## Clinical Context This patient presents with acute ischemic stroke (left middle cerebral artery territory based on right hemiparesis and expressive aphasia) within the thrombolytic window (2 hours from onset). ## Key Point: **Intravenous thrombolysis with alteplase (tPA) is the standard of care for acute ischemic stroke within 4.5 hours of symptom onset**, provided there are no contraindications [cite:Harrison 21e Ch 434]. ## Eligibility Assessment - **Time window:** 2 hours — well within the 4.5-hour window for IV tPA - **CT head:** Non-contrast CT rules out hemorrhage (mandatory before thrombolysis) - **Contraindications check:** No mention of recent surgery, anticoagulation, thrombocytopenia, or INR elevation - **Vital signs:** BP 168/98 is elevated but not an absolute contraindication (tPA can be given if SBP <185 and DBP <110) ## High-Yield: **The next step is NOT to defer or investigate further — it is to rapidly check INR and platelet count (to exclude bleeding diathesis) and then administer tPA.** Every minute of delay increases infarct volume ("time is brain"). ## Mechanism Alteplase is a recombinant tissue plasminogen activator that converts plasminogen to plasmin, dissolving thrombus and restoring cerebral perfusion. The standard dose is 0.9 mg/kg (max 90 mg) IV bolus over 1 minute, followed by infusion over 60 minutes. ## Clinical Pearl: **Aspirin is NOT a substitute for thrombolysis in the acute phase.** It is given *after* thrombolysis or in patients ineligible for tPA. 
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