Stroke

What is a stroke?

A stroke means that the blood supply to a part of the brain is suddenly cut off. The brain cells need a constant supply of oxygen from the blood. Soon after the blood supply is cut off, the cells in the affected area of brain become damaged, or die. A stroke is sometimes called a 'brain attack'.

The blood supply to the brain comes mainly from four arteries - the right and left carotid arteries, and the right and left vertebrobasilar arteries (see diagram below). These branch into many smaller arteries which supply blood to all areas of the brain. The area of brain affected, and the extent of the damage, depends on which blood vessel is affected.

For example, if you lose the blood supply from a main carotid artery, then a large area of your brain is affected which can cause severe symptoms, or death. On the other hand, if a small 'branch' artery is affected, then only a small area of brain is damaged which may cause relatively minor symptoms.

What causes a stroke?

There are two main types of stroke - ischaemic and haemorrhagic.

Ischaemic stroke - occurs in about 7 in 10 cases
Ischaemic means a reduced blood and oxygen supply to a part of the body. This common form of stroke is usually caused by blood clot in an artery which blocks the flow of blood.

• The blood clot often forms within the artery itself. This commonly occurs over a patch of fatty material called atheroma. (Atheroma is sometimes called 'furring' or 'hardening' of the arteries.) Small patches of atheroma form on the inside of arteries in most older people. If a patch of atheroma becomes thick, it can 'trigger' the blood to clot.
• In some cases, the blood clot forms in another part of the body, and then travels in the bloodstream (this is called an embolus). The most common example is a blood clot which forms in a heart chamber as a result of abnormal turbulent blood flow. This may occur in a condition called atrial fibrillation (see separate leaflet). The blood clot is then carried in the bloodstream until it gets stuck in an artery in the brain.
• There are other rare causes of ischaemic stroke.

Haemorrhagic (bleeding) stroke
A damaged or weakened artery may 'burst' and bleed:

• An intracerebral haemorrhage is when the blood vessel bursts inside the brain. The blood then spills into the nearby brain tissue. This can cause the affected brain cells to lose their oxygen supply, and become damaged or die. This accounts for about 1 in 10 strokes.
• A subarachnoid haemorrhage is when a blood vessel bursts in the subarachnoid space. This is the narrow space between the brain and the skull. This space is normally filled with a fluid called the cerebrospinal fluid. About 1 in 20 strokes are due to a subarachnoid haemorrhage.

Uncertain cause
The cause is uncertain in a small number of strokes

Who is affected by stroke?

Each year about 110,000 people in the UK have a first stroke, and about 30,000 have a recurrent stroke. Stroke is the largest cause of disability in the UK, and the third commonest cause of death (after heart disease and cancer.) Most cases occur in people aged over 65. Each year about 1 in 100 people over the age of 75 have a stroke. But, a stroke can occur at any age, even in babies.

What are the symptoms of a stroke?

The functions of the different parts of the body are controlled by different parts of the brain. So, the symptoms vary depending on which part of the brain is affected, and on the size of the damaged area. Symptoms develop suddenly, and usually include one or more of the following.

• Weakness of an arm, leg, or both. This may range from total paralysis of one side of the body, to mild clumsiness of one hand.
• Weakness and 'twisting' of one side of the face. This may cause you to drool saliva.
• Problems with balance, co-ordination, vision, speech, communication, or swallowing.
• Dizziness or unsteadiness.
• Numbness in a part of the body.
• Headache.
• Confusion.
• Loss of consciousness (occurs in severe cases).

What is a mini-stroke (a TIA)?

A mini-stroke is a set of symptoms similar to a stroke, but which last less than 24 hours. It is due to a temporary lack of blood to a part of the brain. It is more correctly called a 'transient ischaemic attack' (TIA). In most cases, a TIA is caused by a tiny blood clot that becomes stuck in a small blood vessel (artery) in the brain. This blocks the blood flow, and a part of the brain is starved of oxygen. The affected part of the brain is without oxygen for just a few minutes, and soon recovers. This is because the blood clot either breaks up quickly, or nearby blood vessels are able to compensate.

