A stroke that is caused by a blood clot is called an ischaemic stroke (is-key-mick).
In everyday life, blood clotting is beneficial. When you are bleeding from a wound, blood clots work to slow and eventually stop the bleeding. In the case of a stroke, however, blood clots are dangerous because they can block arteries and cut off blood flow.
There are two ways an ischaemic stroke can occur:
If a blood clot forms somewhere in the body (usually the heart) it can travel through the bloodstream to your brain. Once in your brain, the clot travels to a blood vessel that’s too small for it to pass through. It gets stuck there and stops blood from getting through.
These kinds of strokes are called embolic strokes.
As the blood flows through the arteries, it may leave behind cholesterol-laden ‘plaques’ that stick to the inner wall of the artery. Over time, these plaques can increase in size and narrow or block the artery and stop blood getting through.
In the case of stroke, the plaques most often affect the major arteries in the neck taking blood to the brain. Strokes caused in this way are called thrombotic strokes.