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Erectile dysfunction
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Exam Tips
- In OSCE history, distinguish organic vs psychogenic clues: gradual onset and absent spontaneous erections suggest organic disease; sudden/situational dysfunction with preserved spontaneous erections suggests psychogenic contribution.
- Treat ED as a cardiovascular red flag: assess BP, diabetes, lipids, smoking, and exercise tolerance because ED can precede major CV events.
- Always check contraindications before prescribing PDE-5 inhibitors, especially concurrent nitrates/riociguat and haemodynamic instability.
- Use IIEF-5/SHIM to baseline severity and monitor response objectively.
- Look for reversible causes (drug adverse effects, endocrine disease, relationship stress) before escalating therapy.
- See Figure: penile vascular anatomy and NO-cGMP pathway (urology textbook sexual medicine chapter) for viva-style mechanism questions.
Definition
Erectile dysfunction is the persistent inability to achieve and/or maintain an erection sufficient for satisfactory sexual activity. It is a symptom complex rather than a single disease entity, and in UK practice is usually multifactorial, with organic (especially vasculogenic) and psychogenic contributors often coexisting.
Pathophysiology
Normal erection depends on nitric oxide-mediated smooth muscle relaxation in the corpora cavernosa (via cGMP), increased arterial inflow, and venous occlusion. Erectile dysfunction commonly reflects endothelial dysfunction and small-vessel atherosclerosis, so reduced penile blood flow may precede overt coronary or cerebrovascular disease; neurogenic, endocrine (for example hypogonadism or hyperprolactinaemia), structural penile disease, medication effects, and psychogenic factors can all disrupt this pathway. See Figure: neurovascular mechanism of erection (standard male sexual function diagrams in urology/endocrine textbooks).
Risk Factors
- Increasing age
- Cardiovascular disease, hypertension, dyslipidaemia, peripheral arterial disease
- Diabetes mellitus (type 1 or type 2)
- Obesity and metabolic syndrome (including NAFLD)
- Smoking, excess alcohol, physical inactivity/sedentary lifestyle
- Obstructive sleep apnoea
- Lower urinary tract symptoms/BPH
- Cycling >3 hours/week (possible pudendal neurovascular compression)
- Pelvic surgery or pelvic/retroperitoneal radiotherapy
- Depression, anxiety, relationship stress, performance anxiety
- Drug-related causes (for example beta-blockers, thiazides, spironolactone, SSRIs, antipsychotics, anti-androgens, 5-alpha-reductase inhibitors, opioids/recreational drugs)
Clinical Features
Symptoms
- Difficulty attaining erection
- Difficulty maintaining erection to complete intercourse
- Reduced rigidity or short-lived erections
- Reduced morning/nocturnal erections (suggests organic component)
- Reduced libido, ejaculatory or orgasmic problems
- Situational dysfunction, performance anxiety, relationship distress
- Symptoms of endocrine disease (low energy/libido, reduced secondary sexual function)
- Penile pain or curvature during erection (possible Peyronie's disease)
Signs
- Hypertension, obesity/central adiposity, metabolic syndrome features
- Evidence of vascular disease (for example diminished peripheral pulses)
- Penile plaques/curvature (Peyronie's disease), phimosis or other structural abnormalities
- Hypogonadism signs (reduced body hair, small testes, gynaecomastia)
- Neurological deficits when neurogenic cause suspected
- Psychological distress (anxious or low mood affect)
Investigations
Validated questionnaire (IIEF-5/SHIM or full IIEF):Quantifies severity and treatment response over time
Cardiovascular risk assessment (BP, QRISK-compatible factors, exercise tolerance):Identifies occult CV disease and safety of sexual activity
HbA1c or fasting plasma glucose:Diabetes/prediabetes may be newly detected
Fasting lipid profile:Dyslipidaemia supporting vasculogenic risk
Early-morning total testosterone (repeat if low):Low testosterone suggests hypogonadism
Prolactin and LH/FSH if testosterone low:Helps distinguish primary vs secondary hypogonadism/hyperprolactinaemia
TSH and free T4:Hyper- or hypothyroidism as reversible contributor
Renal function, liver profile, full blood count:Comorbidity/medication safety baseline
Specialist penile Doppler ultrasound (selected cases):Assesses arterial inflow and veno-occlusive function
Management
Lifestyle Modifications
- Address reversible causes: smoking cessation, weight reduction, regular aerobic exercise, alcohol moderation, sleep optimisation
- Optimise cardiometabolic disease (BP, lipids, glycaemia) and review contributory medicines where safe
- Psychosexual counselling/CBT and couple-focused interventions when psychogenic or mixed aetiology is present
- Advise on safe sexual activity in men with significant cardiovascular symptoms and stratify cardiac risk before treatment
Pharmacological Treatment
PDE-5 inhibitors (first-line if no contraindication)
- Sildenafil 50 mg orally as needed about 1 hour before sex (adjust 25-100 mg; max once daily)
- Tadalafil 10 mg orally as needed at least 30 minutes before sex (adjust 5-20 mg), or 5 mg once daily
- Vardenafil 10 mg orally 25-60 minutes before sex (adjust 5-20 mg; max once daily)
- Avanafil 100 mg orally 15-30 minutes before sex (adjust 50-200 mg; max once daily)
Absolute contraindication with nitrates or nitric oxide donors; avoid with riociguat. Use caution with alpha-blockers (risk of hypotension), unstable cardiovascular disease, recent MI/stroke, severe hypotension, severe hepatic impairment, and retinitis pigmentosa history. Counsel that sexual stimulation is required and common adverse effects include headache, flushing, dyspepsia, nasal congestion, and visual disturbance (notably sildenafil/vardenafil).
