Preventing strokes

Primary prevention to reduce the incidence of stroke should be targeted at the whole population and groups that are at increased risk by increasing awareness and promoting healthy lifestyles that reduce the risk factors for stroke.

THE brain’s functions depend on a constant blood supply for the oxygen and nutrients needed by its cells. The restriction or stoppage of this supply leads to damage, and possibly death of the brain cells.

A stroke, which is also called a cerebrovascular accident (CVA), is a condition in which the blood supply to a part of the brain is cut off. It is a medical emergency and the earlier treatment is provided, the less likely will be the damage.

Strokes are the third most common cause of death in Malaysia. It is estimated that there are about 52,000 strokes per annum (i.e. every hour, six people experience a stroke).

The risk for recurrent vascular events after a stroke or transient ischaemic attack (TIA) is about 5% per year for stroke, 3% per year for heart attack, and 7% per year for any one of stroke, heart attack or vascular death. The risks are higher in patients who are at an increased risk of CVA or who have carotid stenosis.

It has been estimated that without treatment, the likelihood is one in 10 that a stroke will occur within a month after a TIA.

As strokes lead to disability and even death in some instances, TIAs should be treated as seriously as strokes.

Risk factors

A risk factor increases the chances of getting or having a certain health condition. Some risk factors for stroke cannot be changed, but others can be prevented. Changing risk factors over which a person has control will assist in achieving a longer and healthier life.

Strokes are preventable as lifestyle changes can reduce many of the risk factors. However, there are some risk factors that are not preventable. They include:

·Age – The risks are increased in the older person, although about a quarter of strokes occur in the young. The risk doubles in each successive decade after 55 years of age.

·Gender – The risks are increased in males (except in older adults, when it evens out).

·Ethnicity – The risks are increased in Indians and Malays because the incidence of diabetes and hypertension are higher in these groups.

·Medical history – The risks are increased if one has had a heart attack, stroke or TIA. The risks are also increased in pregnancy, abnormal heart beats, chronic renal disease, cancer, some types of arthritis, and in those with abnormal blood vessels or weakness in the wall of an artery.

·Family history – The risks are increased if a close relative has had a stroke.

Primary prevention is vital in any programme to reduce the incidence of stroke. This should be targeted at the whole population and groups that are at increased risk by increasing awareness and promoting healthy lifestyles that reduce the risk factors for stroke.

Secondary prevention are measures used to prevent recurrence of a stroke. They are individualised depending on the person’s pathogenesis based on neuroimaging and other investigations.

The prevention of stroke is similar to the prevention of coronary heart disease.

High blood pressure

High blood pressure (hypertension) is a major risk factor for stroke. The incidence increases in proportion to both the systolic and diastolic blood pressures. Isolated systolic hypertension (systolic blood pressure of more than 160mm Hg and diastolic blood pressure of less than 90mm Hg) is an important risk factor for senior citizens.

A reduction in blood pressure reduces the incidence of stroke. A reduction of the systolic blood pressure by 10mm Hg is associated with a reduction in risk of stroke by about a third, regardless of the baseline blood pressure levels.

Hypertension is controlled by diet, exercise and medicines.

Hyperlipidaemia

There is an association between raised blood lipids and risk of ischaemic stroke. Hyperlipidaemia is controlled by diet, exercise and medicines.

The use of statins in those at increased risk, e.g. those with cardiovascular disease, diabetes, reduces the incidence of coronary events and ischaemic strokes even in individuals whose blood cholesterol levels are normal (less than 5.0mmol/L).

Diabetes

Diabetes increases the risk of ischaemic stroke by 1.8 to 6 times. The incidence of stroke is significantly reduced by stringent control of hypertension in diabetics.

Scientific studies have indicated that strict control of the blood glucose (Hb A1c less than 6%) is critical.

Diabetes is controlled by diet, exercise and medicines.

Diet

Foods rich in fat lead to fatty deposits in the artery walls. The overweight are at risk of hypertension. A low-fat, high-fibre diet, which includes abundant fruits and vegetables (at least five servings daily), is recommended.

Unsaturated fats which increase the blood cholesterol, e.g. meat, ghee, lard, should be avoided. However, a balanced diet has to include some unsaturated fat like fish, olive and vegetable oils.

