The most common type of stroke is called an ischemic stroke and is caused by a blockage cutting-off the blood supply to, or through, part of the brain.
Stroke may also be caused by a bleed from a burst blood vessel, which is called hemorrhagic stroke.
Common causes of stroke
Blood flow to/within brain cut-off by blood clot
|Obstruction forms within the brain||Large artery within or outside the brain||General circulation||General circulation|
|Medical term||Cerebral thrombus||Cerebral embolism||Lacunar stroke|
Blood flow to/within brain cut-off by bleed from a burst blood vessel
|Obstruction forms within||In brain||Between brain and skull|
|Medical term||Intracerebral hemorrhage||Subarachnoid hemorrhage|
There are also other less common causes of stroke, including cerebral hypoperfusion and cerebral venous thrombosis
What happens during stroke?
- Cutting-off the blood supply to brain cells starves the cells ‘downstream’ of the blockage of the essential nutrients and oxygen that are needed for their survival.
- Without these supplies the brain cells can’t work and die within minutes.
- Unlike other cells in the body, once brain cells have died they are not usually replaced.
- The area of dead brain cells caused by the stroke is called an infarct.
- Cells surrounding the infarct may receive insufficient blood supply. This area of cells is called the penumbra. The cells within the penumbra are starved of their normal oxygen and nutrient supply. This leads to the release of damaging chemicals that have the potential to damage or kill healthy brain cells and thus increase the size of the infarct.
- While dying, the cells release chemicals that have the potential to damage or kill the healthy brain cells that surround the inner core of dying cells. The area of healthy cells under threat is called the penumbra.
- The size of the infarct will affect a person’s chance of recovery from a stroke and it will keep growing if treatment is delayed.
To minimize the size of brain injury and to enable patients to achieve their best possible recovery it is essential that they receive medical attention early.
Why protect yourself against stroke?
- Everyone is at risk of stroke and it attacks many people.
- Worldwide approximately 15 million strokes occur every year.
- Stroke is the leading cause of disability in industrialized countries and can rob people of their precious quality of life.
Stroke risk factors we can’t change
Some of us have a higher risk of stroke because of our genes, age or medical history.
Stroke risk factor: Who is at higher risk?
|Age||The chance of having a stroke more than doubles every decade after the age of 55 years.|
|Sex||Stroke is more common in men than women. Almost one in four men and nearly one in five women can expect to have a stroke if they live to their 85th year.|
|Family history||People whose relatives have had a stroke.|
|Ethnic background||People of Asian and African-Caribbean ethinicity. The prevalence of stroke is 40-70% higher among African-Caribbean and South Asian men than in the general population.|
|History of transient ischemic attack (TIA)||The chance of having a stroke after a TIA is almost 10 times greater than someone of the same age and sex who has not had a TIA.|
|Certain medical conditions||Anyone who has already had a stroke or a heart attack or have sickle cell anaemia, high blood pressure, heart disease, diabetes or high cholesterol.|
Although we can’t change these it’s helpful to be aware of them because it can make us think more carefully about how we look after our health.
However, just because someone fulfills a certain criteria, it does not mean that they will get a stroke, just that their risk is increased by a certain amount.
Stroke risk factors that CAN be controlled
Clinical studies have identified several traits and lifestyle habits that directly increase the risk of having a stroke.
The good news is that we can do something about these to reduce our risk of stroke!
Risk factors that are directly linked to stroke include:
- High blood pressure
- High blood cholesterol
- Heart diseases
- Excessive alcohol intake
How to control stroke risk factors
- By making some modifications in our lives we can easily reduce our exposure to these risk factors.
- We can make some changes ourselves and others will require help from our doctor and/or nurse.
- Following these six easy steps can help to reduce your risk of stroke:
Steps to reduce your stroke risk: Why?
Aim to avoid/minimize exposure to stroke risk factor…Who’s best placed to help? Will it help?
|1. Have regular blood pressure checks. If it is high, your doctor/nurse may advise how to reduce it.||High blood pressure||Doctor/nurse||√|
|2. If you smoke, stop.||Smoking||Ourselves/doctor/nurse||√|
|3. Have regular checks of your cholesterol. If it is high, your doctor/nurse may advise how to reduce it.||High blood cholesterol||Doctor/nurse||√|
|4. Have regular checks of the health of your heart (e.g. ECG, chest X-ray and physical examination). If it is abnormal, your doctor may suggest treatment.||Heart disease||Doctor||√|
|5. Have regular blood sugar checks. If it is high, your doctor/nurse may advise how to reduce it.||Diabetes||Doctor/nurse||√|
|6. If you drink alcohol, only do so in moderation.||Binge and excessive alcohol intake||Ourselves/doctor||√|
Everyone is at risk of stroke and it attacks many people. Worldwide approximately 15 million strokes occur every year.
There are several risk factors for stroke. Many we can control or modify either by ourselves or with help from our doctor and/or nurse.
For further information, please visit following sources:
- National Institute of Neurological Disorders and Stroke: Questions and answers about stroke
- Stroke Association UK: What is a stroke?
- American Heart Association: Heart and stroke statistics
- World Health Organization 2004. Global Burden of Stroke. Part three: The burden. The Atlas of Heart Disease and Stroke
- Stroke Association UK: Preventing a stroke