A stroke is a loss of blood flow to part of the brain. It happens when a blood clot blocks an artery in the brain, or when a blood vessel in the head bleeds and creates pressure inside the brain.
In either case, brain cells begin to die, and the brain may be damaged either temporarily or permanently. Depending on which area of the brain is deprived of oxygen, a person may experience loss of memory, movement, speech, or other abilities.
If blood flow is restored or pressure is relieved quickly through medical treatment, the brain may fully recover.
Types of Stroke
There are two main types of stroke: ischemic and hemorrhagic.
Ischemic stroke occurs when a blood clot blocks the flow of blood to the brain. The clot may travel from another part of the body (called an embolus) or form inside an artery that supplies blood to the brain (called a thrombus). According to the American Stroke Association, ischemic strokes account for about 87% of all strokes. Medications that dissolve clots can significantly reduce damage if given soon after symptoms appear.
Hemorrhagic stroke happens when a blood vessel in the brain breaks or leaks due to weakness in the vessel wall. Blood then flows into or around the brain, causing swelling and pressure that damages brain cells and tissue. Hemorrhagic strokes make up about 13% of all strokes but are the most deadly, accounting for approximately 40% of stroke-related deaths.
“When a loved one or a family member has a stroke, knowing which type is really important for the physician because the treatment and the care are very different.”
Effects of a Stroke
Stroke affects the brain in different ways, depending on which area is deprived of oxygen or put under pressure by bleeding. The amount of time that passes before treatment also plays a critical role in the extent of brain damage.
A mild stroke or one treated quickly may cause only minor problems, such as temporary weakness in an arm or leg. A more severe stroke can result in permanent paralysis on one side of the body or loss of speech or memory.
Some people recover fully after a stroke, but many survivors are left with some form of long-term disability.
