Transient ischaemic attack (TIA)

A transient ischaemic attack (TIA), or ‘mini-stroke’, is a temporary fall in the blood supply to part of the brain resulting in a lack of oxygen.

Introduction
Symptoms of a transient ischaemic attack
Causes of a transient ischaemic attack
Diagnosing a transient ischaemic attack
Treating a transient ischaemic attack
Preventing a transient ischaemic attack

Introduction

A transient ischaemic attack (TIA), or ‘mini-stroke’, is caused by a temporary fall in the blood supply to part of the brain which results in a lack of oxygen to the brain. This can cause symptoms that are similar to a stroke, although they dont last as long. TIA takes only a few minutes and is usually resolved within 24 hours.

The main signs and symptoms of a TIA can be remembered by the word FAST:

• Face: weakness or numbness in the face.
• Arms: weakness or numbness in the arms.
• Speech: slurred speech.
• Time: time to call 999 immediately if any one of these signs is present.

If signs and symptoms last longer than 24 hours, it is regarded as a full stroke.

How common are TIAs?

It’s difficult to know how common TIAs are. Many people who have TIA symptoms don’t seek medical attention.

A TIA is a medical emergency

If you have the symptoms of a TIA (see Symptoms, above) you must seek urgent medical attention as soon as possible. TIAs are a warning sign that further TIAs, or a full stroke, may occur soon.

Without treatment, there is a one in five chance that you will have a full stroke within four weeks of having a TIA. A stroke is a serious condition, and can cause permanent disability. In some cases, strokes can be fatal. Approximately 11% of all deaths in the UK are caused by strokes.

As TIAs can have serious health implications, it is important that they are always investigated so that appropriate treatment can be given as soon as possible. With treatment, the risk of a further TIA, or a full stroke, is greatly reduced (see Treatment, above).

Symptoms of a transient ischaemic attack

Recognising the signs and symptoms of a TIA

You can remember the main symptoms of a transient ischaemic attack (TIA) by remembering the word FAST: Face-Arms-Speech-Time.

• Face. The face may have fallen on one side, the person may not be able to smile, their mouth or eye may droop.
• Arms. The person with suspected mini-stroke may not be able to raise both arms and keep them there because of arm weakness or numbness.
• Speech. There may be slurred speech.
• Time. It is time to dial 999 immediately if you see one or more of these signs or symptoms.

It is 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 someone who is elderly or has diabetes or high blood pressure, being aware of these is even more important.

Other signs and symptoms include:

• dizziness,
• communication problems, difficulty talking and difficulty understanding what others are saying,
• problems with balance and coordination,
• difficulty swallowing,
• numbness/weakness resulting in complete paralysis of one side of the body, and
• loss of consciousness (in severe cases).

If you, or someone else, displays three or more of the above signs and symptoms, you should seek immediate medical attention because you (or they) may be having a TIA or a stroke. Call 999 and ask for an ambulance.

If you, or someone you know, is having a full stroke, the symptoms will persist for more than 24 hours. However, you should never wait to see if the symptoms disappear. Seek medical assistance immediately.

Other symptoms of mini-strokes (TIAs)

The symptoms of a TIA are temporary (transient) and should clear up within 24 hours of the attack occurring. The duration of symptoms may vary, but they often disappear within two to 15 minutes.

Different parts of your brain control different parts of your body, so the symptoms that you will experience after having a TIA will depend on what part of your brain is affected.

A TIA can sometimes occur before a full stroke, which can cause serious and permanent damage.

Therefore, the sooner you seek medical attention, the less likely it is that you, or the person who has had a TIA, will experience another TIA or a stroke.

Causes of a transient ischaemic attack

Blocked blood vessels interrupt the brain’s blood supply

Blood is supplied to your brain by two main blood vessels called the carotid arteries. These arteries branch off into a series of smaller blood vessels which help provide blood to every part of your brain.

During a transient ischaemic attack (TIA), one of the small blood vessels that supply your brain with oxygen-rich blood becomes clogged, or blocked.

