Neurology · PANCE / PANRE

Transient Ischemic Attack (TIA)

Transient focal neurologic deficit from cerebral ischemia without infarction.

Also known as: TIA, mini-stroke, transient ischemic attack

Overview

Transient episode of neurologic dysfunction caused by focal brain, spinal cord, or retinal ischemia, without acute infarction on imaging (tissue-based definition, AHA 2009). Symptoms typically resolve within 1 hour.

Epidemiology

~240,000 cases/year in the US. 10-15% of TIA patients have a stroke within 3 months — half within the first 48 hours.

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Risk factors

Same as ischemic stroke: hypertension (strongest), atrial fibrillation, diabetes, dyslipidemia, smoking, carotid stenosis, age, prior stroke/TIA
Cardioembolic sources: AFib, recent MI with mural thrombus, valvular disease, endocarditis, PFO

Pathophysiology

Transient occlusion of a cerebral artery by embolus (cardioembolic or artery-to-artery) or transient hemodynamic compromise from severe stenosis. Reperfusion occurs before irreversible cellular injury. The same mechanisms that produce TIA can produce completed stroke — TIA is a warning sign of unstable vascular disease.

Clinical presentation

Symptoms

Sudden focal deficit identical to ischemic stroke but resolving — unilateral weakness, sensory loss, aphasia, monocular vision loss (amaurosis fugax), diplopia, vertigo, ataxia
Duration usually <1 hour (most <15 min)
Complete resolution by definition (tissue-based)

Signs / physical exam

Often normal exam by the time of evaluation
Carotid bruit, irregular pulse (AFib), murmur (valvular source) clues to etiology

Classic findings

Amaurosis fugax ('curtain coming down over one eye') suggests retinal embolism from ipsilateral carotid stenosis.

Differential diagnosis

Completed ischemic stroke — Persistent deficit >24 h or imaging-confirmed infarction — distinguished only after observation and MRI
Seizure with postictal weakness — Witnessed convulsion, tongue bite, urinary incontinence, gradual recovery
Migraine aura — Slow march of positive symptoms (scintillating scotoma, paresthesias) over minutes, headache follows
Hypoglycemia — Fingerstick glucose; diaphoresis, tremor; resolves with glucose
Syncope / presyncope — Global rather than focal symptoms; bilateral lower extremity weakness, lightheadedness
Vestibular disorders (BPPV, vestibular neuritis) — Isolated vertigo; HINTS exam helpful; sustained nystagmus
Peripheral neuropathy / nerve entrapment — Onset gradual, distribution follows peripheral nerve rather than vascular territory

Diagnostic workup

Diagnostic criteria

Transient focal neurologic symptoms with no imaging evidence of infarction. ABCD2 score (Age, BP, Clinical features, Duration, Diabetes) stratifies short-term stroke risk.

Labs

Fingerstick glucose, CBC, BMP, lipid panel, A1c, PT/INR
ECG (atrial fibrillation, recent MI)

Imaging

MRI brain with DWI — most sensitive; up to one-third of clinical 'TIAs' show acute infarction (reclassified as stroke)
CT or CTA head and neck — evaluates for stenosis and excludes hemorrhage
Carotid duplex if neck CTA not done
Transthoracic echo; transesophageal if cardioembolic source suspected and TTE non-diagnostic
Prolonged cardiac monitoring (30-day event monitor or implantable loop recorder) for cryptogenic events — CRYSTAL-AF found AFib in ~12.4% at 12 months

Diagnostic algorithm

ABCD2 Component	Points
Age ≥60	1
BP ≥140/90 at presentation	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 low / 4-5 moderate / 6-7 high 2-day stroke risk

ABCD2 score for predicting short-term stroke risk after TIA.

Treatment

First-line

Aspirin 325 mg loading dose, then 81 mg daily — start immediately
Dual antiplatelet therapy (aspirin + clopidogrel) for 21-90 days after high-risk TIA (ABCD2 ≥4) or minor stroke, then aspirin monotherapy (CHANCE, POINT, THALES)
High-intensity statin: atorvastatin 80 mg or rosuvastatin 40 mg (SPARCL)
Blood pressure control (long-term goal <130/80; do not aggressively lower in acute phase)
Anticoagulation (DOAC preferred, warfarin if mechanical valve or moderate-severe mitral stenosis) for AFib

Second-line / adjunct

Carotid endarterectomy or stenting for symptomatic ipsilateral stenosis 70-99% — within 2 weeks for maximum benefit (NASCET, ECST)
PFO closure in selected younger patients with cryptogenic stroke/TIA (RESPECT, CLOSE, REDUCE)
Smoking cessation, diabetes control, weight loss, exercise
Treat OSA if present

Complications

Completed stroke (10-15% within 90 days; highest in first 48 hours)
Cardiovascular events (MI, vascular death)
Cognitive decline, vascular dementia from cumulative subclinical infarcts

PANCE pearls

ABCD2 score ≥4 = high short-term stroke risk → admit or rapid TIA clinic evaluation.
TIA is a medical emergency — the same workup and secondary prevention as stroke, just faster.
Amaurosis fugax = ipsilateral carotid disease (or giant cell arteritis in elderly).
'Crescendo TIAs' (multiple within hours/days) carry very high stroke risk — admit for urgent workup.
Cryptogenic stroke/TIA in young patient — workup PFO, hypercoagulable state, dissection, vasculitis, drug use.

References

AHA/ASA 2021 — 2021 Guideline for the Prevention of Stroke in Patients With Stroke and TIA (Kleindorfer et al., Stroke 2021)
POINT Trial — Clopidogrel and Aspirin in Acute Ischemic Stroke and High-Risk TIA (Johnston et al., NEJM 2018)
CHANCE Trial — Clopidogrel with Aspirin in Acute Minor Stroke or TIA (Wang et al., NEJM 2013)
NASCET — Benefit of Carotid Endarterectomy in Patients with Symptomatic Moderate or Severe Stenosis (NASCET Collaborators, NEJM 1998)

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