By Dr Ritesh Kohli, MD (Internal Medicine Specialist)
A stroke is caused by the sudden loss of blood flow to the brain or bleeding inside the head. Both can cause brain cells to stop functioning or die. When brain cells die, the function of the body parts they control is impaired or lost, causing paralysis, speech problems, loss of feeling, memory and reasoning deficits, coma, and possibly death.
Symptoms
Stroke symptoms may not be as dramatic or painful as a heart attack, but the results can be just as devastating. Stroke is an emergency. Get medical attention immediately and know when the symptoms started.
Common symptoms include:
■ sudden weakness, numbness, or paralysis of the face, arm, or leg (especially on one side of the body);
■ sudden loss of speech or difficulty talking;
■ sudden difficulty understanding language or confusion;
■ sudden loss of vision (in one eye or loss of vision to one side) or blurred vision;
■ sudden, severe headache with no apparent cause;
■ sudden loss of balance or co-ordination often associated with dizziness.
Get medical help immediately if you or someone you know experiences any of the above warning signs. Jot down the time the symptoms started. Sometimes these warning signs occur for only a few minutes and then resolve. Even if this happens, or if you think you are getting better, call for help.
Risk factors
Many factors can increase your risk of a stroke. A number of these factors can also increase your chances of having a heart attack. Stroke risk factors include:
■ a family history of stroke, heart attack or TIA;
■ being aged 55 or older;
■ high blood pressure – a systolic blood pressure of 140 millimetres of mercury (mmHg) or higher, or a diastolic pressure of 90 mmHg or higher;
■ high cholesterol;
■ cigarette smoking;
■ diabetes;
■ obesity – a body mass index of 30 or higher;
■ cardiovascular disease, including heart failure, a heart defect, heart infection, or abnormal heart rhythm;
■ previous stroke or TIA;
■ high levels of homocysteine, an amino acid, in your blood;
■ use of birth control pills or other hormone therapy.
Other factors that can increase your risk of stroke include heavy or binge drinking and the use of illicit drugs such as cocaine.
Although men and women have strokes at about the same rate, women more often die of strokes than do men. Blacks are more likely to have strokes than are people of other races.
What causes a stroke?
An ischaemic stroke is caused by an interruption of the blood flow to the brain, while a haemorrhagic stroke is caused by bleeding inside the head. The following defines the various types of stroke:
► Ischaemic – blockage of brain blood vessels, including:
■ embolic – clots travel from the heart or neck blood vessels and lodge in the brain;
■ lacunar – small vessels in the brain are blocked, often due to high blood pressure or diabetes damage;
■ thrombotic – clot forms in the brain blood vessels often due to arteriosclerosis.
► Haemorrhagic – bleeding into or around the brain, including:
■ subarachnoid – weak spots on brain arteries burst and blood covers the brain;
■ bleeding into the brain – blood vessels in the brain break because they have been weakened by damage due to high blood pressure, diabetes and aging.
When blood cannot get to brain cells, they die within minutes to a few hours. Doctors call this area of dead cells an infarct.
The lack of normal blood flow to brain cells sets off a chain reaction called the ‘ischaemic cascade.’ Over hours, this chain reaction endangers brain cells in a progressively larger area of the brain where the blood supply is compromised but not completely cut off. Prompt medical treatment offers the best chance of salvaging this region of brain cells, called the ‘penumbra.’
Treatment
Immediate medical care is critical. New treatment works only if given within a few hours after the onset of a stroke. For example, a clot-busting drug recently approved by the FDA must be given within three hours.
Before treatment, the neurologist or emergency physician must carefully examine the patient to determine the patient’s condition and what caused the stroke. Diagnostic tests to determine treatment could include:
a neurologic exam;
brain imaging tests to determine the type, location and extent of the stroke (CT and MRI scans);
tests that show blood flow and bleeding sites (angiography and carotid and transcranial ultrasound);
blood tests for bleeding or clotting disorders;
ECG or an ultrasound examination of the heart (echocardiogram) to identify cardiac sources of blood clots that can travel to the brain.
Once the doctor completes these tests, the treatment is selected. For all stroke patients, the aim is to prevent further brain damage.
If the stroke is caused by a blockage of blood flow to the brain, treatment could include:
drugs that thin the blood, including anticoagulants (Coumadin) and antiplatelet medications (aspirin or ticlopidine);
drugs that break up clots (thrombolytics);
surgery that cleans the inside of blood vessels (endarterectomy);
drugs that stop the chain reaction of damage from the ischaemic cascade (neuroprotective agents, promising but still experimental);
procedures which dilate blocked blood vessels.
If the stroke is caused by bleeding, treatment could include:
drugs that maintain normal blood clotting;
surgery to remove blood in the brain or decrease pressure on the brain;
surgery to fix the broken blood vessels;
blocking off bleeding vessels with a balloon or coil;
drugs that prevent or reverse brain swelling.
Can a stroke be prevented?
Some risk factors – age, sex, race, and a history of stroke in the family – cannot be changed, but others can be controlled. The most controllable risk factors relate to the health of the heart and blood vessels.
The following can help prevent stroke:
regular medical check-ups;
controlling high blood pressure;
not smoking – if you do smoke, you should stop;
treating heart disease, especially an irregular heartbeat called atrial fibrillation (AF);
improving the diet by avoiding excess fat, salt and alcohol;
Exercising;
controlling diabetes;
seeking immediate medical attention for the warning signs of stroke.
Healthy Diet
Eat healthy foods; a brain-healthy diet should include:
Five or more daily servings of fruits and vegetables, which contain nutrients such as potassium, folate and antioxidants that may protect you against stroke;
roods rich in soluble fibre, such as oatmeal and beans;
roods rich in calcium, a mineral found to reduce stroke risk;
soy products, such as tempeh, miso tofu and soy milk, which can reduce you low-density lipoprotein (LDL) cholesterol and raise your HDL cholesterol level;
foods rich in omega-3 fatty acids, including cold-water fish, such as salmon, mackerel and tuna.
Stroke is a medical emergency, and prompt treatment of it is crucial. Early treatment can minimize damage to the brain and potential stroke complications.
