Erectile Dysfunction

1. Clinical Overview

Definition and Core Concept

Erectile dysfunction (ED) is defined as the persistent or recurrent inability to achieve and/or maintain an erection sufficient for satisfactory sexual performance. [1] The diagnosis requires symptoms persisting for at least 3 months, except in cases of trauma or post-surgical ED where the timeline is shortened. [2]

ED represents far more than a quality-of-life issue. It serves as a vascular sentinel—an early warning system for systemic cardiovascular disease. The penile arteries (1-2mm diameter) are significantly smaller than coronary arteries (3-4mm) and carotid arteries (5-7mm), meaning atherosclerotic disease manifests first in the smallest vessels. This arterial size hypothesis explains why ED typically precedes coronary artery disease by 3-5 years, providing a crucial window for cardiovascular risk modification. [3,4]

The Princeton III Consensus firmly established ED as an independent cardiovascular risk marker, recommending that all men presenting with ED undergo cardiovascular risk stratification regardless of symptom severity. [5]

Key Clinical Facts

The Vascular Sentinel Concept

"The Artery Size Hypothesis": Atherosclerosis is a systemic disease affecting all arterial beds simultaneously. However, the clinical manifestation occurs first where vessel diameter is smallest.

Order of Symptom Appearance:

1. Penile arteries (1-2mm) → ED (earliest)
2. Coronary arteries (3-4mm) → Angina/MI (3-5 years later)
3. Carotid arteries (5-7mm) → Stroke (later still)
4. Femoral arteries (6-8mm) → Claudication (latest)

This concept was validated in the COBRA trial, which demonstrated that men with ED had significantly higher coronary calcium scores than age-matched controls without ED, confirming subclinical coronary artery disease. [8]

Clinical Pearl: "The Penile Stress Test": Sexual activity requires 3-6 METs (equivalent to walking 1 mile in 20 minutes or climbing 2 flights of stairs). If a man cannot achieve this without cardiovascular symptoms, he is not fit for sexual activity OR phosphodiesterase-5 inhibitors. [5]

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2. Epidemiology

Prevalence and Incidence

The Massachusetts Male Aging Study (MMAS) remains the landmark epidemiological study, establishing that ED prevalence approximately equals the decade of age—52% of men aged 40-70 years experience some degree of ED. [6]

The "Age Calculus": As a rough clinical approximation, ED prevalence (%) ≈ Age in years.

Risk Factor Epidemiology

The MMAS identified key modifiable risk factors, each independently contributing to ED risk:

Diabetes Impact: Men with diabetes develop ED 10-15 years earlier than non-diabetic men. Prevalence reaches 75% in diabetic men over age 60. [10]

Metabolic Syndrome and ED

The Metabolic Syndrome creates a "perfect storm" for ED:

Definition (NCEP ATP III):

• Abdominal obesity (waist > 102cm in men)
• Triglycerides ≥1.7 mmol/L
• HDL less than 1.0 mmol/L
• Blood pressure ≥130/85 mmHg
• Fasting glucose ≥5.6 mmol/L

Each component independently damages endothelial function. Combined, they create severe ED resistant to first-line therapy. The EMAS study demonstrated that metabolic syndrome doubles ED risk independent of age. [11]

Reversibility Evidence: A randomised controlled trial demonstrated that 10% body weight loss restored normal erectile function in 31% of obese men with ED, compared to only 5% in controls. [12]

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3. Anatomy and Physiology

Functional Anatomy of the Penis

Structural Components:

Arterial Supply:

• Internal pudendal artery → Penile artery → Cavernous, Dorsal, Bulbourethral arteries
• Cavernous artery supplies erectile tissue (helicine arterioles)
• Dorsal artery supplies glans and skin

Venous Drainage:

• Subtunical venular plexus → Emissary veins → Deep dorsal vein
• Venous drainage is PASSIVE and dependent on tunical compression

Innervation:

• Parasympathetic (S2-S4): Pro-erectile, releases NO via cavernous nerves
• Sympathetic (T10-L2): Anti-erectile, maintains detumescence
• Somatic (pudendal nerve S2-S4): Sensory and bulbocavernosus reflex

The Cavernous Nerves: Surgical Anatomy

The cavernous nerves originate from the pelvic plexus (S2-S4) and travel along the posterolateral aspect of the prostate at the 5 and 7 o'clock positions. Their proximity to the prostate makes them extremely vulnerable during:

• Radical prostatectomy (most common cause of iatrogenic ED)
• Radical cystectomy
• Abdominoperineal resection
• Pelvic radiation

Nerve-Sparing Surgery: Even with meticulous "nerve-sparing" technique, traction neuropraxia causes temporary dysfunction in 50-80% of men. Recovery takes 6-24 months as nerves regenerate at approximately 1mm/day. [13]