Unlike a stroke, the symptoms of a TIA soon go. However, you should see a doctor urgently if you have a TIA as you are at increased risk of having a 'full' stroke. (Further details are in another leaflet called 'Transient Ischaemic Attack'.)

What are the effects from having a stroke?

The type and extent of disability caused by a stroke can vary greatly. It depends on the extent of the damage to the brain.

A large stroke can cause death. A small stroke may cause minor problems, which may go completely over time. In many cases, the effects are somewhere in between these two extremes.

The sort of problems that may occur include one or more of the following:

• Weakness of one side of the body. This may cause problems with walking if a leg is affected, or problems using an arm or hand properly.
• Problems with balance and co-ordination.
• Swallowing problems are common. In some cases this can be dangerous as food may go down the windpipe rather than down the gullet when you eat. Because of this it is usual to do 'swallow test' on all people with a stroke before they are allowed to eat or drink. This is to make sure that swallowing is safe. If there is severe difficulty with swallowing then you may need to have food and drinks passed into your stomach via a tube.
• Speech and communication difficulties. This may range from a difficulty in finding the correct words to say in the middle of a sentence, to being completely unable to speak. Also, understanding speech, reading, or writing may be affected.
• Difficulty with vision. If a part of the brain that deals with vision is affected then problems may arise. For example, some people who have had a stroke have double vision, and some people lose half of their field of vision.
• Difficulties with mental processes. For example, difficulty in learning, concentrating, remembering, etc.
• Inappropriate emotions. For example, following a stroke, some people cry or laugh at times for no apparent reason.
• Tiredness.

In the first few weeks after a stroke the swelling and inflammation around the damaged brain tissue settles down. Some symptoms may then improve. In time, sometimes other parts of the brain can compensate for the damaged part of the brain. With rehabilitation and appropriate therapy, there may be a gradual improvement.

Of those who survive a stroke, about 3 in 10 are fully independent within three weeks, and this rises to about 5 in 10 within six months. However, it is common for some degree of disability to remain.

Are any tests needed?

A doctor can usually diagnose a stroke by the typical symptoms and signs which develop suddenly. Tests which are commonly done include:

• A brain scan (CT scan or MRI scan). This can determine the type of stroke (ischaemic or haemorrhagic) and rule out rare conditions which may have caused the stroke, or which may mimic a stroke.
• Blood tests to check on such things as blood sugar level and cholesterol level. High levels can increase the risk of a further stroke.
• Chest x-ray and ECG (a heart tracing) to check for heart or lung conditions which may be a cause of stroke (for example, atrial fibrillation).
• Ultrasound scan of the carotid arteries in the neck to check if there are large patches of atheroma in these arteries.

Can strokes be prevented?

As described above, a common reason why a blood clot forms is because it develops over a patch of atheroma on the lining of an artery. Certain 'risk factors' increase the chance of atheroma forming - which increase your risk of having a stroke (and heart attack). You can reduce the risk of having a stroke (or a further stroke) if you reduce your 'risk factors'. These are briefly mentioned below, but are dealt with in more detail in the leaflet called 'Preventing Cardiovascular Diseases'.

