A transient ischaemic attack (TIA) or "mini stroke" is caused by a temporary disruption in the blood supply to part of the brain.
The disruption in blood supply results in a lack of oxygen to the brain. This can cause sudden symptoms similar to those of a stroke, such as speech and visual disturbance, and numbness or weakness in the face, arms and legs.
However, a TIA does not last as long as a stroke. The effects often only last for a few minutes or hours and fully resolve within 24 hours.
Signs and symptoms
The main symptoms of a TIA can be remembered with the word FAST: Face-Arms-Speech-Time.
Face – the face may have dropped on one side, the person may not be able to smile, or their mouth or eye may have dropped.
Arms – the person with suspected stroke may not be able to lift both arms and keep them there because of arm weakness or numbness in one arm.
Speech – their speech may be slurred or garbled, or the person may not be able to talk at all, despite appearing to be awake.
Time – it is time to dial 999 immediately if you see any of these signs or symptoms.
Seeking medical advice
In the early stages of a TIA, it's not possible to tell whether you are having a TIA or a full stroke, so it's important to phone 999 immediately and ask for an ambulance.
Even if the symptoms disappear while you are waiting for the ambulance to arrive, an assessment in hospital should still be carried out.
A TIA is a warning that you are at risk of having a full stroke in the near future, and an assessment can help doctors to determine the best way to reduce the chances of this happening.
If you think you may have had a TIA previously, but the symptoms have since passed and you didn't seek medical advice at the time, you should make an urgent appointment with your GP so they can determine whether to refer you for a hospital assessment.
What causes TIAs?
During a TIA, one of the blood vessels that supply your brain with oxygen-rich blood becomes blocked.
This blockage is usually caused by a blood clot that has formed elsewhere in your body and travelled to the blood vessels supplying the brain, although it can also be caused by pieces of fatty material or air bubbles.
Certain things can increase your chances of having a TIA, including:
having high blood pressure (hypertension)
having high cholesterol levels
regularly drinking an excessive amount of alcohol
having atrial fibrillation (a type of irregular heartbeat)
People over 60 years of age, and people of Asian, African or Caribbean descent are also at a higher risk of having a TIA.
How TIAs are treated
Although the symptoms of a TIA resolve in a few minutes or hours, you will need treatment to help prevent another TIA or a full stroke happening in the future.
Your treatment will depend on your individual circumstances, such as your age and medical history.
You are likely to be given advice about lifestyle changes you can make to reduce your stroke risk (see below), in addition to being offered medication to treat the underlying cause of your TIA.
In some cases, surgery may be needed to unblock the carotid arteries (the main blood vessels that supply the brain with blood).
A TIA is often a sign that another one may follow and you are at a high risk of having a full, life-threatening stroke in the near future.
Regardless of whether or not you have had a TIA or stroke in the past, there are a number of ways you can lower your risk of having either in the future. These include:
maintaining a healthy weight
taking regular exercise
limiting your alcohol consumption
Symptoms of a transient ischaemic attack
The symptoms of a transient ischaemic attack (TIA) are the same as those of a stroke, but unlike a stroke they only last for a few minutes or hours.
Recognising the signs of a TIA
Like a stroke, the signs and symptoms of a TIA usually begin suddenly.
The main symptoms can be remembered with the word FAST: Face-Arms-Speech-Time.
Face – the face may have dropped on one side, the person may not be able to smile, or their mouth or eye may have drooped.
Arms – the person with suspected stroke may not be able to lift both arms and keep them there, because of arm weakness or numbness in one arm.
Speech – their speech may be slurred or garbled, or the person may not be able to talk at all, despite appearing to be awake.
Time – it's time to dial 999 immediately if you notice any of these signs or symptoms.
It's important for everyone to be aware of these signs and symptoms. If you live with or care for somebody in a high-risk group, such as an elderly person or someone with diabetes or high blood pressure, being aware of the symptoms is even more important.
Other possible symptoms
Symptoms in the FAST test identify most strokes and TIAs, but they can occasionally cause different symptoms that typically appear suddenly (usually over a few seconds).
