A 52-year-old man with newly diagnosed atrial fibrillation presents with sudden onset left-sided weakness and speech difficulty lasting 45 minutes. CT head (non-contrast) is normal. Vital signs are stable. NIHSS score is 8. Laboratory work shows INR 1.0, platelet count 245,000/μL, and glucose 140 mg/dL. What is the most appropriate next step in management?

Explanation

## Clinical Scenario Analysis This patient presents with acute ischemic stroke (sudden neurological deficit, normal CT head) within the 3-hour thrombolytic window. The stroke is likely cardioembolic due to new-onset atrial fibrillation. **Key Point:** The presence of atrial fibrillation does NOT contraindicate thrombolysis in acute ischemic stroke. Time is brain — every minute of delay increases infarct volume and worsens outcome. ## Thrombolytic Window and Indications **High-Yield:** Intravenous alteplase (tPA) is indicated for acute ischemic stroke if: 1. Symptom onset ≤4.5 hours (3 hours is standard; up to 4.5 hours with careful selection) 2. Non-contrast CT excludes hemorrhage 3. No major contraindications (recent surgery, active bleeding, INR >1.7, platelets <100,000) This patient meets all criteria: - Time: 45 minutes (well within window) - CT: negative for hemorrhage - INR: 1.0 (therapeutic window) - Platelets: 245,000 (normal) - NIHSS: 8 (moderate stroke, benefit from thrombolysis) ## Dosing and Administration **Mnemonic:** **ALTEPLASE DOSE = 0.9 mg/kg** — 10% bolus over 1 minute, remainder over 60 minutes - Total dose capped at 90 mg - For this 52-year-old (assume ~70 kg): 63 mg total ## Atrial Fibrillation and Thrombolysis **Clinical Pearl:** Atrial fibrillation is a *cause* of cardioembolic stroke, not a contraindication to thrombolysis. In fact, AF-related strokes benefit from early reperfusion. After thrombolysis, the patient should be anticoagulated with warfarin or DOAC (not aspirin alone) for secondary prevention. ## Post-Thrombolysis Management 1. Admit to stroke unit / ICU 2. Monitor for hemorrhagic transformation (4–6 hours post-tPA) 3. Avoid antiplatelet or anticoagulant therapy for 24 hours post-tPA 4. After 24 hours: initiate anticoagulation (warfarin target INR 2–3, or DOAC) for AF-related stroke 5. Imaging: MRI brain at 24 hours to assess reperfusion and rule out hemorrhage ## Why Not Heparin Alone? Heparin without thrombolysis is slower and less effective than alteplase in acute ischemic stroke. Thrombolysis restores perfusion in ~50% of patients; anticoagulation alone does not lyse clot and is reserved for patients outside the thrombolytic window.