Transient Ischemic Attack (TIA): Definition, Diagnostic Confirmation, and Stroke Prevention

A Transient Ischemic Attack (TIA) is a transient episode of neurologic dysfunction caused by focal brain, spinal cord, or retinal ischemia without acute infarction (imaging-negative). It is a medical emergency: 10–20% stroke risk within 90 days (half within 48h).

Clinical Features

• Sudden onset, maximal at onset.
• Duration: typically <1 hour (median 10–15 min); by definition <24 hrs.
• Symptoms: Unilateral weakness/numbness, aphasia/dysarthria, monocular blindness (amaurosis fugax), vertigo/diplopia/ataxia (posterior circulation).
• Complete resolution.

Diagnostic Confirmation (AHA/ASA 2021)

1. Brain MRI with DWI: Gold standard. Detects restricted diffusion in 30–50% of clinical TIAs (reclassifies as "TIA with infarction" / minor stroke).
2. CT Head: Low sensitivity for acute ischemia; rules out hemorrhage/mass.
3. Vascular Imaging: CTA or MRA head/neck (carotid/vertebral stenosis, occlusion, dissection). Carotid duplex US alternative.
4. Cardiac Evaluation: ECG (AFib), Echocardiogram (TTE/TEE for cardioembolic source: PFO, thrombus, valve, wall motion), prolonged rhythm monitoring (Holter, ILR, mobile) for occult AFib.
5. Laboratory: CBC, BMP, lipids, HbA1c, coagulation, inflammatory markers.

ABCD² Score (2-Day Stroke Risk Stratification)

Factor	Points
Age ≥60	1
BP ≥140/90	1
Clinical: Unilateral weakness	2
Clinical: Speech impairment without weakness	1
Duration ≥60 min	2
Duration 10–59 min	1
Diabetes	1

Score 0–3: 1% 2-day stroke risk; 4–5: 4%; 6–7: 8%.

Immediate Secondary Prevention

• Antiplatelet: Aspirin 160–325 mg loading → 81 mg daily (or clopidogrel, ASA+dipyridamole). Dual antiplatelet (ASA+clopidogrel) ×21 days for minor stroke/high-risk TIA (CHANCE/POINT trials).
• Statin: High-intensity (atorvastatin 40–80, rosuvastatin 20–40) regardless of LDL.
• Antihypertensive: Target <130/80.
• Carotid endarterectomy/stenting if ≥50% symptomatic stenosis.
• Anticoagulation if cardioembolic (AFib).
• Lifestyle: Smoking cessation, Mediterranean diet, exercise.