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Transient Ischemic Attack (TIA)

BASICS

  • Definition: A transient episode of neurologic dysfunction due to focal ischemia of the brain, retina, or spinal cord without infarction.
  • Key fact: 7.5–17.4% risk of stroke within 3 months post-TIA.
  • Synonym: "Ministroke"

EPIDEMIOLOGY

Parameter Data
Prevalence ~2% general population
Age Risk increases >60 yrs; peak: 70s–80s
Sex Male > Female
Ethnicity African American > Hispanic > Caucasian

ETIOLOGY & PATHOPHYSIOLOGY

  • Mechanism: Transient cerebral hypoperfusion without infarction
  • Common causes:
  • Atherosclerosis: carotid or vertebrobasilar arteries
  • Cardioembolic: atrial fibrillation, valvular disease, LV thrombus
  • Lacunar infarcts: small vessel disease (HTN, DM)
  • Hypercoagulable states: APS, estrogen use, pregnancy
  • Arteritis: vasculitis (e.g., Takayasu)
  • Drugs: Cocaine, sympathomimetics
  • Dissection: Spontaneous/posttraumatic (e.g., chiropractic injury)
  • Fibromuscular dysplasia

RISK FACTORS

Modifiable Non-modifiable
HTN, DM, hyperlipidemia Age >60
Smoking, obesity Male sex
Atrial fibrillation Family history (polygenic)
Estrogen use

ASSOCIATED CONDITIONS

  • Atrial fibrillation
  • Carotid stenosis
  • Pregnancy-specific causes:
  • Preeclampsia, HELLP, TTP, CVT
  • Pediatric causes: congenital heart disease, sickle cell, moyamoya

CLINICAL PRESENTATION

Circulation Symptoms
Carotid Monocular vision loss, aphasia, hemiparesis, hemianesthesia, neglect
Vertebrobasilar Diplopia, vertigo, dysarthria, dysphagia, ataxia, Horner syndrome
  • Symptom onset: Sudden
  • Duration: Usually <1 hour
  • Recovery: Complete resolution within 24 hours

RISK STRATIFICATION TOOLS

ABCD2 Score (Short-term stroke risk)

Component Points
Age > 60 yrs 1
BP ≥140/90 mm Hg 1
Clinical features
– Unilateral weakness 2
– Speech impairment 1
Duration
– ≥60 min 2
– 10–59 min 1
Diabetes 1

Score Interpretation: - 0–1: Low risk (0%) - 2–3: Moderate risk (~1.3%) - 6–7: High risk (~8.1%)

ABCD3-I: Includes dual TIA and imaging

DIFFERENTIAL DIAGNOSIS

  • Hemiplegic migraine
  • Seizure (postictal paralysis)
  • Bell’s palsy
  • Hypoglycemia/electrolyte imbalance
  • Multiple sclerosis
  • CNS infection
  • TIA mimics: syncope, functional symptoms

DIAGNOSIS

Initial Tests

Modality Purpose
MRI with DWI Preferred for detecting ischemia
CT head (noncontrast) If MRI unavailable
Vascular imaging Carotid duplex, CTA, or MRA
ECG + labs Rule out arrhythmia, risk factors
Bloodwork CBC, PT/PTT, lipids, glucose, etc.

Additional Workup

  • TEE: PFO, aortic plaque, valvular disease
  • Prolonged ECG monitoring: paroxysmal AF
  • EEG: suspected seizure

TREATMENT

General Principles

  • Admit high-risk TIA patients (<72 hrs onset, ABCD2 ≥3)
  • Initiate workup within 24 hrs
  • Refer to neurology or stroke unit

Antiplatelet Therapy (Non-cardioembolic TIA)

Drug Dose Comments
Aspirin 81–325 mg/day First-line
Clopidogrel 75 mg/day Alternative if aspirin allergy
Aspirin + Clopidogrel Dual therapy ≤1 month For high-risk patients; not for long-term use
Dipyridamole + Aspirin 200/25 mg BID Not superior to monotherapy; BID dosing burden

Anticoagulation (Cardioembolic TIA)

Agent Indication
Apixaban, Rivaroxaban, Dabigatran Atrial fibrillation, mural thrombus, valvular disease
Warfarin Mechanical valves, INR-based therapy
Idarucizumab Reversal for dabigatran

Secondary Prevention

Intervention Goal
BP control After 24 hrs; thiazides/ACEi/ARB
Statins High-dose statin (e.g., atorvastatin 80 mg)
DM control Optimize HbA1c <7%
Lifestyle No smoking, DASH diet, ≥150 min/wk exercise

PROCEDURES

  • Carotid endarterectomy (CEA):
  • Recommended if ≥70% stenosis and recent TIA
  • Perform within 2 weeks if feasible

ADMISSION CRITERIA

  • Symptoms <72 hrs and:
  • ABCD2-I ≥3
  • Uncertain outpatient access or follow-up
  • Imaging suggests acute ischemia

FOLLOW-UP

Task Timeline
Neurology consult At discharge
Repeat imaging (if indicated) Within weeks
BP/glucose/lipid monitoring Monthly initially
Physical activity advice ≥30 min/day

PATIENT EDUCATION

  • Keep BP, DM, and cholesterol under control
  • Avoid tobacco and alcohol
  • Emergency symptoms to watch for:
  • Facial droop
  • Arm weakness
  • Speech difficulty
  • Vision changes
  • Sudden severe headache

PROGNOSIS

Outcome Risk
Stroke within 48 hrs 1.5–3.5%
Stroke within 3 months Up to 17.4%
1-year mortality (high risk) Up to 25%

CODES

ICD-10 Code Description
G45.9 Unspecified TIA
G45.1 Carotid artery syndrome
G45.0 Vertebrobasilar artery syndrome

CLINICAL PEARLS

  • TIA is a warning sign—urgent evaluation prevents future stroke.
  • Use ABCD2 or ABCD3-I scoring for risk stratification.
  • Consider dual antiplatelet therapy for ≤30 days post-TIA if high risk.
  • Anticoagulation is only for cardioembolic causes.
  • MRI with DWI is more sensitive than CT, but time-critical decisions may be made with CT.