A stroke that can
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
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