what is stroke
What is a Stroke
A stroke is any interruption in blood flow to the brain. This includes blockages cause by clots in a blood vessel or when a vessel bursts and blood leaks into the brain tissue causing damage. Without quick restoration of proper blood flow brain cells may die and permanent damage may occur.
About 80% of strokes are ischemic, which means they are caused by the interruption of blood flow to the brain due to a blood clot. The buildup of plaque (fatty materials, calcium and scar tissue) is involved in most ischemic strokes – narrowing the arteries that supply blood to the brain, interfering with, or blocking the flow of blood. This “narrowing” is called atherosclerosis.
What is TIA?
A TIA, or Transient Ischemic Attack – which is also known as a “mini-stroke” – is caused by a temporary interruption of blood flow to the brain. The symptoms (warning signs) are similar to an ischemic stroke except they go away within a few minutes or hours. Many people can have a TIA without even knowing it. A TIA is an important warning sign that puts you at increased risk of a full-blown stroke.
Stroke cause by blood clots
As we get older, a waxy plaque can build up along the inside of the arteries that feed the brain. Plaque is like the gunk that builds up in the pipes underneath your sink: the thicker it grows, the less room there is for the blood to flow. Smoking, diabetes, high blood pressure and high cholesterol can cause this buildup.
Sometimes, a blood clot can plug an artery narrowed with plaque. This can cut off the flow of blood. A blood clot that causes a stroke can form in the artery where there is a lot of plaque or the blood clot may form someplace else in the body. Sometimes, a blood clot forms in the heart and travels to the brain.
Strokes caused by bleeding
Strokes can also be caused by breaks in the blood vessels in the brain. When the blood vessel bursts, blood rushes into the brain and damages it. This kind of stroke is called a hemorrhagic stroke. High blood pressure can cause this type of bleeding stroke.
Most strokes are caused by blood clots or bleeding. In a few people, the flow of blood through an artery can be interrupted by a growth (such as a tumour), infection or swelling of the brain (edema).