Physiology of Erection: The NO-cGMP Pathway

The Erection Cascade:

1. Sexual stimulation → Central arousal (limbic system)
2. Parasympathetic activation → Cavernous nerve firing
3. Neuronal NO release → From nerve terminals (nNOS)
4. Endothelial NO release → From sinusoidal endothelium (eNOS)
5. Smooth muscle relaxation → Via cGMP accumulation
6. Arterial inflow → Helicine arterioles dilate
7. Sinusoidal filling → Corpora cavernosa expand
8. Veno-occlusion → Subtunical veins compressed against tunica
9. Full rigidity → Intracavernosal pressure = 100mmHg

The Molecular Mechanism:

NO + Guanylyl Cyclase → GTP → cGMP → PKG activation → 
→ K+ channel opening + Ca²+ sequestration → 
→ Smooth muscle relaxation → 
→ Erection

Detumescence (Termination):

• PDE5 enzyme breaks down cGMP → cGMP ↓ → Smooth muscle contraction
• Sympathetic discharge (noradrenaline) → α1-receptor activation → Contraction

PDE5 Inhibitor Mechanism: Block cGMP degradation → Prolonged smooth muscle relaxation → Enhanced erectile response to sexual stimulation. They do NOT cause erection spontaneously—sexual arousal remains essential.

Endothelial Dysfunction: The Common Pathway

Endothelial dysfunction is the unifying mechanism linking ED risk factors:

The endothelium normally produces NO continuously. Damaged endothelium produces less NO, leading to impaired smooth muscle relaxation and ED.

Laplace's Law and Erection Physics:

• Formula: Wall Tension = (Pressure × Radius) / Wall Thickness
• As the cavernosa fill and radius increases, tension on the tunica albuginea increases
• This tension compresses the subtunical venules, trapping blood
• A stiffer tunica (Peyronie's) or large venous channels (congenital) impairs this mechanism

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4. Aetiology: The BREAK Classification

Overview of Causes

B: Blood Components (Hormonal/Metabolic)

Testosterone Deficiency:

• Testosterone is essential for libido and supports erectile function
• Primary effect: Low libido (↓ desire)
• Secondary effect: May impair erectile quality
• Threshold: Total testosterone less than 8 nmol/L = severe deficiency; 8-12 nmol/L = borderline
• Caveat: Rarely the SOLE cause of ED—usually coexists with vascular disease

Hyperprolactinaemia:

• Prolactin inhibits GnRH → Secondary hypogonadism
• Causes: Pituitary adenoma, medications (antipsychotics, metoclopramide)
• Red flag: Visual field defects (chiasmal compression)

Diabetes Mellitus: The Perfect Storm:

1. Macrovascular: Atherosclerosis of iliac/pudendal arteries
2. Microvascular: Fibrosis of cavernosal sinusoids (reduced compliance)
3. Autonomic neuropathy: Damaged cavernous nerves
4. AGE accumulation: Tissue stiffening, impaired collagen
5. Oxidative stress: Endothelial dysfunction

Clinical Implication: ED in diabetes is earlier onset, more severe, and less responsive to PDE5 inhibitors. [10]

Obstructive Sleep Apnoea (OSA):

• Chronic nocturnal hypoxia → ↓ Testosterone, ↑ Sympathetic tone
• Fragmented sleep → ↓ Nocturnal erections (penile rehabilitation impaired)
• CPAP therapy improves erectile function independently of weight loss
• Screen: STOP-BANG questionnaire for snoring, daytime somnolence

R: Reflex (Neurogenic)

Central Nervous System:

• Spinal cord injury (level-dependent)
• Multiple sclerosis
• Parkinson's disease
• Stroke

Peripheral Nervous System:

• Diabetic autonomic neuropathy
• Pelvic surgery (radical prostatectomy, cystectomy, APR)
• Pelvic radiation
• Cauda equina syndrome (RED FLAG: saddle anaesthesia)

Post-Radical Prostatectomy ED:

• Most common cause of iatrogenic ED
• Even with nerve-sparing technique: 50-70% have some ED at 1 year
• Penile rehabilitation: Early use of PDE5i and/or VED to maintain oxygenation
• Recovery timeline: 6-24 months for nerve regeneration
• Predictors of recovery: Younger age, better baseline function, bilateral nerve-sparing [13]

E: Erection Chamber (Structural)

Peyronie's Disease:

• Fibrous plaque in tunica albuginea causing penile curvature
• Phases:
  • "Active phase (6-12 months): Painful erections, changing curvature—NO surgery"
  • "Stable phase: Pain resolved, curvature fixed—surgery may be considered"
• Associated conditions: Dupuytren's contracture (30-40% have both)
• Treatment: Xiapex (collagenase), penile plication, plaque incision/grafting

