Stroke - some questions and answers

• What is stroke?
• What are the symptons of a stroke?
• What is a mini-stroke or TIA?
• How common is stroke?
• Is stroke a serious condition?
• Is complete recovery after a stroke likely?
• Does stroke follow the same course in all people ?
• What causes the brain damages that occurs in stroke?
• What are the main risk factors for stroke?
• What is defined as normal and high blood pressure?
• Is migraine a risk factor for stroke?
• Is there any link between diseased arteries in the heart,
  brain, and the rest of the body?
• Why should blood clots form inside an artery ?
• What are the main types of medicines used in stroke?
• Are there forms of treatment for stroke other than medicines?
• What are the main complications following a stroke?
• Have there been any recent advances in stroke managment and rehabilitation?
• What kind of general information and support is available for people with stroke?

What is stroke?

A stroke is the name given to an illness in which part of the brain is suddenly damaged or destroyed because of problems with its blood supply. This results in a loss of function in those parts that are normally under the control of the damaged area. Typically, loss of function appears rapidly (in a few minutes to a few hours) and persists for longer than 24 hours, with no apparent outward cause.

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What are the symptoms of a stroke?

These are variable and depend on the amount of brain damage and the part of the brain affected. At one extreme, the symptoms can be very mild – perhaps dizziness, visual disturbance, slight speech impediment, or a feeling of heaviness or loss of sensation in a limb. More typically, there is weakness or paralysis of an arm or leg on one side of the body or drooping or twisting of the face due to loss of muscle control. Other effects may be problems of balance, visual disturbance, speech difficulties, and loss of control of the bladder, bowels or swallowing reflex. At the other extreme, a stroke may result in a rapid loss of consciousness and death.

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What is a mini-stroke or TIA?

Sometimes people experience the symptoms of a stroke but find that they pass off quite quickly – often in a few minutes and certainly within 24 hours. Such episodes are called transient ischaemic attacks or TIAs. They are often warning signs of an increased possibility of a stroke. TIAs can be treated and anyone who has one should see their doctor urgently.

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How common is stroke?

The commonest causes of death in the population as a whole in the UK are myocardial infarction (heart attack), followed by all forms of cancer grouped together. Stroke is third and accounts for 12 per cent of deaths, killing some 70,000 people each year. Because of this high mortality, the Government singled out stroke in its 1998 Green Paper ‘Our Healthier Nation’ with a target of reducing it from its 1996 level by one-third by 2010 for under 65 year olds. However, the risk from stroke is very age-dependent and rises rapidly in all countries after the age of 65. In Europe, there are big differences between countries in deaths from stroke. For example, in Switzerland the death rate in the 40-69 year age group is 31-40 per 100,000 people per year, rising to over 150 in several former Eastern Block countries. In England, the figure is 61-70, but in Scotland it is 91-100, perhaps reflecting differences in lifestyle, health care services, and the environment in different parts of Britain.

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Is stroke a serious condition?

Strokes vary considerably in their severity, from mild attacks with short-lasting loss of function (TIAs) to severe episodes that may cause unconsciousness and eventually lead to death. However, all strokes must be regarded as potentially serious and even mild symptoms necessitate a visit to the doctor. With the right medical attention, a more serious attack can often be avoided.

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Is complete recovery after a stroke likely?

This depends on its severity, but those unlucky enough to have a stroke as opposed to a TIA have about a 1 in 4 chance of living an independent existence at home within six months. A similar number will require some assistance either at home or in a long-term care institution. However, the brain is very adaptable and, given time, it is likely that there will be a partial or complete recovery of lost functions. This occurs by the repair of injured brain cells or by other parts of the brain taking on the lost function. Many people are also able to adapt their lifestyle in ways that permit a full life, even with a degree of disability. Perhaps the most important factor is to remain positive about the future and never abandon hope, even if recovery seems frustratingly slow at times.

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Does stroke follow the same course in all people?

