Stroke

A stroke is a singular, damaging event, but the conditions leading to a stroke often develop over time. It is important to be aware of the risk factors linked with strokes and to take preventive measures where possible.

People with the following conditions are at higher risk of suffering from stroke:

• High blood pressure (hypertension)
• Heart disease
• Diabetes
• Cigarette smoking habit
• High alcohol consumption
• High blood cholesterol level

These are risk factors that can be modified by lifestyle changes and medication.

Certain risk factors that cannot be changed include:

• Increasing age
• Previous stroke or TIA
• A family history of stroke
• Uncommon genetic or congenital conditions.

With certain lifestyle changes, selected risk factors like high blood pressure and cholesterol levels can be managed. Speak to a doctor to understand more.

Symptoms of stroke commonly involve the following:

• Sudden weakness and/or numbness on one side of the body
• Sudden double vision or other visual disturbances
• Sudden confusion or dizziness
• Sudden, severe headache
• Sudden sensitivity to light
• Difficulty in speech or swallowing
• Loss of balance or coordination
• Loss of consciousness
• Loss of memory or concentration
• Nausea or light vomiting

If you experience any of the above warning signs, it is important to seek medical attention quickly. Immediate medical treatment (within 3 hours of the start of the stroke) can greatly reduce any potential disability. Talk to a doctor to find out more about what to do when suffering from a stroke.

Methods of stroke prevention and treatment include:

• Blood thinners (eg. aspirin) to help with blood flow and to reduce the risk of a stroke from reoccurring
• Medication or dietary changes to control blood pressure, cholesterol, or blood glucose levels
• Rehabilitation treatment which may include individualised physiotherapy and/or speech therapy to help patients resume their daily activities
• Surgical intervention if necessary to reduce the risk of stroke, eg. carotid endarterectomy surgery (CEA) to correct the narrowing of an artery

Your doctor will evaluate your condition and advise the appropriate treatment for you.

Primary prevention is to prevent stroke in people who are diagnosed with risk factors but have never experienced a stroke before. For patients with high blood pressure, medications like antihypertensive drugs may be prescribed. Studies show the benefits of high blood pressure treatment in elderly patients, where even small reductions in blood pressure can effectively reduce stroke risk by 30 – 40%.² Patients with heart disease like irregular heartbeat (atrial fibrillation) may be prescribed anticoagulants (blood thinners) to manage their condition and to reduce risk.

Secondary prevention means reducing the chance of a stroke reoccurring after a past stroke or TIA. The risk of a stroke reoccurring after a stroke or TIA is 5 – 15% yearly.³ Prescription of medication in the form of antiplatelet drugs that reduce the tendency of blood to clot, or cholesterol-lowering medication, may reduce the risk of another stroke by up to 5 times over a 90 day period.⁴ Depending on the severity of the case, surgical involvement may be needed.

By understanding the risk factors and adjusting your lifestyle, you can reduce your chances of getting a stroke. Take charge of your health today by applying the following general guidelines:

• Stop smoking
• Limit alcohol intake
• Exercise moderately
• Eat healthy with a diet low in salt, sugar and refined carbohydrates (eg. white bread and noodles), complemented by fruits and vegetables
• Go for regular check-ups to understand your risk factors ie. cholesterol, blood glucose levels, heart health, and whether you have disordered breathing in sleep (sleep apnoea) which leads to increased blood pressure
• Seek medical treatment if blood pressure is diagnosed as more than 140/90mmHg across 3 separate measurements

Talk to your doctor to find out more. Learn more about stroke prevention and the screening options available.

If you have risk factors linked with stroke, it is important to talk to your doctor and find out if there are suitable screenings you can take to manage your risk of getting a stroke.