Corporeal Venous Leak:

• Failure of the veno-occlusive mechanism
• Demographics: Young men with primary (lifelong) ED
• Diagnosis: Penile Doppler—normal arterial inflow but persistent venous outflow
• Aetiology: Congenital large veins, tunical abnormality, or damage
• Treatment: Poor response to oral therapy; often requires injection therapy or prosthesis

A: Arterial (Vascular)

Atherosclerosis (Most Common Cause):

• Same risk factors as coronary artery disease
• Affects iliac, pudendal, and penile arteries
• Clinical Pearl: The artery size hypothesis explains the ED-CVD temporal relationship

Traumatic Arterial Injury:

• Straddle injury (bicycle handlebar, fence)
• Pelvic fracture
• Young men with sudden-onset ED post-trauma
• Investigation: Angiography for potential surgical revascularization

Cyclist's Syndrome (Pudendal Artery Entrapment):

• Narrow bicycle saddle compresses pudendal artery against pubis
• Symptoms: Perineal/penile numbness after riding ("Sleepy Pee-Pee")
• Prevention: Noseless saddles, regular standing every 10 minutes
• Evidence: Professional cyclists have higher ED rates than age-matched controls

Smoking:

• Acute effect: Nicotine causes immediate penile arterial spasm (lasts 1-2 hours)
• Chronic effect: Accelerates atherosclerosis, endothelial damage
• Dose-response: Risk increases with pack-years
• Reversibility: Acute spasm resolves within 24 hours of cessation; vascular damage takes years

K: Kinetic (Psychogenic)

Performance Anxiety:

• The most common psychogenic cause
• Mechanism: Anxiety → Sympathetic overdrive → α1-receptor activation → Smooth muscle contraction → Failed erection
• "Spectatoring": Self-monitoring during sex rather than being immersed

Depression:

• Strong bidirectional relationship with ED
• Depression causes ED (↓ libido, anhedonia)
• ED causes depression (↓ self-esteem, relationship strain)
• Both may share common pathways (inflammation, HPA axis dysfunction)

Porn-Induced Erectile Dysfunction (PIED):

• Demographic: Young men with high pornography consumption
• Mechanism: Desensitization to normal sexual stimuli; requires escalating novelty
• Clinical pattern: Difficulty achieving/maintaining erection with real partner despite functioning with pornography
• Treatment: "Dopamine detox"—abstinence from pornography (typically 3-6 months)

Post-Finasteride Syndrome:

• Persistent sexual dysfunction after stopping finasteride/dutasteride
• Symptoms: Decreased libido, ED, ejaculatory dysfunction
• Mechanism: Unclear—possibly epigenetic/neurosteroid alterations
• Important: Counsel young men starting hair loss medication

Drug-Induced ED

Clinical Approach: Review medications in every ED patient. Some can be switched (thiazide → ACE inhibitor; atenolol → nebivolol).

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5. Clinical Assessment

History Taking: Structured Approach

The "Big Three" Screening Questions:

1. "Do you get morning erections?"

   • YES → Hardware intact, likely psychogenic
   • NO → Suggests organic aetiology (vascular/neurogenic)

2. "Is the problem with a specific partner or situation?"

   • YES → Psychogenic component likely
   • NO → Organic cause more likely

3. "Did the problem start suddenly or gradually?"

   • SUDDEN → Psychogenic, medication change, or trauma
   • GRADUAL → Vascular (atherosclerosis is progressive)

Comprehensive History Components:

Erection Hardness Score (EHS)

A validated simple measure for clinical documentation and treatment monitoring:

Treatment Goal: Achieve Grade 3 or 4 sufficient for satisfactory intercourse.

International Index of Erectile Function (IIEF-5)

The abbreviated IIEF-5 (SHIM - Sexual Health Inventory for Men) is a validated 5-question screening tool:

Physical Examination

General Inspection:

• Body habitus (obesity, gynaecomastia)
• Secondary sexual characteristics (hypogonadism signs)
• Skin changes (diabetes, liver disease)

Cardiovascular:

• Blood pressure (hypertension)
• Peripheral pulses (peripheral vascular disease)
• Cardiac examination (murmurs, heart failure)

Genital Examination:

• Penis: Size, Peyronie's plaques, phimosis
• Testes: Size (atrophy suggests hypogonadism), masses
• Prostate (if indicated): Size, nodules

Neurological:

• Lower limb reflexes (S2-S4 arc)
• Perineal sensation (saddle anaesthesia = RED FLAG)
• Bulbocavernosus reflex (squeeze glans → anal contraction)

Cardiovascular Risk Stratification

Princeton III Consensus Classification: [5]

Risk Factors: Smoking, hypertension, diabetes, dyslipidaemia, sedentary lifestyle, obesity, family history of premature CVD.

