A stroke happens when the blood supply to part of the brain is interrupted in some way. 

If brain cells lose their supply of oxygen from the blood, they will be damaged or will die. 

The symptoms of a stroke depend on the part of the brain affected and the extent of the damage. 

So, no two strokes are the same and recovery is different from person to person. 

How does a stroke happen? 

Most strokes occur when a blood clot blocks one of the arteries which carry blood to the brain. 

This type of stroke is referred to as an ischaemic stroke, meaning there is not enough flow of blood to the brain. 

The blood clot can either originate in one of the main arteries leading to the brain, or develop elsewhere in the body and get transported to the brain in the bloodstream. 

Some strokes are caused by bleeding within or around the brain from a burst blood vessel. 

This type of stroke is called a haemorrhagic stroke, haemorrhage is the medical term for bleeding. 

In an intracerebral haemorrhage, the bleeding occurs inside the brain itself. 

A subarachnoid haemorrhage is when a burst blood vessel bleeds into the space surrounding the brain. 

The blood presses on the brain, damaging its delicate tissue. Meanwhile, other brain cells are starved of blood and are damaged. 

What are the symptoms of a stroke? 

The symptoms of a stroke usually come on suddenly, and can include: 

• Weakness and numbness of the face, arm or leg usually on one side of the body 
• Problems with balance and coordination 
• Communication problems in talking or understanding what others are saying 
• Difficulty swallowing 
• Sudden blurred vision or loss of sight 
• Severe headache 

Act FAST 

A stroke is a medical EMERGENCY. If you see the signs of a stroke act quickly and call 999. Early treatment saves lives and increases the chance of making a better recovery. 

Northern Ireland Chest Heart & Stroke supports the FAST campaign.

Facial weakness

Can the person smile? 

Has their mouth or eye drooped? 

Arm weakness

Can the person raise both arms? 

Is one arm weak? 

Speech problems

Can the person speak clearly and understand what you say? 

Time to call 999

If the person has failed any of these tests call 999 immediately