A stroke is essentially the same as a heart attack, but it happens when the oxygen supply to the brain (rather than the heart) is interrupted. The blood supply, carrying oxygen, can be stopped because of narrowed arteries or a burst blood vessel.
When brain cells are starved of oxygen they become damaged and this can result in the devastating effects of stroke such as loss of speech. If damage to the brain is to be limited the blood supply needs to be restored quickly, and inflammation or swelling of the brain needs to be stopped. If you suspect anyone is suffering a stroke it is vital to call 999 or get medical help immediately. Signs that a stroke is happening include:
- Sudden numbness or weakness of the face, arm or leg, especially on one side of the body
- Sudden confusion, trouble speaking or understanding
- Sudden trouble seeing in one or both eyes
- Sudden trouble walking, loss of balance or coordination, inability to walk and dizziness
- Sudden severe headache with no known cause
The most common type of stroke is an ischaemic stroke in which the artery is blocked by a clot that stops the blood and oxygen reaching the brain. The clot may be formed in the arteries leading to the brain (thrombotic stroke), or the clot could be formed elsewhere (embolic stroke), for example the legs on a long haul flight, before travelling to the brain.
Tiny blood vessels inside the brain can also become blocked and damage a small area of tissue in the brain. The other common type of stroke is haemorrhagic in which a blood vessel in the brain ruptures and bleeds – in other words it haemorrhages. This causes a build up of pressure and damage in the brain, starving cells of oxygen.
So called mini strokes are another term for TIA stroke, or transient ischaemic attack which is an attack that doesn’t last very long and may cause only temporary, or slight, damage because the blood supply is soon restored.
People often get a weakness of an arm or leg for about 20 minutes during a mini stroke and the weakness passes when the blood supply to the brain resumes. Mini strokes are a warning that there is a problem with the blood supply to the brain such as atherosclerosis.
Atherosclerosis is one cause of strokes. It is a build up of fatty plaques on the inner lining of the arteries. It is a gradual process over years, and it starts in many people in their teens or twenties, that slowly limits the blood supply to the heart muscle.
Fatty plaque builds up when LDL (bad) cholesterol is damaged by free radicals that occur naturally in the body and result from smoking and pollution. The LDL becomes oxidised after which it cannot be transported back to the liver to be excreted, but instead is laid down as plaque in arteries causing atherosclerosis.
Other causes of stroke include weaken areas on artery walls (aneurysms) and these may burst causing bleeding in the brain (haemmorhagic stroke). Irregular heartbeat (arrhythmia) has also been linked to formation of blood clots in the heart which may then travel to the brain and cause a stroke.
The same healthy diet that protects against heart disease and high cholesterol, will also protect against stroke, in the same way that the new tomato pill does. Not smoking and avoiding binge drinking or regular heavy alcohol use is also preventive.
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