What is a Stroke?

Quite simply – A stroke is a brain attack which happens when the blood supply to part of the brain is cut off. Blood is essential to the brain as it carries essential nutrients and oxygen and without blood, brain cells can be damaged or die. This damage has different effects, depending on where it happens in the brain. It can affect physical movement, how thoughts are processed, feelings and communication.

A TIA or Trans Ischaemic Attack (sometimes called a mini stroke or a warning stroke) causes the same symptoms as a stroke and the only difference is that the blockage is temporary – it either dissolves on its own or moves, so that the blood supply returns to normal and your symptoms disappear. However, it’s still a serious occurrence as it means that the risk of having a more serious stroke is high. Some people have several mini strokes without having a bigger one, but it’s best to get checked out each and every time.

What causes stroke?

Arteries become harder and narrower with age which makes them more likely to become blocked. The risk for stroke increases after the age of 55 and continues to rise thereafter. Some medical conditions and lifestyle factors can also speed up this process and increase the risk of having a stroke.

Main risk factors:

High blood pressure

Blood pressure is the measure of how strongly the blood presses against the walls of the arteries when it’s pumped around the body. High blood pressure is when the pressure is consistently too high. The pressure puts a strain on all blood vessels, including the ones leading to the brain which makes a blockage more likely to develop or a blood vessel in the brain to weaken and bleed, both of which cause a stroke.


High levels of sugar in the blood can damage blood vessels, making them harder and narrower and more likely to become blocked. If this happens in a blood vessel leading to the brain, it can cause a stroke. Diabetes almost doubles the risk of stroke and is a contributing factor in 20% of strokes in England, Wales and Northern Ireland.

Atrial fibrillation

Atrial fibrillation (AF) is a type of fast, irregular heartbeat. Because the heart isn’t beating properly or effectively, it might not empty itself of blood after each beat, and a clot can form in the blood left behind. There is then a risk that a clot could travel in the bloodstream towards the brain, causing a stroke or TIA.  Symptoms of AF include: palpitations (the heart beating really fast), being out of breath or chest pain.

High cholesterol

Cholesterol is a fatty substance, vital for the body to function properly. Most of the cholesterol in our body is made by the liver, but it can also be absorbed from some of the foods we eat. Very high levels of cholesterol in the blood can cause fatty deposits to build up in the arteries, restricting the flow of blood and also increases the chance of a blood clot developing. High cholesterol has no noticeable symptoms, so cholesterol levels need to be checked, especially in those over 40 who have any of the other risk factors.

Lifestyle factors
Smoking, drinking too much alcohol, being overweight and eating unhealthy foods can damage blood vessels, increasing blood pressure and making blood more likely to clot. There is also a higher risk if a close relative (parent, grandparent, brother or sister) has had a stroke. Ethnicity
can also play a part with those from South Asian or African or Caribbean origins more at risk.

Different types of stroke

Most strokes are caused by a blockage cutting off blood supply to the brain.  This is called an ischaemic stroke.  A blockage can be caused by a blood clot forming in an artery or within one of the small vessels deep inside the brain and is called a cerebral thrombosis.  Blockages in the brain can also be caused by a blood clot or other matter (such as an air bubble) moving through the blood stream from another part of the body.  This is called a cerebral embolism.

If the stroke is caused by a blood clot, it can be treated with a clot-busting medicine, known as thrombolysis. This breaks down and gets rid of the clot that’s preventing the blood from reaching the brain. For it to have the best effect, it needs to be given within four and a half hours of the stroke symptoms starting. After treatment, most people will be given anti-platelet medication, which helps to prevent more blood clots from forming, and usually they then have to take this medication for life.

Strokes caused by bleeding in or around the brain are called haemorrhagic strokes. Whilst these are not as common as ischaemic strokes, they are usually more serious. A haemorrhagic stroke can happen when an artery inside the brain bursts causing bleeding within the brain. This is known as an intracerebral haemorrhage.

It can also happen because of bleeding on the surface of the brain, beneath the membranes that protect the brain from the skull. This known as a subarachnoid haemorrhage.

Some of the things that can cause bleeding in and around the brain include:

  • High blood pressure – which is a contributing factor in around half of all strokes
  • Cerebral amyloid angiopathy – a condition where a protein called amyloid builds up inside the blood vessels in the brain. This causes damage and makes blood vessels more likely to tear. This condition is more common among older people
  • An aneurysm – a weak spot on an artery, where the walls have become thin and weak. This means that they can sometimes burst, especially if there is high blood pressure. Some aneurysms are present from birth, but some things can make them more likely, including smoking, high blood pressure, and having a family history of aneurysm.
  • Anticoagulant medication – helps to prevent blood clots forming in conditions like Atrial Fibrillation (which can also cause strokes). However it can make people more likely to bleed so careful monitoring is necessary to ensure the right levels are within the blood
  • Illegal drugs – such as cocaine can irritate blood vessel walls making them weaker and more likely to rupture.

Although there are well known risk factors, strokes can happen to anyone, of any age, at any time. It’s vital to know how to spot the warning signs to get urgent medical help. The quicker help is given, the better chance of survival and minimising damage to the brain.

The FAST test is the best way to do this.

  • Face: Can the person smile? Has their face fallen on one side?
  • Arms: Can the person raise both arms and keep them there?
  • Speech problems: Can the person speak clearly and understand what you say? Is their speech slurred?
  • Time: If you see any of these three signs, it’s time to call 999.

There’s no way of knowing if symptoms will pass or get better when they first start, so immediate medical help is essential. A stroke is a medical emergency so always dial 999. The quicker the person arrives at a specialist stroke unit, the quicker they will receive appropriate treatment.

Other symptoms of stroke

The FAST test helps to spot the three most common symptoms of stroke. But there are other signs that should always be taken seriously. These include:

  • sudden weakness or numbness on one side of the body, including legs, hands or feet.
  • difficulty finding words or speaking in clear sentences.
  • sudden blurred vision or loss of sight in one or both eyes.
  • sudden memory loss or confusion, and dizziness; or a sudden fall.
  • a sudden, severe headache.

If there any of these signs of a stroke, 999 should be called straight away.


Please share your experiences or family members’ experiences of having a stroke.