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.
There are two main causes of strokes:
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.
In England, strokes are a major health problem. Every year over 150,000 people have a stroke and it is the third largest cause of death, after heart disease and cancer. The brain damage caused by strokes means that they are the largest cause of adult disability in the UK.
People who are over 65 years of age are most at risk from having strokes, although 25% of strokes occur in people who are under 65. It is also possible for children to have strokes.
If you are south Asian, African or Caribbean, your risk of stroke is higher. This is partly because of a predisposition (a natural tendency) to developing diabetes and heart disease, which are two conditions that can cause strokes.
Smoking, being overweight, lack of exercise and a poor diet are also risk factors for stroke. Also, conditions that affect the circulation of the blood, such as high blood pressure, high cholesterol, atrial fibrillation (an irregular heartbeat) and diabetes, increase your risk of having a stroke.
Strokes can usually be successfully treated and also prevented. Eating a healthy diet, taking regular exercise, drinking alcohol in moderation and not smoking will dramatically reduce your risk of having a stroke. Lowering high blood pressure and cholesterol levels with medication also lowers the risk of stroke substantially.
See the prevention section for more information about reducing the risk of having a stroke.
Strokes can be treated using a combination of medicines and, in some cases, surgery.
However, many people will require a long period of rehabilitation after a stroke and not all will recover fully.