Stroke, or brain attack, occurs when the brain is damaged
due to a disruption of blood supply. The brain requires
a constant supply of energy to perform its functions.
If blood flow to the brain is restricted or cut off at
any point, the brain suffers injury. Should the disruption
continue for more than several minutes, the brain cells
may become permanently damaged and tissue in the affected
region may die. The resultant loss or alteration of bodily
functions due to an inadequate supply of blood to one
or several parts of the brain is called a stroke.
There are two main types of stroke – ischaemic
and haemorrhagic.
In ischaemic stroke, which accounts for approximately
80% of all strokes, blood supply to the brain is disrupted
due to an obstruction in one or more blood vessels. Such
obstruction often occurs in one of the two carotid arteries
in the neck carrying oxygenated blood from the heart to
the brain. A blood clot may also develop at other locations
in the body and travel through the bloodstream until it
lodges itself in a blood vessel which is already narrowed
by a pre-existing condition such as atherosclerosis. About
10% of ischaemic strokes are preceded by transient ischaemic
attacks (TIAs). These are mini strokes arising from a
temporary interruption of blood supply to the brain. They
usually last for only a few minutes, and most of their
symptoms disappear completely within 24 hours.
Less common is haemorrhagic stroke which occurs when one
or more blood vessels in the brain rupture. Blood leaking
from the ruptured vessel compresses other vessels nearby
and eventually forms into a clot, cutting off blood supply
to the surrounding brain tissue. In general, a haemorrhagic
stroke tends to affect larger areas of the brain than
does an ischaemic stroke, resulting in greater impairment
of the victim’s bodily functions.
The symptoms of both types of stroke are similar, although
those of haemorrhagic stroke may be more sudden and severe.
Common symptoms include: Weakness
and/or numbness on one side of the body; Slurred
speech; Loss
of vision in either or both eyes; Giddiness; Asudden,
severe headache; Drowsiness,
followed in some cases by coma; Unsteadiness
and loss of muscular coordination.
The symptoms experienced by a stroke victim vary depending
on the size and location of the blood clot which precipitates
the stroke. For some patients, the symptoms may occur
suddenly; for others, they may develop slowly over the
course of several hours or even a few days.
The main risk factors for stroke are: Age; High
blood pressure (hypertension); High
levels of LDL/“bad” cholesterol; Diabetes
mellitus; Smoking,
including passive smoking; Excessive
alcohol consumption.
All of these factors contribute to atherosclerosis
(hardening of the arteries), which in turn increases the
likelihood of an ischaemic stroke occurring. Similarly,
these risk factors may cause blood vessels to weaken,
resulting in a haemorrhagic stroke.
Fortunately, although some of the risk factors for stroke
(for instance, age) cannot be altered, the majority can
be reduced by adopting healthy living practices such as:
Monitoring your blood pressure regularly
and seeking prompt medical treatment if you are
found to be hypertensive;
Having your blood sugar and cholesterol
levels tested periodically;
Maintaining a healthy body weight;
Eating a healthy, well-balanced diet;
Incorporating regular exercise into
your daily routine;
If you are a smoker, giving up smoking;
Avoiding or stopping drug and alcohol
abuse.
Taken together, these measures can go a long way in preventing
stroke.
Weakness
and/or numbness on one side of the body;