The daily intake of salt should not be more than 6gm (0.2 oz), which is about one teaspoonful.

Exercise

A combination of a healthy diet with regular exercise is the best method to maintain a healthy weight, which reduces the risk of developing hypertension.

Regular exercise ensures that the heart and circulation are efficient, keeps the blood pressure normal, and lowers the blood cholesterol.

The recommendation is that there be at least 150 minutes of exercise of moderate intensity, e.g. fast walking, per week (about 30 minutes daily).

A person who has had a stroke should discuss with his healthcare provider about possible exercise plans. It may not be possible to have regular exercise immediately after a stroke, but exercise should begin when there has been progress with stroke rehabilitation.

It is essential that weight be maintained at healthy levels. Many people go on weight reduction programmes only to find that they gain back the kilogrammes they lost. It would be better to accept a steady rate of weight loss instead of overnight success.

Programmes that promise an ideal weight within a short period of time do not usually work out in the long term. The key to keeping the weight loss is to make changes to diet and lifestyle that one can live with. One has to adhere to these changes for life; they have to be part and parcel of everyday life.

Smoking

Both active and passive smoking increase the risk of stroke. Smoking doubles the risk as it leads to narrowing of the arteries and increases the likelihood of the blood clotting.

Smoking cessation can reduce the risk of a stroke by up to half. In addition, it will also improve general health and reduce the risk of developing other serious conditions like heart disease and lung cancer.

Smokers who have stopped for more than five years have the same risk of stroke as non-smokers.

Alcohol consumption

Heavy alcohol consumption increases the risk of stroke by three times as it can lead to high blood pressure and irregular heart beats, which are both major risk factors for stroke. In addition, alcohol causes weight gain because they are high-calorie compounds.

Consumption of more than three units a day (one unit = one glass of wine = a peg of hard liquor) increases the risk while light or moderate alcohol intake protects against all strokes.

Aspirin

Aspirin has been reported to be of benefit to women aged 65 years or more in the primary prevention of stroke due to its blood thinning effects.

There is substantial evidence of the benefits of aspirin in secondary prevention of recurrent strokes, with a 25% reduction in risk in all patients with strokes who have received aspirin.

When given within 48 hours of a stroke, it has also been beneficial in reducing recurrent strokes and death.

Other anti-platelet medicines

Alternative antiplatelet medicines are prescribed in patients intolerant or allergic to aspirin, have contraindications to aspirin, or when aspirin has failed. The medicines include ticlopidine and clopidogrel.

It is essential to take aspirin or other anti-platelet medicines under the supervision of a doctor. In addition, one should take measures to avoid falls or tripping when taking these blood-thinning medicines.

In a nutshell

There are several measures that can be taken to prevent a stroke or a recurrent stroke, if one has had a stroke. The following will reduce the likelihood of a stroke or recurrent stroke:

• Control high blood pressure through diet, exercise, and medicines, when necessary.
• Control diabetes through diet, exercise, and medicines, when necessary.
• Control raised cholesterol through diet, exercise, and medicines, when necessary.
• Exercise at least 30 minutes a day.
• Maintain a healthy weight by eating healthy foods, eating less, and joining a weight reduction programme, if necessary.
• Do not smoke, or stop smoking.
• Limit alcohol consumption to one drink a day for women and two a day for men.
• Avoid illicit drugs.
• Have regular medical checks and consultations with the family doctor or physician.

Source: Dr Milton Lum

Life after a stroke

The harder you work during rehabilitation, the better your chances of significant recovery after a stroke.

THERE are many questions that come to the minds of stroke victims and their caregivers. Some people view a stroke negatively, whilst others take up the challenge of recovery and restoration of function as much as is possible.

Importantly, the stroke victim’s attitude has a substantial influence on recovery.

The care of stroke patients requires a multidisciplinary approach. The ideal is for all stroke patients to be managed in a stroke unit, which is a dedicated unit in the hospital that only manages strokes. Such a unit would be staffed by neurologists, geriatricians, general physicians with an interest in stroke, trained nurses, physiotherapists, occupational therapists and speech therapists. It would also include neurosurgeons, social workers and dietitians.

The extent of recovery of motor functions is often influenced by the extent of compliance with the rehabilitation plan.

