This fact sheet provides information on strokes. Our fact sheets are designed as general introductions to each subject and are intended to be concise. Sources of further support and more detailed information are listed in the Useful Contacts section. Each person is affected differently by strokes and you should speak with your doctor or specialist for individual advice.
What is a stroke?
A stroke is a disruption in the blood supply to the brain. Most strokes are caused by blockages (usually blood clots) disrupting the brain’s blood supply. These are called ischaemic strokes. Some strokes are caused by bleeds. These are called haemorrhagic strokes.
The brain depends on a supply of blood for the oxygen and nutrients it requires to function properly. When the blood supply is disrupted, brain cells are starved of oxygen and nutrients. This causes damage to the brain tissue.
Stroke is a medical emergency. If you suspect someone is having a stroke, call 999. Stroke is the leading cause of adult disability in the UK. Strokes can affect people of any age but are more common in older people.
Some people have a temporary blockage in the blood supply to their brain which clears of its own accord, quickly and before any lasting damage to the brain is done. This is called a transient ischaemic attack (TIA).
(You might like to read our fact sheet on TIAs for further information.)
What are the symptoms of stroke?
Each person is affected differently by stroke and individual symptoms depend on which parts of the brain are affected and for what specific functions these parts of the brain are responsible. The severity of the symptoms depends on how much damage is done to the brain.
The main symptoms of stroke are:
- physical problems in one side of the body (numbness, weakness),
- drooping in one side of the face,
- speech problems (slurred speech, muddled words) and
- visual problems (blurred vision, loss of vision)
In more serious cases, the person might lose consciousness.
The onset of stroke symptoms is usually sudden. Strokes can occur while people are sleeping. If this happens, people can wake up with the symptoms.
People might also experience longer-term effects such as:
- psychological problems (for example, depression or difficulty controlling emotions),
- bowel or bladder problems (incontinence) and
- problems with swallowing
Other symptoms can include
- dizziness and balance problems,
- memory problems,
- a loss of awareness of one side of the body (neglect) and
What causes strokes?
Most strokes are caused by damaged arteries (the blood vessels through which blood flows from the heart to the rest of the body). Damage to the arteries carrying blood to the brain can cause strokes in the same way that damaged arteries in the heart can cause heart attacks.
Our arteries tend to harden, narrow and weaken as we get older but people with high blood pressure, smokers, people with high cholesterol, and people with heart disease or diabetes (or a family history of heart disease or diabetes) are at an increased risk.
Ischaemic strokes are caused by blockages (usually blood clots) in one of the arteries supplying the brain. Clots can form in these arteries themselves or form in a blood vessel elsewhere in the body and travel to the brain. Clots commonly form where arteries have narrowed due to a build-up of fatty deposits (cholesterol) on their inner walls. The narrowing or furring of the arteries is called atherosclerosis.
Although stroke affects the brain and not the heart, people with an irregular heartbeat (atrial fibrillation) are at an increased risk. An irregular heartbeat can cause blood clots which can travel to the brain and cause a stroke.
Haemorrhagic strokes are caused by one of the blood vessels supplying the brain bursting and causing a bleed. The most common cause is high blood pressure which damages and weakens the arteries making them more likely to tear.
Some people have haemorrhagic strokes because they have aneurysms (balloon-like swellings in the arteries) which burst. If an aneurysm bursts and causes bleeding over the surface of the brain, it is called a subarachnoid haemorrhage (SAH).
(You might like to read our booklet on subarachnoid haemorrhage for further information.)
Serious head injuries can also cause haemorrhagic strokes.
Tests and investigations
The key test for stroke is a brain scan. You might have a CT (Computerised Tomography) scan or an MRI (Magnetic Resonance Imaging) scan. Your scan results can show whether your stroke is ischaemic or haemorrhagic. This is important because the treatments differ depending on the type of stroke.
(You might like to read our fact sheet on brain scans for further information.)
You might also have an ultrasound test to check for any blockages in the main arteries in your neck which supply your brain with blood (the carotid arteries).
Your blood pressure will be checked, you will have blood tests to check your cholesterol and glucose levels, and other tests to check your heart.
What are the treatments?
People who have had a stroke are at an increased risk of further strokes so it is important to try to reduce this risk. If your stroke was ischaemic you might be given medication to thin your blood and make it less sticky to reduce your risk of blood clots. If you have high blood pressure or high cholesterol you might be given medication to reduce and control your levels.
A small number of people having ischaemic strokes might benefit from a treatment called thrombolysis which dissolves the clot blocking an artery. This treatment needs to be given within a short period of time after the onset of symptoms (within three hours). It can significantly reduce the effects of the stroke but it is not available in all hospitals and is not suitable for everyone.
If you have a partial blockage in your carotid arteries you might benefit from surgery to clear it. This operation is called a carotid endarterectomy. Your doctors will discuss your suitability for this procedure with you.
Most people tend to make their best recovery in the first few weeks and months after the stroke but people can continue to recover slowly over months and even years.
If you have any physical problems after your stroke it is likely that you will benefit from physiotherapy. A physiotherapist can help your physical recovery and the recovery of movements such as walking.
If you have any speech problems it is likely that you will benefit from speech and language therapy. A speech and language therapist can help with the recovery of your communication skills. They can also help if you have swallowing problems.
You might also benefit from occupational therapy. An occupational therapist can help you redevelop the skills you need to perform everyday activities at home like washing and cooking. They can also recommend special equipment or adaptations to your home to make your life easier.
Around a third of people make a good or full recovery, around a third are left with some form of disability and around a third die from their stroke.
How can I reduce my risk of having a stroke?
- Stop smoking
- Cut down on how much alcohol you drink
- Eat a healthy diet (cut down on salt and fatty foods)
- Exercise regularly
- Have your blood pressure checked
Brain and Spine Helpline
0808 808 1000
Run by neuroscience nurses, providing support and information on all aspects of neurological conditions for patients, their families and carers, and health professionals.
The Stroke Association
Stroke Information Service
240 City Road
London EC1V 2PR
0303 303 3100
Support and information on stroke.
9 Canon Harnett Court
Milton Keynes MK12 5NF
0845 130 7172
Support and information for younger people affected by stroke.
Chest, Heart and Stroke Scotland
9 Haymarket Terrace
General: 0845 077 6000
Advice Line: 0808 801 0899
Support and information on stroke.
0845 46 47
Medical advice and information on health services.
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This information was last checked in July 2013. Due for review in July 2014.
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