Stroke

If the blood supply to part of the brain is interrupted, the affected region no longer functions normally. This condition is called a stroke, although today it is often described as a “brain attack” to highlight the need for urgent medical attention. A stroke may be due to either a blockage or bleeding from one of the arteries supplying the brain. There is usually little or no warning of a stroke. Immediate admission to hospital for assessment and treatment is essential if there is to be a chance of preventing permanent brain damage. The after effects of a stroke vary depending on the location and extent of the brain tissue affected. They range from mild, temporary symptoms, such as blurred vision, to lifelong disability or death.


If the symptoms disappear within 24 hours, the condition is known as a transient ischaemic attack, which is a warning sign of a possible future stroke.

How common is it?

Each year, about 120,000 people in the UK have a stroke. The condition is more common in men and in older people. A 70 year old living in the UK is about 100 times more likely to have a stroke than a 40 year old. Although the number of deaths from stroke has fallen over the last 50 years, stroke is still the third most common cause of death in the UK after heart attacks and cancer.

What are the causes?

About half of all strokes occur when a blood clot forms in an artery in the brain, a process called cerebral thrombosis. Other major causes are cerebral embolism and cerebral haemorrhage (bleeding). Cerebral embolism occurs when a fragment of a blood clot that has formed in an other part of the body, such as in the heart or the main arteries of the neck, travels in the blood and lodges in an artery supplying the brain. Just under one-third of all strokes are caused by cerebral embolism. Cerebral heamorrhage, which causes about one-fifth of all strokes, occurs when an artery supplying the brain ruptures and blood seeps out into the surrounding tissue. The blood clots that lead to cerebral thrombosis and cerebral embolism are more likely to form in an artery that has been damaged by atherosclerosis, an condition in which fatty deposits build up in artery walls. Factors that increase the risk of atherosclerosis developing are a high-fat diet, smoking, diabetes mellitus, and high levels of lipids in the blood.

Cerebral embolism may be a complication of heart rhythm disorders, heart valve disorders, and recent myocardial infarction, all of which can cause blood clots to form in the heart. The risk of cerebral embolism, thrombosis, or haemorrhage is increased by high blood pressure. Sickle-cell disease, an abnormality of the red cells, also increases the risk of cerebral thrombosis because abnormal blood cells tend to clump together and block blood vessels. Less commonly, thrombosis is caused by narrowing of the arteries supplying the brain due to inflammation. The inflammation may be due to an autoimmune disorder, such as polyarteritis nodosa, in which the immune system attacks the body’s own healthy tissue.

What are the symptoms?

In most people, the symptoms develop rapidly over a matter of seconds or minutes. The exact symptoms depend on the area of the brain affected. The symptoms may include:

- Weakness or inability to move on one side of the body.
- Numbness on one side of the body.
- Clumsiness, or loss of control of fine movements.
- Visual disturbances, such as blurred vision or loss of vision in one eye.
- Slurred speech.
- Difficulty in finding words and understanding what others are saying.
- Vomiting, and difficulty in maintaining balance.

If the stroke is severe, areas of the brain that control breathing and blood pressure may be affected or the person may lapse into coma. In these circumstances, the outcome can be fatal.

How is it diagnosed?

If you suspect that a person has had a stroke, he or she should be taken to hospital immediately so that a cause can be identified and treatment can begin.

Imaging of the brain, such as CT scanning or MRI, may be used to find out whether the stroke was caused by bleeding or a blockage in a vessel. Cerebral angiography or carotid Doppler scanning may be performed to help to identify narrowed areas of arteries that can be corrected by surgery. Further tests may be carried out to look for the source of an embolus. These tests may include echocardiography to assess the heart valves and heart monitoring to check the heart rhythm.

What is the treatment?

The initial treatment following a stroke is close monitoring and nursing care to protect the person’s airways during recovery. If CT scanning reveals a clot in a blood vessel, immediate treatment with thrombolytic drugs to dissolve the dot may be considered. This treatment may improve the outcome, but it is not given routinely because it increases the risk of bleeding within the brain.

Long-term treatment to reduce the risk of further strokes will depend on the cause of the stroke. If the cause was a cerebral embolism, you may be given drugs such as aspirin or warfarin, which act on clotting factors in the blood to reduce the risk of further clots. If a narrowed artery has been identified, it may be widened surgically. After a cerebral haemorrhage, treatment tends to be focused on the underlying cause, although in a few cases, surgery to remove a clot from the brain is carried out first. Long-term treatment may include antihypertensive drugs to lower blood pressure. If the stroke is the result of inflammation of the arteries, corticosteroids may be given.

In all cases of stroke, rehabilitative therapies, such as physiotherapy and speech therapy, provided in hospital or at home, are essential. Lifestyle changes, such as reducing far in your diet and giving up ‘s smoking, can reduce the risk of another stroke.

What is the prognosis?

The outlook after a stroke is often difficult to predict at first and depends to some extent on the cause. Following a stroke, about one-third of people make a full or almost full recovery. Another third have some disability, and some of these may need long-term care in a nursing home. Symptoms that persist for more than 6 months are likely to be permanent. About 1 in 5 people dies within a month of the stroke.