When a blockage in a blood vessel occurs, the blood flow to your brain is disrupted. With a TIA, the disruption passes quickly and the blood supply to your brain soon returns to normal. With a full stroke, the blood flow to your brain is disrupted for much longer. Without a constant supply of blood, your brain cells start to die.

The blockage in your blood vessels is usually caused by stenosis (narrowing of the arteries), or as a result of the formation of a blood clot.

Atherosclerosis

Atherosclerosis is a common condition that causes stenosis. It occurs when plaque (fatty deposits) develop on the inner lining of your blood vessels. This can cause your blood vessels to become hardened, thickened, and less elastic, making it more difficult for blood to flow through them.

Blood clots

As well as being caused by stenosis, a TIA can also occur as a result of a blood clot, forming in a blood vessel, which blocks the blood supply to your brain.

A blood clot may be caused by a number of factors some of which are listed below.

• Heart conditions, such as atrial fibrillation, which causes your heartbeat to be irregular, or congestive heart muscle disease which is where your heart does not pump blood effectively.
• Blood conditions, such as leukaemia (cancer of the blood cells), sickle cell anaemia (an inherited blood disorder), high levels of fat in your blood (hyperlipidaemia), abnormally thickened blood (polycythaemia), or overproduction of platelets in your blood (thrombocyaemia).
• Infections, such as phlebitis, which inflames the blood vessel walls and encourages the formation of blood clots.

Sometimes, a TIA can occur when a blood clot from a blood vessel in another part of your body moves into one of the arteries that supply blood to your brain. This is known as an embolism.

Haemorrhage

In very rare cases, a TIA can be caused by a small amount of bleeding in the brain. This is known as a haemorrhage.

Risk factors

There are a number of factors that can increase your chances of having a TIA. Some factors, such as age and gender, are fixed (unchangeable). However, others can be changed, and by making a number of alterations to your lifestyle, you may be able to reduce your risk of having a TIA. See the ‘prevention’ section for more information about how you can do this.

Fixed risk factors

Some of the fixed risk factors associated with TIA are outlined below.

Age

As you get older, your arteries begin to harden and narrow, increasing your risk of having a TIA. Most TIAs occur in people who are over 60 years of age.

Gender

Men have a greater risk of having a TIA compared with pre-menopausal women. However, the risk of TIA and stroke increases in postmenopausal women.

It is not fully understood why a woman’s risk of having a TIA increases after the menopause. However, the female hormones oestrogen and progesterone are thought to play a role as they can affect the elasticity of your blood vessels. In menopausal women, oestrogen and progesterone levels fall, which may cause the blood vessels to become harder and less elastic.

Ethnicity

African and south Asian people have an increased risk of developing high blood pressure and diabetes, and therefore also have a greater risk of having a TIA.

Family history

If you have a history of stroke, or TIA, in your family, your risk of having a TIA is increased. However, the risk is relatively small, and having family members who have had a TIA will not necessarily mean that you will have one.

Lifestyle risk factors

High blood pressure

High blood pressure, or hypertension, is one of the biggest risk factors that is associated with TIA. Having high blood pressure puts extra strain on your blood vessels in your body, causing them to become narrowed or clogged.

Weight and diet

Eating a poor diet that is high in saturated fat increases your risk of developing atherosclerosis. If there is too much salt in your diet, it is likely that your blood pressure will be elevated which, like atherosclerosis, is a major risk factor for TIA. Being overweight also puts your heart under strain, and weakens your blood vessels.

Smoking

Smoking can double your risk of having a TIA, or stroke. This is because the harmful chemicals in cigarette smoke cause the lining in the arteries to thicken, making your blood more likely to clot.

Stopping smoking is therefore one of the main ways that you can help to prevent a TIA, or stroke occurring. See the ‘prevention’ section for more information about how to give up smoking.

Medical conditions

Some medical conditions, such as diabetes mellitus (type 1 diabetes) can increase your risk of having a TIA. This is because type1 diabetes causes a high level of glucose to be produced in the bloodstream, which increases your risk of developing atherosclerosis (the formation of fatty deposits in the blood vessels).

Diagnosing a transient ischaemic attack

If you, or someone you know, is displaying symptoms of a transient ischaemic attack (TIA) you should seek medical assistance immediately. This will help minimise the risk of a further TIA, or full stroke occurring.

