Ischemic stroke
Formal Definition
Sudden focal neurological deficit caused by interruption of blood supply to a region of the brain, most commonly from thrombosis (large artery atherosclerosis, small vessel lipohyalinosis) or embolism (cardiac source — atrial fibrillation, valvular disease; or arterial-to-arterial from carotid plaque); diagnosed by CT head (to rule out hemorrhage) followed by MRI DWI; treated within the window (4.5h for IV tPA, 6-24h for mechanical thrombectomy depending on core/penumbra mismatch) with reperfusion therapy.
How It's Used on the Ward
"Stroke" or "CVA" — the patient had a sudden onset of weakness or speech trouble and it is from a blocked artery in the brain; the key is that time is brain and we need to figure out if they are a tPA candidate or a thrombectomy candidate; think "blocked artery, not broken blood vessel."
Example
""72-year-old female with atrial fibrillation off anticoagulation (patient preference) presents at 2.5h from onset with right facial droop, right arm weakness (0/5 strength), expressive aphasia. BP 168/88. CT head negative for hemorrhage. CT perfusion shows large penumbra with small core infarct. Diagnosis: acute ischemic stroke in the left MCA territory, cardioembolic from AFib. Patient within tPA window (3h from onset). Alteplase 0.9 mg/kg IV started. CT angiography shows left MCA M1 occlusion — referred to IR for mechanical thrombectomy. Door-to-needle time: 28 minutes.""
Clinical Context
Time is brain: every minute of untreated stroke = ~1.9 million neurons lost. tPA (alteplase): 0-4.5h window, door-to-needle goal <60 min. Contraindications: any hemorrhage on CT, recent surgery/head trauma, platelet <100, INR >1.7, BP >185/110. Mechanical thrombectomy: up to 24h for selected patients (DAWN, DEFUSE3 criteria — large vessel occlusion with favorable imaging). Stroke workup: CT head + CTA (rule out hemorrhage + find large vessel occlusion), labs (glucose, CBC, PT/INR, troponin), cardiac monitoring (rule out Afib), TTE (bubble study for PFO), carotid imaging (for symptomatic carotid stenosis). Secondary prevention: antiplatelet (aspirin 325mg within 24-48h, then 81mg; clopidogrel for 90 days if minor stroke/TIA from large artery atherosclerosis), anticoagulation for AFib (delayed 4-14 days after cardioembolic stroke to avoid hemorrhagic conversion), statin (high intensity), BP control <140/90.