There are two main categories of strokes. Ischemic (top), typically caused by a blood clot in an artery resulting in brain death to the affected area Hemorrhagic (bottom), caused by blood leaking into or around the brain from a ruptured blood vessel allowing blood to pool in the affected area thus increasing the pressure on the brain.
A slice of brain from the autopsy of a person who had an acute middle cerebral artery (MCA) stroke
Strokes can be classified into two major categories: ischemic and hemorrhagic. Ischemic strokes are caused by interruption of the blood supply to the brain, while hemorrhagic strokes result from the rupture of a blood vessel or an abnormal vascular structure. About 87% of strokes are ischemic, the rest being hemorrhagic. Bleeding can develop inside areas of ischemia, a condition known as “hemorrhagic transformation.” It is unknown how many hemorrhagic strokes actually start as ischemic strokes.