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Abstract
Stroke is defined as acute focal loss of perfusion to a vascular territory of the brain, resulting in ischemia with corresponding loss of neurological function. It is the third leading cause of death on a global basis.
It may be organized into ischemic and hemorrhagic forms. In ischemic stroke the primary pathology is occlusion of one of arteries carrying blood to the brain, which consists about 85% of cerebrovascular stroke. The three main mechanisms causing ischemic strokes are:
• thrombosis
• embolism
• global ischemia (hypotensive) stroke.
Within an hour of hypoxic- ischemic insult, there is a core of infarction surrounded by an oligemic zone called the ischemic penumbra (IP) where autoregulation mechanisms of cerebral blood flow are ineffective. In the core zone, which is an area of severe ischemia (blood flow below 10% to 25%), the loss of inadequate supply of oxygen and glucose results in rapid depletion of energy stores.