Stroke carries a high risk of death. Survivors can experience loss of vision and/or speech, paralysis and confusion. Stroke is so called because of the way it strikes people down. The risk of further episodes is significantly increased for people having experienced a previous stroke. The risk of death depends on the type of stroke. Transient ischaemic attacks or TIA – where symptoms resolve in less than 24 hours – have the best outcome, followed by stroke caused by carotid stenosis (narrowing of the artery in the neck that supplies blood to the brain). Blockage of an artery is more dangerous, with rupture of a cerebral blood vessel the most dangerous of all.
Annually, 15 million people worldwide suffer a stroke. Of these, 5 million die and another 5 million are left permanently disabled, placing a burden on family and community. Stroke is uncommon in people under 40 years; when it does occur, the main cause is high blood pressure. However, stroke also occurs in about 8% of children with sickle cell disease.
High blood pressure and tobacco use are the most significant modifiable risks. For every 10 people who die of stroke, four could have been saved if their blood pressure had been regulated. Among those aged under 65, two-fifths of deaths from stroke are linked to smoking. Atrial fibrillation, heart failure and heart attack are other important risk factors. The incidence of stroke is declining in many developed countries, largely as a result of better control of high blood pressure and reduced levels of smoking. However, the absolute number of strokes continues to increase because of the ageing population.