What is Stroke?

A stroke occurs when a blood clot blocks an or a blood vessel breaks, interrupting blood flow to an area of the brain. When either of these things happen, brain cells begin to die and brain damage occurs. Stroke is the fifth leading cause of death in America and a leading cause of adult disability. Stroke can happen to anyone—at any time and any age.

When brain cells die during a stroke, abilities controlled by that area of the brain are lost. These abilities include speech, movement or memory. How a stroke patient is affected depends on where the stroke occurs in the brain and how much of the brain is damaged.

Types of Stroke


Hemorrhagic Stroke


A hemorrhagic stroke is a blood vessel leak. Blood spills into or around the brain and creates swelling and pressure, damaging cells and tissue in the brain. Hemorrhagic strokes are less common and represent less than 20 percent of all strokes.

Subarachnoid hemorrhage

This occurs when a blood vessel on the surface of the brain ruptures and bleeds into the space between the brain and skull. The most common cause is a ruptured aneurysm (link to new content) caused by high blood pressure. Other causes are rupture of an AVM (arteriovenous malformation), bleeding from an injury due to a blow to the head or venous or capillary problems.

Intracerebral hemorrhage

This is bleeding into the tissue deep within the brain. High blood pressure is often the cause of this type of stroke. Injury and rupture due to problem vessels can also be the cause.


Ischemic Stroke


This type of stroke occurs when a clot or piece of clot blocks a narrowed blood vessel, cutting off the blood flow to a part of the brain. Too little blood reaching a part of the brain is called an ischemic stroke. This type of stroke is more common and represents over 80 percent of all strokes.


Narrowing of Blood Vessels (Thrombotic Stroke)


This stroke occurs when fatty deposits, also known as “plaques” form in the blood vessels that feed your brain. This called atherosclerosis. This plaque can reduce or stop the blood flow to the brain.


Embolic Stroke


This stroke happens when a blood clot is formed in another place, many times the heart, and goes through your blood to lodge in the brain arteries. This type of blood clot is called an “embolus.”


Small Vessel (Lacunar Stroke)


This type of stroke occurs in very small vessels deep in the brain.