Neurology · USMLE Step 1 and Step 2

Ischemic Stroke song

Ischemic Stroke - Types, Window & Deficits, as a song. Hear the short teaser here. The full song is on YouTube and Spotify.

Ischemic Stroke

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Key points in this song10

Thrombotic strokes occur due to in-situ atherosclerotic plaque rupture in large vessels (carotids, MCA) or lipohyalinosis in small vessels (lacunar infarcts), while embolic strokes arise from cardiac sources (A-fib, mural thrombus, endocarditis) or artery-to-artery embolism.
A-fib is the most common cardiac cause of embolic stroke; the left atrial appendage is the primary thrombus source, and anticoagulation (not antiplatelet therapy) is the treatment of choice for stroke prevention.
The MCA territory is the most commonly affected in embolic stroke, producing contralateral hemiplegia (face and arm > leg), contralateral hemianesthesia, and homonymous hemianopsia; dominant hemisphere involvement causes aphasia.
IV alteplase (tPA) must be administered within 4.5 hours of symptom onset in eligible patients; contraindications include recent surgery, active bleeding, BP >185/110 mmHg uncontrolled, and prior intracranial hemorrhage.
Mechanical thrombectomy (endovascular clot retrieval) is indicated within 24 hours of onset for large vessel occlusion (LVO) confirmed on CT angiography, even beyond the tPA window.
Lacunar infarcts result from small vessel lipohyalinosis in hypertensive or diabetic patients; classic syndromes include pure motor hemiplegia (posterior limb of internal capsule), pure sensory stroke (thalamus), and ataxic hemiparesis.
Non-contrast CT head is the first-line imaging in acute stroke to exclude hemorrhage; CT is initially negative in ischemic stroke for the first 6–24 hours, while MRI diffusion-weighted imaging (DWI) detects ischemia within minutes.
Antiplatelet therapy (aspirin ± clopidogrel for 21 days in minor stroke) is initiated within 24–48 hours of ischemic stroke onset when tPA has not been given, as dual antiplatelet therapy reduces early recurrence risk.
The penumbra is the ischemic but potentially salvageable tissue surrounding the infarcted core; reperfusion therapy aims to rescue penumbral tissue before irreversible infarction occurs (time = neurons: ~1.9 million neurons lost per minute of LVO).
Posterior circulation (vertebrobasilar) strokes present with the "5 D's": Dizziness, Diplopia, Dysarthria, Dysphagia, and Drop attacks; lateral medullary (Wallenberg) syndrome features ipsilateral facial pain/temperature loss, contralateral body loss, Horner syndrome, and dysphagia.