What is a stroke?

A stroke is a serious life-threatening medical condition that happens when the blood supply to part of the brain is cut off.

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

If you suspect that you or someone else is having a stroke, phone 999 immediately and ask for an ambulance.

Causes of a stroke

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 injury, disability and possibly death.

There are two main causes of a stroke:

  • ischaemic: where the blood supply is stopped because of a blood clot, accounting for 85% of all cases
  • haemorrhagic: where a weakened blood vessel supplying the brain bursts

Certain conditions increase the risk of having a stroke, including:

  • high blood pressure (hypertension)
  • high cholesterol
  • irregular heart beats (atrial fibrillation)
  • diabetes.