Stroke can be caused by which mechanisms?

• A. Infection and edema
• B. Tumor and hydrocephalus
• C. Dehydration and electrolyte imbalance
• D. Blockage (ischemic) and bleeding (hemorrhagic)

Answer: (D)

Stroke occurs when blood flow to a portion of the brain is interrupted. The two main mechanisms are blockage of a cerebral artery (ischemic stroke) and rupture of a vessel with bleeding into the brain (hemorrhagic stroke). In ischemic stroke, a clot forms or travels to occlude a vessel, sharply reducing perfusion and causing brain tissue damage if not quickly restored. In hemorrhagic stroke, a vessel bursts, leading to bleeding that damages brain tissue and raises pressure inside the skull. Together, these mechanisms explain why stroke presents suddenly with focal neurological deficits. Other conditions like infection, edema, tumor, hydrocephalus, or dehydration can cause brain symptoms, but they do not describe the vascular failure at the heart of stroke.