TYPES OF STROKES
There are two main types of stroke, ischemic and hemorrhagic. Both starve brain cells of needed blood supply, but via different mechanisms of injury.
An ischemic stroke results from blockage of the artery bringing blood to the brain. The vast majority (85%) of strokes arise in this way.
A hemorrhagic stroke results from rupture of the artery. About 15% of strokes arise in this way. Hemorrhagic stroke can occur inside the brain, called an intraparenchymal hemorrhage, or in the space surrounding the brain, called a subarachnoid hemorrhage.
Ischemic Stroke can be caused by:
- A clot that forms in the artery at the site of blockage. This is sometimes called a thrombosis, and it can happen in the brain arteries, or in the neck arteries that supply blood to the brain.
- A clot that travels from another part of the body, for example, from the heart to a brain artery. This is sometimes called an embolism.
- A clot that forms because the blood is abnormal. This is sometimes called hypercoagulable blood.
Ischemic stroke from thrombosis or embolism can therefore be due to a primary problem in the arteries, heart, or blood.
Hemorrhagic Stroke can be caused by:
- A ruptured aneurysm, sometimes also called a “berry aneurysm”
- Ruptured small arteries damaged over time from high blood pressure
- Arteriovenous malformation (“AVM”), a tangle of abnormal blood vessels