What is a stroke?
A stroke occurs when the blood supply to an area of the brain is reduced or blocked causing brain tissue to be starved of oxygen. The medical name for stroke is cerebrovascular accident - or CVA for short.
Who is affected?
Nine out of 10 strokes affect people over 55 (children and young babies can also get stokes). Of those having their first stroke roughly a third will recover well, a third will have a moderate to severe disability and a third will die in the coming year. In the UK 300,000 people are living with stroke-related disability.
Causes:
There are two main types of stroke - ischaemic stroke which accounts for about two thirds of strokes and haemorrhagic stroke. The former is when the blood supply to a certain part of the body is reduced or blocked, so stopping the supply of oxygen. The main cause of ischaemia is the build up of fatty deposits on the walls of the blood vessels that supply blood to the brain.
This process, known as atherosclerosis, makes the arteries narrower and this makes it more likely that a blood clot can block the supply of blood to the brain.
The latter, haemorrhagic strokes are caused by bleeding inside the brain from a ruptured blood vessel. Bleeding in the brain can also result from the rupture of an aneurysm - a weakness in a blood vessel that may have existed from birth.
Blood vessels can also weaken because of infection, a head injury, radiotherapy to the head or a blood clotting disorder.
Symptoms and warning signs:
* numbness, weakness or inability to move the face, arm or leg to one side of the body * trouble with vision - sudden loss in one eye or of vision in one area; double vision * confusion or difficulty understanding * difficulty speaking with swallowing * problems walking, dizziness, loss of balance or co-ordination * severe headaches
Symptoms usually occur suddenly coming on within seconds or minutes. Occasionally it can be over a period of hours or, more rarely, days.
* After a few minutes without blood (and therefore oxygen) brain cells become damaged and if blood flow is not restore in about an hour, the resulting damage is usually permanent.
Risk factors:
* Men are at higher risk than women until age 55, then both sexes are affected equally * smoking * a family history of strokes * high blood pressure * high blood cholesterol * obesity and an inactive lifestyle * taking the oral contraceptive for women who smoke * heavy alcohol use and binge drinking * cocaine use