Stroke: symptoms, causes, risk factors and treatment
What is a stroke?
The most common type of stroke involves a blockage that cuts off the blood supply to your brain. This deprives it of oxygen and nutrients, damaging or killing brain cells, and is referred to as an ischaemic stroke. Eighty-seven percent of strokes are ischaemic.
A transient ischaemic attack (TIA), or mini-stroke, is a blockage that lasts only for a short period. The symptoms resolve within 24 hours, but a TIA is a warning sign that a stroke may happen soon, and you should never ignore it and hope that the problem will go away.
A haemorrhagic stroke is caused by the rupturing of a weakened blood vessel. Around 80 percent of cases are caused by uncontrolled high blood pressure, and this type of stroke is far more likely to be fatal.
There’s a simple test you can perform if you think you or someone else has had a stroke. It’s called the FAST test:
F stands for face. If you ask someone to smile and one half of their face droops, this may indicate a stroke.
A is for arms. If the person raises both arms, and has difficulty in holding one up, this may also be an indicator.
S is for speech. The person’s speech may be slurred, or they have difficulty finding the right words.
T is for time: It’s time to call the emergency services. The acronym FAST is well chosen, because speed is of the essence: some two million brain cells die every minute that the blockage lasts. A suspected stroke will obviously be treated very quickly once the patient arrives at the hospital, so much of the onus is on you to recognise possible symptoms and act on them fast. Every stroke is a medical emergency that may result in disability or death, and these three symptoms are present in 85 percent of strokes.
Other symptoms include:
- Numbness or weakness, often affecting one side of the body
- Sudden changes in vision
- Difficulty in swallowing
- Problems with dizziness and balance
- Sudden confusion and difficulty in understanding
What causes an ischaemic stroke?
There are two main types of ischaemic stroke:
This happens when a blood clot blocks diseased or damaged arteries in or close to your brain. It is also referred to as a cerebral infarction, and accounts for 50 percent of all strokes.
An embolic stroke is one in which the blood clot forms somewhere other than in your brain, and travels around your body until it becomes stuck in position and blocks the blood flow to your brain.
And what causes the clot?
Blood clots most commonly occur as a result of atherosclerosis, arteries narrowed by cholesterol deposits that cause the blood cells to clump together.
How is stroke treated?
There are two main treatments for stroke.
Thrombolysis involves the administration of a clot-busting drug called alteplase or recombinant tissue plasminogen activator (rt-PA). Speed is of the essence, as this normally has to be given within four and a half hours of the stroke.
Thrombectomy is a procedure in which a catheter is inserted either to administer the clot-busting drug or to physically break up and suck out the clot.
If you’ve had an ischaemic stroke, you’ll probably also be given aspirin or another drug to reduce the likelihood of further blood clots.
What are the risk factors for stroke?
There are some factors that you can’t control:
- Previous stroke, TIA, or heart attack
And some that you can:
- High blood pressure: This is the leading cause of stroke.
- High cholesterol: This may result in narrowing of the blood vessels that causes clots to form.
- Smoking: Nicotine and carbon dioxide damage the cardiovascular system and make you more prone to strokes.
- Diabetes: Uncontrolled blood sugar is another important risk factor.
- Diet and weight: Too much fatty food can increase your blood cholesterol. Too much salt is bad for your blood pressure, and too many calories may make you overweight and place extra stress on your heart.
- Lack of exercise: Inactivity increases your vulnerability to stroke, heart disease, and many other disorders.