Minimum Workup for All ED Patients:

• Fasting glucose or HbA1c
• Lipid profile
• Blood pressure
• Cardiovascular risk score (QRISK3 or Framingham)

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6. Investigations

First-Line (Essential for All Patients)

Testosterone Assessment Protocol

When to Check:

• Low libido accompanying ED
• Clinical features of hypogonadism
• Age > 50 years
• Diabetes, obesity, metabolic syndrome

Testing Protocol:

1. First sample: Morning (8-11 AM), fasting, total testosterone
2. If borderline (8-12 nmol/L): Repeat in 2-4 weeks
3. If confirmed low: Check LH, FSH, prolactin, SHBG

Interpretation:

Further Hormonal Workup (if testosterone low):

If secondary hypogonadism: MRI pituitary to exclude adenoma.

Second-Line (Specialist Investigations)

Penile Doppler Ultrasound:

• Gold standard for haemodynamic assessment
• Technique: Intracavernosal injection of PGE1 → Ultrasound assessment
• Parameters: Peak systolic velocity (PSV), end-diastolic velocity (EDV)

Indications for Doppler:

• Young men (less than 40) with primary ED
• Post-traumatic ED (arterial injury)
• Consideration of penile revascularisation
• Poor response to PDE5i

Nocturnal Penile Tumescence (RigiScan):

• Measures nocturnal erections objectively
• Useful for differentiating organic vs psychogenic
• Normal: 3-5 erections per night, 10-15 mins each, > 60% rigidity

Angiography:

• Reserved for young men with traumatic arterial injury
• Potential for surgical revascularisation

The Young Patient Protocol (less than 40 Years)

Young men with ED represent a different population—vascular disease is less likely:

Priority Investigations:

1. Exclude psychogenic causes (detailed history)
2. Screen for venous leak (Doppler if indicated)
3. Consider Peyronie's disease
4. Assess for porn-induced ED
5. Drug and recreational substance history
6. Hormonal workup (low threshold)

Referral Indications:

• Primary (lifelong) ED
• Traumatic ED
• Anatomical abnormality
• Failure of first-line therapy

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7. Management: Overview and Algorithm

Treatment Algorithm

ED Presentation
      ↓
[Cardiovascular Risk Assessment + Basic Investigations]
      ↓
[Lifestyle Modification - ALL PATIENTS]
      ↓
[Risk Category Assessment - Princeton III]
      ↓
─────────────────────────────────────────
|              |              |         |
Low Risk    Intermediate   High Risk
|              |              |         |
↓              ↓              ↓         |
FIRST LINE   Cardiac       Stabilise   |
(PDE5i)      Workup        First       |
|              |              |         |
↓              ↓                        |
Success?     Clear for                  |
|            Treatment                  |
YES → Continue                          |
NO                                      |
↓                                       |
SECOND LINE (Optimise PDE5i / Daily dosing / VED)
|                                       |
↓ Fails                                 |
THIRD LINE (Intracavernosal injection / MUSE)
|                                       |
↓ Fails                                 |
FOURTH LINE (Penile Prosthesis)

Lifestyle Modification (ALL Patients)

Evidence-Based Interventions:

The "Erection Diet" (Mediterranean Pattern):

• Nuts (walnuts, pistachios) → Arginine (NO precursor)
• Olive oil → Polyphenols (endothelial function)
• Oily fish → Omega-3 (anti-inflammatory)
• Avoid: Processed foods, trans fats, excess sugar

Pelvic Floor Exercises (Kegels):

• Target the ischiocavernosus and bulbospongiosus muscles
• Function: Compress base of penis to enhance rigidity and trap blood
• Protocol: 3 sets of 10 contractions, held 5-10 seconds, daily
• Evidence: RCT showed 40% improvement in ED with pelvic floor training [15]

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8. Management: First-Line Therapy (PDE5 Inhibitors)

Mechanism of Action

PDE5 inhibitors block the phosphodiesterase type 5 enzyme, which normally degrades cGMP. By preventing cGMP breakdown, smooth muscle relaxation is prolonged and enhanced.

Critical Point: PDE5 inhibitors are FACILITATORS, not initiators. Sexual arousal and NO release are still required—the drug amplifies the response to stimulation.

