A stroke is a condition in which the brain cells suddenly die because of a lack of oxygen. This can be caused by an obstruction in the blood flow, or the rupture of an artery that feeds the brain. The patient may suddenly lose the ability to speak, there may be memory problems, or one side of the body can become paralyzed.
The two main types of stroke include ischemic stroke and hemorrhagic stroke
Ischemic stroke accounts for about three-quarters of all strokes and occurs when a blood clot, or thrombus, forms that blocks blood flow to part of the brain. If a blood clot forms somewhere in the body and breaks off to become free-floating, it is called an embolus. This wandering clot may be carried through the bloodstream to the brain where it can cause ischemic stroke.
A hemorrhagic stroke occurs when a blood vessel on the brain's surface ruptures and fills the space between the brain and skull with blood (subarachnoid hemorrhage) or when a defective artery in the brain bursts and fills the surrounding tissue with blood (cerebral hemorrhage).
Both types of stroke result in a lack of blood flow to the brain and a buildup of blood that puts too much pressure on the brain.
The outcome after a stroke depends on where the stroke occurs and how much of the brain is affected. Smaller strokes may result in minor problems, such as weakness in an arm or leg. Larger strokes may lead to paralysis or death. Many stroke patients are left with weakness on one side of the body, difficulty speaking, incontinence, and bladder problems. Both types of stroke result in a lack of blood flow to the brain and a buildup of blood that puts too much pressure on the brain.
Risk factors for stroke include the following
Ischemic strokes are ultimately caused by a thrombus or embolus that blocks blood flow to the brain. Blood clots (thrombus clots) usually occur in areas of the arteries that have been damaged by atherosclerosis from a buildup of plaques.
Hemorrhagic strokes can be caused by uncontrolled high blood pressure, a head injury, or aneurysms. High blood pressure is the most common cause of cerebral hemorrhage, as it causes small arteries inside the brain to burst.