No. Stroke is a highly variable condition, ranging from a TIA to a severe episode leading to major disability. Between these extremes, there can be almost any type and degree of disability, affecting almost any bodily function. Recovery is often quite good and many people can resume a near normal life. However, the speed and completeness of recovery will partly depend on the severity and type of stroke, and on the age and overall state of health of the individual. Above all, patience, loving care and a will to get better are essential ingredients to good recovery.

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What causes the brain damage that occurs in stroke?

Unlike some other tissues, the brain has no reserves of oxygen and energy and is dependent on a continuous flow of blood. Blood vessels entering the brain branch repeatedly (rather like the branches of a tree), distributing oxygen and nutrients to the brain cells. An interruption in this blood flow for even a few minutes can cause damage to nerve cells in the brain. Several different kinds of event can disturb blood flow and the doctor will quickly need to decide whether the symptoms are due to a blockage of blood flow or to bleeding inside the brain, as this will affect the type of treatment needed. More specialised tests will help decide which type of stroke an individual has had.

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What are the main risk factors for stroke?

In general, it is possible to divide the risk factors for stroke into two groups:

• those we can do nothing about
• those which we can reduce or avoid. This group can be broken down into
  • treatable medical conditions – e.g. high   blood pressure, diabetes
  • lifestyle factors such as smoking, salt intake, weight and activity level

The unavoidable factors include age, sex, family history, race, diabetes, or having had a first stroke. The risk of stroke increases steadily with age. In fact, 90 per cent of all stroke cases are in people who are 55 or older. At any age, men are more likely to have a stroke than women. However, because women live on average significantly longer than men, the total number of strokes is in a ratio of about 60:40 women to men.

There is increasing evidence that the genes we inherit may predispose us to develop high blood pressure, diabetes, or ‘furring-up’ of the arteries (atherosclerosis) – all factors which increase the risk of having a stroke. If our parents had these conditions, we are more likely to develop them as well.

Studies in the USA indicate that race may have an influence and black African-Americans have a 60 per cent greater risk of stroke than Caucasians. There are many possible reasons why race may be a factor – including the gene pools inherited, or such things as diet, customs, or weight. Having already had a first stroke also increases risk and as many as one in six people who have had a stroke have a second within two years.

Of the treatable risk factors, the most important is high blood pressure. Over the years, this causes significant damage to many organs, including the heart and blood vessels. This can lead to atherosclerosis and heart disease, which themselves are stroke risk factors. Everyone should aim to have their blood pressure measured from time to time, especially as they approach middle age. This is important because high blood pressure has no symptoms and a person can be apparently fit and active with this condition. Once found, it can be readily treated.

Everything possible should be done to reduce the number of risk factors, because if you have more than one, then they multiply together: they do not just add up. With none, the risk is very small, but with six, there is an 80-95 per cent chance of stroke, depending on blood pressure.

 

Thrombotic stroke. The formation of a blood clot or thrombus in an artery feeding the brain can cause oxygen starvation (ischaemia) and brain damage. This kind of event accounts for about 60 per cent of all strokes. Embolic stroke. This is similar to thrombotic stroke except that the blood clot has formed elsewhere in the body, usually the heart or neck arteries, and has detached and travelled in the blood stream to the brain, where it has blocked an artery. This accounts for about 20 per cent of all strokes. Lacunar stroke. Also known as small vessel stroke. They are ischaemic strokes in small arteries (arterioles) that penetrate into the brain tissue. A very common form associated with diabetes and hypertension. Unlike Transient Ischaemic Attacks, these leave permanent damage – albeit in a small area. Subarachnoid haemorrhage. This is the name given to bleeding into the fluid-filled space between the surface of the brain and the skull. It usually happens when a weak area in the wall of a blood vessel (called an aneurysm) bursts. It accounts for about 10 per cent of all strokes. Intracerebral haemorrhage (ICH). In this type, a blood vessel deep inside the brain tissues bursts. The pressure of the leaking blood on the soft brain tissue destroys it. ICH accounts for about 10 per cent of all strokes.

