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Erectile Dysfunction

BASICS

DESCRIPTION

  • Erectile dysfunction (ED): consistent/recurrent inability to obtain or maintain an erection for sexual intercourse.
  • Previously thought to be a natural part of aging; now recognized often due to medical conditions or medications.
  • Synonym: impotence.

EPIDEMIOLOGY

  • 600,000 new ED cases diagnosed yearly in the US; largely underreported.

  • Overall prevalence: 52% in men aged 40-70 years.
  • Age-related increase: 12.4% in 40-49 years, 46.6% in 50-69 years.

ETIOLOGY AND PATHOPHYSIOLOGY

  • Erections are neurovascular events involving:
  • Nitrous oxide release → increased cGMP → cavernous smooth muscle relaxation → increased penile blood flow.
  • Passive venous compression → erection maintenance.
  • ED results from disruption in these pathways due to:
  • Vascular disease: peripheral vascular disease, diabetes, arteriosclerosis, hypertension, medication effects.
  • Neurologic disease: spinal cord injury, stroke, diabetic neuropathy.
  • Endocrine abnormalities: low testosterone, altered LH/prolactin.
  • Structural abnormalities: phimosis, Peyronie’s disease, congenital curvature.
  • Psychological: depression, anxiety, performance anxiety, premature ejaculation.
  • Lifestyle: smoking, excessive alcohol.
  • Medications: SSRIs, beta-blockers, clonidine, digoxin, spironolactone, antiandrogens, corticosteroids, H2 blockers, anticonvulsants.
  • Prostate cancer treatment, trauma (e.g., bicycling accident).

RISK FACTORS

  • Advancing age.
  • Cardiovascular disease (CVD).
  • Diabetes mellitus.
  • Metabolic syndrome.
  • Sedentary lifestyle.
  • Smoking.
  • Pelvic surgery, radiation, trauma, spinal cord injury.
  • Medications inducing ED.
  • Substance abuse: alcohol, cocaine, opioids, marijuana.
  • Psychological stress, sexual abuse, relationship problems.

GENERAL PREVENTION

  • Healthy lifestyle: exercise, limit alcohol, no smoking.
  • Manage existing diseases: diabetes, CVD.

Alert: Aging alone is not a cause of ED.

COMMONLY ASSOCIATED CONDITIONS

  • CVD: bidirectional relationship; ED is independent risk marker.
  • Diabetes.
  • Neurologic/psychiatric conditions.
  • Metabolic syndrome.

DIAGNOSIS

HISTORY

  • Concurrent illnesses, surgeries, trauma, medications.
  • Psychosocial: smoking, alcohol, drug use, anxiety, depression, relationship satisfaction.
  • Presence/absence of morning erections.
  • Onset speed and duration.
  • Relation to libido.
  • Rule out premature ejaculation (common confusion).
  • Use International Index of Erectile Function (IIEF) questionnaire.

PHYSICAL EXAM

  • Signs of hypogonadism: gynecomastia, small testes, decreased body hair.
  • Penile plaques (Peyronie disease).
  • Cardiovascular, neurologic, genitourinary exam.
  • Vitals including blood pressure, BMI, waist circumference.
  • Peripheral pulses (femoral, lower extremity).
  • Anal sphincter tone, genital reflexes (cremasteric, bulbocavernosus).
  • DRE optional but may evaluate for BPH/LUTS before testosterone therapy.

DIFFERENTIAL DIAGNOSIS

  • Premature ejaculation.
  • Decreased libido.
  • Anorgasmia.
  • Acute vs chronic ED.

DIAGNOSTIC TESTS

  • Vascular/neuro tests and nocturnal erection monitoring reserved for complex cases.

Initial labs

  • HbA1c, lipid panel, CBC, BMP, TSH.
  • Morning total/free testosterone.

Specialized tests

  • Doppler US, angiography, cavernosography in select cases (not routine).

Questionnaires

  • IIEF, Sexual Health Inventory for Men (SHIM).