The specially trained staff of the unit provides co-coordinated multidisciplinary 24-hour care throughout the year. There is ample evidence that stroke patients managed in such units have significantly lower death, dependency and institutionalisation rates. In addition, their length of hospital stay is lower when compared to management in general medical wards.

The benefits of a stroke unit include early acute treatment, reduced infection rates, reduced systemic complications and effective rehabilitation. The benefits are independent of the patients’ age, gender, extent of the stroke and the presence of other medical conditions.

The functioning of a stroke unit is enhanced by an efficient referral and rehabilitation network that includes the family doctor.

Cognitive matters

Every human brain has processes and functions which it uses to process information from the environment. These cognitive functions include thinking, memory, concentration, communication skills, spatial awareness and praxis, which is the ability to carry out skilled physical activities.

After a diagnosis of stroke has been made, the doctor and other healthcare professionals will make an assessment of the patient’s cognitive functions, especially the degree to which it has been affected by the stroke.

The assessments, which may take a few days to be completed, enable the formulation of treatment and rehabilitation plans that are specific for the individual patient.

Most cognitive functions affected by the stroke will return with the passage of time, especially with compliance to the treatment and rehabilitation plans. However, full recovery may not occur in some patients.

Many stroke patients have problems with understanding, speech, reading and writing, a condition called aphasia. This results from damage to the part of the brain that controls language, or the muscles involved in speech may be affected.

In such situations, the patient’s recovery of cognitive functions will require interactions with other healthcare professionals, e.g. a speech therapist to assist in the recovery of communication skills.

Various other methodologies are used to assist the patient who has lost some particular cognitive function, e.g. memory aids or diaries for daily tasks.

Recovering physical functioning

Many stroke patients have weakness or paralysis of one side of the body. Many also have difficulties with balance and co-ordination of the body’s movements.

There is often marked tiredness in the initial weeks after the stroke. There may also be problems getting to sleep, thereby aggravating the tiredness.

As soon as a patient’s medical condition permits, he or she should be attended to by a physiotherapist who will formulate a treatment and rehabilitation plan after making an assessment of the degree of physical disability. The primary goal of rehabilitation is to achieve an improvement in the patient’s functional status.

There are various phases in a rehabilitation plan. It starts with evaluation, which is followed by setting of objectives, delivery of management, task reacquisition and environmental modification.

The initial objectives are to improve balance and then to regain muscle strength and control. The exercises are of a short duration initially, which then increases with the recovery of motor function, e.g. the patient may have to pick up an object initially, and later, stand up and walk.

It is vital to follow the instructions and advice of the physiotherapist, although progress may be perceived as difficult and slow initially. The extent of recovery of motor functions is often influenced by the extent of compliance with the rehabilitation plan.

The involvement of a family member or caregiver is always encouraged because the physiotherapist can teach the patient and the caregiver the exercises that can be carried out at home.

The duration of physiotherapy varies and can last for months, or sometimes, years. The decision as to when to stop physiotherapy should only be made after a full discussion with the doctor and physiotherapist.

Bladder and bowel function may be affected if the part of the brain which controls these functions is damaged by the stroke. This can lead to urinary and/or bowel incontinence.

Most patients recover these functions within a fortnight or so. If the problem persists, help could be sought from nurses, and supplemented by aids like incontinence pads.

There are occasions when a stroke leads in damage to the parts of the brain that receive, process and interpret information from the eye(s). This results in various visual problems like double vision, and partial or total blindness in one eye. The management of these problems would require the expertise of an eye specialist (ophthalmologist).

Some patients give up on sex after a stroke. It is important to know that sex does not increase the risk of another stroke. Although there is no guarantee that another stroke will not recur, there is no reason why it should occur while having sex.

Other ways of having sex can be found even if there is severe disability. If there are any problems, a discussion with the doctor will be helpful. This is especially so as sex drive (libido) is reduced by certain medicines.

Some stroke patients enquire about driving. This depends on residual disabilities and the type of vehicle in question. An assessment by a specialist or family doctor will be helpful. The patient’s medical status and the safety of other road users will have to be taken into consideration.

Psychologically speaking

The majority of psychological disorders after a stroke are depression, in which there are feelings of hopelessness and withdrawal from social life, and anxiety disorder, in which there is intense and often uncontrollable fear and anxiety.

