What is a Stroke?
A stroke, also called a cerebrovascular accident, cerebrovascular disease or CVA, is damage to the brain due either to blockage in blood flow or to loss of blood from blood vessels in the brain. Blockage in blood flow or loss of blood causes the brain to lack oxygen and blood nutrients.
The brain requires a constant flow of blood to work properly. If the blood flow is disrupted, brain cells do not receive enough oxygen, resulting in cell death. The degree of damage that results from a stroke is dependent on where and how much blood flow to the brain is interrupted.
A stroke can be a symptom of a serious condition such as brain cancer.
Categories of Strokes
There are two major categories of stroke: hemorrhagic and ischemic. Within the major categories are different kinds of strokes.
In ischemic strokes, there is a blockage of blood flow to the brain. About 80% of all strokes are ischemic. Ischemic strokes usually occur when a blood clot forms in a blood vessel in the brain or neck. Blood clots can also travel from other parts of the body, such as the heart, to the neck or brain and cause a stroke. A blood vessel that is extremely narrowed can also cause an ischemic stroke.
In hemorrhagic strokes a blood vessel in the brain is leaking or broken. These types of strokes accounts for approximately one out of five strokes. Hemorrhagic stroke is associated with a higher death rate than ischemic stroke. Hemorrhage can occur from a weak or thinned out area on the artery wall that balloons out over time, and then ruptures.
Kinds of Strokes
A stroke may also develop paralysis in one or both sides of the body.
How Does it Occur?
A stroke occurs when a blood vessel bringing oxygen and nutrients to the brain bursts or becomes blocked. Vessels can be blocked by blood clots or other particles. When blockage occurs, nerve cells in the part of the brain that is deprived of oxygen becomes dysfunctional. When the nerve cells become dysfunctional, the part of the body that is controlled by these cells is also unable to perform.