TREATMENT

GENERAL MEASURES

  • Lifestyle modification and medication review first-line.
  • Cardiovascular risk stratification and management essential for vasculogenic ED.
  • Smoking cessation improves erectile function.
  • Psychosexual therapy for ED related to anxiety/depression.
  • Weight loss, exercise in obese and metabolic syndrome patients.

MEDICATION

First Line

  • PDE-5 inhibitors (all similar efficacy):
  • Sildenafil (Viagra): 50-100 mg 1-4 hrs prior intercourse.
  • Vardenafil (Levitra, Staxyn): 10 mg ~1 hr prior.
  • Tadalafil (Cialis): daily (2.5-5 mg) or on-demand (5-20 mg) up to 36 hrs prior.
  • Avanafil (Stendra): 50-200 mg 15-30 mins prior.
  • Adverse effects: headache, flushing, dyspepsia, nasal congestion, dizziness, hypotension, vision changes, priapism.
  • Elderly: start at lower doses (Sildenafil 25 mg/day, Vardenafil 5 mg/day).

Second Line

  • Intraurethral and intracavernosal alprostadil (prostaglandin E1).
  • Vacuum erection devices (VED).
  • Penile prosthesis implantation.

Alert: Intracavernosal therapy trial should be supervised; seek care if erection >4 hrs.
Avoid vacuum devices in sickle cell or blood dyscrasias.

  • Testosterone supplementation if hypogonadal (not if normal levels).
  • Avoid nitrates with PDE-5 inhibitors (risk severe hypotension).

Precautions/Interactions

  • PDE-5 inhibitors affected by CYP3A4 inhibitors and inducers.
  • Caution with cardiac disease, prolonged QT, α-blockers.

ADDITIONAL THERAPIES

  • Psychosocial therapy combined with sildenafil improves outcomes.
  • MED3000 hydroalcoholic gel (UK OTC) recently FDA approved topical option.

SURGERY/OTHER PROCEDURES

  • Penile prostheses: inflatable and malleable/semirigid options.

COMPLEMENTARY & ALTERNATIVE MEDICINE

  • Trazodone, yohimbine, herbal therapies not recommended.
  • Low-intensity shockwave therapy not FDA approved but may help.

ONGOING CARE

FOLLOW-UP

  • Assess after 1-3 weeks of therapy.
  • Monitor erection quality/quantity and patient satisfaction.

DIET

  • Healthy diet and exercise to maintain normal BMI; limit alcohol.

PROGNOSIS

  • PDE-5 inhibitors 55-80% effective with stimulation.
  • Lower success with diabetes and post-prostatectomy.
  • Intracavernosal alprostadil: 70-90% effective; intraurethral: 43-60%.
  • Penile prostheses: 85-90% patient satisfaction.

REFERENCES

  1. Burnett AL, Nehra A, Breau RH, et al. Erectile dysfunction: AUA guideline. J Urol. 2018;200(3):633-641.
  2. Rew KT, Heidelbaugh JJ. Erectile dysfunction. Am Fam Physician. 2016;94(10):820-827.
  3. Melnik T, Soares BGO, Nasselo AG. Psychosocial interventions for erectile dysfunction. Cochrane Database Syst Rev. 2007;2007(3):CD004825.

CODES

  • ICD10 N52.03 Combined arterial insufficiency and corporo-venous occlusive erectile dysfunction
  • ICD10 N52.2 Drug-induced erectile dysfunction
  • ICD10 F52.21 Male erectile disorder

CLINICAL PEARLS

  • Nitrates contraindicated with PDE-5 inhibitors due to risk of severe hypotension and syncope.
  • Reserve surgery for drug nonresponders.
  • PDE-5 inhibitors with α-blockers increase hypotension risk; tamsulosin least likely to cause orthostasis.
  • ED may be marker of subclinical CVD; assess cardiovascular risks thoroughly in nonpsychogenic ED.