Neurological examination

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

Your GP, or health professional, may still need to carry out a neurological examination, even if you feel that your symptoms have resolved. This will involve you carrying out a series of simple tasks to check skills, such as your co-ordination and memory.

When you are being assessed, the health professional will ask you in detail about the symptoms that you experienced during the TIA. For example, they will need to know how long the symptoms lasted for, and how they affected you. This will help them to rule out other conditions which may have caused your symptoms.

Referral

If your GP, or health professional, suspects that you have had a TIA, you should be referred for further testing.

You may either be referred to a neurologist (a doctor who specialises in treating conditions which affect the brain and spine), or a consultant who specialises in strokes. Some people may be referred to a specialist TIA clinic, which are available at some hospitals and GP clinics.

You should be referred to a specialist, or TIA clinic, within seven days of your TIA occurring. If you have experienced more than one TIA in the space of seven days, you should be seen immediately by a specialist.

Testing

Following a TIA, you may have a number of tests that are designed to check for any underlying factors, or conditions, which may have caused your mini-stroke. Some of the tests you may undergo are listed below.

Blood tests

If you have had a TIA, you might require a series of blood tests which may include:

• a blood pressure test – your blood pressure will be checked because high blood pressure (hypertension) is a major risk factor for TIA and stroke,
• a blood clotting test – your blood clotting ability will be tested to check how ‘thin’ your blood is and how likely it is to clot, and
• a cholesterol test – a serum cholesterol test may be used to check your cholesterol levels. If you have high cholesterol, you are at a greater risk of having a TIA, or stroke.

Tests and scans

Electrocardiogram (ECG)

An electrocardiogram (ECG) is a test that measures the electrical activity of your heart using a number of adhesive electrodes which are attached to your skin. An ECG can detect any abnormal heart rhythms, which may be a sign of conditions such as atrial fibrillation (see ‘causes’ section).

Echocardiogram

You may have an echocardiogram to check for various forms of heart disease.

Chest X-ray

You may have a chest X-ray to help rule out any other health conditions.

Computerised tomography (CT) scan

A computerised tomography (CT) scan uses a series of X-rays to produce an image of the inside of your body. It can be used to check for other factors which may have caused your TIA, such as a haemorrhage, or tumour.

Magnetic resonance imaging (MRI) scan

Like a CT scan, a magnetic resonance imaging (MRI) scan produces an image of the inside of your body but, instead of using X-rays, it uses a strong magnetic field and radio waves. An MRI scan may be able to give a more detailed image of the body than a CT scan.

Ultrasound

An ultrasound scan uses high frequency sound waves to produce an image of the inside of your body. You are most likely to have an ultrasound scan of the carotid arteries in your neck in order to see if they are narrowed, or blocked. This type of ultrasound scan is sometimes known as a Doppler scan, or a Duplex scan.

Treating a transient ischaemic attack

If you have had a transient ischaemic attack (TIA), you will need to have treatment to help prevent you from having another TIA, or a full stroke.

The treatment that you will require will depend on your individual circumstances, such as your age and your medical history. Your GP will be able to talk through the available treatment options with you, and will be able to make you aware of the benefits and risks which may be involved.

Further TIAs, or strokes, are primarily prevented using medication. However, there are also lifestyle changes that you can make which will help to reduce your risk of having a TIA. These are outlined in the ‘prevention’ section. Some people may also require surgery as part of their TIA treatment.

The medical and surgical treatments you may be offered following a TIA are outlined below.

Medication

Anti-platelet medication

Platelets are the cells in your blood which help it to clot. When a blood vessel is damaged, platelets stick together to form a blood clot in order to prevent bleeding. Anti-platelet 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 need to take anti-platelet medication.

The most commonly prescribed anti-platelet medicines for preventing a TIA are described below.

Aspirin and dipyridamole

Aspirin is the most commonly prescribed anti-platelet, and it is often taken in conjunction with another anti-platelet medicine called dipyridamole.

Aspirin and dipyridamole are often prescribed together because they are more effective at preventing TIA and stroke when they are used in combination compared to when they are taken separately.

