A stroke happens when normal blood flow in an area of your brain is interrupted. This can happen either because a blood vessel (a tube-like structure carrying blood around the body) has become blocked by a clot or has broken or burst. Our brain cells need a constant supply of fresh blood carrying oxygen and nutrients to stay alive. Therefore, if blood is unable to get to these cells, even for a very short time, the cells start to die very quickly. As a result, a person may suffer brain damage in the affected area. For this reason, a stroke is sometimes called a “brain attack.” Another term for stroke is “cerebrovascular accident,” or CVA.
Depending on the location of the stroke, a stroke may cause a disability because the affected part of the brain can no longer send signals to some parts of the body to control movements, sensations. and other bodily functions For example, if the cells die in an area of the brain that controls speech, a person may have trouble speaking or understanding speech. In some strokes, the person may have trouble moving certain parts of their body, or their memory may be affected.
Common Types of Stroke
Most strokes are categorized as either an ischemic stroke or a hemorrhagic stroke.
Ischemic stroke is the most common type of stroke. This type of stroke occurs if a blood vessel gets blocked by a blood clot (thrombus) or by fat deposits (plaque). Ischemic strokes are further described by the location of the clot.
A thrombotic stroke is caused by a blood clot that forms along the wall of a blood vessel or because of a blockage of fat deposits.
Embolic Stroke/Cerebral Embolism
An embolic stroke or cerebral embolism happens when a clot (an embolus) from another part of your body travels into the brain and blocks a blood vessel there. Most commonly, those blood clots come from the heart after a heart attack or when someone has irregular heartbeats, like with atrial fibrillation.
A hemorrhagic stroke is much less common than an ischemic stroke. This type of stroke occurs when a blood vessel carrying blood to part of the brain hemorrhages (breaks or bursts). This allows blood to leak into the brain. The two main types of hemorrhagic strokes are intracerebral and subarachnoid.
Intracerebral Hemorrhagic Stroke
In an intracerebral hemorrhagic stroke, blood from a broken blood vessel leaks into the brain and damages brain cells. Also, cells beyond the broken blood vessel die because they are unable to get their normal blood supply.
Subarachnoid Hemorrhagic Stroke
A subarachnoid hemorrhagic stroke occurs when a blood vessel near the surface of the brain breaks, causing blood to collect between the skull and the surface of the brain. This causes irritation to the lining of the brain and is often very painful.
Transient Ischemic Attack (TIA)
A TIA, also known as a “mini” stroke, is an ischemic stroke that goes away quickly because the blockage breaks up. Symptoms may last for only a few minutes or one or two hours. Since the blockage resolves quickly, brain cells do not die, and the TIA doesn’t cause permanent disability.
How Common are Strokes?
Almost 800,000 people have strokes each year in the United States. Of these, about 140,000 people die annually from their strokes, making it the third most common cause of death in this country. Older men tend to have more strokes than older women. But older women are more likely to die from strokes than older men. Also, African Americans have twice the risk of a first stroke compared to white Americans. The likelihood of suffering a TIA also increases with age. Up to 40% of all people who suffer a TIA will go on to have a full stroke later in life.
Although just over 1 out of 10 strokes are the hemorrhagic type, they account for 3 of 10 deaths from stroke each year.
Last Updated September 2020