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What is defined as normal and high blood pressure?

The measurement of blood pressure is a painless and simple process that uses a cuff round the upper arm which is inflated to squeeze the arteries and restrict blood flow. While listening to the pulse at the elbow with a stethoscope, the doctor takes two measurements, the systolic pressure, which is the maximum pressure generated by each heart beat, and the diastolic pressure, which is the low point when the heart rests between beats. Each is expressed in millimetres of mercury and readings in the region of 120/80 are normal. Blood pressure greater than 140/90 in several consecutive readings should be treated. Pressures of 160/95 or more increase the risk from stroke many times, depending on age.

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Is migraine a risk factor for stroke?

Research published in 1999 showed that a personal history of migraine in women of childbearing age is associated with a significantly increased risk of ischaemic stroke. In this study, 25.4 per cent of women who had a stroke also reported suffering from migraine, compared with only 13 per cent in a control group matched for age. Also, a family history of migraine was a risk factor. Notably, the combination of the contraceptive pill, raised blood pressure and smoking gave a further increase in the risk.

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Is there any link between diseased arteries in the heart, brain, and the rest of the body?

These conditions are often found together in older people. In a recent study, 8 per cent had plaques (atherosclerosis) in their blood vessels, 21 per cent had coronary heart disease and 9 per cent had diseased blood vessels in the brain. These conditions overlapped and 5 per cent had all three. Atherosclerosis coupled with clot formation by platelets is a major cause of both heart attack and stroke.

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Why should blood clots form inside an artery?

Blood clots do not form in healthy arteries but can develop in those of older people whose arteries have become damaged. As we age, the walls of our arteries suffer slight damage through normal wear and tear, or because of our lifestyle. This injures the inner layer of cells and the muscular coat and allows the gradual formation of fatty streaks and the build-up of waste material to form a plaque. Even though early signs of plaque can be found in young people hardly out of their teens, it becomes much more widespread in older people, where the wall is thickened, loses its flexibility and may eventually crack and ulcerate. The resultant rough surface slows blood flow, causes turbulence and triggers platelet aggregation, leading to the formation of clots. These may get large enough to block the vessel or, as often happens, a fragment (embolus) may detach and block a smaller artery further up the branching tree.

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What are the main types of medicines used in stroke?

There are two main types: medicines that can help prevent a first stroke and those that are used to treat stroke after the event.

Primary Prevention: In the last few years aspirin has emerged as an important medicine for stroke prevention. Clinical trials have also shown that medicines that control moderate to high blood pressure reduce stroke by up to 38 per cent and people in this group should be treated. Several types of medicine will control blood pressure including:

• diuretics
• beta-blockers
• calcium channel blockers
• ACE inhibitors
• vasodilators
• angiotensin II receptor antagonists

Each of these has a different mechanism of action and the choice of which to use will be made by the doctor and will depend on the needs of the individual.

There are also medicines available that can help reduce high cholesterol levels (though the link between high cholesterol and stroke remains unclear at present), control diabetes, or help reduce the tendency of blood to clot. The anticoagulant warfarin is also used in primary prevention in people at very high risk, such as those with artificial mechanical heart valves, rheumatic mitral valve disease and arterial fibrillation, and in other clinical situations for which surgery and antiplatelet medicines are not appropriate.

Treatment and Secondary Prevention: Medicines for blood pressure are not usually given in the few days after a stroke – in fact, raised blood pressure may even help sustain a better brain blood flow than a low one. However, if high blood pressure persists after two to three weeks, then treatment may be required. Again, the selection of the treatment type will be made by the doctor according to individual circumstances.

Many trials suggest a benefit of low doses of aspirin (50-325mg/day) in reducing risk from a second stroke. Though widely used and available over the counter, aspirin is not risk-free and should not be taken without first discussing it with a doctor. Other compounds are also available that offer alternatives to aspirin (e.g. modified-release dipyridamole and clopidogrel). These are only available on prescription. Pravastatin has also been licensed for the reduction of the risk from stroke, while other compounds in this class may also be beneficial.

