Types of stroke

Types of stroke: How the two types of stroke happen

A stroke can happen in two main ways. Either there is a blood clot or plaque that blocks a blood vessel in the brain or a blood vessel in the brain breaks or ruptures.

Blocked artery (causes an ischaemic stroke)

Strokes caused by a blood clot is called an ischaemic stroke. In everyday life, blood clotting is beneficial. When you are bleeding from a wound, blood clots work to slow and eventually stop the bleeding. In the case of stroke, however, blood clots are dangerous because they can block arteries and cut off blood flow.

About 4 out of every 5 strokes are ischaemic. There are two ways an ischaemic stroke can occur.

Bleed in the brain (causes an Haemorrhagic stroke)

Strokes caused by a break in the wall of a blood vessel in the brain are called haemorrhagic strokes. This causes blood to leak into the brain, again stopping the delivery of oxygen and nutrients. Haemorrhagic stroke can be caused by a number of disorders which affect the blood vessels, including long-standing high blood pressure and cerebral aneurysms.

An aneurysm is a weak or thin spot on a blood vessel wall. The weak spots that cause aneurysms are usually present at birth. Aneurysms develop over a number of years and usually don’t cause detectable problems until they break.

About 1 in every 5 strokes is haemorrhagic. There are two types of haemorrhagic stroke.

Mini stroke

A transient ischaemic attack (TIA) is sometimes termed a minor stroke or “mini stroke”. When the signs of stroke are present but go away within 24 hours, the term TIA is used. The causes and symptoms of a transient ischaemic attack (TIA) are similar to those of a stroke.

TIA episodes usually last only a few minutes but may last for several hours. They generally disappear quickly and unfortunately, are often ignored. Just like a stroke, a TIA will require emergency treatment. About 1 in 5 people who have a TIA will have a major stroke within the next three months and a large part of the risk occurs in the first few days. TIA should never be ignored.

TIA’s should be regarded as a warning sign that the person is at risk of a stroke and should be investigated promptly.

It is important that if stroke symptoms occur the person sees a doctor promptly, even if the signs go away and you feel completely better. The doctor will try to find the underlying cause of the TIA and then organise treatment to lower your risk of another transient ischemic attack or stroke.