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Ischemic stroke is the most common type of stroke, resulting from interruption of cerebral blood flow due to arterial occlusion, leading to brain tissue ischemia and infarction. It accounts for ~85% of all strokes and requires urgent diagnosis and intervention to minimize irreversible brain damage.
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https://www.youtube.com/watch?v=2IgFri0B85Q
https://www.youtube.com/watch?v=gxJuVO-Yf8c
Major pathophysiological mechanisms:
| Mechanism | Examples |
|---|---|
| Thrombotic | Atherosclerotic plaque rupture (e.g., carotid stenosis) |
| Embolic | Cardioembolic (e.g., atrial fibrillation, mural thrombus) |
| Lacunar infarction | Small vessel lipohyalinosis in hypertension/diabetes |
| Watershed infarction | Hypotension affecting border zones |
| Dissection | Carotid or vertebral artery dissection |
Etiologic subtypes: TOAST (Trial of Org 10172 in Acute Stroke Treatment) Classification
| Type | Details |
|---|---|
| 1. Large artery atherosclerosis | Extracranial/intracranial stenosis |
| 2. Cardioembolism | A-fib, recent MI, PFO, endocarditis |
| 3. Small vessel occlusion (lacunes) | Deep perforator infarcts (<15 mm) |
| 4. Stroke of other determined cause | Hypercoagulable states, vasculitis, dissection |
| 5. Stroke of undetermined cause | No clear etiology (cryptogenic) |
Histopathology:
https://www.youtube.com/watch?v=5aAJF485I3g
| Feature | Notes |
|---|---|
| Onset | Sudden (minutes); sometimes during sleep |
| Neurological deficits | Depend on vascular territory affected (see below) |
| Common symptoms | Hemiparesis, facial droop, aphasia, visual field defects, ataxia |
| Warning signs (TIA) | Transient symptoms <24 hrs (usually <1 hr), high stroke risk |
Neuroanatomical Correlation
| Vessel | Typical Deficits |
|---|---|
| MCA | Contralateral face+arm > leg weakness, aphasia (dominant), neglect (non-dominant) |
| ACA | Leg > arm weakness, abulia, urinary incontinence |
| PCA | Contralateral homonymous hemianopia, memory deficit |
| Basilar artery | Locked-in syndrome, quadriparesis, coma |
| Lacunar infarcts | Pure motor or sensory stroke, dysarthria-clumsy hand syndrome |