What happens when someone has a stroke?

Safiya Zaloum

What is a stroke?

A stroke is a medical emergency where part of the blood flow to the brain has been stopped. This can be life-threatening and it is important that someone who is having a stroke gets to hospital to have treatment as soon as possible. There are two different types of stroke – haemorrhagic and ischaemic. 

Ischaemic strokes make up the majority of all strokes that occur and happen when there is a blockage of a blood vessel, usually an artery. Arteries supply the brain with blood and oxygen. If there is a blockage in one of these arteries, that area of the brain cannot get enough blood and becomes ischaemic – this means that this brain tissue can die due to the lack of oxygen.


Ischaemic strokes usually occur in blood vessels that have been narrowing over a long period of time, usually due to atherosclerosis where fat is deposited in the blood vessels. Blood vessels can narrow as you get older but some factors such as smoking, high blood pressure and obesity can speed this process up. Usually it is a blood clot that blocks the artery, causing a stroke.


Haemorrhagic strokes account for only about 13% of all strokes and happen due to bleeding. This is where a blood vessel in the brain bursts and bleeds. High blood pressure is the main cause for haemorrhagic strokes as it weakens the blood vessels, making them more likely to burst. Blood vessels can be weak due to an aneurysm or an arterio-venous malformation. An aneurysm is when the walls of a blood vessel have been weakened so the blood flowing through it causes the wall to bulge out, like a balloon. This makes this bit of the blood vessel more likely to burst than usual. An arterio-venous malformation occurs when the arteries (blood vessels taking blood away from the heart) and veins (blood vessels taking blood back to the heart) get tangled and aren’t connected in the way they usually are. This tangle of blood vessels is more likely to rupture and bleed, causing a haemorrhagic stroke.


When the blood supply to part of the brain is restricted and the brain cells aren’t getting the nutrients and oxygen that they need, they start to die. This can result in the person having long lasting disability or even dying.


There is another type of stroke called transient ischaemic attack. This is not as serious as a stroke but is a strong warning sign that the person is likely to have a stroke soon. The blood supply to the brain is temporarily interrupted but resolves, meaning the person will have symptoms of a stroke that then usually resolve. It can last anywhere from a few minutes to 24 hours.


What should you do if someone is having a stroke?

If you think someone is having a stroke, it is important to call 999 immediately and ask for an ambulance. The sooner someone who is having a stroke gets to hospital and gets treatment, the better their chances of survival and are less likely to be left with severe long-term consequences.


The symptoms of a stroke vary depending on what part of the brain is affected, as different parts of the brain are responsible for different functions of our body. The main symptoms of a stroke can be remembered using the word fast:

  • F: Face – the person may be unable to smile or part of the face may be dropped
  • A: Arms – the person may be unable to lift both arms and hold them up or they may have weakness or numbness on one side
  • S: Speech – the person may have slurred speech or not be able to talk at all
  • T: Time to call 999 if you notice any of these symptoms


These aren’t the only symptoms of a stroke, here are some others to look out for:

  • Sudden loss or blurring of vision
  • Dizziness or confusion
  • Problems with balance and coordination
  • Sudden very severe headache

What happens once someone who is having a stroke gets to hospital?

Once someone gets to hospital, it is important that the doctors determine what type of stroke the person is having by doing a brain scan. 


If it is an ischaemic stroke, “clot-busting” medication should be given within 4 and a half hours to break down blood clots and restore blood flow to the affected part of the brain. A brain scan must be done before giving this medication – if clot busting medication is given to a person with a haemorrhagic stroke, this will make the bleeding much worse. For some ischaemic strokes, surgery may be required to physically remove blood clots from the brain.


If the stroke is haemorrhagic some people may need surgery to remove blood from the brain and repair the bleeding blood vessel. If bleeding is ongoing, blood pressure lowering medications may help to reduce the bleeding.


Rehabilitation is often needed for those who survive a stroke. A stroke can leave a person with long-lasting disability and rehabilitation may be needed in order to help them to relearn skills or build up functions that they have lost as a result of the stroke. This may be physical therapy to relearn how to walk or someone may need to learn to talk again. The support a person needs depends on which area of the brain the stroke affected and how severe this was.


When a person is in recovery, they may be offered some medications to prevent stroke happening again in the future. Someone who has had an ischaemic stroke may take an anticoagulant to reduce the chance of blood clots forming again in the future. They are also likely to take medications to lower their blood pressure and cholesterol.


Prevention of another stroke is essential. People can reduce their risk of stroke but stopping smoking, not drinking alcohol in excess, exercising regularly and eating healthily all help to reduce risk of stroke.