When you have a TIA, a clot blocks the blood supply in your brain for a short time.

Causes of TIA

Clots that cause a TIA can happen for different reasons.

  • One type of clot is caused by a build-up of fatty deposits in the blood vessels around your body, known as atherosclerosis.
  • Another type of clot is due to heart conditions such as atrial fibrillation (a type of irregular heartbeat). This can lead to a clot forming in the heart and travelling to the brain.
  • Damage to the arteries in the neck, known as arterial dissection, can also cause clots.
  • Small vessel disease is a condition where the tiny blood vessels deep inside your brain get damaged. This can also lead to clots forming and causing a TIA or stroke.

Risk factors for TIA

There are certain things which can make you more likely to have a TIA or a stroke. These are known as risk factors.

The risk factors for TIA are the same as for ischaemic stroke. Things that can make you more likely to have a stroke include your age, certain health conditions, your lifestyle, ethnicity, and family history of stroke.

You cannot change some risk factors, like your family history, but you can change others, like your lifestyle.

You can read more about stroke risk factors. Our section on Managing Risk has more information on making healthy lifestyle changes, such as being more active and cutting down on alcohol.

Health conditions linked to TIA and stroke

At your TIA appointment, you'll be tested for health conditions linked to stroke. Some people only find out they have a health condition after a TIA or stroke.

You may need to take long-term medication to help reduce your stroke risk. By following treatments and advice, you can help reduce your risk of another TIA or stroke.

High blood pressure

High blood pressure is the biggest single risk factor for TIA and stroke. It plays a part in around half of all strokes.

Atrial fibrillation (AF)

Atrial fibrillation (AF) is a heart condition that causes an irregular or abnormally fast heartbeat. It means the heart does not always empty itself of blood at each beat. A clot can form in the heart and travel to the brain, causing a stroke.

Diabetes

Diabetes causes high levels of sugar in your blood. Over time, this damages the blood vessels, which can lead to clots forming.

High cholesterol

Cholesterol is a vital substance in our bodies. But if there is too much cholesterol in your blood, it can clog up the arteries with fatty deposits, leading to a clot forming.

TIA of unknown cause

Sometimes, doctors cannot find out exactly what caused a TIA. You will be checked for the main risk factors for stroke such as high blood pressure.

Even if the cause of a TIA is not found, you will probably be given the same treatment used for any TIA, along with advice on reducing your risk of stroke, including healthy lifestyle changes.

Read ‘How to reduce your risk of stroke after a TIA’ for more information.

More information about TIA
Transient ischaemic attack (TIA)
With a transient ischaemic attack (TIA or mini-stroke), you get stroke symptoms because a clot is blocking the blood supply in your brain. When the clot moves away, the stroke symptoms stop.
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TIA diagnosis and treatment
Learn how a TIA is diagnosed, how health professionals will assess symptoms, and what tests may be used. As well as what treatment options may be offered.
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How to reduce your risk of a stroke after a TIA
Steps everyone can take that can help reduce the risk of a stroke after a TIA. By looking after your health, you can give yourself the best possible chance of staying well.
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Effects of TIA
TIA can have some long-term effects. This page looks at what you can do to get help with them and find more support for your well-being.
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