There are two types of stroke, hemorrhagic and ischemic. Hemorrhagic strokes are less common, in fact only 15 percent of all strokes are hemorrhagic, but they are responsible for about 40 percent of all stroke deaths.
A hemorrhagic stroke is either a brain aneurysm burst or a weakened blood vessel leak. Blood spills into or around the brain and creates swelling and pressure, damaging cells and tissue in the brain. There are two types of hemorrhagic stroke called intracerebal and subarachnoid.
The most common hemorrhagic stroke happens when a blood vessel inside the brain bursts and leaks blood into surrounding brain tissue (intracerebal hemorrhage). The bleeding causes brain cells to die and the affected part of the brain stops working correctly. High blood pressure and aging blood vessels are the most common causes of this type of stroke.
Sometimes intracerebral hemorrhagic stroke can be caused by an arteriovenous malformation (AVM). AVM is a genetic condition of abnormal connection between arteries and veins and most often occurs in the brain or spine. If AVM occurs in the brain, vessels can break and bleed into the brain. The cause of AVM is unclear but once diagnosed it can be treated successfully.
This type of stroke involves bleeding in the area between the brain and the tissue covering the brain, known as the subarachnoid space. This type of stroke is most often caused by a burst aneurysm. Other causes include:
- Bleeding disorders
- Head injury
- Blood thinners