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Are there forms of treatment for stroke other than medicines?

Some people who have experienced a stroke, and others with significant blockage of the carotid artery or evidence of aneurysms in brain scans, may be considered as candidates for specialised surgery.

If there is a narrowing of the carotid artery due to plaque, an operation called a carotid endarterectomy may be considered. This involves either surgically opening the artery to remove the plaque or using a balloon-like device which is inserted into the artery and then inflated to expand the artery. Though these have been widely used, especially in the USA, there are few well-controlled studies on the benefits, and the risk of an induced stroke during the procedure is quite high.

In a few people, the detection of an aneurysm is made before it ruptures. In this case, an operation to tie off the bulging vessel wall may be possible. However, an aneurysm is not necessarily a ‘time bomb’, because only about one in ten ever ruptures. Whether an operation is necessary will be decided by a specialist after careful consideration of the age of the individual, their family history and the size of the aneurysm. If rupture has occurred, an operation may be essential to remove pressure on the brain and hence reduce tissue damage.

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What are the main complications following a stroke?

Some people develop secondary complications after a stroke, but with good nursing and prompt action, many of these can be minimised.

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Have there been any recent advances in stroke management and rehabilitation?

It is almost 50 years since the first reports were published of organised stroke care and since then there have been many trials of stroke units compared with conventional treatment. A stroke unit is a team of stroke specialists within a hospital (sometimes, but not necessarily, in a dedicated stroke area) who combine to provide specialist assessment, treatment and aftercare. They comprise a multi-disciplinary team which will include medical staff, nurses, physiotherapists, occupational therapists, speech and language therapists and social workers.

By 1991, the value of such support teams had been clearly demonstrated in randomised controlled trials. Since then studies by the Stroke Unit Trialists Collaboration have clearly shown that stroke units are able to prevent premature death in many people who have had a stroke and increase their likelihood of long-term independence. Their success has been attributed to the early recognition of complications such as chest and urinary infections, deep vein thromboses, etc, and attention to details such as early mobilisation, body position, feeding management and prompt therapy.

These developments led to an increased appreciation of the value of integrated stroke care, recognised in a World Health Organisation declaration in 1995, which set standards for the management of stroke. Combined with the Government’s stated aim to reduce stroke deaths, there are clearly grounds for optimism that, in the coming decade, fewer people may die unnecessarily from stroke and long-term dependence will be reduced.

 

Complications of stroke and some treatments Oedema of the brain (swelling) Injections of dexamethasone or the sugar mannitol Surgery to relieve pressure Heart problems Various, depending on the problem Blood vessel problems Anti-coagulants such as heparin to prevent deep vein thrombosis Various others, depending on the condition Frozen shoulder & other muscular problems Primary approach is physiotherapy Persisting problems may warrant the use of muscle relaxing medicines Pneumonia Antibiotics Urinary infections Antibiotics Seizures Anti-convulsant medicines Depression Anti-depressant

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What kind of general information and support is available for people with stroke?

The leading patient group for stroke in the UK is The Stroke Association, whose contact address and telephone numbers are on the back of this booklet. It produces a wide range of excellent booklets and guides for people who have had a stroke and their families. The charity also runs a network of Dysphasia Support Services and Family Support Services. An accessible and useful paperback is the ‘Family Guide to Stroke’ by L. R. Caplan, M. L. Dyken and J. D. Easton, from the American Heart Association, published by Times Books.

Services that may be needed after a stroke include speech and language therapy, physiotherapy, and occupational therapy. In addition, the family will often require special help at this time. To address this, The Stroke Association has pioneered the concept of Family Support. This aims to inform families and prepare them for lifestyle changes that may be necessary after a stroke has occurred. The service is free to the families involved and is set up by The Stroke Association with funding from a health authority. Information about this service in your area can be obtained from The Stroke Association.

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