A stroke is a serious medical condition that occurs when the blood supply to part of the brain is cut off.

Like all organs, the brain needs the oxygen and nutrients provided by blood to function properly. If the supply of blood is restricted or stopped, brain cells begin to die. This can lead to brain damage and possibly death.

Strokes are a medical emergency and prompt treatment is essential because the sooner a person receives treatment for a stroke, the less damage is likely to happen.

Types of stroke

There are two main causes of strokes:

• ischaemic (accounting for over 80% of all cases): the blood supply is stopped due to a blood clot
• haemorrhagic: a weakened blood vessel supplying the brain bursts and causes brain damage

There is also a related condition known as a transient ischaemic attack (TIA), where the supply of blood to the brain is temporarily interrupted, causing a 'mini-stroke'. TIAs should be treated seriously as they are often a warning sign that a stroke is coming.

Stroke

The symptoms, causes, diagnosis and treatment of a stroke.