A 12-year-old boy with sickle cell disease on hydroxyurea therapy presents with sudden onset severe headache, focal neurological deficit (left-sided weakness), and slurred speech. Blood pressure is 145/92 mmHg. Urgent non-contrast CT head shows no acute hemorrhage. What is the most appropriate immediate next step in management?

Explanation

## Clinical Scenario: Acute Ischemic Stroke in Sickle Cell Disease This child presents with **acute stroke** — a life-threatening neurological emergency in the context of SCD. ### Key Clinical Features **High-Yield:** Stroke in SCD is: - Caused by **large-vessel arterial stenosis** (intimal proliferation and narrowing) or small-vessel occlusion - Due to sickling, hemolysis, chronic hemodynamic stress, and endothelial dysfunction - Most common cause of death and disability in children with SCD - Requires **urgent imaging and exchange transfusion** ### Why This Is a Stroke Emergency The combination of: - Acute focal neurological deficit (left-sided weakness, slurred speech) - Headache - Hypertension (reactive to stroke) - Normal non-contrast CT (rules out hemorrhage) ...indicates **acute ischemic stroke** requiring immediate intervention. ## Management Algorithm ```mermaid flowchart TD A[Acute focal neuro deficit + SCD]:::outcome --> B{Non-contrast CT}:::decision B -->|Hemorrhage| C[Neurosurgery consult; manage ICH]:::urgent B -->|No hemorrhage| D[Acute ischemic stroke]:::outcome D --> E[Urgent MRI/MRA]:::action E --> F{Arterial stenosis or occlusion?}:::decision F -->|Yes| G[Exchange transfusion to HbS <30%]:::action F -->|No| H[Transfuse to Hb 10-11 g/dL]:::action G --> I[Neurology + Hematology co-management]:::action H --> I I --> J[Long-term transfusion program ± hydroxyurea]:::action ``` ### Rationale for Correct Answer 1. **MRI/MRA is essential** — identifies: - Acute ischemic lesion (DWI/ADC) - Large-vessel stenosis or occlusion (MRA) - Guides severity assessment and prognosis 2. **Exchange transfusion is urgent** — reduces HbS% to <30%, improving rheology and cerebral perfusion. This is the definitive acute intervention in SCD stroke. 3. **Time-sensitive** — every minute of ischemia causes irreversible neuronal death. Exchange transfusion must be initiated emergently. ### Exchange Transfusion vs. Simple Transfusion | Intervention | Indication | Goal | |---|---|---| | **Exchange transfusion** | Acute stroke, acute chest syndrome with severe hypoxemia, splenic sequestration crisis | HbS <30%; Hb 10–11 g/dL | | **Simple transfusion** | Chronic transfusion program, pre-operative prophylaxis | Hb 10–11 g/dL | **Key Point:** Exchange transfusion is preferred in acute stroke because it reduces HbS without volume overload (risk of pulmonary edema in children with chronic anemia). ### Why NOT Thrombolytic Therapy? Thrombolytics (alteplase) are contraindicated in SCD stroke because: - Stroke is primarily due to **vasculopathy and sickling**, not thromboembolism - High risk of hemorrhagic transformation in SCD (endothelial fragility) - Exchange transfusion is the proven, safe intervention **Warning:** Do not confuse SCD stroke with acute ischemic stroke in the general population — thrombolytics are NOT standard of care in SCD.