

Epidemiology

Incidence
It is estimated that >600,000 new cases of ED will be diagnosed annually in the United States, although this may be an underestimation of the true incidence, as ED is vastly underreported.

Prevalence
Overall prevalence for some degree of ED:

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

Etiology and Pathophysiology

• Erections are neurovascular events.
  • With stimulation, there is 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 malaise, depression, performance anxiety
• Social habits such as smoking or excessive alcohol intake
• Medications may cause ED (see “Risk Factors”).
• Prostate cancer treatment
• Structural injury or trauma (bicycling accident)

Genetics
Rarely related to chromosomal disorders

Risk Factors

• Advancing age
• Cardiovascular disease
• 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

The two best ways to prevent ED are by the following:

• Making healthy lifestyle choices by exercising regularly, eating well-balanced meals, limiting alcohol, and avoiding smoking
• Treating existing health problems and working with your patients to manage diabetes, heart disease, and other chronic problems

Commonly Associated Conditions

• Cardiovascular disease:
  • 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 (1).
• Diabetes
• Neurologic conditions
• Metabolic syndrome
• Psychiatric disorders