Comparative Pharmacology

Prescribing Guidance

Sildenafil:

• Starting dose: 50mg
• Range: 25-100mg
• Timing: 1 hour before sexual activity
• Instructions: Take on empty stomach (2 hours after eating)
• Maximum frequency: Once per 24 hours

Tadalafil (On-Demand):

• Starting dose: 10mg
• Range: 5-20mg
• Timing: 2 hours before (but works up to 36 hours)
• Instructions: Can take with food; more spontaneous

Tadalafil (Daily Dosing):

• Dose: 5mg once daily (same time each day)
• Advantages: Removes planning, continuous efficacy, also treats LUTS/BPH
• Best for: Frequent sexual activity (> 2x/week), LUTS, performance anxiety

Avanafil:

• Starting dose: 100mg
• Range: 50-200mg
• Timing: 15-30 minutes before
• Best for: Need for rapid onset, unplanned intimacy

Patient Counselling: Keys to Success

The "Rule of 8": Do not declare treatment failure until the patient has tried the medication 8 times at maximum dose with proper technique. [1]

Common Reasons for Failure:

Contraindications

Absolute Contraindications:

The Nitrate-PDE5i Interaction:

• Nitrates increase cGMP production
• PDE5i prevents cGMP breakdown
• Combined: Massive cGMP accumulation → Profound vasodilation → Irreversible hypotension

If nitrate given by mistake:

• Do NOT give more nitrates
• Fluid resuscitation
• Alpha-agonist (phenylephrine) if needed
• Supportive care; effect may last hours

Relative Contraindications/Cautions:

• Alpha-blockers: Separate dosing by 4-6 hours (hypotension)
• Severe hepatic impairment: Reduce dose
• Severe renal impairment: Start low
• Anatomical penile abnormality: Caution
• Conditions predisposing to priapism: Sickle cell, leukaemia

Efficacy and Safety

Efficacy by Aetiology: [1]

Common Side Effects:

Serious but Rare:

• NAION (non-arteritic anterior ischaemic optic neuropathy): Rare, causality debated
• Sudden hearing loss: Very rare, report immediately

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9. Management: Second-Line Therapy

Optimisation of PDE5 Inhibitors

Before escalating, ensure first-line therapy was truly optimised:

1. Correct timing and food avoidance
2. Maximum tolerated dose
3. Minimum 8 attempts
4. Adequate sexual stimulation
5. Address performance anxiety
6. Consider switching agents (some patients respond to one but not another)

Daily Tadalafil (5mg)

Rationale: Continuous drug levels remove the need to "plan" sex, reducing performance anxiety and enabling spontaneity.

Evidence: Studies show daily tadalafil produces continuous improvement in erectile function compared to on-demand dosing. [16]

Additional Benefit: Also approved for LUTS/BPH—can treat both with one medication.

Vacuum Erection Devices (VED)

Mechanism:

1. Create negative pressure (vacuum) around penis
2. Blood drawn into corpora cavernosa
3. Constriction band placed at base to maintain erection

Advantages:

• Non-pharmacological
• No systemic side effects
• Can combine with other therapies
• Used in penile rehabilitation post-prostatectomy

Disadvantages:

• Penis feels cold/numb (no arterial inflow)
• "Hinge effect" at base
• Cumbersome, not spontaneous
• Bruising (especially on anticoagulants)

Safety Warning: Constriction band must be removed within 30 minutes to prevent ischaemia.

Low-Intensity Shockwave Therapy (Li-ESWT)

Mechanism (proposed):

• Acoustic waves cause microtrauma
• Stimulate angiogenesis and neovascularisation
• Recruit stem cells
• Improve endothelial function

Evidence:

• EAU 2023 lists Li-ESWT as experimental but promising for mild vasculogenic ED
• Meta-analyses show improvement in IIEF scores, but heterogeneity in protocols
• May offer a "cure" rather than treatment—regenerative effect [17]

Protocol: Typically 6-12 sessions over 6-12 weeks.

Caveat: Many private clinics market this aggressively. Ensure focused shockwave devices are used (not radial).

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10. Management: Third-Line Therapy (Injections)

Intracavernosal Injection (ICI)

Drugs:

• Alprostadil (PGE1): Caverject, Viridal Duo
• Trimix: Alprostadil + Papaverine + Phentolamine
• Bimix: Papaverine + Phentolamine
• Quadmix: Trimix + Atropine

Mechanism: Alprostadil directly stimulates adenylyl cyclase → ↑ cAMP → Smooth muscle relaxation. Works independently of NO pathway—effective even with neurogenic ED. [18]

Efficacy: > 80% success rate even in patients who fail PDE5 inhibitors.

