Common symptoms of a stroke

The first signs that someone has had a stroke are very sudden. Symptoms include:

Symptoms of stroke

numbness, weakness or paralysis on one side of the body (signs of this may be a drooping arm, leg or lower eyelid, or a dribbling mouth);
slurred speech or difficulty finding words or understanding speech;
sudden blurred vision or loss of sight;
confusion or unsteadiness; and
a severe headache.

Use the Face–Arm–Speech Test (FAST)

Three simple checks can help you recognise whether someone has had a stroke or mini-stroke (transient ischaemic attack – TIA).

F Facial weakness: Can the person smile? Has their mouth or an eye drooped?
A Arm weakness: Can the person raise both arms?
S Speech problems: Can the person speak clearly and understand what you say?
T Test all three signs.

If you see any of these signs, call 999 immediately.

Causes of stroke

There are two main causes of stroke

An illustration of the type of blockage that can cause an ischaemic stroke.

The most common type of stroke is a blockage. This is called an ischaemic stroke, which happens when a clot blocks an artery that carries blood to the brain. It may be caused by:

a cerebral thrombosis, when a blood clot (thrombus) forms in a main artery to the brain;

a cerebral embolism, when a blockage caused by a blood clot, air bubble or fat globule (embolism) forms in a blood vessel somewhere else in the body and is carried in the bloodstream to the brain; or

a blockage in the tiny blood vessels deep within the brain (lacunar stroke).

Brain haemorrhage

The second type of stroke is a bleed, when a blood vessel bursts, causing bleeding (haemorrhage) into the brain. This is called a haemorrhagic stroke. It may be caused by:

an intracerebral haemorrhage, when a blood vessel bursts within the brain; or

a subarachnoid haemorrhage, when a blood vessel on the surface of the brain bleeds into the area between the brain and the skull (subarachnoid space).