Finding out the causes of stroke is not just an academic exercise, it can actually save your life.
On this page you'll find the answer to these questions:
A stroke occurs when the supply of blood to the brain gets interrupted and oxygen can't reach every part of the brain resulting in loss of brain function and death of brain tissue, either in a small part of the brain or a larger one.
Each part of the brain controls and receives messages from different parts of the body, so when a particular part of the brain dies, the part of the body corresponding to it ceases to function.
Stroke is unfortunately very common, mainly amongst older people, being the third largest cause of death in industrialized countries after heart disease and cancer and affecting about one in 500 people.
In most cases, the causes of stroke are the same that affect heart disease.
Many factors can cause blood vessels walls to get damaged.
When blood vessels are injured (like for example through high blood pressure), cells of the immune system rush in to repair the damage causing inflammation.
Inflammation actually damages blood vessels further, thickening the blood, and contributing to the formation of blood clots.
The clots usually form in a part of the artery that has been damaged by atherosclerosis (hardening of the arteries).
In the same way as blood vessels can be blocked by clots and restrict blood flow to the heart and cause a heart attack, the same thing can happen to the brain and cause a stroke.
There are two main types of strokes:
About 80% of strokes are caused by a blood clot, or thrombus that forms in any of the arteries in the brain or leading to the brain and blocks blood flow.
A blood clot may also form elsewhere in the body, then break off from its anchor and form a mobile clot, or embolus and travel via the bloodstream to the brain, where it may partially or completely 'plug' a smaller vessel, causing the stroke.
The remaining 20% happen when a vessels rupture, spilling blood into the brain.
This may occur in a artery affected by atherosclerosis or one with a congenital weakness which can swell and bulge outwards like a balloon.
This bulge is called aneurysm and as it gets bigger can burst and cause bleeding into surrounding brain tissue, damaging it and causing a stroke.
A tendency to develop aneurysms may be inherited and people who have them may suffer a stroke at a relatively early age.
The symptoms of stroke vary according to the part of the brain affected, but can typically include:
The right half of the brain controls the left side of the body and vice versa.
Common symptoms like weakness in some parts of the body or not being able to use an arm or a leg (paralysis) happens on the opposite side of the body to the stroke side of the brain.
In most people, the left half of the brain is responsible for language (talking, understanding, reading and writing), and the right half is responsible for perceptual skills (making sense of what you see, hear and touch) and spatial skills (judging size, speed, distance or position in space).
Symptoms may occur suddenly or develop over a period of days, fluctuating in severity.
If, on the other hand, numerous small clots develop in the brain rather than one major event, this may manifest itself as a gradual deterioration in the person's mental function, leading to dementia.
A precursor to a stroke is often a Transient Ischemic Attack (TIA), or "mini stroke" in which the deprivation of blood is not sufficient to cause permanent damage.
The symptoms may manifest themselves by short-lived weakness or numbness in an arm or leg or a period of confusion, but are temporary and the affected person makes a full recovery, usually within 24 hours.
The episode serves as a warning of the possibility of a complete stroke in the future.
Three simple checks can help you recognize whether someone has had a stroke or may be experiencing a Transient Ischaemic Attack (TIA). These are:
Having a stroke can affect the quality of life considerably, but it's not always bad news.
Function will return to affected parts of the body only if and when the brain recovers and messages are again sent down the appropriate nerves.
It's true that dead brain cells can’t start working again, but those just outside the area of the dead cells may recover as the swelling caused by the stroke goes down.
It’s also possible that other parts of the brain can learn to take over from areas that have died.
Most recovery happens in the first few months, but people can continue to recover for several years after the stroke, although in severe cases, there may be long-term disability.
Simple movements are more likely to recover than delicate ones and sophisticated functions have the worst outlook.
So movement of the thigh, for example, may improve more easily than fine movements of the fingers, and any speech impairment is more likely to be permanent.
A rehabilitation team can help to compensate for any disabilities the person may have.
Physiotherapists maintain muscle tone and joint flexibility, whilst waiting for power to return; occupational therapists advise about functional problems and supply equipment to help the person overcome their disabilities; and speech therapists help with difficulties in swallowing, improve the clarity of remaining speech or offer alternative methods of communication.
So the effects of a stroke will depend on:
A diet high in fatty foods causes cholesterol to build up in the blood and the arteries to narrow. Too much salt can lead to high blood pressure. Being very overweight (obese) puts extra strain on the heart.
Too much alcohol
Regular heavy drinking raises blood pressure. Binge drinking (drinking a lot of alcohol in a short time) can cause a blood vessel in the brain to burst.
An inactive lifestyle can contribute to furring of the arteries. Regular exercise helps keep the heart and bloodstream healthy.
Smoking causes higher blood pressure and makes the blood thicker. The chemicals in tobacco smoke are absorbed into the body, damaging blood vessel walls.
Prolonged stress can lead to high blood pressure, heart disease and damage to arteries.
High blood pressure is considered the leading modifiable risk factor for stroke.
As you grow older, your odds of having a stroke rise steadily.
Yet there is dramatic evidence that what you eat can slash your chances of stroke as well as the damage it may cause and even help determine whether it's fatal!
High blood pressure, high cholesterol, diabetes and a dangerous prediabetic condition called metabolic syndrome all raise your risk of stroke.
As most causes of stroke are due to clots in blood vessels, foods that help ward off clots, keep blood vessels flexible and unclogged and keep blood pressure normal are good bets for preventing stroke.
Even one extra daily portion of the right stuff may cut an astounding 40 to 60% or even more off your chances of having or dying of a stroke.
Could you imagine what would happen if a drug that promised to prevent that many strokes a year was discovered?
No doubt it would become an overnight sensation, despite its cost and potential side effects.
Yet such an effective and certainly safer and cheaper drug is in everyone's possession right now, so why not use it?
Once you understand the causes of stroke it's quite obvious what you need to do to prevent them.
Are you willing to make changes in your diet in order to prevent this terrible debilitating condition?
The following articles contain a list of foods to include in your diet that can help you prevent strokes.
As the causes of stroke are the same as for heart disease, have a look also at the list of foods that help prevent cardiovascular disease, high blood pressure and high cholesterol.
Articles in This Series:
A wonderful source of omega-3 fatty acids, which has been shown to reduce all the risk factors leading to strokes
An extra strong garlic supplement that can help keep your arteries clean and free from clots
A wonderful antioxidant that can help prevent oxidation of cholesterol