These psychological disorders impact upon family and sexual relationships. They are common but will usually disappear with the passage of time. Doctors and other healthcare professionals will provide advice and assistance in addressing the psychological aspects of stroke. They will usually carry out regular reviews of the patient’s psychological functioning.

If the psychological disorders are severe or persistent for a long period of time, a referral will be made to a psychiatrist, who will use various modalities to manage the patient. This includes medicines, counselling and cognitive behavioural therapy.

Looking towards the future

After a stroke, many patients and their caregivers are interested in what the future holds (prognosis) .

The prognosis of stroke depends on the type, size and location of the pathology. A Malaysian study in 2003 reported that mortality is higher in haemorrhagic stroke (27.3%) compared to ischaemic stroke (11%). However, there is better neurological and functional recovery in haemorrhagic stroke.

Strokes that involve the brainstem or are large have a poorer prognosis. The lowest mortality rates are in small focal strokes.

Deaths in the initial month after a stroke are often due to direct effects of the brain damage. Subsequent mortality is usually due to the complications of immobilisation, i.e. bronchopneumonia, deep vein thrombosis, recurrent stroke and coronary heart disease.

In general, a third will recover almost completely and should be able to lead a normal life. Another third will have substantial disability which is variable, eg requiring assistance with bathing (which is mild) and assistance with getting in and out of bed (which is severe). Another third will be severely affected and will die within a year, with the majority of deaths occurring in the initial weeks after the stroke.

Recent studies have reported that mortality rates after a first-ever stroke (all types) were 10% at one week, 20% at one month, 30% at one year, 60% at five years and 76% at 10 years.

The risks of recurrent stroke are 4% in the first month and 12% in the first year. The risks decrease subsequently to about 4-5% per year so that 30% will have suffered a recurrent stroke five years after the first stroke.

The incidence of deaths following a stroke has decreased in the past few decades in both sexes. This has been due to the introduction of stroke units and better prevention in those with risk factors.

Source: Dr Milton Lum

Handling stroke

The management of stroke and ‘mini-strokes’. THE brain’s functions depend on a constant blood supply for the oxygen and nutrients needed by its cells. The restriction or stoppage of this supply leads to damage and possibly death of the brain cells.

A stroke, which is also called a cerebrovascular accident (CVA), is a condition in which the blood supply to a part of the brain is cut off.

A transient ischaemic attack (TIA) is due to a temporary interruption of the blood supply to part of the brain, leading to a “mini-stroke”. Its features are similar to that of a stroke, but the duration is about a few minutes. The TIA usually resolves within 24 hours.

TIAs provide a warning that further TIAs or a stroke is on the way.

The incidence of TIA is not well known as many people who have TIA do not seek medical attention.

Imaging tests like computerised tomography (CT) scan and magnetic resonance identify the type of stroke and TIA, its location in the brain and the extent to which the brain is affected. – Courtesy of HSC Medical Centre

It has been estimated that without treatment, the likelihood is one in 10 that a stroke will occur within a month after a TIA. As strokes lead to disability and even death in some instances, TIAs should be treated as seriously as strokes.

Strokes and TIAs are medical emergencies, and the earlier management is instituted, the less likely will be the damage to the brain, and consequently, the affected part of the body.

Making a diagnosis

There are two main types of strokes.

Ischaemic strokes, which comprise the majority of stroke cases, occur when the blood supply to the brain stops because the vessel is blocked by a blood clot. This may be due to thrombosis, in which a blood clot forms in one of the brain’s arteries, or to an embolism, in which a blood clot formed elsewhere in the body gets into the brain’s arteries to reach a blood vessel small enough to block its passage.

Haemorrhagic strokes occur when bleeding results from the bursting of a blood vessel supplying the brain because of weakness in its wall. The blood collection compresses the brain, causing damage and loss of function.

The diagnosis of stroke and TIA is made from a detailed history-taking, physical examination and selected diagnostic tests. The history provides vital information, and every effort should be made to obtain information from the patient, family members, friends, or witnesses.

The diagnosis provides answers to questions about the type of stroke, its site in the brain, the extent to which the brain is affected, why it occurred, as well as the potential complications and prognosis.

