Erectile Dysfunction
Persistent inability to achieve or maintain erection adequate for satisfactory sex — vascular disease until proven otherwise.
Also known as: ED, erectile dysfunction, impotence, vasculogenic ED
Overview
Persistent or recurrent inability to attain and/or maintain a penile erection sufficient for sexual satisfaction for at least 3 months. Subtypes are vasculogenic, neurogenic, hormonal, psychogenic, or drug-induced — often multifactorial.
Epidemiology
Affects ~50% of men aged 40-70 to some degree; prevalence rises with age. Strongly associated with cardiovascular disease — ED often heralds CAD by 3-5 years.
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Risk factors
- Cardiovascular disease, hypertension, hyperlipidemia
- Diabetes mellitus (both vasculogenic and neurogenic mechanisms)
- Smoking, obesity, sedentary lifestyle
- Hypogonadism (low testosterone)
- Pelvic surgery (radical prostatectomy, cystectomy), pelvic radiation
- Neurologic disease: multiple sclerosis, spinal cord injury, stroke
- Medications: thiazides, beta-blockers, SSRIs, antiandrogens, 5-alpha reductase inhibitors, opioids
- Depression, anxiety, relationship issues
- Peyronie's disease
- Sleep apnea, alcohol/substance use
Pathophysiology
Erection requires intact arterial inflow, venous occlusion (veno-occlusive mechanism), parasympathetic neural signaling (nitric oxide release → cGMP → smooth muscle relaxation in cavernosal sinusoids), and adequate testosterone for libido. Endothelial dysfunction in atherosclerosis impairs NO-mediated vasodilation — the same mechanism affects penile and coronary arteries (penile arteries are smaller, manifest dysfunction earlier).
Clinical presentation
Symptoms
- Inability to achieve or maintain erection
- Reduced rigidity or duration of erections
- Loss of nocturnal/morning erections (organic ED) vs preserved (psychogenic)
- Reduced libido (especially with hypogonadism)
- Relationship distress, depression
Signs / physical exam
- Often normal exam
- Cardiovascular: peripheral pulses, blood pressure, signs of PAD
- Genitourinary: testicular size, Peyronie's plaque, gynecomastia (hypogonadism)
- Neurologic: sensation, anal sphincter tone, bulbocavernosus reflex
- Body habitus, secondary sex characteristics
Differential diagnosis
- Hypogonadism — Low libido + ED, fatigue; low morning total testosterone (confirm with repeat + free T)
- Psychogenic ED — Sudden onset, intermittent, situation-dependent, preserved nocturnal/morning erections; younger men
- Peyronie's disease — Penile curvature, palpable plaque, pain with erection; often coexists with ED
- Premature ejaculation — Distinct primary complaint; treat with SSRIs (paroxetine, sertraline) or dapoxetine
- Medication side effect — Temporal relation; common with SSRIs, beta-blockers, thiazides, finasteride
- Pelvic vascular disease (Leriche) — Buttock claudication, ED, absent femoral pulses; aortoiliac disease
Diagnostic workup
Labs
- Fasting glucose or A1c, lipid panel
- Morning total testosterone (8-11 AM; repeat if low); free testosterone, SHBG, LH, FSH, prolactin if low T
- TSH
- Consider CBC, BMP, PSA (age-appropriate)
- Cardiac risk assessment — ED is a marker for cardiovascular disease
Imaging
- Penile Doppler ultrasound — for refractory ED or to differentiate arterial insufficiency from venous leak
- Nocturnal penile tumescence testing — distinguishes organic from psychogenic (preserved nocturnal erections favor psychogenic)
- Limited routine imaging
Diagnostic algorithm
| Class | Drugs | Notes |
|---|---|---|
| PDE5 inhibitor | Sildenafil, tadalafil, vardenafil, avanafil | First-line; nitrate contraindication; α-blocker caution |
| Intracavernosal injection | Alprostadil; Trimix (alprostadil + papaverine + phentolamine) | High efficacy; priapism risk |