Prostaglandin E1 therapy (second-line/specialist use)
- Alprostadil intracavernosal injection: initiate under specialist supervision (commonly 2.5-10 micrograms test dose, titrated to effective dose; max frequency usually once in 24 hours and up to 3 times weekly)
- Alprostadil urethral pellet: typically 500 micrograms to 1 mg as needed
Warn about penile pain, fibrosis, and priapism risk; provide clear emergency advice for erections lasting >4 hours. Avoid in conditions predisposing to priapism (for example sickle cell disease) unless specialist-directed.
Hormone replacement when biochemical hypogonadism confirmed
- Testosterone gel (for example 40.5 mg once daily, adjusted to serum levels)
- Testosterone undecanoate IM 1000 mg, then at 6 weeks, then every 10-14 weeks (specialist protocols vary)
Only use when true androgen deficiency is demonstrated; monitor testosterone, haematocrit, PSA/prostate risk, and adverse effects. Not a routine treatment for eugonadal men with ED.
Surgical / Interventional
- Vacuum erection device (mechanical option, often before invasive surgery)
- Penile prosthesis implantation for refractory ED after failed conservative therapy
- Selected penile revascularisation surgery in young men with focal post-traumatic arterial injury
Complications
- Anxiety, low self-esteem, and secondary performance anxiety
- Depression
- Relationship and partner distress, avoidance of intimacy
- Reduced quality of life and psychosocial functioning
- Marker of increased future cardiovascular events, stroke, peripheral arterial disease, and all-cause mortality
Prognosis
Outcome depends on cause and comorbidity burden. Psychogenic, hormonal, and some drug-induced cases can be reversible, while vasculogenic disease is often chronic but treatable; many men achieve satisfactory intercourse with PDE-5 inhibitors (commonly around 60-65% response), though response may decline if underlying endothelial disease progresses.
Sources & References
🏥BMJ Best Practice(3)
💊BNF Drug References(7)
- Alprostadil[management.pharmacological]
- Avanafil[management.pharmacological]
- Aviptadil with phentolamine mesilate[management.pharmacological]
- Sildenafil[management.pharmacological]
- Tadalafil[management.pharmacological]
- Tadalafil[contraindications]
- Vardenafil[management.pharmacological]
✅NICE Guidelines(1)
- Erectile dysfunction[overview]
📖Textbook References(20)
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1272)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1726)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1726)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1726)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1272)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1726)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1720)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 883)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1733)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 198)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1726, 1727)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1219)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1221)[context]
- Guyton and Hall Textbook of Medical Physiology (John E. Hall, Michael E. Hall) (Z-Library).pdf(pp. 1011)[context]
- _OceanofPDF.com_Netters_Anatomy_-_8th_edition_-_Frank_H_Netter_MD.pdf(pp. 3168)[context]
- _OceanofPDF.com_Netters_Anatomy_-_8th_edition_-_Frank_H_Netter_MD.pdf(pp. 2655, 2656)[context]
- _OceanofPDF.com_Netters_Anatomy_-_8th_edition_-_Frank_H_Netter_MD.pdf(pp. 3167, 3168)[context]
- [Oxford Medical Handbooks] Ian Wilkinson, Tim Raine, Kate Wiles, Anna Goodhart, Catriona Ha - Oxford Handbook of Clinical Medicine (2017, Oxford University Press) - libgen.li.pdf(pp. 225)[context]
- [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 1376)[context]
- [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 1389, 1390)[context]