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What is a stroke?

When the brain has a injury caused by an interruption of blood supply, this is called a stroke. 


A stroke occurs when the blood supply in the brain is compromised by either a clogged artery (ischemic stroke) or burst artery (hemorrhagic stroke). This occurrence deprives a part of the brain of oxygen, thereby damaging some brain cells. The body and mental functions controlled by those brain cells are affected after that. (You might hear a stroke called a CVA, which stands for a cerebrovascular accident.)

The breakdown of types of strokes, using medical terms:

1. Ischemic
      1-a. thrombosis
      1-b. embolism
2. Hemorrhagic
      2-a. subarachnoid hemorrhage (an aneurysm)
      2-b. intracerebral hemorrhage

These four types are true strokes, not mini-strokes or TIAs (transient ischemic attacks). A TIA is a brief interruption of blood flow to the brain, which may cause temporary stroke-like symptoms but does not damage brain cells or cause permanent disability. See What Is a TIA and Mini-Stroke Recovery.

The types of strokes are usually classified by what caused the stroke in a first place.

There are 2 main types of strokes:


1. Those caused by some kind of BLOCKAGE (called ischemic strokes). Nearly 80% of all strokes are ischemic. 

a stationary clot caused by plaque

There are 2 sub-types of blockages:

1-A: When blood flow to the brain becomes trapped and blocked by plaque on the mall on an artery (thrombosis). 





1-B: When a blood clot forms in the heart and travels into an artery in the brain, blocking blood flow (an embolism).
caused by a travelling clot

2. Those caused by some kind of BLEED (called hemorrhagic strokes). Nearly 20% of all strokes are hemorrhagic.

There are 2 sub-types of bleeds:

2-A: When an aneurysm (a bulge of an artery wall) ruptures outside the brain, causing a build-up of damaging pressure (subarachnoid hemorrhage).

2-B: When a blood vessel within the brain ruptures, causing rapidly increasing pressure (intracerebral hemorrhage).
Bleeds can come from outside or within the brain