Back to Home Page

Stroke...What is a Stroke?

A stroke is a life-threatening event that occurs when there is insufficient blood flow to some part of the brain. There are two common types of strokes: "Ischemic Strokes" and "Hemorrhagic Strokes".

What is an Ischemic Stroke?

Ischemic strokes account for approximately 83 percent of all stroke events. Most commonly, ischemic strokes occur because of blood clotting in an artery (a "thrombus") or atheromatous plaque in the wall of the artery. As a result, the artery is narrowed, and blood flow stops.

What is a Hemorrhagic Stroke?

Hemorrhagic strokes account for 15 percent of all strokes. If bleeding occurs in the substance of the brain, it is called a cerebral hemorrhage. Cerebral hemorrhage occurs most frequently in patients with poorly controlled high blood pressure. If bleeding occurs between the brain and skull (but not in the substance of the brain), it is termed either a "subdural hemorrhage" or a " subarachnoid hemorrhage". Subdural hemorrhage occurs between the inside of the skull and the outer most layer of the linings of the brain known as the meninges. Such hemorrhages typically result from head injury. Subarachnoid hemorrhage, on the other hand, occurs within the linings of the brain, and usually results from rupture of an aneurysm (a balloon-like structure that develops on the wall of an artery) or an abnormal collection of blood vessels known as an arteriovenous malformation. Arteriovenous malformations are developmental abnormalities in the brain present from birth.

Both ischemic and hemorrhagic strokes cause death of brain cells in the area of stroke. This results in temporary or permanent, or partial or complete impairment of various functions such as speech, vision, memory and movement.

Source: American Stroke Association