What is a stroke?
A stroke is the sudden death of a portion of the brain cells due to
lack of oxygen. A stroke occurs when blood flow to the brain is impaired
resulting in abnormal brain function. Brain blood flow can be impaired
by blockage or rupture of an artery to the brain.
What causes a stroke?
Blockage of an artery of the brain by a clot (thrombosis), leading to
deprivation of blood and oxygen, can cause a stroke. Typically, a clot
will form in a blood vessel that has been previously narrowed due to
atherosclerosis ("hardening of the artery").
When a blood clot or a piece of atherosclerotic plaque (cholesterol and
calcium deposits on the wall of the artery) lodges in an artery of the
brain, blocking the flow of oxygen-rich blood, a stroke occurs.
A cerebral hemorrhage occurs when a blood vessel in the brain bursts
and bleeds into the surrounding brain tissue. This too can be the cause
of a stroke.
All the above causes of stroke lead to deprivation
of oxygen to the brain tissue and its resultant death.
Risk factors for stroke:
- Arterial Hypertension
- Cigarette smoking
- Diabetes mellitus
- Hyperlipedaemia
- Polycythaemia
- Thrombocythaemia
- High alcohol intake
- Positive family history
- Oral contraceptives
- Trauma
What are the features of stroke?
The most common symptom is weakness or paralysis of either side of the
body.There may be partial or complete loss of voluntary movement of
and/or sensation in a leg and/or arm. A stroke can result in speech
problems and weak facial muscles which can cause drooling. Numbness or
tingling is very common. A stroke can cause difficulty in breathing and
even unconsciousness.