• Smoking. If you smoke, you should make every effort to stop. The chemicals in tobacco are carried in your bloodstream and can damage your arteries. If you smoke, stopping smoking can greatly cut your risk of having a stroke.
• High blood pressure. Make sure your blood pressure is checked at least once a year. If it is high it can be treated. High blood pressure usually causes no symptoms, but can be damaging to the arteries. If you have high blood pressure, treatment of the blood pressure is likely to have the greatest effect on reducing your risk of having a stroke.
• If you are overweight, losing some weight is advised.
• A high cholesterol. This can be treated if it is high.
• Inactivity. If able, you should aim to do some moderate physical activity on most days of the week for at least 30 minutes. For example, brisk walking, swimming, cycling, dancing, gardening, etc.
• Diet. You should aim to eat a healthy diet. Briefly, a healthy diet means:
  • AT LEAST five portions of a variety of fruit and vegetables per day.
  • THE BULK OF MOST MEALS should be starch-based foods (such as cereals, wholegrain bread, potatoes, rice, pasta), plus fruit and vegetables.
  • NOT MUCH fatty food such as fatty meats, cheeses, full-cream milk, fried food, butter, etc. Use low fat, mono-, or poly-unsaturated spreads.
  • INCLUDE 2-3 portions of fish per week. At least one of which should be 'oily' (such as herring, mackerel, sardines, kippers, pilchards, salmon, or fresh tuna).
  • If you eat meat it is best to eat lean meat, or poultry such as chicken.
  • If you do fry, choose a vegetable oil such as sunflower, rapeseed or olive oil.
  • Try not to add salt to food, and limit foods which are salty.
• Alcohol. A small amount of alcohol (1-2 units per day) may be beneficial. One unit is in about half a pint of normal strength beer, or two thirds of a small glass of wine, or one small pub measure of spirits. However, too much can be harmful. In particular, binge drinking can increase your blood pressure.
  • Men should drink no more than 21 units per week (and no more than four units in any one day).
  • Women should drink no more than 14 units per week (and no more than three units in any one day).
• Diabetes is a risk factor. If you have diabetes, treatment to keep your blood sugar as near normal as possible is important.

Atrial fibrillation
If you have atrial fibrillation (or certain other heart conditions) warfarin or aspirin may be prescribed. These reduce the 'stickiness' of the blood and lowers the chance of blood clots forming in the heart and travelling to the brain.

Carotid stenosis
Carotid stenosis means a narrowing of one of your carotid arteries due to atheroma. If you are found to have this then you have an increased risk of having a stroke. In some situations you may be advised to have surgery to 'strip out' the atheroma. Your doctor will advise if this is an option.

What treatment and care is usual for people who have a stroke?

If you have a stroke you are likely to be admitted to hospital where your condition can be fully assessed, and tests can be done quickly. A plan for your treatment and rehabilitation can be devised, started as soon as possible, and should be tailored to your particular needs. This will depend on the severity of the stroke, and the effects it has had on you.

Medication

• Aspirin is usually given. Low dose aspirin helps to prevent blood clots forming inside arteries, which helps to prevent a further stroke.
• Medication may be advised to reduce any risk factors (mentioned above). For example, medication to lower a raised blood pressure, sugar level, or cholesterol level.
• 'Clot busting' drugs are sometimes used. Some people who have an ischaemic stroke are given drugs to 'dissolve' the blood clot. However, the treatment has to be done within a few hours of the stroke occurring. There is also a risk in giving this treatment and it is not 'routine'. Research continues to see if this kind of treatment can be improved.

Surgery
An operation to fix the leaking artery may be done if you have a subarachnoid haemorrhage. Surgery for other types of stroke is not usually an option.

Rehabilitation
The aim or rehabilitation is to maximise your activity and quality of life following a stroke. Hospitals which deal with stroke patients have a range of specialists who help in rehabilitation. These include: physiotherapists, occupational therapists, speech therapists, dieticians, psychologists, specialist nurses and doctors. One or more of these may be required depending on how the stroke has affected you. Good quality rehabilitation is the most important part of treatment following a stroke, and can make a big difference your eventual outcome.

Further help and information

The Stroke Association, 240 City Road, London, EC1V 2PR
Tel: 0845 30 33 100    Web: www.stroke.org.uk
Provides information and help for people who have had a stroke, and their carers.

Chest Heart & Stroke Scotland, 65 North Castle Street, Edinburgh, EH2 3LT
Tel: 0845 077 6000 phone/textphone - local call rate   Web: www.chss.org.uk
Aims to improve the quality of life for people in Scotland affected by chest, heart and stroke illness.

Different Strokes, 9 Canon Harnett Court, Wolverton Mill, Milton Keynes, MK12 5NF
Tel: 0845 130 7172   Web: www.differentstrokes.co.uk
A national charity for young stroke survivors.

© EMIS and PIP 2006   Updated: October 2006