What is a stroke?

A stroke or a brain attack occurs when a blood clot blocks a blood vessel or when a blood vessel bursts, interrupting blood flow to an area of the brain. An ischemic stroke occurs when the blood vessel is blocked. This is the most common type of stroke. A hemorrhagic stroke (brain bleed) occurs when a blood vessels breaks. This type of stroke is less common.

• What happens to the brain when a stroke occurs?
• The most important thing to remember is that the earlier a stroke victim gets to the emergency department, the better the chance that they will be able to receive treatment that stops or reduces the amount of brain damage from the stroke.
• When brain cells die, functions that were under control of the dying brain are lost. These include functions such as language, speech, movement, and sensation. The specific abilities lost or affected depend on where in the brain the stroke occurs and on the size of the stroke.

The brain needs oxygen in the blood to survive, when the blood flow is disrupted, the cells in the part of the brain that were receiving this blood can die. These cells usually die within minutes to a few hours after the stroke starts. When cells die, chemicals are released that can cause even more cells to die. This is why there is a small window of opportunity for treatment of ischemic stroke.

For example, someone who has a small stroke may experience only minor effects such as weakness of an arm or leg. On the other hand, someone who has a larger stroke may be left paralyzed on one side or lose his/her ability to express and process language. Some people recover completely from less serious strokes, while other individuals lose their lives to very severe strokes.