What tests are used to diagnose a Transient Ischemic Attack (TIA) or mini-stroke?

Diagnostic Testing for Transient Ischemic Attack (Mini-Stroke)

Yes, there are specific tests to diagnose a TIA (mini-stroke), and all patients with suspected TIA should undergo brain imaging, vascular imaging of the carotid arteries, ECG, and laboratory investigations as part of their initial assessment. 1

Essential Imaging Studies

Brain Imaging (Required for All Patients)

• CT or MRI of the brain must be performed, with MRI (including diffusion sequences) preferred when available as it is more sensitive for detecting ischemic changes 1, 2
• Brain imaging should be completed within 24 hours of symptom onset for high-risk patients, and within 48-72 hours for lower-risk patients 1
• Approximately 33% of TIA patients will show acute brain infarction on imaging despite transient symptoms 3

Vascular Imaging (Required for All Patients)

• CT angiography (CTA) from aortic arch to vertex is the preferred initial vascular imaging test, performed at the same time as brain CT to assess both extracranial and intracranial circulation 1
• CTA allows visualization of the intracranial circulation, posterior circulation, and aortic arch to identify stroke etiology and guide management decisions 1
• Carotid ultrasound and MR angiography are acceptable alternatives when CTA is not immediately available 1
• Extracranial vascular imaging is critical to identify carotid stenosis >50%, as these patients require urgent referral for possible carotid revascularization 1

Required Laboratory Tests

Initial Blood Work (All Patients)

• Complete blood count (CBC) 1
• Electrolytes 1
• Coagulation studies: aPTT and INR 1
• Renal function: creatinine and estimated glomerular filtration rate 1
• Random or capillary glucose to rule out hypoglycemia as a stroke mimic 1
• Troponin to identify concurrent cardiac injury 1, 4

Subsequent Laboratory Tests

• Lipid profile (fasting or non-fasting) for secondary stroke prevention planning 1, 4
• HbA1c or 75g oral glucose tolerance test to screen for diabetes as a stroke risk factor 1, 4

Cardiac Evaluation

Electrocardiogram (Required for All Patients)

• 12-lead ECG should be performed to assess cardiac rhythm and identify structural heart disease (previous MI, left ventricular hypertrophy) 1
• Approximately 10% of TIA patients have atrial fibrillation detected on initial evaluation 3

Extended Cardiac Monitoring

• Prolonged ECG monitoring up to 30 days is recommended when initial ECG or 24-48 hour monitoring does not show atrial fibrillation but a cardioembolic mechanism is suspected 1
• Echocardiogram may be considered when the stroke mechanism has not been identified after initial testing 1

Timing of Evaluation Based on Risk Stratification

Highest Risk (Requires Immediate Assessment)

Patients presenting within 48 hours with unilateral weakness (face, arm, leg) or speech/language disturbance should receive comprehensive evaluation and investigations within 24 hours of first healthcare contact 1

Moderate Risk (Urgent Assessment)

Patients presenting 48 hours to 2 weeks after symptoms without motor weakness or speech disturbance (e.g., hemibody sensory loss, monocular vision loss, diplopia, ataxia) should be evaluated within 2 weeks 1

Lower Risk (Less Urgent)

Patients presenting more than 2 weeks after symptoms should be evaluated within 1 month 1

Critical Clinical Pitfalls

Do not delay urgent interventions waiting for non-essential laboratory results, as time is critical in TIA management to prevent stroke recurrence 4

Recognize that approximately 70% of patients do not correctly identify their TIA symptoms, and 30% delay seeking medical attention for more than 24 hours, regardless of demographic factors 5. This emphasizes the importance of rapid evaluation once patients do present.

Be aware that 23% of TIA patients have significant stenosis (≥50%) of extracranial or intracranial vessels, making vascular imaging essential 3

Understand that patients with multiple infarctions on brain imaging, large-artery atherosclerosis, or ABCD2 score ≥6 have more than double the risk of recurrent stroke, requiring more aggressive monitoring and treatment 3, 2