Transient ischaemic attack (TIA)

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

Definition

A transient ischaemic attack (TIA) is a temporary disruption of blood flow to the brain, causing neurological symptoms that resolve completely within 24 hours and without evidence of infarction on imaging.

Aetiology

TIA occurs due to transient blockage of cerebral arteries.

Common Causes:

  • Atherosclerosis: plaque formation in carotid or vertebral arteries.
  • Cardioembolism: atrial fibrillation, recent myocardial infarction.
  • Small vessel disease: hypertension-related microvascular occlusion.
  • Hypercoagulability: thrombophilia, malignancy.

Pathophysiology

  • Brief arterial occlusion leads to focal ischaemia.
  • Reperfusion occurs before permanent infarction develops.
  • Symptoms resolve as blood flow is restored.
  • TIA increases the risk of subsequent stroke.

Risk factors

  • Hypertension.
  • Atrial fibrillation.
  • Diabetes mellitus.
  • Smoking.
  • Hyperlipidaemia.
  • Previous stroke or TIA.
  • Obesity and sedentary lifestyle.

Signs and symptoms

TIA symptoms depend on the affected vascular territory.

Carotid Territory (Anterior Circulation):

  • Unilateral weakness: face, arm, or leg.
  • Aphasia: if dominant hemisphere is affected.
  • Amaurosis fugax: temporary monocular vision loss.

Vertebrobasilar Territory (Posterior Circulation):

  • Vertigo, ataxia.
  • Diplopia: double vision.
  • Dysarthria: slurred speech.
  • Bilateral limb weakness or sensory loss.

Investigations

  • Urgent CT or MRI brain: to exclude stroke and haemorrhage.
  • Carotid Doppler ultrasound: assesses for carotid stenosis.
  • ECG: screens for atrial fibrillation.
  • Blood tests:
    • Lipid profile: assesses cardiovascular risk.
    • HbA1c: screens for diabetes.
    • Full blood count: identifies anaemia or polycythaemia.
  • Echocardiogram: If a cardiac source of embolism is suspected.

Management

1. Immediate Secondary Prevention:

  • Antiplatelet therapy: aspirin 300 mg daily (initially), then switch to clopidogrel 75 mg daily.
  • Anticoagulation (if atrial fibrillation present): consider DOAC (e.g., apixaban).
  • Blood pressure control: aim for <130/80 mmHg.
  • Lipid lowering therapy: atorvastatin 80 mg daily.

2. Carotid Endarterectomy:

  • Indicated if carotid stenosis is ≥50% in symptomatic patients.

3. Lifestyle Modifications:

  • Smoking cessation.
  • Regular exercise (at least 30 minutes/day).
  • Healthy diet (low salt, Mediterranean diet).
  • Weight management.

4. Specialist Referral:

  • Rapid-access TIA clinic within 24 hours for high-risk cases.
  • Neurovascular assessment for secondary stroke prevention.
NeurologymypanotesTransient ischaemic attack (TIA)