A stroke is also known as a cerebral vascular accident (CVA), brain attack or transient ischaemic attack (TIA). When you have a stroke the blood supply to a part of your brain is blocked or compromised. Within 3 minutes brain cells in that part of the brain start to die. Unless rapid action is taken a large number of cells die which causes brain injury and potentially severe and long lasting damage.
Transient ischaemic attack (TIA)
TIA’s are also known as ‘mini strokes’. They usually get better within 24 hours. They are usually caused by a temporary block to the blood supply, which lasts for only 1-2 minutes before returning to normal. The short lived loss of blood supply ‘shocks’ the brain cells which need 24 hours to get back to normal. Mini strokes can be seen as a warning that a major stroke is possible. You should have a full range of medical tests done and any problems treated. A change of lifestyle may also be needed.
Types of strokes
There are 2 types of strokes (i) ischaemic and (ii) haemorrhagic. It’s important for the hospital emergency department to know which you have as it’s essential for the correct emergency treatment
Ischaemic (Is-ski-mic) strokes happen when the brain blood vessel is blocked by a blood clot or the blood vessel is too narrow due to vascular disease for blood to flow. The cells rapidly die due to lack of oxygen and also lack of glucose (sugar). It is the same as happens in angina or a heart attack. The main risk factors are high blood pressure, atherosclerosis (thickening and narrowing of the blood vessels), smoking and irregular heartbeat.
Haemorrhagic (hem-or-agic) strokes happen when the blood vessel bursts and blood leaks into the brain causing damage. The main risk factors are aneurysms (weak blood vessel walls which stretch like a balloon before ‘popping’), high blood pressure (especially if untreated or unknown) and blood clotting disorders.
How is the brain damaged?
Your brain is made up of hundreds of millions of cells and they all need a constant blood supply to give them oxygen and glucose and take away the acidic ‘waste products’. The blood supply of the brain is just enough but doesn’t have much spare capacity to compensate for the sudden loss of supply that occurs during a stroke. So during a stroke damage happens to your brain cells after 3-4 minutes and is rapidly permanent.
Unfortunately the dead brain cells swell up quite a lot. As the skull surrounds the brain the healthy brain cells near them are squashed which if left untreated can kill them and cause more damage!
The end result is an area of dead brain cells and permanent brain damage. This disrupts the normal working of the brain. The part of the brain damaged dictates which of the different problems seen after a stroke such as poor speech, difficulty swallowing, and loss of arm or leg movement affect you.
Brain cells can’t recover but the brain can make new pathways round the damaged areas and other areas of the brain can take over some functions. This is why a long and intense period of active rehabilitation is essential after a stroke.
The best thing to do is reduce your risk factors by stopping smoking, treating high blood pressure, lose weight, get more active and take blood thinners such as aspirin if medically advised.