A stroke, sometimes called a "brain attack," occurs when blood flow to an area in the brain is cut off. The brain cells, deprived of the oxygen and glucose needed to survive, die. If not caught early, permanent brain damage and death can result.
Ischemic stroke is similar to a heart attack, except it occurs in the blood vessels of the brain. Clots can form either in the brain's blood vessels, in blood vessels leading to the brain, or even blood vessels elsewhere in the body that travel to the brain. These clots block blood flow to the brain's cells. Ischemic stroke can also occur when too much plaque (fatty deposits and cholesterol) clogs the brain's blood vessels. About 80% of all strokes are ischemic.
Hemorrhagic (heh-more-raj-ik) 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. An aneurysm is a weakness or thinness in the blood vessel wall.
What Are the Symptoms of Stroke?
The most common symptoms of a stroke are:
Weakness or numbness of the face, arm, or leg on one side of the body
Loss of vision or dimming (like a curtain falling) in one or both eyes
Loss of speech, difficulty talking, or understanding what others are saying
Sudden, severe headache with no known cause
Loss of balance or unstable walking, usually combined with another symptom
What Should I Do If I Have Symptoms of a Stroke?
Immediately call 911 if you or someone you know has symptoms of a stroke. Stroke is a medical emergency. Immediate treatment can save your life or increase your chances for a full recovery.
Are Strokes Preventable?
Up to half of all strokes are preventable. Many risk factors can be controlled before they cause problems.