The Tribune - Spectrum


, February 24, 2002

A stroke that can debilitate
B.K. Sharma

THE brain stroke is an abrupt onset of a localised neurological deficit in the form of weakness or sensory loss or disturbance in speech or coordination. It may become stationary, regress quickly or progress. It occurs due to either blockade of an artery of the brain due to clot formation or bleeding in some part of the brain. The word ‘stroke’ has been used historically implying as if it has come like a bolt from a blue without any particular reason. A stroke has many similarities to the heart attack in the sense that both are based on problem with the blood supply to the respective organ. But there are dissimilarities also. It seems the public is much more familiar with the heart attack than the brain stroke because of the wide publicity which a dramatic cardiac death receives.

Nature has endowed the brain with a very rich blood supply because of the extreme sensitiveness of the brain cells to the lack of glucose and oxygen. There are two sets of arteries which supply blood to the brain from the front and behind and there is a rich communication between these arteries. In spite of this, however, with advancing age and processes like atherosclerosis which blocks the arteries, a particular portion of the brain can suffer when its supply line is blocked or is the seat of hemorrhage. Within 10 seconds of the lack of blood supply, brain cells can suffer but can recover if flow is restored within a few minutes. If the flow is not restored the area of the brain undergoes death, pathologically known as infarction. The former is known as the transient ischemic attack and the latter is called as the completed stroke. This kind of stroke due to blockade of an artery can come fairly quickly but often progresses slowly in a slow stuttering manner.

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A less common form of stroke can occur due to a clot which can travel from a diseased heart or a big artery and block one of the arteries of the brain and produce a similar effect. The third variety of stroke is when an artery gives way, leading to exudation of blood in the brain tissue and is known as the hemorrhagic stroke, the most common cause of which is high blood pressure.

What causes a stroke?

As mentioned above, there is a lot of similarity between the disease process which blocks the arteries of the heart and the brain. This process is known as atherosclerosis and is the subject of research for last many decades. A lot of secrets have been unravelled but it has still defied prevention. The well known predisposing causes of this process, have been mentioned many times, but bear repetition.

Predisposing causes include the ageing process itself, family history of stroke, diabetes mellitus, high blood pressure, smoking, obesity, high cholesterol levels, lack of exercise and a high alcohol intake. Apart from this process which is responsible for majority of the strokes, there are other disease processes which can cause occlusion of the blood vessels of the brain. They include inflammation of the arteries (vasculitis), intake of oral contraceptives, intake of notorious drugs like cocaine and amphetamin. There are also certain diseases in which the ability to coagulate of the blood is increased thereby there is an increased tendency to clot formation. This group of diseases has now been recognised more and more in individuals in whom no apparent cause for the stroke was found. This would often occur more commonly in younger individuals. It is for the attending physicians and the neurologists to investigate and try to find out various factors responsible for a stroke in a given individual.

Prevention and treatment

A stroke is a very disabling and can cut down a person’s productive career rather abruptly. The treatment of stroke when it has occurred requires many facilities for treatment and rehabilitation. This has both medical and economic implications. In the developed countries there are specialised stroke units in which treatment is carried out almost as it is in the case of heart attack. Even our best institutes do not have yet this facility.

Prevention of a stroke, therefore, is much more feasible in view of its high prevalence and relatively low cost and effectiveness of simple preventive measures and this can be done even by those societies which do not have high-tech treatment units. Preventive education is critical both for the medical profession and the public at large.

Prevention of stroke before it occurs (primary prevention) is based on the management of factors mentioned above including control of weight, blood pressure, diabetes mellitus, keeping the cholesterol level in check, control of the smoking epidemic and active physical habits. It is evident that none of these preventive measures cost too much including the control of blood pressure and diabetes mellitus. But a lot of public education and promotion of any active lifestyle is needed. It is worth mentioning that in USA the incident of stroke was brought down to nearly 40 per cent during 70s and 80s by these preventive measures particularly by the effective control of hypertension.

We are paying a very high price by readily copying the western lifestyle. However we continue to suffer from infections due to the lack of a clean water supply, lack of proper disposal of excreta and pollution in the environment.

If the person is diagnosed as having a stroke within a few hours, the clot can be dissolved by various drugs. Such a therapy is not yet readily available in India but principles are well recognised and one hopes this can be done at least in some centres at a reasonable cost. During the acute period of a stroke, the treatment consists in controlling the blood pressure, taking care of the skin and bladder of the patient, treatment of associated conditions like diabetes or heart diseases. Finally a lot of physiotherapy and rehabilitation of the patient is needed. A person who has suffered from stroke once is more prone to getting another one. Therefore, the secondary preventive measures are extremely important to prevent such a recurrence. Apart from controlling blood pressure, diabetes, high cholesterol and other factors mentioned above, prevention of clot formation by the use of drugs like aspirin is extremely important. This group of drugs is now an established method to prevent the recurrence a stroke. Aspirin has been used for this purpose for a long time and it reduces the stickiness of the cells (platelets) and it is this stickiness which promotes formation of a clot. There was some confusion about the dose required for this purpose. A recent analysis of a large number of studies conducted has shown that dose as low as 75-150 mgs is good enough and high doses of aspirin are not necessary. This decreases the side-effects of the drug also. With the use of this simple measure, the risk of recurrence can come down as much as by 25-30 per cent. There is a suggestion that even those people who have not had a stroke yet but have certain risk factors can also use this preventive therapy under medical supervision. Any patient who has a clot travelling from the heart or big arteries to the brain, another group of drugs known as anti-coagulant drugs are used. They are much more potent than aspirin is but also carry greater risk of bleeding.

Certain surgical measures like opening up of the clogged artery and putting a stent like the coronary artery is also being done as a preventive measure. The overall scenario of a stroke is, therefore, not as disheartening as it used to be. But we will need a lot of input and organisation to make use of the known scientific knowledge.