Other signs and symptoms may include:
complete paralysis of one side of the body
sudden loss or blurring of vision
difficulty understanding what others are saying
problems with balance and co-ordination
difficulty swallowing (dysphagia)
However, there may be other causes for these symptoms.
Seeking medical advice
In the early stages of a TIA, it's not possible to tell whether you are having a TIA or a full stroke, so it's important to phone 999 immediately and ask for an ambulance if you or someone else are showing symptoms.
Even if the symptoms disappear while you are waiting for the ambulance to arrive, an assessment in a hospital should still be carried out.
A TIA is a warning that you are at risk of having a full stroke in the near future, and an assessment can help doctors determine the best way to reduce the chances of this happening.
If you think you may have had a TIA previously, but the symptoms have since passed and you didn't seek medical advice at the time, you should make an urgent appointment with your GP so they can refer you for a hospital assessment, if appropriate.
Causes of a transient ischaemic attack
Transient ischaemic attacks (TIAs) occur when one of the blood vessels that supply your brain with oxygen-rich blood becomes blocked.
This interruption in the flow of blood to the brain means that the brain cannot carry out some of its normal functions properly, leading to symptoms such as slurred speech and weakness.
In TIAs, the blockage quickly resolves and your brain's blood supply returns to normal before there's any significant damage. In a full stroke, the blood flow to your brain is disrupted for much longer, leading to more severe damage to the brain and longer-term problems.
The blockage in the blood vessels responsible for most TIAs is usually caused by a blood clot that has formed elsewhere in your body and travelled to the blood vessels supplying the brain, although it can also be caused by pieces of fatty material or air bubbles.
In very rare cases, TIAs can be caused by a small amount of bleeding in the brain known as a haemorrhage.
Blood clots that cause TIAs typically form in areas where arteries have been narrowed or blocked over time by the build-up of fatty deposits known as plaques. These plaques are formed during a process called atherosclerosis.
As you get older, the arteries can become narrower naturally, but certain things can dangerously accelerate the process. These include:
high blood pressure (hypertension)
high cholesterol levels
excessive alcohol consumption
A type of irregular heartbeat called atrial fibrillation can also cause TIAs. It can lead to the formation of blood clots that escape from the heart and become lodged in the blood vessels supplying the brain.
Who's most at risk?
Certain things can increase your chances of having a TIA. Some of these factors are changeable – such as your lifestyle.
Some of the main risk factors for TIA are:
age – although TIAs can occur at any age (including in children and young adults), they are most common in people over 60
ethnicity – people of south Asian, African or Caribbean descent have a higher TIA risk, partly because rates of high blood pressure are higher in these groups
medical history – as well as the conditions mentioned above, other health conditions such as diabetes can increase your risk of having a TIA
weight and diet – your risk of having a TIA is higher if you are overweight and/or have an unhealthy diet high in fat and salt
smoking and alcohol – smoking and/or regularly drinking excessive amounts of alcohol can increase your TIA risk
Tackling the things you can change will help to lower your risk of having a TIA, or reduce your chances or having a full stroke in the future.
Diagnosing a transient ischaemic attack
It's important to be assessed by a healthcare professional as soon as possible if you think you have had a transient ischaemic attack (TIA).
After an initial assessment of your symptoms, you may be referred to a specialist for further tests to help determine the cause of the TIA.
A TIA is a warning sign that you are at risk of having a full stroke in the near future, and a detailed assessment can help your doctor decide the best way to reduce this risk.
TIAs are often over very quickly, so you may not have any symptoms by the time you see a doctor.
You will be asked about the symptoms you experienced during the TIA and how long they lasted. This will help to rule out other conditions that may have caused your symptoms.
Even if you no longer have symptoms, a neurological examination may still be needed. This involves simple tasks designed to check your strength, sensation and co-ordination skills.
Referral to a specialist
If a TIA is suspected, you will be referred to a specialist for further tests. If you are at a particularly high risk of having a stroke or another TIA in the near future, you should be seen within 24 hours. People at a lower risk should be seen within seven days.
You will normally be offered aspirin to take while you are waiting for specialist assessment, as this can help to reduce your risk of having a stroke or another TIA in the meantime.
