Transient ischaemic attack (TIA)

TIAs happen when the blood supply to part of the brain is cut off for a short while.

In a TIA, the blockage clears before it can cause any lasting damage. A full stroke cuts off blood flow to the brain for much longer, which is why it causes more serious damage and longer-lasting problems.

Most TIAs are caused by a blood clot that has travelled through the bloodstream and lodged in one of the vessels supplying the brain.

An irregular heart rhythm called atrial fibrillation can also cause TIAs. It can allow blood clots to form in the heart, and these can break loose and become stuck in the blood vessels supplying the brain.

Who is at risk of a TIA?

Anyone can have a TIA or a stroke, but the following can make you more likely to have one:

• a poor diet
• not getting enough exercise
• being overweight or obese
• smoking
• drinking too much alcohol
• high cholesterol
• high blood pressure (hypertension)
• diabetes
• atrial fibrillation

You can make lifestyle changes to help bring some of these risk factors under control, and you may also need to take regular medication.

If you have an irregular heartbeat caused by atrial fibrillation, taking anticoagulant medication will help lower your risk of stroke.

If you have already had a stroke or a TIA, these steps matter even more, since you are more likely to have another stroke in the future.

Some risk factors cannot be changed, such as:

• age: people over 65 are most at risk of stroke, though it can happen at any age, including in children
• family history: if a close relative, such as a parent, grandparent, brother or sister, has had a stroke, your own risk is likely to be higher
• ethnicity: if you are South Asian, African or Caribbean, your risk of stroke is higher, partly because rates of diabetes and high blood pressure are higher in these groups
• your medical history: if you have already had a stroke, a TIA or a heart attack, your risk of stroke is higher

Diagnosing a TIA

You should have an assessment by a health professional as soon as possible if you think you’ve had a TIA.

Initial assessment

TIAs are often over very quickly, so you may not have any symptoms by the time you see a health professional.

You should tell the person assessing you about the symptoms you experienced and how long they lasted. This will help to rule out other conditions.

Even if you no longer have symptoms, you might still need a neurological examination. This involves simple tasks designed to check your strength, sensation and co-ordination skills.

If a TIA is suspected you should be started on medication to reduce the risk of a further TIA or stroke. The risk of another is highest in the days after a TIA or stroke so it’s important to start this medication as soon as you are advised to.

Referral to a specialist

If a TIA is suspected, you’ll see a specialist for further tests as soon as possible.

It’s important that you attend for this assessment as soon as it’s available. Seeing you urgently means you can receive appropriate treatment to prevent a further TIA or stroke.

It’s likely you’ll see a doctor who specialises in strokes.

Tests

You might have some tests to rule out other causes of your symptoms and to help identify the underlying cause of your TIA.

You might need blood tests to determine whether you have high cholesterol, and to check if you have diabetes.

An electrocardiogram (ECG) measures your heart’s electrical activity using electrodes (small, sticky patches) on your skin.

An ECG can detect abnormal heart rhythms, which may be a sign of conditions like atrial fibrillation (where your heart beats irregularly).

A carotid ultrasound scan can show if there’s narrowing or blockages in the neck arteries leading to your brain.

A small probe (transducer) sends high-frequency sound waves into your body. When these sound waves bounce back, they create an image of the inside of your body.

Brain scans are not always necessary if you’ve had a TIA.

You might have a magnetic resonance imaging (MRI) scan. This scan uses a strong magnetic field and radio waves to create an image of your brain.

You might have a computerised tomography (CT) scan if an MRI scan is not suitable for you. This type of scan uses a series of X-rays to produce an image of the inside of brain.

After a TIA, the symptoms go away on their own, but you'll still need treatment, because it lowers the chance of another TIA or a full stroke happening later.

Getting the right treatment after a TIA can meaningfully cut down that risk.

Your doctor will talk you through lifestyle changes that help protect you from a stroke, and will prescribe medication aimed at whatever caused your TIA in the first place. In some cases, surgery may also be part of the plan.

Lifestyle changes that can lower your chances of a stroke after a TIA include:

• eating well, generally a diet low in fat and salt, high in fibre, with plenty of fresh fruit, vegetables and whole grains
• staying physically active, since this helps bring down cholesterol and keep blood pressure at a healthy level
• quitting smoking, if you smoke
• cutting back on alcohol

Most people who have had a TIA end up taking medication to reduce their chances of a stroke or another TIA.

In the days right after a TIA, the main goal is to bring down stroke risk as quickly as possible, so doctors usually recommend a combination of treatments. These may include:

• antiplatelet medicines such as aspirin and clopidogrel
• anticoagulants such as apixaban, edoxaban, rivaroxaban, dabigatran or warfarin
• medication to lower blood pressure (antihypertensives)
• statins, to bring down cholesterol

Antiplatelet medication needs to start right away. The other medicines may be added later, and are usually needed for the long term.

If a blockage is found, your doctor may recommend a carotid endarterectomy, a procedure to remove part of the lining of the carotid artery along with any blockage there. Clearing the artery this way can lower the risk of a stroke or another TIA happening.