Cerebrovascular accident

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.

Prevention

Prevention is an important public health concern. Identification of patients with treatable risk factors for stroke is paramount. Treatment of risk factors in patients who have already had strokes (secondary prevention) is also very important as they are at high risk of subsequent events compared with those who have never had a stroke. Medication or drug therapy is the most common method of stroke prevention. Surgery such as Carotid endarterectomy can be used to remove significant narrowing of the neck (internal) carotid artery which supplies blood to the brain and this operation has been shown to be an effective way to prevent stroke in particular groups of patients.

Related Topics:
Carotid endarterectomy - Carotid artery

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Some brain damage that results from stroke may be secondary to the initial death of brain cells caused by the lack of blood flow to the brain tissue. This brain damage is a result of a toxic reaction to the primary damage. Researchers are studying the mechanisms of this toxic reaction and ways to prevent this secondary injury to the brain. Scientists hope to develop neuroprotective agents to prevent this damage. Another area of research involves experiments with vasodilators, medications that expand or dilate blood vessels and thus increase the blood flow to the brain. Basic research has also focused on the genetics of stroke and stroke risk factors. One area of research involving genetics is gene therapy. One promising area of stroke animal research involves hibernation. The dramatic decrease of blood flow to the brain in hibernating animals is extensive enough that it would kill a non-hibernating animal. If scientists can discover how animals hibernate without experiencing brain damage, then maybe they can discover ways to stop the brain damage associated with decreased blood flow in stroke patients. Other studies are looking at the role of hypothermia, or decreased body temperature, on metabolism and neuroprotection. Scientists are working to develop new and better ways to help the brain repair itself and restore important functions to the stroke patients. Some evidence suggests that transcranial magnetic stimulation (TMS), in which a small magnetic current is delivered to an area of the brain, may possibly increase brain plasticity and speed up recovery of function after stroke.

Related Topics:
Gene therapy - Transcranial magnetic stimulation

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