Key Facts

Ischaemic stroke is a medical emergency where rapid assessment and treatment can dramatically improve outcomes. The phrase "time is brain" reflects that ~1.9 million neurones are lost per minute during a large vessel occlusion.

Epidemiology

~100,000 strokes per year in the UK (~85% ischaemic). Fourth leading cause of death in the UK. Leading cause of adult disability. Incidence increases sharply with age (doubles every decade after age 55). Lifetime risk ~25%. Annual NHS cost >£8 billion.

Aetiology

• Large artery atherosclerosis (~25%): carotid stenosis, intracranial atherosclerosis
• Cardioembolism (~25%): AF (most common source), valvular heart disease, recent MI, cardiomyopathy, PFO
• Small vessel disease/lacunar (~25%): lipohyalinosis of penetrating arteries (hypertension, diabetes)
• Other determined (~5%): dissection (carotid/vertebral), vasculitis, hypercoagulable states, sickle cell
• Cryptogenic (~20%): no cause identified despite investigation

Pathophysiology

Arterial occlusion → ischaemia → ischaemic core (irreversible within minutes) surrounded by ischaemic penumbra (salvageable tissue — target of reperfusion therapy). The penumbra receives collateral blood flow that maintains cell viability temporarily. Reperfusion therapy (thrombolysis/thrombectomy) aims to restore blood flow to the penumbra before irreversible infarction. Cytotoxic oedema develops within hours; vasogenic oedema peaks at 3-5 days (risk of herniation in large infarcts).

Anterior Circulation (Carotid Territory)

• MCA: contralateral hemiparesis (face + arm > leg), hemisensory loss, homonymous hemianopia, dysphasia (dominant hemisphere), neglect (non-dominant)
• ACA: contralateral leg weakness > arm, personality change, urinary incontinence
• Lacunar syndromes: pure motor hemiparesis, pure sensory stroke, ataxic hemiparesis, dysarthria-clumsy hand

Posterior Circulation (Vertebrobasilar)

• PCA: homonymous hemianopia with macular sparing, visual agnosia
• Basilar: devastating — quadriplegia, locked-in syndrome, decreased consciousness
• Cerebellar: vertigo, ataxia, nystagmus, headache
• Brainstem: cranial nerve palsies + contralateral motor/sensory deficits (crossed signs)

Red Flags

• Sudden onset neurological deficit (stroke until proven otherwise)
• Decreasing consciousness (large infarct, basilar occlusion, haemorrhagic transformation)
• Neck pain + neurological deficit in young person (dissection)
• New AF + stroke (cardioembolism)

Bedside

• Blood glucose: exclude hypoglycaemia (common stroke mimic)
• NIHSS (National Institutes of Health Stroke Scale): quantify deficit severity (0-42); guides treatment decisions
• ECG: detect AF
• Observations: BP, pulse, SpO₂, temperature

Imaging

• CT head (non-contrast): IMMEDIATE — exclude haemorrhage; may show early ischaemic signs (loss of grey-white differentiation, sulcal effacement, hyperdense vessel sign)
• CT angiography (CTA): identify large vessel occlusion for thrombectomy consideration; assess carotid stenosis
• CT perfusion: assess ischaemic core vs penumbra (extended window thrombectomy — DAWN/DEFUSE-3 criteria)
• MRI DWI: most sensitive for early ischaemia (restricted diffusion within minutes); if diagnosis uncertain

Bloods

• FBC, U&Es, coagulation: baseline
• Glucose: confirm bedside reading
• Lipids: fasting profile for secondary prevention
• HbA1c: diabetes screening
• ESR/CRP: if vasculitis suspected
• Thrombophilia screen: in young stroke (<50) without clear cause

Special Tests

• Carotid duplex USS: assess for carotid stenosis (if anterior circulation stroke)
• Echocardiography: TTE ± TOE — source of embolism (AF, valvular disease, PFO)
• Prolonged cardiac monitoring (72 hours minimum, ideally 30-day loop): detect paroxysmal AF
• Bubble contrast echo: if PFO/ASD suspected (cryptogenic stroke in young patient)

Acute (Hyperacute)

• Thrombolysis: IV alteplase 0.9 mg/kg (max 90 mg; 10% bolus, 90% over 1 hour) if within 4.5 hours of symptom onset and no contraindications (NICE NG128)
  • Key contraindications: haemorrhage on CT, BP >185/110, recent surgery/trauma, active bleeding, INR >1.7, platelets <100
  • IST-3 trial: benefit in patients up to 80+ years
• Thrombectomy: mechanical clot retrieval for large vessel occlusion (ICA/M1 MCA) within 6 hours (MR CLEAN, ESCAPE, EXTEND-IA, SWIFT PRIME, REVASCAT trials); up to 24 hours with favourable perfusion imaging (DAWN, DEFUSE-3); can be combined with thrombolysis
• Aspirin: 300 mg stat (after CT excludes haemorrhage); continue 300 mg OD for 14 days then switch to long-term antiplatelet
• Admit to hyperacute stroke unit: reduces mortality and disability (NICE NG128)

Early (Days 1-14)

• Swallow assessment: before any oral intake (aspiration risk)
• DVT prophylaxis: intermittent pneumatic compression (NOT routine LMWH in first 14 days — increases haemorrhagic transformation risk)
• Blood pressure: permissive hypertension acutely (do NOT treat unless >220/120 or thrombolysed >185/110)
• Blood glucose: maintain 4-11 mmol/L
• Decompressive craniectomy: for malignant MCA infarction (<60 years, within 48 hours) — reduces mortality but increases severe disability (DECIMAL, DESTINY, HAMLET trials)

Secondary Prevention

• Antiplatelet: clopidogrel 75 mg OD long-term (NICE NG128); dual antiplatelet (aspirin + clopidogrel) for first 21 days if minor stroke/TIA (CHANCE, POINT trials)
• Anticoagulation for AF: start DOAC at day 4-14 depending on infarct size (use 1-3-6-12 day rule based on NIHSS); apixaban 5 mg BD (ARISTOTLE) or edoxaban 60 mg OD (ENGAGE AF) or dabigatran 150 mg BD (RE-LY)
• Statin: atorvastatin 20-80 mg (target >40% LDL reduction)
• Antihypertensive: after acute phase — target <130/80; choice depends on patient factors
• Carotid endarterectomy: for symptomatic carotid stenosis 50-99% (NASCET criteria); within 2 weeks of event (NICE NG128); ECST, NASCET trials

Referral Criteria

• Hyperacute stroke team: all suspected strokes (999, pre-alert)
• Neurosurgery: malignant MCA infarction, cerebellar infarction with hydrocephalus
• Vascular surgery: symptomatic carotid stenosis >50%
• Cardiac: PFO closure consideration (young cryptogenic stroke — CLOSE, RESPECT trials)

30-day mortality ~10-15%. 1-year mortality ~25%. Of survivors, ~50% have significant residual disability. Thrombolysis: NNT ~7 for good outcome at 3 months if treated within 3 hours. Thrombectomy: NNT ~3-4 for functional independence. Recurrence risk: ~5% in first year (higher if untreated AF). Carotid endarterectomy: reduces 5-year stroke risk from 26% to 9% for >70% stenosis. Post-stroke depression affects ~30%.

Stroke Classification (Bamford/Oxford)

Key Stroke Trials