It is likely that you will be referred to a neurologist (a doctor who specialises in conditions that affect the brain and spine), or a consultant who specialises in strokes. This may be in a specialist stroke or TIA clinic.
Several tests may be carried out to confirm a TIA and look for underlying problems that may have caused it. Some of these tests are described below.
Blood pressure tests
Your blood pressure will be checked, because high blood pressure (hypertension) can lead to TIAs.
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 a number of electrodes (small, sticky patches) attached to your skin.
An ECG can detect abnormal heart rhythms, which may be a sign of conditions such as atrial fibrillation (where your heart beats irregularly), which can increase your risk of TIAs.
A carotid ultrasound scan can show if there is 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 can be used to create an image of the inside of your body.
Brain scans are not always necessary if you have had a TIA. They are normally only carried out if it's not clear which part of your brain was affected.
A magnetic resonance imaging (MRI) scan will most often be carried out in these cases. This type of scan uses a strong magnetic field and radio waves to create an image of your brain.
Occasionally, a computerised tomography (CT) scan may be used 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.
Treating a transient ischaemic attack
Although the symptoms of a transient ischaemic attack (TIA) resolve in a few minutes or hours without any specific treatment, you will need treatment to help prevent another TIA or a full stroke occurring in the future.
A TIA is a warning sign that you are at a significantly increased risk of having a full stroke in the near future, with the highest risk in the days and weeks following the attack.
A stroke is a serious health condition that can cause permanent disability and can be fatal in some cases, but appropriate treatment following a TIA can help to reduce your risk of having one.
Your treatment will depend on your individual circumstances, such as your age and medical history. The healthcare team can discuss treatment options with you, and tell you about possible benefits and risks.
It’s likely that you will be advised about lifestyle changes you can make to reduce your stroke risk, in addition to being offered medication to treat the underlying cause of your TIA.
You may also need surgery as part of your treatment.
There are a number of lifestyle changes you can make that may help reduce your chances of having a stroke after a TIA.
eating a healthy diet – a low-fat, reduced salt, high-fibre diet is usually recommended, including plenty of fresh fruit and vegetables
exercising regularly – for most people, at least 150 minutes of moderate-intensity aerobic activity, such as cycling or fast walking, every week is recommended
stopping smoking – if you smoke, stopping may significantly reduce your risk of having a stroke in the future
cutting down on alcohol – you should aim not to exceed the recommended alcohol limits of three to four units a day for men and two to three units a day for women
In addition to lifestyle changes, most people who have had a TIA will need to take one or more daily medications indefinitely to help reduce their chances of having a stroke or another TIA.
Some of the main medications used are outlined below.
Platelets are blood cells that help blood to clot (thicken). If a blood vessel is damaged, platelets stick together to form a blood clot to prevent bleeding.
Antiplatelet medicines work by reducing the ability of the platelets to stick together and form clots. If you have had a TIA, it is likely that you will be offered antiplatelet medication.
Two common antiplatelets offered to people who have had a TIA are aspirin and clopidogrel. Aspirin may also sometimes be taken with another antiplatelet medicine called dipyridamole because this can be more effective than taking these medications separately.
The main side effects of antiplatelet medications include indigestion and an increased risk of bleeding – for example, you may bleed for longer if you cut yourself, and you may bruise easily.
Anticoagulant medicines can help to prevent blood clots by changing the chemical composition of the blood in a way that prevents clots.
They are usually offered to people who have had a TIA if the blood clot that caused your TIA originated in your heart. This is often due to a condition called atrial fibrillation, which causes your heart to beat irregularly.
Warfarin, rivaroxaban, dabigatran and apixaban are examples of anticoagulants offered to some people who have had a TIA.
A side effect of all anticoagulants is the risk of bleeding caused by the reduction in the blood's ability to clot. You may need regular blood tests while taking warfarin, so doctors can ensure your dose is not too high or too low.
Antihypertensives (blood pressure medication)
If you have high blood pressure (hypertension), you will be offered a type of medication called an antihypertensive to control it. This is because high blood pressure significantly increases your risk of having a TIA or stroke.
