Transient ischemic attack (TIA) and acute stroke represent a spectrum of cerebrovascular disease caused by disruption of blood flow to the brain.
A TIA produces transient neurological dysfunction without established cerebral infarction, while stroke results in persistent neurological injury caused by either ischemia or hemorrhage.
Both conditions require urgent evaluation because a TIA may precede a completed stroke, and acute stroke treatment is highly time-dependent.
Clinical Pearl: Sudden focal neurological symptoms should be treated as a stroke emergency even when the symptoms begin improving or completely resolve.
A transient ischemic attack is an acute episode of focal neurological dysfunction caused by temporary ischemia affecting the brain, spinal cord, or retina.
Historically, TIA was defined as neurological symptoms that resolved within 24 hours. Modern definitions are more precise and emphasize the absence of acute infarction rather than a strict time limit.
Most TIAs last several minutes to less than one hour (occasionally several hours). Typical manifestations include:
Because these symptoms may disappear before medical evaluation, obtaining a detailed history from the patient and witnesses is particularly important.
A TIA indicates that blood flow to part of the nervous system was temporarily compromised. Although the neurological symptoms resolve, the underlying cause may remain active, including:
A patient may therefore remain at significant risk for a subsequent ischemic stroke.
Clinical Pearl: Symptom resolution after a TIA does not mean the vascular problem has resolved.
Many TIA risk factors overlap with those for ischemic stroke:
A previous TIA or stroke substantially increases the risk of another cerebrovascular event.
Stroke occurs when blood circulation to an area of the brain is suddenly interrupted or when a cerebral blood vessel ruptures.
The resulting neurological deficit depends on which blood vessel is affected, the size of the affected brain region, duration of interrupted blood flow, availability of collateral circulation, and whether bleeding causes additional mass effect or intracranial pressure.
Stroke is often referred to as a “brain attack” because, like myocardial infarction, rapid restoration of blood flow can preserve threatened tissue.
Ischemic stroke accounts for the majority of cerebrovascular events and occurs when an artery supplying the brain becomes blocked via local thrombosis, embolism (from the heart or proximal artery), small-vessel occlusion, or arterial dissection.
Arterial obstruction → reduced oxygen delivery → cerebral ischemia → neuronal dysfunction → infarction if prolonged
During ischemic stroke, the central region of severe ischemia may become irreversibly infarcted, while surrounding tissue may remain viable for a limited period. This potentially salvageable region is called the ischemic penumbra. Restoring circulation before penumbral tissue progresses to infarction is the biological basis for the phrase: “Time is brain.”
Hemorrhagic stroke occurs when a blood vessel ruptures and blood enters brain tissue. Compared with ischemic stroke, hemorrhagic stroke is more commonly associated with severe headache, nausea, vomiting, rapid decline in consciousness, and seizures. However, clinical presentation alone cannot reliably distinguish hemorrhage from ischemia; emergency neuroimaging is essential.
Subarachnoid Hemorrhage (SAH): Occurs when bleeding enters the subarachnoid space (often from a ruptured intracranial aneurysm). Patients describe “the worst headache of my life” (sudden thunderclap headache, neck stiffness, nausea, vomiting, photophobia, loss of consciousness, neurological deficits).
Carotid or vertebral artery dissection is an important cause of ischemic stroke in younger adults. Associated with head/neck trauma, high-impact sports, sudden neck rotation/extension, or connective tissue disorders, dissection causes vessel narrowing, thrombus formation, and artery-to-artery embolism.
Symptoms include unilateral headache, neck pain, facial pain, Horner syndrome, TIA, or stroke.
Clinical Pearl: A new severe headache with neurological deficits should never be assumed to represent a primary headache disorder until dangerous secondary causes have been excluded.
| Condition | Definition | Key Characteristics |
|---|---|---|
| Aphasia | Disorder of language. | Difficulty speaking, understanding speech, naming objects, reading, or writing. |
| Dysarthria | Impaired motor production of speech. | Language remains intact, but speech is slurred, slow, weak, or difficult to understand. |
Stroke mimics include hypoglycemia, seizures (Todd paralysis), migraine with aura, MS, meningitis, functional neurological disorders, brain tumors, and peripheral vestibular disease.
Hypoglycemia as a Critical Mimic: Point-of-care blood glucose must be assessed rapidly in acute neurological presentations because correcting hypoglycemia can completely resolve deficits.
Establishing the Last Known Well (LKW) time—the last time the patient was known to be neurologically normal—is essential because eligibility for reperfusion therapy depends partly on timing. For wake-up strokes, LKW guides imaging selection.
| Modality | Primary Utility | Clinical Considerations |
|---|---|---|
| Noncontrast Head CT | Excludes intracranial hemorrhage, subarachnoid blood, and mass lesions. | First test in emergency settings; early ischemic stroke may not be immediately visible. |
| Brain MRI (DWI) | Superior sensitivity for acute ischemic lesions, small infarcts, and posterior circulation strokes. | Availability and scan duration may limit hyperacute use. |
| CTA / MRA | Evaluates intracranial large-vessel occlusion (LVO), carotid stenosis, and arterial dissection. | Essential for determining eligibility for mechanical thrombectomy. |
| Cardiac Evaluation | Identifies cardioembolic sources (AFib, thrombi, valvular pathology). | Includes ECG, telemetry, TTE (ventricular/valvular assessment), and TEE (left atrial appendage/aortic arch). |
Thrombolytic therapy is strictly contraindicated. Management focuses on blood pressure control, anticoagulation reversal, intracranial pressure management, neurosurgical consultation, hydrocephalus treatment, and seizure control.
| Etiology | Primary Strategy | Key Agents / Targets |
|---|---|---|
| Non-Cardioembolic | Antiplatelet Therapy | Aspirin, Clopidogrel, or Aspirin + extended-release Dipyridamole. Short-term DAPT for high-risk TIA/minor stroke. |
| Cardioembolic (AFib) | Anticoagulation | DOACs (Apixaban, Rivaroxaban, Dabigatran, Edoxaban) or Warfarin (target INR 2.0–3.0 for mechanical valves). |
| Hypertension | BP Lowering | Long-term target <130/80 mmHg (Note: Acute BP targets differ from chronic targets to preserve penumbral perfusion). |
| Dyslipidemia | Lipid Lowering | High-intensity statin therapy following atherosclerotic stroke/TIA. |
| Lifestyle & Vascular | Risk Modification | Smoking cessation, diabetes control, exercise, weight management, and obstructive sleep apnea treatment. |
Any sudden focal neurological deficit should be treated as a stroke until proven otherwise.
A TIA may resolve completely but indicates a dangerous underlying vascular process, while acute stroke produces rapid, irreversible brain injury. Do not wait for stroke symptoms to improve—activate emergency care immediately.
Educational content only. Acute stroke diagnosis, thrombolysis, thrombectomy, antiplatelet therapy, anticoagulation, blood-pressure management, and secondary prevention should follow current stroke guidelines and individualized specialist assessment.
