A stroke is a medical emergency which happens when the blood flow to the brain has been disrupted or reduced, thereby causing a lack of oxygen and nutrients to a part of the brain.
Consequently, brain cells start to die in minutes. Early intervention can reduce brain damage and other complications.
What causes stroke?
There are 3 main types of stroke: transient ischaemic attack (TIA), ischaemic stroke, and haemorrhagic stroke.
Transient ischaemic attack (TIA)
A transient ischaemic attack, known as TIA or a ministroke, occurs when blood flow to the brain is temporarily blocked, often due to a blood clot. The symptoms observed may be similar to a full stroke but are temporary and disappear in a matter of minutes or hours.
TIA is a warning sign for future strokes – many who get TIA will also have a major stroke within the year. The same treatment should be sought for TIA as for a major stroke.
Ischaemic stroke
An ischaemic stroke is the most common type of stroke. It occurs when the blood vessels of the brain become narrow or blocked, causing a severe reduction in blood flow known as ischaemia. These are normally caused by fatty deposits that build up in blood vessels or by blood clots that travel in the blood and become lodged in brain blood vessels.
Haemorrhagic stroke
A haemorrhagic stroke happens when an artery in the brain ruptures and leaks blood. This blood from the artery puts excess pressure in the skull, causing swelling which damages brain cells.
There are two types of haemorrhagic strokes: intracerebral haemorrhage (ICH) and subarachnoid haemorrhage (SAH). An intracerebral haemorrhagic stroke is the most common type of haemorrhagic stroke. The main difference is the location of the bleed: ICH occurs when there is a haemorrhage in the brain parenchyma, the functional tissue in the brain made up of neurons and glial cells. On the other hand, SAH is when there is a haemorrhage in the subarachnoid space, the area between the brain and the skill.
What are the symptoms of stroke?
Some symptoms of stroke include:
Trouble speaking and understanding speech – there may be confusion, slurring or difficulty understanding what others are saying.
Paralysis or numbness of the face, arm or leg – there may be numbness, weakness or paralysis in the face, arm or leg that often occurs only in one side of the body. If you try to lift both your arms over the head and one arm begins to fall, you may be having a stroke. One side of your mouth may also droop when you try to smile.
Problems seeing in one or both eyes – there may be blurred or blackened vision in one or both eyes, or there could be double vision.
Trouble walking – you could stumble or lose your balance. There may also be sudden dizziness or a loss of coordination.
Who is at risk for stroke?
Some risk factors for stroke include:
Obesity or sedentary lifestyle
Heavy drinking
Use of illegal drugs such as cocaine or methamphetamine
High blood pressure
Smoking or secondhand smoke exposure
High cholesterol
Diabetes
Obstructive sleep apnea
Cardiovascular disease such as heart failure, heart defects, heart infection or abnormal heart rhythm
Personal or family history of stroke, heart attack or transient ischaemic attack
COVID-19 infection
Other factors that could be associated with a higher risk of stroke include:
Age – People aged 55 or older have a higher risk of stroke than young people.
Race – African Americans have a higher risk of stroke.
Sex – Men have a higher risk of stroke than women. When women have strokes, they are usually older and are more likely to die of stroke than men.
Hormones – Those who use birth control pills or hormone therapies such as oestrogen are at higher risk of stroke.
How is stroke diagnosed?
Strokes are usually diagnosed through physical tests and studying images of the brain from a scan.
There are some tests that can be done to confirm the diagnosis and determine the cause of the stroke, such as:
A blood test to find out your cholesterol and blood sugar level.
Check the pulse for an irregular heartbeat
Taking your blood pressure
Brain scans may be done to determine:
Whether the stroke was caused by a blocked artery (ischaemic stroke) or a burst blood vessel (haemorrhagic stroke).
Which part of the brain was affected.
How severe the stroke is.
There are also 2 main types of scans that can be used to assess the brain in people who have had a suspected stroke: CT scan and MRI scan
Computerised Tomography (CT) scan
A CT scan is something like an X-ray that uses multiple images to build a 3-dimensional image of the brain to help doctors identify areas of concern.
You may be given an injection of a special dye into a vein in your arm so as to improve the clarity of the CT scan to look at blood vessels that supply the brain.
This process of using a CT scan is usually faster than an MRI scan.
Magnetic Resonance Imaging (MRI) scan
An MRI scan uses a strong magnetic field and radio waves to produce a detailed image of the inside of your body.
It is usually used for people with complex symptoms and the extent or location of the damage is unknown. It is also used for patients who have recovered from TIA.
This type of scan portrays a more detailed picture of the brain tissues, allowing smaller or unusual locations affected by a stroke to be identified.
How is stroke treated?
The treatment depends on which type of stroke it is, whether it is caused by:
A blood clot blocking the flow of blood to the brain – an ischaemic stroke
Bleeding in or around the brain - a haemorrhagic stroke
Treatment can involve taking medicines or having surgery.
Treatment for an ischaemic stroke
Medicines A combination of medicines are used to treat ischaemic strokes and prevent it from happening again. Some of them need to be taken immediately and only for a short time, while others may be taken after the stroke and for a longer period of time.
“Clot-busting medicines” for thrombolysis
Alteplase – may be injected to dissolve blood clots (thrombolysis), restoring blood flow to the brain. It is most effective within 4.5 hours of the occurrence of the stroke. It is only used when it is confirmed to be an ischaemic stroke by a brain scan, as it can worsen bleeding in haemorrhagic strokes.
Aspirin and other antiplatelets
Aspirin– a painkiller and an antiplatelet that can prevent another clot from forming
Clopidogrel
Dipyridamole
Anticoagulants – changes the chemical composition of blood to prevent blood clots
Anticoagulants may be offered if you:
Have a type of irregular heartbeat known as atrial fibrillation, which can cause blood clots.
Have a history of blood clots.
Develop a blood clot in your leg veins (deep vein thrombosis) because a stroke caused inability to move one of your legs.
Examples of anticoagulants for long-term use are:
Warfarin
Apixaban
Dabigatran
Edoxaban
Rivaroxaban
Examples of anticoagulants for short-term use is:
Heparins
Blood pressure medicines – to lower blood pressure if it is too high
Thiazide diuretics
Angiotensin-converting enzyme (ACE) inhibitors
Calcium channel blockers
Beta-blockers
Alpha-blockers
Statins – used to lower blood cholesterol to lower the risk of future strokes
Surgery
Thrombectomy – to remove blood clots by inserting a small device through a catheter into the artery
Carotid endarterectomy – to unblock an artery in the neck that supplies blood to the brain (carotid artery), by removing the fatty deposits that have built up in the artery in a condition known as carotid stenosis.
Treatment for haemorrhagic strokes
Medicine Medicine may be offered to haemorrhagic stroke patients to lower their blood pressure and prevent further strokes. If you were taking anticoagulants before the stroke, you may need treatment to reverse its effects in order to reduce the risk of further bleeding.
Surgery
Craniotomy
Surgery such as a craniotomy may be required to remove blood from the brain and repair burst blood vessels. In a craniotomy, a section of the skull is removed and the surgeon repairs the damaged blood vessels and ensures there are no blood clots.
After the bleeding is stopped, the piece of bone removed from the skull is replaced by an artificial metal plate.
What does stroke rehabilitation involve?
Your rehabilitation plan will differ depending on the abilities and parts of the body affected by the stroke, but generally include:
Physiotherapy and physical activities
Technology-assisted physical activities
Cognitive and emotional activities
Experimental therapies
You may choose to do rehabilitation in inpatient rehabilitation units, outpatient units, nursing homes, or in the comfort of your own home in home-based programmes.