The investigations for stroke and TIA have been discussed in previous articles. Imaging tests like computerised tomography (CT) scan and magnetic resonance identify the type of stroke and TIA, its location in the brain and the extent to which the brain is affected.

Ultrasound examination of the heart (echocardiogram) or carotid artery in the neck (Doppler scan) help to identify causes of stroke and TIA. Dye may be injected into the carotid or vertebral arteries (arteriography) to enable a detailed examination of the arteries in the brain.

Other tests include blood tests like clotting factors, glucose and cholesterol, electrocardiogram to detect any abnormal heart rhythms, and chest and other x-rays to exclude other medical conditions.

Managing ischaemic strokes

The restoration of perfusion to the ischaemic brain is a vital therapeutic strategy. Although a core of brain tissue might not be salvageable in a stroke, the adjacent dysfunctional tissue may be saved if its circulation is restored and metabolism is normalised.

Ischaemic strokes are treated with medicines that dissolve blood clots (thrombolysis). These medicines are effective if given intravenously within about three to four hours after the onset of the stroke. After that, the medicine has not been shown to have beneficial effects. The earlier thrombolysis is instituted, the better the likelihood of recovery. However, thrombolysis cannot be prescribed for all patients.

Patients will also be prescribed aspirin, which reduces the stickiness in platelets, thereby reducing further blood clot formation. Other medicines will be prescribed if there is allergy to aspirin.

Some patients may be prescribed blood thinning (anti-coagulant) medicines, i.e. heparin or warfarin, that alter blood composition to prevent blood clot formation. However, the use of heparins is not routinely recommended as it does not reduce the mortality in patients with ischaemic stroke.

Anticoagulants are often prescribed in those with an irregular heartbeat.

Ischaemic strokes that are due to narrowing (stenosis) of the carotid artery in the neck are treated surgically, especially if the stenosis is severe. A surgical incision is made in the neck and the fatty deposits in the carotid artery removed.

Management of haemorrhagic strokes

Haemorrhagic strokes are managed by emergency surgery to remove blood from the brain and to ligate any burst blood vessels. The procedure, called a craniotomy, involves a surgical incision of the skull to allow access to the bleeding site(s). After the blood collection has been removed and any bleeding stopped, the bone removed from the skull will be replaced.

The patient may need to be put on a ventilator in the intensive care unit to assist his or her breathing. Medicines will also be prescribed to reduce the likelihood of further strokes, e.g. medicines to lower blood pressure and reduce swelling of the brain (cerebral oedema).

General management of strokes

The objectives are to provide supportive care and treatment of acute complication(s) in order to avoid mortality and functional disability.

Oxygen and airway support are necessary to ensure adequate tissue oxygenation and potential worsening of brain injury.

Regular monitoring and observations are necessary for detection of impaired lung and circulatory function. As high blood pressure is common following a stroke, it is gradually reduced with various medicines.

As there is an association between raised blood sugar following an acute stroke and subsequent mortality and impaired recovery, whether in diabetics or non-diabetics, it is vital that the blood sugar be well controlled.

Strokes may lead to impaired swallowing and consequent aspiration, which increases mortality. As such, a water-swallowing test is performed in all stroke patients before they are allowed to drink or eat. Incomplete oral-labial closure or a coughing reflex is indicative of an increased risk of swallowing. If the patient fails the swallowing test, a nasogastric tube is inserted for feeding.

When a fever occurs, doctors will localise the infection. Antibiotics are prescribed for infections, especially of the lungs and urinary tract, which are the commonest complications after a stroke.

Urinary catheters are avoided, if possible. Anti-pyretics are prescribed for fever, which is also associated with an increased risk of mortality and morbidity.

The majority of stroke patients are prescribed bed rest initially. Mobilisation is initiated as soon as the patient’s condition is stabilised (to prevent complications). Frequent turning, alternating pressure (ripple) mattresses and passive and full-range-of-motion exercises are beneficial.

There has to be close skin monitoring for early detection of bed sores and measures have to be taken to avoid falls.

Management of TIA

The objective is to address the risk factors that led to TIAs in order to prevent a stroke from occurring.

The treatment prescribed depends on the cause(s) of the TIA. High blood pressure, which is the single most important risk factor, is treated with hypotensive medicines.

