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Stroke

What is stroke?

A stroke occurs when an are of the brain is damaged following interruption to its blood supply. This results in deterioration of the mental and physical functions controlled by that particular area.

What is the cause?

There are three main causes:

• thrombosis: a clot forming in the artery to the area
• embolus: a small clot from elsewhere blocking the artery
• haemorrhage: bleeding into the brain (unlike the others, where the artery is blocked)

Some common underlying causes are high blood pressure and hardening of the arteries (atherosclerosis).

What are the symptoms?

The symptoms depend on the area of the brain affected and the cause. A haemorrhage usually has a sudden onset and a less favourable outlook. Sometimes a stroke is mild and the effects pass off in a day or so.

Symptoms include:

• unconsciousness
• confusion
• loss of power of speech
• loss of movement of part of the body(e.g. on one side of the body)
• double or blurred vision
• difficulty understanding questions
• dizziness
• difficulty walking or using arms
• numbness on one side of the body

What is a transient ischaemic attack?

This is a transient loss of function due to a temporary blockage in the artery. It is usually caused by a small embolus and the patient recovers in a period ranging from a few minutes to 24 hours (average time 5 minutes). It can be a warning of an impending stroke, and so it needs urgent medical attention.

How common are strokes?

They are very common, especially in people over 65 years and more so in males. In Western countries they are the third commonest cause of death and after coronary attacks the second commonest cause of sudden death. Those at special risk are those with high blood pressure, diabetes, heart disease or high blood cholesterol and heavy smokers.

What is the outcome?

About one-third recover almost completely, one-third have some permanent disability and one-third will die.

How can strokes be prevented?

The risk factors need to be checked, especially high blood pressure, which must be kept under control. Other things to do are avoid smoking, avoid excessive alcohol intake, eat a low-fat healthy diet, keep to ideal weight and have regular exercise.

If you have been found to have hardening of the arteries to the brain, you may be advised to have tablets to prevent blood clots (thrombosis) forming. Aspirin can do this, and only a small dose is needed. Garlic tablets are reported to help prevent clots, and special blood-thinning tablets called anticoagulants (commonly warfarin) can be prescribed.

Surgery

If a person has partially clogged arteries to the brain (the carotids), it may be possible to clean them out rather like a brush cleaning out a chimney. This is a good option in some patients, especially in those who have had transient ischaemic attacks.

What is the treatment for stroke?

Once the stroke has occurred, the brain tissue will not heal normally. Even though the person has survived, it is important to still attend to the risk factors, especially checking the blood pressure. Intense rehabilitation to get limbs and speech working again will begin. This involves a team approach with the physiotherapist being the key person. The results are usually a pleasant surprise to all concerned, with a gradual improvement occurring over 2 years (at least).

Important points

• Many patients make an excellent recovery.
• Excellent support services are available.
• Regular medical checks are necessary.
• High blood pressure is the main risk factor.
  

Copyright 1995: John Murtagh, Professor of General Practice
Monash University, Melbourne, Australia