TIA

Transient ischemic attack (TIA) is a temporary disruption of blood flow to part of the brain or eye, producing neurological symptoms that resolve completely within a short time. Unlike a stroke, TIAs do not cause permanent brain injury, but they signal an increased risk of future stroke. In modern practice, TIAs are defined by the presence of focal neurological symptoms lasting less than 24 hours and, when imaging is performed, the absence of acute infarction.

Symptoms include sudden weakness or numbness on one side of the face or body, difficulty speaking or understanding speech, vision changes, dizziness, loss of balance, or sudden severe headache. Symptoms are typically unilateral and abrupt.

Causes include reduced blood flow from a narrowed artery (carotid stenosis) or temporary blockage by a clot (emboli) from the heart or arteries. Common risk factors are hypertension, diabetes, high cholesterol, smoking, age, prior TIA or stroke, and atrial fibrillation.

Diagnosis is an emergency evaluation with imaging and tests to identify the source. Imaging options include MRI, which best detects small infarcts, and CT to exclude hemorrhage. Vascular studies (carotid ultrasound, CT/MR angiography) and cardiac evaluation (ECG, echocardiography) help identify sources. Blood tests assess risk factors and overall health.

Treatment and prevention aim to reduce stroke risk and manage risk factors. Immediate measures include antiplatelet therapy (such as aspirin, sometimes with clopidogrel), statin therapy, and control of blood pressure and diabetes, along with lifestyle changes. If a cardioembolic source is identified, anticoagulation may be indicated. For significant carotid stenosis, carotid endarterectomy or stenting may be considered. Secondary prevention includes lifestyle modification, ongoing risk-factor management, and close follow-up.

Prognosis: most TIAs resolve quickly, but about a third of subsequent strokes occur within 48 hours after a TIA. Rapid evaluation within 24 hours is recommended.