High blood cholesterol levels are treated with diet, exercise and statins.

Diabetes is treated with diet, exercise, oral hypoglycaemic agents or insulin.

Smoking cessation is vital as smoking doubles the likelihood of TIA or stroke because of the chemicals in the cigarette.

Carotid artery stenosis may require surgery (endarterectomy) to remove the fatty plaques.

Time is of the essence

The effective treatment of stroke and TIA saves lives and prevents long-term disability. The window of opportunity is no more than three to four hours in the case of stroke. Therefore, it behoves everyone with risk factors of stroke and TIA and their caregivers to remember that time is of the essence. In short, TIME = BRAIN.

Source: Dr Milton Lum

Brain attacks

When blood supply to the brain is compromised, it can lead to damage, and possibly death, of the brain cells, a condition called stroke.

THE human brain has been compared to a supercomputer. But the brain is much more complicated than that, a fact that is confirmed with each new discovery about its capabilities, which is still largely unknown.

This single organ controls all the body’s functions, which include heartbeat, breathing, sexual function, thinking, speech, memory, emotions, movement, and sleep. It influences the immune system’s response to ill health, and determines, to some extent, how a person responds to medical treatment.

In short, the brain makes us human and separates us from other living creatures on planet Earth.

The brain, which is encased in the bony skull, is divided into two sides (hemispheres), each controlling the opposite side of the body.

Different parts of the brain have different functions. The frontal lobe is responsible for the highest intellectual functions like thinking and problem-solving. The parietal lobe is responsible for sensory and motor function. The hippocampus is involved in memory. The thalamus is the relay station for almost all of the information coming into the brain, and the hypothalamus, the relay stations for the systems regulating the body’s functions.

The midbrain has cells that relay specific sensory information from the sense organs to the brain. The hindbrain comprises the pons and medulla oblongata, which control breathing and heart functions, and the cerebellum, which controls movement and cognitive processes that require precise timing.

The brain’s functions depend on a constant blood supply for the oxygen and nutrients needed by its cells. The restriction or stoppage of this supply leads to damage, and possibly death, of the brain cells. This is called a stroke.

A stroke, also called a cerebrovascular accident (CVA), is a condition whereby the blood supply to a part of the brain is cut off. It is a medical emergency, and the earlier treatment is provided, the less severe it will be.

Strokes are the third most common cause of death in Malaysia. It is estimated that there are about 52,000 strokes per annum, i.e. strokes occur in six persons every hour.

Different types

There are two main types of strokes.

Ischaemic strokes, which comprise the majority of stroke cases, occur when the blood supply to the brain stops because the vessel is blocked by a blood clot. This may be due to thrombosis, in which a blood clot forms in one of the brain’s arteries, or to an embolism, in which a blood clot formed elsewhere in the body gets into the brain’s arteries to reach a blood vessel small enough to block its passage.

Haemorrhagic strokes occur when bleeding results from a burst blood vessel supplying the brain because of weakness in its wall. The blood collection compresses the brain, causing damage and loss of function.

A related condition is transient ischaemic attack (TIA) in which there is temporary interruption of the blood supply to part of the brain, leading to a “mini-stroke”. As TIAs provide a warning that a stroke is on the way, they should be treated seriously.

Causes of stroke

Strokes are preventable as lifestyle changes can reduce many of the risk factors. However, there are some risk factors that are not preventable. They include:

·Age – The risks are increased in the older person, although about a quarter of strokes occur in the young.

·Ethnicity – The risks are increased in Indians and Malays because the incidence of diabetes and hypertension are higher in these groups.

·Medical history – The risks are increased if one has had a heart attack, stroke, or TIA.

·Family history – The risks are increased if a close relative has had a stroke.

Ischaemic strokes occur when the brain’s blood supply is blocked by clots formed where the arteries are narrowed or blocked by cholesterol deposits due to atherosclerosis.

Everyone’s arteries get narrower with age, but the process is hastened by factors like high blood pressure, poorly controlled diabetes, raised blood cholesterol, smoking, excessive alcohol intake, obesity and a family history of diabetes or heart disease.