There are lots of different types of medicine that can help control your blood pressure, including:
angiotensin-converting enzyme (ACE) inhibitors
calcium channel blockers
Your doctor will advise you about which antihypertensive is the most suitable for you. Some people may be offered a combination of two or three different medications.
If you have high cholesterol, you will be advised to take a medicine known as a statin. Statins reduce the level of cholesterol in your blood by blocking an enzyme in the liver that produces cholesterol.
Statins may also help to reduce your risk of a stroke whatever your cholesterol level is, so you may be offered a statin even if your cholesterol level is not particularly high.
Examples of statins often offered to people who have had a TIA include atorvastatin, simvastatin and rosuvastatin.
In some cases, a surgical procedure called a carotid endarterectomy may be recommended after having a TIA.
A carotid endarterectomy is an operation that involves removing part of the lining of the carotid artery, plus any blockage that has built up in the artery.
The carotid arteries deliver blood to your brain. When fatty deposits build up inside the carotid arteries, they become hard and narrow, making it more difficult for blood to flow through them.
This is known as atherosclerosis and it can lead to TIAs and strokes if the blood supply to the brain becomes disrupted.
By unblocking the carotid arteries in people whose arteries are moderately or severely narrowed, a carotid endarterectomy can significantly reduce the risk of having a stroke or another TIA.
Driving after a TIA
Although a TIA shouldn't have any long-term impact on your daily activities, you must stop driving immediately.
If your doctor is happy that you have made a good recovery and there are no lasting effects after one month, you can start driving again.
You do not need to inform the DVLA, but you should contact your driving insurance company.
Preventing a transient ischaemic attack
The best way to help prevent a TIA is to eat a healthy diet, exercise regularly and avoid smoking and drinking too much alcohol.
These lifestyle changes can reduce your risk of problems such as atherosclerosis (where arteries become clogged up by fatty substances), high blood pressure and high cholesterol levels, all of which can lead to TIAs.
If you have already had a TIA, making these changes can help to reduce your risk of having a full stroke or another TIA in the future.
An unhealthy diet can increase your chances of having a TIA or stroke because it may lead to an increase in your blood pressure and cholesterol levels.
Therefore, a low-fat, high-fibre diet is usually recommended, including plenty of fresh fruit and vegetables (five portions a day) and whole grains.
Ensuring a balance in your diet is important. Don’t eat too much of any single food – particularly foods that are high in salt and processed foods.
You should limit the amount of salt you eat to no more than 6g (0.2oz) a day because too much salt will increase your blood pressure. 6g of salt is about one teaspoonful.
Combining a healthy diet with regular exercise is the best way to maintain a healthy weight, and regular exercise can also help lower your cholesterol level and keep your blood pressure at a healthy level.
For most people, at least 150 minutes (2 hours and 30 minutes) of moderate-intensity aerobic activity, such as cycling or fast walking, every week is recommended.
Smoking significantly increases your risk of having a TIA or stroke. This is because it narrows your arteries and makes your blood more likely to clot.
If you stop smoking, you can reduce your risk of having a TIA or stroke. Not smoking will also improve your general health and reduce your risk of developing other serious conditions, such as lung cancer and heart disease.
The Smoking Helpline can offer advice and encouragement to help you quit smoking. You can call 0300 123 1044, or visit Smokefree.
Cut down on alcohol
Excessive alcohol consumption can lead to weight gain, high blood pressure and trigger an irregular heartbeat (atrial fibrillation), all of which can increase your risk of having a TIA or stroke.
If you choose to drink alcohol, you should aim not to exceed the recommended limits. These are that:
men should not regularly drink more than three to four units of alcohol a day
women should not regularly drink more than two to three units a day
Managing underlying conditions
If you have been diagnosed with a condition that is known to increase your risk of TIAs and strokes – such as high cholesterol, high blood pressure, atrial fibrillation or diabetes – ensuring that the condition is well controlled is also important.
The lifestyle changes mentioned above can help to control these conditions to a large degree, but you may also need to take regular medication.
For more information, see:
treating high cholesterol
treating high blood pressure
treating atrial fibrillation
treating type 1 diabetes and treating type 2 diabetes