Neurology · Topic 2 of 22

Transient Ischemic Attack

Neurology · cerebrovascular

Transient Ischemic Attack

A transient deficit without infarction — and a loud warning: image brain and vessels now, score ABCD2, and start short-course dual antiplatelets.

Key numbers

Stroke risk peaks within 48 hours~½ of strokes ≤ 48 h

ABCD2 ≥ 4 means high-risk TIAABCD2 ≥ 4

Aspirin plus clopidogrel for high-risk TIADAPT 21–90 days

Carotid endarterectomy for 70–99% stenosis70–99% → CEA ≤ 2 wk

01 · RiskStroke risk peaks within 48 hours

Ninety-day stroke risk after TIA can reach about 18%, and nearly half of those strokes occur within 2 days — so evaluate urgently, usually with admission or a same-day pathway.

02 · CalculateABCD2 ≥ 4 means high-risk TIA

ABCD2: age ≥ 60 (1), BP ≥ 140/90 (1), unilateral weakness (2) or speech disturbance alone (1), duration ≥ 60 min (2) or 10–59 min (1), diabetes (1); ≥ 4 is high risk.

03 · GiveAspirin plus clopidogrel for high-risk TIA

For high-risk TIA (ABCD2 ≥ 4) or minor stroke, start aspirin plus clopidogrel early — ideally within 12–24 hours — continue 21 to 90 days, then one antiplatelet; long-term DAPT adds bleeding without benefit.

What it is

Core idea

TIA: transient deficit, no infarct on MRI must knowTIA is a transient focal neurologic deficit from ischemia without acute infarction on diffusion-weighted MRI; most resolve within 1 hour, and longer deficits often show infarction — making it a stroke.

Presentation

What you'll see

Amaurosis fugax is a carotid-territory TIATransient monocular blindness (amaurosis fugax), usually lasting < 5 minutes, reflects ophthalmic-artery (internal carotid) ischemia and needs the same urgent carotid work-up.

Diagnosis & monitoring

Work-up

Search for atrial fibrillationGet an ECG, cardiac rhythm monitoring (longer monitoring finds more AF) and an echocardiogram; TIA from AF or another cardioembolic source is treated with anticoagulation, not antiplatelets.

Long-term BP goal below 130/80After TIA, treat hypertension to an office BP < 130/80 mmHg for most patients, using a thiazide, ACE inhibitor or ARB.

Do right now

In this order

First moves

Image brain and vessels urgently

→

ABCD2 ≥ 4 means high-risk TIAABCD2 ≥ 4

→

Aspirin plus clopidogrel for high-risk TIADAPT 21–90 days

→

Carotid endarterectomy for 70–99% stenosis70–99% → CEA ≤ 2 wk

Why each step

Image brain and vessels urgentlyEvery TIA needs prompt brain imaging — diffusion-weighted MRI is most accurate — plus imaging of the head and neck vessels (CTA, MRA or carotid ultrasound) to find a treatable source.

ABCD2 ≥ 4 means high-risk TIAABCD2: age ≥ 60 (1), BP ≥ 140/90 (1), unilateral weakness (2) or speech disturbance alone (1), duration ≥ 60 min (2) or 10–59 min (1), diabetes (1); ≥ 4 is high risk.

Aspirin plus clopidogrel for high-risk TIAFor high-risk TIA (ABCD2 ≥ 4) or minor stroke, start aspirin plus clopidogrel early — ideally within 12–24 hours — continue 21 to 90 days, then one antiplatelet; long-term DAPT adds bleeding without benefit.

Carotid endarterectomy for 70–99% stenosisIpsilateral severe (70–99%) carotid stenosis after TIA or non-disabling stroke: carotid endarterectomy is recommended when perioperative risk is < 6%, ideally within 2 weeks of the event.

Management

Orders

Atorvastatin 80 mg, LDL below 70Start high-intensity statin therapy (atorvastatin 80 mg) after atherosclerotic TIA or stroke; the AHA/ASA stroke goal is LDL < 70 mg/dL, adding ezetimibe, then a PCSK9 inhibitor, if needed.

One antiplatelet for long-term preventionFor long-term noncardioembolic prevention, use a single agent: aspirin 50–325 mg daily, clopidogrel 75 mg daily, or aspirin–extended-release dipyridamole twice daily.

TIA or minor ischemic stroke?

Commonly confused

Diffusion-weighted MRI	No acute infarct
Typical course	Resolves, usually within 1 hour
Short-course DAPT trigger	ABCD2 ≥ 4
Antiplatelet plan	Aspirin + clopidogrel 21–90 days, then one agent

Commonly confused

Tell apart

Loss of consciousness is not a TIAIsolated syncope or impaired consciousness, or an isolated peripheral facial palsy, does not suggest TIA; consider mimics such as postictal (Todd) paralysis, migraine aura and hypoglycemia.

More detail

Reference

Show 5 reference facts

A low ABCD2 score (0–2) carries < 1% 7-day stroke risk in low-risk populations; such patients may be evaluated as outpatients if studies and consultation are completed within 24 hours.

Symptomatic 70–99% stenosis of a major intracranial artery: adding clopidogrel to aspirin for up to 90 days is reasonable; angioplasty and stenting should not be the initial treatment.

Clopidogrel needs CYP2C19 activation; with recurrent events on clopidogrel or a known loss-of-function allele, ticagrelor plus aspirin is an alternative.

Age 18–60 with a nonlacunar cryptogenic stroke and a high-risk patent foramen ovale: transcatheter closure plus antiplatelet therapy is reasonable, decided jointly with cardiology and neurology.

Most TIAs are embolic from the carotid or vertebral arteries or the heart; subclavian steal (proximal subclavian stenosis) can cause vertebrobasilar symptoms with arm exertion.

Pearl

A TIA is a warning shot: nearly half of the strokes that follow it come within 2 days.

Sources · Merck Manual Professional — Transient Ischemic Attack (updated Jan 2026) · Kleindorfer DO et al. 2021 AHA/ASA Guideline for the Prevention of Stroke in Patients With Stroke and TIA. Stroke 2021;52:e364–e467 (full-text PDF copy) · MDCalc — ABCD² Score for TIA · Amin HP et al. Diagnosis, Workup, Risk Reduction of TIA in the Emergency Department Setting (AHA Scientific Statement). Stroke 2023 — abstract via Europe PMC · emDocs — 2026 Guideline Update: Early Management of Acute Ischemic Stroke (section 4.8 antiplatelet treatment) · Merck Manual Professional — Ischemic Stroke (secondary prevention) · ACC — Ten Points to Remember: 2021 AHA/ASA Guideline for the Prevention of Stroke in Patients With Stroke and TIA · Starter sheet built from the verified AGACNP fact map (facts reviewed 2026-10-15).