Indication:

• PDE5i failure/contraindication
• Post-radical prostatectomy (especially if nerve-sparing failed)
• Neurogenic ED (spinal cord injury)
• Diabetic ED unresponsive to oral therapy

Patient Training Protocol

Injection Technique:

1. Site: Lateral aspect of penis at 10 o'clock or 2 o'clock position
2. Avoid: 12 o'clock (dorsal nerves/vessels), 6 o'clock (urethra)
3. Needle: 27-30 gauge (insulin syringe)
4. Insert: Perpendicular (90°) to stretched penile shaft
5. Inject: Slowly over 5 seconds
6. Compress: Hold for 2-3 minutes
7. Alternate sides: Left one time, right the next (prevents fibrosis)

Starting Doses:

• Alprostadil: 10 mcg (titrate 5-40 mcg)
• Trimix: 0.1ml of standard mixture (variable)

Side Effects:

• Penile pain (especially alprostadil)
• Fibrosis at injection site (long-term)
• Haematoma
• PRIAPISM (most serious—see Emergency section)

Intra-Urethral Alprostadil (MUSE)

Method: Alprostadil pellet inserted into urethra via applicator.

Efficacy: 40-50% (less than ICI).

Advantages: No needle required.

Disadvantages:

• Urethral burning/pain (common)
• Dizziness (absorption)
• Less effective than injection

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11. Management: Fourth-Line Therapy (Surgery)

Penile Prosthesis Implantation

Indication: Failure of all conservative measures in motivated patients.

Types:

Outcomes:

• Patient satisfaction: > 90% (highest of all ED treatments) [19]
• Partner satisfaction: > 85%
• Mechanical failure: 5-10% at 10 years (3-piece)

Complications:

• Infection (1-3%): Devastating—requires explantation
• Erosion: Through skin or urethra
• Mechanical failure: Cylinder leak, pump malfunction
• Autoinflation
• Length loss: Perceived 1-2cm loss is common

Critical Points:

• Irreversible: Surgery destroys natural cavernosal tissue
• Partner involvement: Essential in decision-making
• Infection prevention: Antibiotic-coated devices recommended
• Not a libido treatment: Desire must be intact

Penile Revascularisation

Indication: Young men (less than 55 years) with isolated pudendal/penile artery injury (usually trauma).

Procedure: Inferior epigastric artery anastomosed to dorsal penile artery.

Success: 60-70% in properly selected patients.

Selection criteria: Documented arterial insufficiency on Doppler, normal venous function.

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12. Emergency: Priapism

Definition and Classification

Priapism is a persistent erection lasting > 4 hours unrelated to sexual stimulation.

Ischaemic Priapism: Emergency Management

Time is Critical:

• less than 4 hours: Reversible
• 4-12 hours: Increasing risk of fibrosis

• 24 hours: Likely permanent ED

Management Algorithm:

Step 1: Conservative (first 1-2 hours):

• Ice packs
• Exercise (climbing stairs)
• Ejaculation (if possible)

Step 2: Aspiration:

• Insert 19G butterfly into corpus cavernosum (2 o'clock position)
• Aspirate 20-50ml dark blood
• May need to irrigate with saline

Step 3: Phenylephrine Injection:

• Dilute: 200 mcg in 1ml saline
• Inject 200-500 mcg every 5-10 minutes
• Maximum: 1mg total
• Monitor BP and HR (α1-agonist)

Step 4: Surgical Shunting (if above fails):

• Distal shunts: Winter's (percutaneous), Ebbehoj, Al-Ghorab
• Proximal shunts: Quackels, Barry

Non-Ischaemic Priapism

• Usually post-traumatic (straddle injury)
• Fistula between cavernosal artery and sinusoids
• Diagnosis: Doppler shows high-flow arterial pattern
• Treatment: Observation initially; selective arterial embolisation if persistent

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13. Special Populations

Post-Radical Prostatectomy

Pathophysiology:

• Cavernous nerve injury (even with nerve-sparing)
• Neuropraxia from traction, thermal injury, ischaemia
• Time to recovery: 6-24 months

Penile Rehabilitation:

• Early PDE5i use (daily tadalafil)
• VED use 2-3 times weekly
• Goal: Maintain tissue oxygenation and prevent fibrosis
• Evidence: Mixed—some trials show benefit, others equivocal [13]

Diabetes Mellitus

Challenges:

• Multiple mechanisms (vascular + neurogenic + metabolic)
• Often more severe and treatment-resistant
• Higher PDE5i failure rates

Approach:

• Optimise glycaemic control
• Address all cardiovascular risk factors
• Higher doses of PDE5i may be needed
• Lower threshold for ICI

Spinal Cord Injury

Level-dependent response:

• Upper motor neuron lesion (above T10): Reflex erections preserved, psychogenic lost
• Lower motor neuron lesion (below S2): Reflex erections lost, psychogenic may be preserved

Treatment: PDE5i effective in 70-80%. ICI for failures.

