A stroke is caused by the interruption of the blood supply to the brain, usually because a blood vessel bursts or is blocked by a clot. This cuts off the supply of oxygen and nutrients, causing damage to the brain tissue.
The most common symptom of a stroke is sudden weakness or numbness of the face, arm or leg, most often on one side of the body. Other symptoms include: confusion, difficulty speaking or understanding speech; difficulty seeing with one or both eyes; difficulty walking, dizziness, loss of balance or coordination; severe headache with no known cause; fainting or unconsciousness.
The effects of a stroke depend on which part of the brain is injured and how severely it is affected. A very severe stroke can cause sudden death.
Stroke is the clinical term for acute loss of perfusion to vascular territory of the brain resulting in ischemia and corresponding loss of neurologic function.
Stroke is the third leading cause of death and a leading cause of morbidity and long-term disability.
Broadly classified as ischemic stroke (80% to 85%) and hemorrhagic stroke (15% to 20%).
Eighty percent of strokes are ischemic, and about 25% are caused by cerebral emboli.
Causes. Infarction from thrombus or emboli
- Progressing stroke: unstable, progressing neurologic deficits.
- Completed stroke: stable, non-progressing neurologic deficit.
- Intracerebral hemorrhage: hemorrhage in or around brain.
- Subarachnoid hemorrhage: accounts for 5% to 10% of strokes.