An irregular heartbeat leads to blood clots being thrown off to block the brain’s blood supply. The causes of irregular heartbeats include high blood pressure, coronary artery disease, disease of the heart’s mitral valve, overactive thyroid gland and excessive alcohol intake.

Haemorrhagic strokes occur when a blood vessel of the brain bursts, resulting in bleeding into the brain itself (intracerebral haemorrhage). Sometimes, the bleeding is on the brain surface (subarachnoid haemorrhage).

The primary cause of haemorrhagic stroke is high blood pressure, the risk factors of which include smoking, overweight or obesity, lack of exercise, excessive alcohol intake and stress.

Blood-thinning medicines can also cause haemorrhagic strokes, which can also occur from blood vessel malformations in the brain or an aneurysm, which is a balloon-like swelling of a blood vessel.

Trauma can also cause bleeding in the brain. Although the cause is usually apparent, bleeding into the brain’s lining (subdural haematoma) may occur without signs of trauma.

A rare cause of stroke is blood clot formation in the brain’s veins, which is usually due to clotting abnormalities.

Signs and symptoms

The features vary depending on the part of the brain that is affected and the extent to which it is affected. Strokes usually occur suddenly.

The common features are:

·Face – There may be an inability to smile, open the mouth or the face or eye may hang downwards.

·Arms – There may be an inability to lift one or both arms due to numbness or weakness.

·Legs – There may be an inability to move one or both legs due to numbness or weakness.

·Speech – There may be slurring of speech or an inability to talk at all.

Other features may include sudden vision loss, dizziness, difficulty talking and understanding what others say, difficulty swallowing, balancing problems, sudden and severe headache, and blacking out.

Awareness of the above features is crucial, particularly for those at increased risk of a stroke, and their caregivers.

The complications of stroke include swallowing problems (dysphagia), which affect about a third of stroke patients. This leads to small food particles entering the respiratory tract causing lung infection (pneumonia).

Stroke can also lead to excess cerebrospinal fluid (CSF) in the brain’s ventricles (hydrocephalus) in about 10% of haemorrhagic strokes. CSF, which is produced by the brain, is continuously drained away and absorbed by the body. When its drainage is stopped following a haemorrhagic stroke, the excess CSF causes headaches, loss of balance, nausea and vomiting.

A small percentage of stroke victims who have lost some or all movement in their legs will have blood clot formation in their legs. The features of this deep vein thrombosis (DVT) include swelling, pain, tenderness, warmth and redness, especially in the calf. Urgent diagnosis and treatment is necessary to avoid the clot moving to the lungs, causing pulmonary embolism, which is potentially fatal.

Diagnosing stroke

The diagnosis of a stroke is made by history taking and physical examination. However, imaging of the brain is essential to determine if it is an ischaemic or haemorrhagic stroke, the part of the brain that is affected, and the severity of the stroke.

As the treatments of the different types of stroke vary, a speedy diagnosis will facilitate its management.

The common methods of brain imaging are computerised tomography (CT) scans and magnetic resonance imaging (MRI).

The CT scan involves multiple x-ray imaging to produce detailed three-dimensional images of the brain. MRI involves the use of magnetic and radio waves to produce detailed images of the brain.

Both the CT scan and MRI are used to take images of the brain’s blood vessels, as well as the blood vessels in the neck that connect the heart and the brain’s blood vessels. This procedure, called a CT or MR angiogram. involves injecting a dye into a vein in the arm.

The brain imaging modality used depends on the availability of a CT scan and/or MRI. A CT scan provides enough information if the suspected stroke is major. The MRI is useful if there are complex symptoms, the extent or location of the affected area is unknown, and in patients who have recovered from a TIA.

Brain imaging should be done early; in some patients, within an hour of admission.

A swallow test is usually done for all stroke patients because of the risk of aspiration pneumonia due to dysphagia. This involves giving a few teaspoons of water to the patient and if there is no choking or coughing, to be followed by half a glass of water.

Other investigations of the cardiovascular system will be carried out to determine the cause of the stroke.

It includes ultrasound examination of the heart (echocardiogram) or carotid artery in the neck (Doppler scan). It can also include injecting dye into the carotid or vertebral arteries (arteriography) to enable a detailed examination of the arteries in the brain.

The management of stroke will be discussed in a subsequent article.

Source: Dr Milton Lum