Elderly Patients (> 70 years)

Considerations:

• Goals of treatment: Intimacy vs. intercourse
• Partner's ability and desire
• Comorbidities and polypharmacy
• Refractory period increases (24-48 hours normal)
• Lower starting doses of medications

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14. Psychosexual Considerations

The "Psychogenic Loop"

Initial failure (alcohol, fatigue, stress)
         ↓
    Anxiety about next time
         ↓
    Sympathetic overdrive during foreplay
         ↓
    Adrenaline → Arterial constriction
         ↓
    Failed erection
         ↓
    Increased anxiety ← ────────────┘
    (Loop perpetuates)

Psychosexual Therapy

Sensate Focus Technique:

1. Ban intercourse initially (removes performance pressure)
2. Focus on non-genital touching (Week 1-2)
3. Progress to genital touching without intercourse (Week 3-4)
4. Gradually reintroduce intercourse when anxiety reduced

Cognitive Behavioural Therapy:

• Challenge catastrophising thoughts ("I'll never be able to perform")
• Address "spectatoring" (self-monitoring during sex)
• Reframe expectations

Partner Involvement

Critical for Success:

• ED is a couple's problem, not just the man's
• Partners often feel rejected, unattractive, or suspicious
• Untreated: Total cessation of intimacy
• Include partner in consultations when possible

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15. Exam-Focused Content

Common Exam Questions

1. "What are the causes of erectile dysfunction?"
2. "How would you assess a 55-year-old man presenting with ED?"
3. "What is the cardiovascular significance of ED?"
4. "Describe the mechanism of action of PDE5 inhibitors."
5. "What are the contraindications to PDE5 inhibitors?"
6. "How would you manage ischaemic priapism?"
7. "What is penile rehabilitation post-prostatectomy?"

Viva Opening Statements

Definition Statement:

"Erectile dysfunction is the persistent inability to achieve or maintain an erection sufficient for satisfactory sexual performance. It affects over 50% of men aged 40-70 and is now recognised as an important cardiovascular sentinel—often preceding coronary artery disease by 3-5 years."

Aetiology Statement:

"ED has vasculogenic, neurogenic, hormonal, structural, and psychogenic causes. In most patients, it is multifactorial. Vasculogenic causes predominate, which explains the strong association with cardiovascular risk factors."

Treatment Statement:

"Management follows a stepwise approach: lifestyle modification for all, PDE5 inhibitors as first-line pharmacotherapy, intracavernosal injection for failures, and penile prosthesis for refractory cases."

Model Answers

Q: A 58-year-old man presents with ED of gradual onset over 2 years. He has type 2 diabetes and hypertension. How would you assess and manage him?

A: "I would take a systematic approach. First, I'd confirm the diagnosis and characterise the ED—onset, severity using the EHS, presence of morning erections, libido, and relationship factors. I'd enquire about cardiovascular symptoms and risk factors.

Physical examination would include BMI, blood pressure, peripheral pulses, and genital examination for Peyronie's or hypogonadism.

Investigations would include fasting glucose, HbA1c, lipid profile, and morning testosterone. I'd calculate his cardiovascular risk score.

Given his risk factors, this is likely vasculogenic ED. I'd emphasise lifestyle modification—weight loss, exercise, smoking cessation if relevant, and optimise diabetes and blood pressure control.

For pharmacotherapy, assuming no contraindications like nitrate use, I'd initiate a PDE5 inhibitor—likely tadalafil given its long duration and additional benefit for potential LUTS. I'd counsel on correct usage and arrange follow-up.

If unresponsive after adequate trials, I'd consider second-line options including vacuum devices or intracavernosal injections, and ultimately referral for consideration of penile prosthesis if appropriate."

Common Mistakes That Fail Candidates

❌ Not performing cardiovascular risk assessment in ED ❌ Missing nitrate contraindication before prescribing PDE5i ❌ Not asking about morning erections (differentiates organic/psychogenic) ❌ Forgetting drug-induced causes ❌ Not involving the partner in management ❌ Failing to escalate therapy appropriately ❌ Missing priapism as a urological emergency

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16. Key Guidelines Summary

EAU Guidelines (2023) [1]

• ED is an independent cardiovascular risk marker
• All men with ED need CV risk stratification
• PDE5i are first-line pharmacotherapy
• Li-ESWT is promising for mild vasculogenic ED
• Penile prosthesis for refractory cases

Princeton III Consensus (2012) [5]

• Classify as low/intermediate/high cardiovascular risk
• Low-risk patients safe for PDE5i and sexual activity
• Intermediate-risk require further cardiac workup
• High-risk defer treatment until stabilised