Following a TIA, you will usually be prescribed aspirin and dipyridamole for two years. After this time, you may be able to stop taking dipyridamole and take a low-dose of aspirin instead. You may have to take low-dose aspirin indefinitely depending on what your GP feels is the best course of treatment for you.

Taking a daily, low-dose of aspirin is thought to cut your risk of having a TIA by 25%. It can also reduce your risk of having a heart attack.

Side effects of aspirin may include:

• irritation of your stomach,
• indigestion, and
• nausea.

Side effects of dipyridamole may include:

• headaches,
• dizziness,
• nausea, and
• diarrhoea.

Clopidogrel

Clopidogrel is another anti-platelet medicine which is normally only prescribed if:

• you experience severe side effects from taking aspirin,
• you have had a further TIA, despite taking aspirin, or
• you have arterial disease.

Side effects of clopidogrel may include:

• diarrhoea,
• abdominal pain,
• indigestion,
• bruising, and
• bleeding.

Anti-coagulant medication

Anti-coagulant medicines work by reducing the level of certain chemicals in your blood which are needed in order to help it clot.

You will normally only be prescribed an anti-coagulant medicine if the blood clot which caused your TIA came from your heart. This is often the result of a condition called atrial fibrillation (see the ‘causes’ section).

Warfarin

Warfarin is the anti-coagulant medicine that is used to help prevent further TIAs.

It is important that the dosage of warfarin that you receive is enough to ensure that the blood is ‘thinner’ (less able to clot), but not so thin that it causes problems such as internal bleeding.

Because having the correct dosage of warfarin is so important, your condition will be carefully monitored while you are taking the medication. You will need to have regular blood tests, known as international normalised ratio (INR) tests.

An INR test measures how long it takes your blood to clot. Your warfarin dosage may have to be adjusted following an INR test to ensure you are getting the right amount.

Bleeding is the most serious side effect of warfarin. If you notice any of the following symptoms when taking warfarin, you should seek medical attention immediately:

• passing blood in your urine, or faeces,
• passing black faeces,
• severe bruising,
• prolonged nosebleeds (lasting longer than 10 minutes),
• blood in your vomit,
• coughing up blood,
• unusual headaches, and
• in women, heavy, or increased bleeding during your period, or any other bleeding from your vagina.

High blood pressure medication

If you have high blood pressure (hypertension), you may have to take medication to help control it. This is because high blood pressure greatly increases your risk of having a TIA, or stroke (see ‘causes’ section).

There are lots of different types of medicine which can help manage your blood pressure. Your GP will advise you about which one is most suitable for you. In order to be effective, some people have to take a combination of two or three different blood pressure medicines.

Cholesterol medication

High cholesterol is another factor which may increase your risk of having a TIA. You can help to lower your cholesterol by making a number of lifestyle changes, such as eating a healthy, balanced diet. See the ‘prevention’ section for more information about making lifestyle changes.

If your cholesterol needs to be lowered using medication, you will normally be prescribed a type of medicine known as a statin. Statins help to reduce the production of cholesterol in the liver.

Surgery

Carotid endarterectomy

A carotid endarterectomy is an operation which involves removing part of the lining of the damaged carotid artery, plus any blockage that has built up in the artery.

The carotid arteries are responsible for delivering 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 (see the ‘causes’ section).

If you have atherosclerosis, you may need to have a carotid endarterectomy in order to help reduce your risk of having a further TIA, or stroke.

A carotid endarterectomy is not suitable for everyone with atherosclerosis. For example, if your arteries are almost completely blocked, a carotid endarterectomy is unlikely to be effective. If you only have a partial blockage in your carotid arteries, you may also be unsuitable for this type of surgery because your risk of experiencing a stroke during the procedure may outweigh the potential benefits of surgery.

A carotid endarterectomy is most suitable for people who have a moderate to severe blockage in their arteries.

If your arteries are 50-69% blocked, following a carotid endarterectomy, your risk of having a stroke is reduced by a third. If your arteries are 70% blocked, or more, following the procedure, your risk of having a stroke in the future is halved.

How is the operation performed?

