A 65-year-old woman from Mumbai is brought to the hospital 6 hours after sudden onset left-sided weakness and facial droop. Neurological examination confirms right-sided hemiparesis (3/5) with right facial weakness. Non-contrast CT head shows no hemorrhage. MRI brain with DWI shows acute ischemia in the distribution of the left middle cerebral artery affecting the internal capsule. What is the most appropriate immediate next step in management?

Explanation

## Clinical Context: Acute Ischemic Stroke Management This patient presents **6 hours after symptom onset** with left-sided weakness, facial droop, and MRI-confirmed acute ischemia in the left MCA territory affecting the internal capsule. Non-contrast CT shows no hemorrhage. ### Key Temporal Consideration **High-Yield:** The standard IV thrombolysis window for alteplase is **0–4.5 hours** from symptom onset. At **6 hours**, IV thrombolysis is **outside** the approved window and is therefore not the correct immediate next step. ### Why Mechanical Thrombectomy (Option D) Is the Correct Answer **Key Point:** The internal capsule stroke with MCA territory involvement on DWI strongly suggests a **large vessel occlusion (LVO)**. In the **6–24 hour window**, mechanical thrombectomy is the standard of care for eligible patients with LVO and evidence of salvageable tissue. **Clinical Pearl:** The **DAWN** (6–24 hours, clinical-imaging mismatch) and **DEFUSE 3** (6–16 hours, perfusion-imaging mismatch) trials established that mechanical thrombectomy provides significant benefit beyond the thrombolysis window when: 1. Large vessel occlusion is present 2. Salvageable ischemic penumbra exists (DWI/PWI mismatch or clinical mismatch) 3. Patient meets clinical criteria (NIHSS ≥ 6) This patient has a significant motor deficit (3/5 hemiparesis + facial weakness), MCA territory DWI ischemia, and presentation at 6 hours — meeting criteria for thrombectomy evaluation per AHA/ASA 2018 guidelines. Since the patient is already **beyond the 4.5-hour IV alteplase window**, proceeding directly to mechanical thrombectomy (without prior thrombolysis) is appropriate. ### Management Algorithm | Time Window | LVO Present? | Recommended Action | |-------------|-------------|-------------------| | 0–4.5 hours | Yes | IV thrombolysis + mechanical thrombectomy | | 0–4.5 hours | No | IV thrombolysis alone | | 4.5–24 hours | Yes + salvageable tissue | **Mechanical thrombectomy** | | 4.5–24 hours | No LVO | Antiplatelet + supportive care | ### Why Each Distractor Is Incorrect | Option | Why It's Wrong | |--------|---------------| | **A) Dual antiplatelet therapy** | Aspirin + clopidogrel is for secondary prevention or acute non-LVO minor stroke (e.g., POINT/CHANCE trial criteria). This patient has an acute LVO requiring immediate mechanical reperfusion. | | **B) IV thrombolysis immediately** | Patient is 6 hours post-onset — beyond the 4.5-hour IV alteplase window. Administering thrombolysis at this timepoint increases hemorrhagic transformation risk without proven benefit. | | **C) Observe 24 hours then anticoagulate** | Delays definitive reperfusion. Anticoagulation has no role in acute ischemic stroke reperfusion; thrombectomy is the standard of care for LVO in the extended window. | **High-Yield Mnemonic:** **"DAWN to DEFUSE"** — the thrombectomy window extends from symptom onset to 24 hours in selected patients with LVO and salvageable tissue. [cite: Harrison's Principles of Internal Medicine, 21e, Ch. 370; AHA/ASA Acute Ischemic Stroke Guidelines 2018; DAWN Trial NEJM 2018; DEFUSE 3 Trial NEJM 2018]