BSSM Guidelines (2018) [20]

• Comprehensive assessment including psychosocial factors
• Stepwise treatment escalation
• Specialist referral for complex cases

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17. References

1. Salonia A, et al. EAU Guidelines on Sexual and Reproductive Health. Eur Urol. 2023;83(5):437-471. doi:10.1016/j.eururo.2022.12.019

2. Burnett AL, et al. Erectile dysfunction: AUA Guideline. J Urol. 2018;200(3):633-641. doi:10.1016/j.juro.2018.05.004

3. Montorsi P, et al. The artery size hypothesis: a macrovascular link between erectile dysfunction and coronary artery disease. Am J Cardiol. 2005;96(12B):19M-23M. doi:10.1016/j.amjcard.2005.07.006

4. Dong JY, et al. Erectile dysfunction and risk of cardiovascular disease: meta-analysis of prospective cohort studies. J Am Coll Cardiol. 2011;58(13):1378-1385. doi:10.1016/j.jacc.2011.06.024

5. Nehra A, et al. The Princeton III Consensus recommendations for the management of erectile dysfunction and cardiovascular disease. Mayo Clin Proc. 2012;87(8):766-778. doi:10.1016/j.mayocp.2012.06.015

6. Feldman HA, et al. Impotence and its medical and psychosocial correlates: results of the Massachusetts Male Aging Study. J Urol. 1994;151(1):54-61. doi:10.1016/s0022-5347(17)34871-1

7. Vlachopoulos CV, et al. Prediction of cardiovascular events and all-cause mortality with erectile dysfunction: a systematic review and meta-analysis of cohort studies. Circ Cardiovasc Qual Outcomes. 2013;6(1):99-109. doi:10.1161/CIRCOUTCOMES.112.966903

8. Montorsi P, et al. Prevalence of coronary artery disease and association with erectile dysfunction in men undergoing coronary angiography. Eur Urol. 2006;50(5):1001-1007. doi:10.1016/j.eururo.2006.05.021

9. Corona G, et al. The age-related decline of testosterone is associated with different specific symptoms and signs in patients with sexual dysfunction. Int J Androl. 2009;32(6):720-728. doi:10.1111/j.1365-2605.2009.00952.x

10. Malavige LS, Levy JC. Erectile dysfunction in diabetes mellitus. J Sex Med. 2009;6(5):1232-1247. doi:10.1111/j.1743-6109.2008.01168.x

11. Corona G, et al. Hypogonadism as a risk factor for cardiovascular mortality in men: a meta-analytic study. Eur J Endocrinol. 2011;165(5):687-701. doi:10.1530/EJE-11-0447

12. Esposito K, et al. Effect of lifestyle changes on erectile dysfunction in obese men: a randomized controlled trial. JAMA. 2004;291(24):2978-2984. doi:10.1001/jama.291.24.2978

13. Capogrosso P, et al. Penile rehabilitation after radical prostatectomy. Eur Urol Focus. 2019;5(3):399-401. doi:10.1016/j.euf.2019.04.003

14. Silva AB, et al. Physical activity and exercise for erectile dysfunction: systematic review and meta-analysis. Br J Sports Med. 2017;51(19):1419-1424. doi:10.1136/bjsports-2016-096418

15. Dorey G, et al. Pelvic floor exercises for erectile dysfunction. BJU Int. 2005;96(4):595-597. doi:10.1111/j.1464-410X.2005.05690.x

16. McMahon C, et al. Efficacy and safety of daily tadalafil in men with erectile dysfunction previously unresponsive to on-demand tadalafil. J Sex Med. 2004;1(3):292-300. doi:10.1111/j.1743-6109.2004.04043.x

17. Lu Z, et al. Low-intensity extracorporeal shock wave treatment improves erectile function: a systematic review and meta-analysis. Eur Urol. 2017;71(2):223-233. doi:10.1016/j.eururo.2016.05.050

18. Porst H, et al. Efficacy and safety of intracavernosal alprostadil in men with erectile dysfunction. Urology. 1996;47(6):835-839. doi:10.1016/s0090-4295(96)00054-0

19. Bettocchi C, et al. Patient and partner satisfaction after AMS inflatable penile prosthesis implant. J Sex Med. 2010;7(1):304-309. doi:10.1111/j.1743-6109.2009.01499.x

20. Hackett G, et al. British Society for Sexual Medicine Guidelines on the Management of Erectile Dysfunction in Men-2017. J Sex Med. 2018;15(4):430-457. doi:10.1016/j.jsxm.2018.01.023

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Senior Editor: Dr. N. Goyal (Urology). Guideline Check: EAU 2023 / AUA 2022 / BSSM 2018 verified.

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