Types Of Strokes
There are two types of strokes: Hemorrhagic Stroke and Ischemic Stroke.
When a blood vessel in the brain bursts or leaks, the blood spills into the brain, causing swelling, pressure and obstruction in oxygen delivery. This results in damage of brain cells and tissue; and can prove fatal if left untreated.
Hemorrhagic strokes can be caused due to various disorders that affect the blood vessels, including prolonged high blood pressure (hypertension), aneurysms and arteriovenuous malformations.
What is Cerebral Aneurysm?
A weak spot in the wall of an artery that expands and bursts, cerebral aneurysms lead to blood leaks in the brain.
A burst aneurysm can be caused by high blood pressure (hypertension) or trauma (a sudden injury to the head).
What Is Arteriovenuous Malformation (AVM)?
A tangled mass of blood vessel present from birth, AVMs can occur anywhere in the body, including the brain and spine. The AVM gets bigger and weaker as the person gets older. If an AVM in the brain bursts, the person will get a hemorrhagic stroke.
There are two types of hemorrhagic strokes, based on their location in the brain: Intracerebal and Subarachnoid.
When an artery within the brain bursts, causing blood leak the brain, it is called intracerebral haemorrhage. The most common causes of this condition are high blood pressure (hypertension), ageing blood vessels and AVMs.
When there is bleeding in the subarachnoid space (there are 3 layers of membrane or meninges that cover the brain. The subarachnoid space is the area between the layer closest to the brain and the second layer).
This type of stroke, which is mostly caused by burst aneurysms, can also be a result of:
- Bleeding disorders
- Head injury
- Blood thinners
The most common type of stroke, an ischemic stroke occurs when a blood vessel carrying blood to the brain is blocked by a blood clot.
This can occur in two ways:
1. Embolic Stroke
This happens when a blood clot or plaque fragment formed in the body (usually the heart) travels to the brain, lodges in a blood vessel and blocks the blood flow.
2. Thrombotic Stroke
This occurs when a clot (thrombus) formed inside an artery supplying blood to the brain blocks the blood flow. There are two types of blood clots that cause this condition:
(a) Large Vessel Thrombosis
(b) Small Vessel Disease
Thrombotic Stroke is usually seen in people with high cholesterol levels and atherosclerosis.