What is a Stroke?

A stroke occurs because blood flow to part of the brain is interrupted, either by a clot or a bleed within the brain. A small part of the brain then dies because of this lack of blood flow.

There are three types of strokes which can occur:

Ischemic Stroke
Ischemic stroke occurs when an artery to the brain is blocked. The brain depends on its arteries to bring fresh blood from the heart and lungs.

These blockages are caused by: a problem with the blood vessels, a problem with the blood itself or by clots from the heart.

If the artery remains blocked for more than a few minutes, the brain cells may die. This is why immediate medical treatment is absolutely critical.

About 80% of strokes are Ischemic Strokes.

Hemorrhagic Stroke
Hemorrhagic stroke occurs when a diseased blood vessel within the brain bursts, allowing blood to leak inside the brain. The sudden increase in pressure within the brain can cause damage to the brain cells surrounding the blood. If the amount of blood increases rapidly, the sudden pressure can lead to unconsciousness or death.

The most common cause of hemorrhagic stroke is high blood pressure (hypertension). Less common causes include trauma, infections, tumors, blood clotting deficiencies, and abnormalities in blood vessels.

Hemorrhage stroke occurs at all ages. The average age is lower than for ischemic stroke. Hemorrhagic strokes make up about 20% of all strokes.

Transient Ischemic Attack (TIA)
A TIA is sometimes wrongly referred to as a mini-stroke. It is not a stroke but is a warning sign that someone is at risk for having a larger stroke.

TIA's do not cause permanent damage because they only cause temporary stoppage of blood flow to an area of the brain that is momentarily starved, but is not permanently damaged.

Signs of a TIA are:

slurred speech
vision disturbances
limb weakness that resolves soon after

Source of information: www.strokecenter.org