| Intraurethral suppository | Alprostadil (MUSE) | Less effective than injection |
| Vacuum erection device | (Mechanical) | Drug-free; suitable in nitrate users |
| Testosterone replacement | Transdermal gel, IM injection, pellets | Only if confirmed hypogonadism; monitor PSA, Hct |
| Penile prosthesis | Inflatable or malleable | Refractory cases; high satisfaction |
Treatment
First-line
- Address modifiable factors: smoking cessation, weight loss, exercise, glycemic and BP control, lipid management, treat depression
- Review and modify medications when feasible (e.g., swap thiazide for ARB; selegiline/bupropion if SSRI-induced)
- PDE5 inhibitor — sildenafil, tadalafil, vardenafil — first-line pharmacotherapy
- • Sildenafil 25-100 mg 30-60 min before sex; effect ~4 h; fatty meals delay onset
- • Tadalafil 5-20 mg as needed (effect 24-36 h, 'weekend pill') OR 2.5-5 mg daily for continuous coverage
- • Vardenafil 5-20 mg
- • Absolute contraindication: nitrate use (severe hypotension)
- • Caution: alpha-blockers (separate dosing), severe cardiac disease, retinal disease
ED + cardiovascular disease
- Cardiac risk stratification before initiating sexual activity (Princeton Consensus)
- Low-risk: PDE5 inhibitors safe
- Intermediate-risk: stress testing, defer therapy until stabilized
- High-risk: defer until cardiology cleared
Post-prostatectomy ED
- Early penile rehabilitation: PDE5 inhibitor (daily low-dose tadalafil) ± vacuum device
- Nerve-sparing technique improves outcomes
- Recovery may take 12-24 months; intracavernosal injections or prosthesis if persistent
Second-line / adjunct
- Testosterone replacement — only if confirmed hypogonadism (low T + symptoms); contraindicated in untreated prostate or breast cancer; monitor PSA and hematocrit
- Vacuum erection devices (VED) — mechanical, no pharmacology
- Intraurethral alprostadil (MUSE) suppositories
- Intracavernosal injections — alprostadil, papaverine, phentolamine (Trimix); high efficacy when PDE5i fails; risk of priapism, fibrosis
- Penile prosthesis (inflatable or malleable) — for refractory ED; highest patient satisfaction in selected cases
- Psychosexual counseling, couples therapy
Complications
- Psychological distress, depression, relationship strain
- Untreated cardiovascular disease (ED as harbinger of CAD)
- Priapism from intracavernosal therapy or PDE5 inhibitor + sickle cell
- Cardiovascular events with concurrent nitrate use
- Treatment side effects: headache, flushing, dyspepsia, NAION (rare), hearing loss (rare)
PANCE pearls
- Erectile dysfunction is an independent risk marker for cardiovascular disease — comprehensive cardiac risk assessment is part of ED workup.
- PDE5 inhibitors are absolutely contraindicated with any nitrate (oral, sublingual, paste, patch) within 24 hours (48 hours for tadalafil) — severe hypotension can be fatal.
- Confirm low testosterone with TWO morning measurements + symptoms before initiating replacement therapy.
- Testosterone replacement is contraindicated in active prostate or breast cancer; monitor PSA, hematocrit, lipids during therapy.
- Daily low-dose tadalafil (2.5-5 mg) also treats lower urinary tract symptoms from BPH — useful when conditions coexist.
- Sudden hearing loss or vision loss (NAION) on PDE5i requires immediate discontinuation and evaluation.
- Preserved nocturnal or morning erections argue strongly for psychogenic ED.
References
- AUA 2018 — Erectile Dysfunction: AUA Guideline (Burnett et al., J Urol 2018; reaffirmed)
- Princeton III — The Princeton III Consensus Recommendations for the Management of Erectile Dysfunction and Cardiovascular Disease (Nehra et al., Mayo Clin Proc 2012)
- Endocrine Society 2018 — Testosterone Therapy in Men with Hypogonadism: Endocrine Society Clinical Practice Guideline (Bhasin et al., JCEM 2018)
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