A stroke (cerebrovascular accident, CVA, cerebral vascular accident or brain attack) occurs when a part of the brain is damaged or destroyed because it is deprived of blood.
There are 2 main types of strokes: ischaemic stroke and haemorrhagic stroke.
Ischaemic stroke is the most common type of stroke and is caused by a blockage of the blood vessels supplying the brain. This may be due to ‘hardening’ and narrowing of the arteries (atherosclerosis) or by a blood clot blocking a blood vessel.
One type of ischaemic stroke is a thrombotic stroke. This is caused by a blood clot (thrombus) in one of the arteries of the head or neck, which severely reduces the blood flow. The thrombus may be a result of a build-up of fatty deposits (plaques) in the blood vessels.
Another type of ischaemic stroke is an embolic stroke (or cerebral embolism), caused when a blood clot that forms elsewhere in the body (for example, the chambers of the heart) travels through the circulatory system to the brain. The travelling clot is called an embolus.
The most severe type of stroke is a haemorrhagic stroke. It occurs when a blood vessel in the brain bursts, allowing blood to leak and cause damage to an area of the brain. There are 2 types: subarachnoid haemorrhage, which occurs in the space around the brain; and an intracerebral haemorrhage, the more common type, which involves bleeding within the brain tissue itself.
The symptoms of a stroke usually appear suddenly. Initially the person may feel sick, and look pale and very unwell. They may complain of a sudden headache. They may have sudden numbness in their face or limbs, particularly down one side of their body. They may appear confused and have trouble talking or understanding what is being said to them. They may have vision problems, and trouble walking or keeping their balance. Sometimes a seizure (fit) or loss of consciousness occurs.
Depending on what function the damaged part of the brain had, a person may lose one or more of the following functions:
Some strokes are preceded by mini or temporary strokes — transient ischaemic attacks (TIAs). Mini strokes occur when there is a temporary blood clot and part of the brain does not get the supply of blood it needs.
Symptoms occur rapidly and usually last a short time, from a few minutes to a couple of hours. Like a stroke, the symptoms will vary depending on which part of the brain is affected.
While the symptoms of a TIA are similar to those of a stroke, they are usually temporary and reversible.
However, mini strokes should not be ignored as people who have had a temporary stroke are much more likely to have a stroke than people of the same age and sex who have not had a temporary stroke.
It is important that you see your doctor immediately when the warning signs of stroke occur. Your doctor will determine whether a stroke, a mini stroke or another medical condition with similar symptoms has occurred, such as a seizure or migraine.
The older you get, the greater the risk of having a stroke, however, a significant number of young and middle-aged people also have strokes. Men are also more likely to have a stroke, as are people with diabetes. People who have had a previous stroke are also more likely to have another one.
Cigarette smoking, excessive alcohol intake, being overweight and raised blood cholesterol increase the risk of high blood pressure and artery disease, which in turn increase the risk of having a stroke. Stroke is a vascular disease, and so shares many risk factors with coronary vascular disease (also known as coronary artery disease).
Another risk factor is a type of irregular heartbeat known as atrial fibrillation (AF). Also, some medications can increase stroke risk.
The physical changes that cause a stroke usually take place over many years. Some people are born with a higher risk of having a stroke. Age, sex, race and having had a prior stroke are risk factors that can’t be changed.
High blood pressure, heart disease, mini strokes (TIAs) and the build-up of fatty deposits and cholesterol on the artery walls (atherosclerosis) are risk factors that can be reduced by changes to your lifestyle and good medical care.
Confirmation of diagnosis and initial treatment of strokes almost always takes place in a hospital. An early diagnosis is made by evaluating symptoms, reviewing your medical history and conducting tests.
If a stroke has occurred, treatment should begin as soon as the stroke is diagnosed to ensure that no further damage to the brain occurs. Initially, the doctor may administer oxygen and insert an intravenous drip to provide the affected person with adequate nutrients and fluids.
In cases of ischaemic stroke, it is common to give aspirin to reduce the risk of death or of a second stroke.
If the cause of the stroke was a clot, it is possible that the quick administration of certain clot-dissolving drugs, such as alteplase, may prevent some symptoms such as paralysis. However, this is not a suitable treatment for all strokes, and can increase the risk of haemorrhagic stroke, so there are strict guidelines determining the circumstances in which it should be used.
Once a stroke has permanently damaged the brain, the damage can't be undone. However, many symptoms can improve considerably in the days following a stroke, because the areas of brain on the periphery of the stroke can recover. Also, your doctor will suggest ways to prevent a future stroke, including modifying your lifestyle to minimise your risks of stroke, and taking medications.
Depending on the type and cause of the stroke, anticoagulant drugs (‘blood thinners’) may be prescribed to help prevent new blood clots from forming, in order to prevent a future stroke. Examples include aspirin, aspirin plus dipyridamole (Asasantin), clopidogrel (e.g. Plavix) and warfarin (Coumadin or Marevan).
Where there is a blockage in a neck artery, surgery may be performed to remove the build-up of plaque in order to prevent a future stroke. This operation is called a carotid endarterectomy.
Successful rehabilitation following a stroke depends on many factors, including the extent of brain damage, attitude, the skill of the rehabilitation team and the support of family and friends. As a result of advances in treatment and rehabilitation, many people who have had a stroke are able to live full lives. For some, recovery takes only a few weeks while for others it may take months or even years.
Strokes affect people in different ways depending on the type of stroke and area of the brain affected. Often old skills have been lost, so new ones will need to be learned. It is also important to maintain and improve physical condition whenever possible. Rehabilitation should begin as soon after a stroke as possible and may continue at home.
Rehabilitation may consist of various types of therapy including:
Family is also important in the rehabilitation process. Family members will probably be asked to help the person regain lost skills by encouraging them to use the affected arm or leg, helping them with their speech or teaching them how to do tasks which may have been forgotten, such as combing their hair or using a cup, knife and fork.
Last Reviewed: 27 April 2009
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