Stroke

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management

Definition

Stroke is an acute neurological deficit caused by disruption of cerebral blood flow, leading to brain infarction (ischaemic stroke) or haemorrhage (haemorrhagic stroke).

Aetiology

Stroke is classified into two main types:

1. Ischaemic Stroke (85% of cases):

  • Large artery atherosclerosis: carotid stenosis, emboli from atherosclerotic plaques.
  • Cardioembolic stroke: due to atrial fibrillation, left ventricular thrombus.
  • Small vessel disease (Lacunar stroke): occlusion of small penetrating arteries.
  • Hypercoagulability: thrombophilia, malignancy.

2. Haemorrhagic Stroke (15% of cases):

  • Intracerebral haemorrhage (ICH): hypertension related small vessel rupture.
  • Subarachnoid haemorrhage (SAH): usually due to aneurysm rupture.

Pathophysiology

  • Interruption of cerebral blood flow leads to neuronal ischaemia.
  • Energy failure results in neuronal death and infarction.
  • Haemorrhagic strokes cause direct damage and increased intracranial pressure.

Risk factors

  • Hypertension (strongest modifiable risk factor).
  • Atrial fibrillation (AF), high risk of cardioembolic stroke.
  • Diabetes mellitus.
  • Smoking.
  • Hyperlipidaemia.
  • Obesity and physical inactivity.
  • Excess alcohol consumption.

Signs and symptoms

Stroke symptoms depend on the affected vascular territory.

Anterior Circulation Stroke (Carotid Territory):

  • Unilateral weakness or sensory loss: face, arm, or leg.
  • Aphasia: if dominant hemisphere affected.
  • Hemianopia: loss of vision on one side.

Posterior Circulation Stroke (Vertebrobasilar Territory):

  • Diplopia, vertigo.
  • Ataxia, dysarthria.
  • Contralateral sensory deficits.
  • Loss of consciousness (brainstem involvement).

Investigations

  • Urgent non-contrast CT brain: first-line to differentiate ischaemic vs haemorrhagic stroke.
  • CT angiography: identifies large vessel occlusion or aneurysms.
  • MRI brain: more sensitive for detecting early infarction.
  • Carotid Doppler ultrasound: assesses carotid stenosis.
  • ECG: screens for atrial fibrillation.
  • Echocardiogram: assesses for cardiac embolic source.
  • Blood tests:
    • Full blood count (FBC): detects infection or anaemia.
    • Coagulation screen: assesses bleeding risk.
    • Lipid profile and HbA1c: identifies cardiovascular risk factors.

Management

1. Acute Stroke Treatment:

  • Thrombolysis (if eligible): IV Alteplase within 4.5 hours of symptom onset.
  • Thrombectomy: considered for large vessel occlusion up to 6–24 hours post-onset.
  • Blood pressure management: avoid aggressive lowering unless hypertensive crisis.

2. Secondary Prevention:

  • Antiplatelet therapy: aspirin 300 mg for 14 days, then Clopidogrel 75 mg daily.
  • Anticoagulation (if AF present): DOAC (e.g., Apixaban) after exclusion of haemorrhage.
  • Statin therapy: atorvastatin 80 mg to reduce stroke risk.
  • Blood pressure control: Target <130/80 mmHg.
  • Carotid endarterectomy: if ≥50% stenosis in symptomatic patients.

3. Rehabilitation:

  • Multidisciplinary stroke unit admission.
  • Physiotherapy for motor recovery.
  • Speech therapy for dysphasia.
  • Occupational therapy for daily living adaptations.

4. Lifestyle Modifications:

  • Smoking cessation.
  • Regular exercise (≥30 minutes daily).
  • Healthy diet (low salt, Mediterranean diet).
  • Weight reduction in obese patients.
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