A carotid endarterectomy is carried out in hospital, either under general, or local, anaesthetic. Your surgeon will advise you about which type of anaesthetic will be most suitable for you.

During the operation, your surgeon will make an incision (cut) in your neck and open up the blocked artery. They will then be able to remove the fatty deposits from the artery. If the damage to your artery is severe, your surgeon may need to replace part of the artery using a blood vessel from another part of your body. After the artery has been cleared, it can be stitched up.

The operation itself usually takes between 1-2 hours to perform. After the operation, you will usually be able to return home with 48 hours.

Preventing a transient ischaemic attack

A transient ischaemic attack (TIA) will often occur without warning. Having a TIA is a sign that another one may follow. And, further TIAs may have more serious effects, or develop into a full, life-threatening, stroke.

Whether or not you have previously had a TIA, or stroke, there are a number of ways that you can lower your risk of having a TIA, or stroke, in the future. These are outlined below.

Weight

If you are overweight, your risk of having a TIA, or stroke, is increased. Being overweight will also increase your risk of developing high blood pressure (hypertension), heart disease, and diabetes. Losing excess weight will reduce your chances of having a TIA, or stroke.

Exercise

Regular exercise can lower your blood pressure, helping to prevent many potentially life-threatening conditions including stroke, heart disease, and cancer. It is also an effective way of maintaining a healthy weight, and can help to combat stress and depression.

You should aim to do at least 30 minutes of exercise, five times a week..

Healthy eating

Eating a healthy, balanced diet will help you to lose any excess weight, and will also help keep your arteries healthy.

Make sure that you eat plenty of fruit and vegetables (at least five portions a day) because they are a great source of essential vitamins and minerals.

Fruit and vegetables also contain substances called anti-oxidants, which help to reduce the risk of stroke by protecting the walls of your blood vessels from damage.

Limit the amount of salt that you eat. You should not be eating more than 6g a day. Too much salt can increase your blood pressure, increasing your risk of TIA and stroke. Do not add salt toy your food and be aware that lots of processed foods include ‘hidden’ salts. Therefore, make sure that you always check the nutritional information on the label before buying food products.

Limiting the amount of saturated fats that you have in your diet will help to keep your cholesterol under control. Foods that are high in saturated fats include:

• meat pies,
• sausages and fatty cuts of meat,
• butter,
• ghee (a type of butter that is often used in Indian cooking),
• lard,
• cream,
• hard cheese,
• cakes and biscuits, and
• foods containing coconut, or palm, oil.

If you eat a lot of fatty foods, you are more at risk of your arteries becoming clogged up with the fatty deposits (plaques).

Alcohol

Drinking an excessive amount of alcohol may increase you risk of having TIA and a stroke. Therefore, you should make sure that you stay within the recommended limits of alcohol. These limits are:

• 2-3 units a day for women, and
• 3-4 units a day for men.

One unit of alcohol is equal to about half a pint of normal strength lager, cider, or bitter, a pub measure (25ml) of spirits, or a 50ml pub measure of fortified wine, such as sherry or port.

If you have had a TIA, you will not need to cut out alcohol altogether. Some studies have suggested that drinking a small amount of alcohol (within the recommended daily amount) may actually reduce your risk of having a TIA or stroke. This is because alcohol can thin the blood.

However, binge drinking should always be avoided. Drinking excessive amounts of alcohol is likely to increase your blood pressure, and the risk of a blood vessel bursting and causing bleeding into your brain. This, in turn, will increase your risk of having a TIA, or stroke.

Stop smoking

Smoking doubles your risk of having a stroke. This is because it narrows your arteries and makes your blood more likely to clot.

If you stop smoking, you can reduce the risk of you having a stroke by up to half. Not smoking will also improve your general health, and reduce your risk of developing other, serious conditions, such as lung cancer and heart disease.

You can get confidential guidance and advice about giving up smoking by calling the NHS smoking helpline free on 0800 022 4 332. Lines are open seven days a week, between 7am-11pm.

Regular cholesterol tests

It is a good idea to have regular cholesterol tests, particularly if you have high blood pressure (hypertension), or high cholesterol levels