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Stroke |
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A stroke or cerebrovascular accident (CVA) occurs when the blood supply to a part of the brain is suddenly interrupted by occlusion (called an ischemic stroke -- approximately 90% of strokes), by hemorrhage (called a hemorrhagic stroke -- about 10% of strokes) or other causes. Ischemia is a reduction of blood flow most commonly due to occlusion (an obstruction). On the other hand, hemorrhagic stroke (or intracranial hemorrhage), occurs when a blood vessel in the brain bursts, spilling blood into the spaces surrounding the brain cells or when a cerebral aneurysm ruptures. The mortality and long-term morbidity prognosis is generally worse for hemorrhagic strokes than for ischemic strokes. A small proportion of strokes are watershed strokes caused by hypoperfusion (usually due to hypotension) or other vascular problems including vasculitis.
A stroke is a medical emergency. It generally presents with loss of function of the area of the body controlled by the affected part of the brain, e.g. hemiplegia, loss of speech or vision, impaired swallowing reflex or altered sensation. The immediate and long-term results lead to marked morbidity and mortality.
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