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Strokes, otherwise known as cerebrovascular accidents (CVA), occur
when blood supply to the brain is interrupted or insufficient. Symptoms
vary according to which part of the brain is affected but the most common
are sudden loss of speech or movement, blurred vision, confusion, dizziness
and memory loss. Many people with strokes experience difficulty in swallowing.
Other symptoms include depression and vertigo.
If symptoms last for 24 hours or more, it is a full stroke. If they
last a few hours then this is called a Transient (not permanent) Ischaemic
(loss of blood supply) Attack or TIA. In either case urgent medical
help is required. One in three first strokes is fatal. Of those who
survive, half make a complete recovery within a year, the other half
remain permanently disabled to a greater or lesser degree, depending
on the severity of the stroke and the sort of care given afterwards.
What causes strokes?
A stroke is caused by reduced blood flow (ischaemia) which results in
deficient blood supply to the brain. Once damaged, brain cells do not
regenerate but healthy cells sometimes take over their function.
The cause of the ischaemia itself may be cerebral thrombosis, a closing
off of an actual part of the brain. An embolism has a similar effect.
This may have come from the lungs or lower down in the body. A sudden
haemorrhage can also be a cause of loss of brain function.
The most common cause of strokes is hardening of the arteries (atherosclerosis).
With this condition fatty deposits build up on the inner lining of the
arteries, restricting flow of blood.
What contributes to strokes?
Factors that make a stroke more likely include high blood pressure (present
in about 70% of cases), smoking and raised cholesterol levels. Therefore,
lifestyle factors to watch out for are diet (eating too much animal
fat, not enough fibre, fresh fruit or vegetables), stress and not exercising
enough. It's a good idea to learn to relax or meditate as this helps
reduce blood pressure.
Young women are generally at low risk for strokes but the use of contraceptive
pills increase that risk.
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