These are general steps you should take in order to better understand and reduce your risk:

• Check your blood pressure and get it treated if it is high. High blood pressure, or hypertension, is defined as having a blood pressure (BP) of more than 140/90mmHg on 3 separate occasions. Hypertension increases stroke risk up to 6 times.
• Find out if you have diabetes. Diabetes raises the risk of stroke by 4 times, and high blood sugar levels worsen recovery when a stroke occurs.
• Check your cholesterol level and take steps to lower it if it is high. A raised cholesterol may increase stroke risk up to 3 times.
• Find out if you have heart disease. Atrial fibrillation (irregular heartbeat), in particular, can increase stroke risk by 4 – 6 times. In this condition, blood in the heart tends to form clots that can travel to any part of your body. If they travel to the brain, these clots can cause a stroke.
• Find out if you have carotid artery disease. The carotids are the vessels that carry most of the blood supply to the brain, and an operation can be done to clear them of deposits if they are severely narrowed.
• Find out if you have disordered breathing in your sleep (sleep apnoea). Sleep apnoea is almost always found in people who snore when asleep. It can lead to increased blood pressure, which in turn leads to stroke and heart attack. People with sleep apnoea develop dangerously low levels of oxygen in the blood while carbon dioxide levels rise, possibly causing strokes in sleep.

Although stroke is the third leading cause of death in Singapore, many myths surround this condition. Knowing the facts can help you respond appropriately and quickly during the event of a stroke.

MYTH: Strokes only happen to older people

FACT: Strokes can strike anyone at any age. While it is true that the risk of stroke increases with age, it is dangerous to think that a stroke cannot happen to a young person, and to ignore the symptoms when they occur. It is also important to note risk factors like high blood pressure and obesity, and to make the proper lifestyle changes like exercising well and eating right.

MYTH: Strokes occur in the heart

FACT: Strokes occur in the brain. A stroke happens when blood supply to part of the brain via the blood vessels (arteries) is suddenly disrupted or severely reduced, leading to the brain tissue receiving less oxygen and nutrients. This causes the brain cells to die and may result in permanent injury or disability, depending on the part of brain affected.

Myth: Small strokes do not need medical attention

FACT: Every stroke, no matter how minor, needs immediate medical attention. Some people may experience a transient ischaemic attack (TIA), where the blood supply to the brain is temporarily interrupted due to a transient (temporary) blood clot. This causes a ‘mini-stroke’ with symptoms occurring quickly and lasting for a relatively short time. People who experience TIA should consider this as a serious warning sign and seek immediate medical assistance to prevent a major stroke in the future.

MYTH: Strokes never happen in infants

FACT: Stroke can strike anyone, including infants. In younger patients, stroke may occur due to congenital heart disease or due to autoimmune disease where the syndrome results in blood clotting irregularities.

MYTH: Severe headache is a sign of a stroke

FACT: A headache can be due to many reasons and is usually not a sign of a stroke. However, some strokes may result in sudden and severe headaches. A stroke severe enough to cause a headache will always be enough to cause other symptoms. Headaches due to a sudden bleed are severe and are accompanied by symptoms like nausea, light vomiting and sudden light sensitivity.

MYTH: Strokes cannot be prevented

FACT: Many of the risk factors for stroke can be managed by lifestyle changes or medication. Managing your high blood pressure, high blood cholesterol levels, heart disease and diabetes are all ways to reduce your chances of having a stroke. Other preventive measures include not smoking, limiting alcohol consumption and controlling your weight.

Information contributed by Dr Ho King Hee, neurologist, Gleneagles Hospital.

References

1. Ministry of Health, Principal Causes of Death, Retrieved 2016 https://www.moh.gov.sg/content/moh_web/home/statistics/Health_Facts_Singapore/Principal_Causes_of_Death.html
2. BMJ. 15 Feb 1992; 304(6824): 405 – 412. Medical Research Council trial of treatment of hypertension in older adults: principal results. MRC Working Party
3. Cillessen J. P., Kappelle L. J., van Sweiten J. C., Algra A., van Gijn J. Does cerebral infarction after a previous warning occur in the same vascular territory. Stroke 1993, 24:351-4, Johnston S. C., Gress D. R., Browner W. S., Sidney S. Short-term prognosis after emergency department diagnosis of TIA. JAMA 2000, 284:2901 – 6
4. Rothwell P. M., Giles M. F., Chandratheva A., et al. Effect of urgent treatment of transient ischaemic attack and minor stroke on early recurrent stroke (EXPRESS study): a prospective population-based sequential comparison. Lancet 2007, 370(9596):1432 – 42