What Is a Stroke?

A stroke is a brain attack. It occurs when blood flow to an area of brain is cut off. Without oxygen, brain cells start to die after a few minutes. When brain cells die during a stroke, abilities controlled by that area of the brain such as memory and muscle control are lost.

How a person is affected depends on where the stroke occurs in the brain and how much the brain is damaged. Examples of stroke symptoms include sudden weakness; paralysis or numbness of the face, arms, or legs; trouble speaking or understanding speech; and trouble seeing. Some people recover completely from strokes, but more than 2/3 of survivors will have some type of disability.

Stroke types

Hemorrhagic stroke
Hemorrhagic strokes occur when a blood vessel in the brain breaks or ruptures. The result is blood seeping into the brain tissue, causing damage to brain cells. The most common causes of hemorrhagic stroke are high blood pressure and brain aneurysms. Aneurysms are balloon-like bulges in an artery that can stretch and burst.

Ischemic stroke
A blood vessel carrying blood to the brain is blocked by a blood clot. Clots can form in the brain's blood vessels, in blood vessels leading to the brain, or even in blood vessels elsewhere in the body and then travel to the brain. About 80% of all strokes are ischemic.

Transient ischemic attack (TIA) or mini-stroke
A TIA occurs if blood flow to a portion of the brain is blocked only for a short time. Thus, damage to the brain cells isn’t permanent. Although TIAs are not full-blown strokes, they greatly increase the risk of having a stroke.

Risk factors

The main risk factor for stroke is high blood pressure. Other risk factors include tobacco smoking, obesity, high blood cholesterol, diabetes mellitus, previous TIA, and atrial fibrillation among others. Stroke can happen to anyone including babies and children.

Prevention

The risk of having a stroke can be significantly reduced through a healthy lifestyle, such as eating a healthy diet, taking regular exercise, drinking alcohol in moderation and not smoking. Lowering high blood pressure and cholesterol levels with medication also lowers the risk of stroke substantially, as does taking anticoagulant medication (warfarin) if the patient has an irregular heartbeat due to a condition called atrial fibrillation.
If you have had a stroke or TIA in the past, these measures are particularly important because your risk of having another stroke in the future is greatly increased.

Treatment

Treatment depends on the type of stroke, including which part of the brain was affected and what caused it.
For acute ischemic stroke, tissue plasminogen activator (tPA) is given via intravenous therapy (IV) and works by dissolving the clot and improving blood flow to the part of the brain being deprived of blood flow. From onset of symptoms, there is only a 3 to 4 1/2 hour window to use thrombolytics to try to restore blood supply to the affected part of the brain.
In cases of haemorrhagic strokes, surgery may be required to treat brain swelling and reduce the risk of further bleeding.

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