In sickle cell disease, pediatric stroke risk is increased primarily due to which mechanism?

• A. Hypercoagulability
• B. Vascular rupture
• C. Vaso-occlusion from sickled cells
• D. Bacterial infection

Answer: (C)

Blockage of brain vessels by sickled red blood cells is the main driver of pediatric stroke in sickle cell disease. The sickled cells are rigid and sticky, so they can’t flow smoothly through the cerebral microcirculation. They tend to adhere to the endothelium and obstruct small arteries and arterioles, cutting off blood flow and delivering less oxygen to brain tissue. This vaso-occlusive process directly causes ischemic injury, which manifests as a stroke in children.

Over time, repeated vaso-occlusion injures vessel walls, promoting narrowing of intracranial arteries (vasculopathy) and sometimes leading to Moyamoya-type collateral formation. While fever, dehydration, or infection can precipitate a crisis, and a hypercoagulable state can contribute, the initiating mechanism behind the stroke itself is the occlusion caused by sickled cells rather than rupture or infection. Hemorrhagic strokes from rupture are less typical in this context.