TYPES OF STROKE
Ischemic stroke can be divided into two main types: thrombotic and embolic.
A thrombotic stroke occurs when diseased or damaged cerebral arteries become blocked by the formation of a blood clot within the brain. Clinically referred to as cerebral thrombosis or cerebral infarction, this type of event is responsible for almost 50 percent of all strokes. Cerebral thrombosis can also be divided into an additional two categories that correlate to the location of the blockage within the brain: large-vessel thrombosis and small-vessel thrombosis. Large-vessel thrombosis is the term used when the blockage is in one of the brain’s larger blood-supplying arteries such as the carotid or middle cerebral, while small-vessel thrombosis involves one (or more) of the brain’s smaller, yet deeper, penetrating arteries. This latter type of stroke is also called a lacuner stroke.
An embolic stroke is also caused by a clot within an artery, but in this case the clot (or emboli) forms somewhere other than in the brain itself. Often from the heart, these emboli will travel in the bloodstream until they become lodged and cannot travel any farther. This naturally restricts the flow of blood to the brain and results in near-immediate physical and neurological deficits.
Ischemic stroke is by far the most common kind of stroke, accounting for about 88 percent of all strokes. Stroke can affect people of all ages, including children. Many people with ischemic strokes are older (60 or more years old), and the risk of stroke increases with age. Each year, about 55,000 more women than men have a stroke, and it is more common among African-Americans than members of other ethnic groups. Many people with stroke have other problems or conditions which put them at higher risk for stroke, such as high blood pressure (hypertension), heart disease, smoking, or diabetes. Read more about stroke risk factors and how to reduce your risk.
Hemorrhagic stroke (caused by ruptured blood vessels that cause brain bleeding)
Hemorrhagic strokes are less common, in fact only 15 percent of all strokes are hemorrhagic, but they are responsible for about 40 percent of all stroke deaths.
A hemorrhagic stroke is either a brain aneurysm burst or a weakened blood vessel leak. Blood spills into or around the brain and creates swelling and pressure, damaging cells and tissue in the brain.
Transient ischemic attack (TIA) (a “mini-stroke,” caused by a temporary blood clot)
TIAs lead to major strokes?
While TIAs generally do not cause permanent brain damage, they are a serious warning sign that a stroke may happen in the future and should not be ignored. TIAs are usually caused by one of three things: Low blood flow at a narrow part of a major artery carrying blood to the brain, such as the carotid artery.