What are the types of stroke?

Broadly classified, there are different types of stroke.

Hemorrhagic stroke

Hemorrhagic stroke is a type of stroke where bleeding occurs within or around the brain. It is a less common type of stroke and is only seen in around 10 – 15% of cases.

A hemorrhagic stroke occurs because of rupture of a brain aneurysm or weak blood vessel. When this happens, blood from within the vessel leaks into the brain tissue, starting to compress it. Bleeding is usually accompanied by swelling of the surrounding areas, and this can worsen the symptoms and damage to the brain.

There are 2 types of hemorrhagic stroke –  intracerebral and subarachnoid.

Intracerebral bleeds are a type of stroke where the blood spills into the brain tissue itself, rather than around the brain. This bleeding causes the brain cells to start dying, which in turn greatly affects brain functions.

The most common cause of bleeding within the brain is high blood pressure, though advancing age is another important risk factor. Usually, bleeding occurs from rupture of an arterio-venous malformation (AVM). An AVM is a birth defect of the blood vessels that renders it weak and vulnerable to increased pressure. Unfortunately, it remains undetected for a number of years, and only becomes evident when a stroke occurs. If it is caught early, AVMs can be successfully treated by neurosurgeons.

A subarachnoid bleed is a type of stroke where bleeding occurs within a space in the brain called ‘subarachnoid space’. It usually follows rupture of an aneurysm in the brain, though it may also be seen due to AVMs, head injury and when taking blood thinners.

Both types of bleeds are medical emergencies,and must be dealt with immediately in a hospital.

Ischemic stroke

An ischemic stroke is one where the blood supply is cut off due to blockage of the blood vessel supplying the brain.

There are 2 types of ischemic stroke – thrombotic and embolic.

Thrombotic stroke is a type of ischemic stroke where the blood vessel is blocked by a small blood clot. The word ‘thrombus’ means ‘blood clot’. This blood clot forms due to underlying atherosclerosis and high cholesterol.

Blood clots can form in both large vessels and small caliber vessels. Large vessels thrombosis