A stroke, sometimes called a "brain attack," occurs when blood flow to an area in the brain is cut off. As a result, the brain cells, deprived of the oxygen and glucose needed to survive, die. If not caught early, permanent brain damage 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 which then 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 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. An aneurysm is a weakness or thinness in the blood vessel wall that causes it to balloon outward.
Signs of Stroke
If you experience any of the following signs you or a loved one are having a stroke, call 911 immediately.
Sudden numbness or weakness in the face, arm, or leg (especially on one side of the body)
Difficulty speaking or understanding words or simple sentences
Dizziness, loss of balance, or poor coordination
Brief loss of consciousness
A transient ischemic attack (TIA), often called a “mini-stroke,” may be a warning of an impending stroke. It typically consists of the same signs and symptoms of stroke, but the symptoms are temporary. It occurs when blood flow to a certain part of the brain is cut off for a short period of time, usually 15 minutes or less. A TIA can occur anywhere from a few minutes to several months before a stroke. A TIA is a painless episode, but it is a warning that something is wrong. It should be treated as seriously as a stroke.