Understanding stroke

A haemorrhagic stroke occurs when the wall of a blood vessel in the brain breaks, causing blood to leak from the vessel into the brain. Delivery of oxygen and nutrients to the brain is stopped, causing brain cells to die.

Haemorrhagic stroke is caused by various disorders affecting the blood vessels. Long-term high blood pressure is a key risk factor.

More information about high blood pressure

Depending on the location of the burst artery, a haemorrhagic stroke can be classified as:

• Intracerebral haemorrhage – when an artery bursts inside the brain
• Subarachnoid haemorrhage – when the bleeding occurs on the surface of the brain (between the layer nearest the brain and the second layer)

An ischaemic stroke is caused by a blood clot. It can occur in two ways:

• Embolic stroke – when a blood clot forms in the body, usually the heart, and travels through the bloodstream into the brain where it is lodged in a blood vessel.
• Thrombotic stroke – caused by deposits of cholesterol plaques, that adhere to the inner wall of an artery, usually in the neck, and block the flow of blood to the brain.