What Is A Transient Ischaemic Attack?

Overview

A transient ischaemic attack (TIA) is a brief stroke-like attack that resolves within minutes to hours and requires immediate medical attention to distinguish from a traditional stroke. There is a disruption in the blood supply to the brain and thus a lack of oxygen. The only difference is the level to which the effects last. In TIAs, the effects fully resolve within 24 hours.

TIAs can serve as warning signs, pointing towards the beginning of more serious conditions and the need for starting prophylactic treatment and a lifestyle change. These changes might include maintaining a healthy weight, eating a healthy diet, limiting alcohol, and quitting smoking. Therefore, people need a multi-modal treatment approach to prevent another episode or a full stroke from happening in the future. Treatment is tailor-made for individuals, while some people need conservative management, others may have a need for pharmacotherapy with or without surgical intervention.

Causes of transient ischaemic attacks

A TIA occurs when one of the blood vessels that supply oxygenated blood to a part of your brain gets blocked. 

This is different from a full-blown stroke in the percentage of the blockage. Wherein, a full stroke, the vessel is completely blocked which often leads to irreversible damage. In contrast, TIAs result in a smaller percentage of vessel blockage and so the amount of oxygenated blood reaching the brain varies but is not cut off completely.

The most common cause of TIAs is blood clots. Blood clots can either form within the brain or somewhere else in the body. When they form in other parts of the body, they then move to a site that can get blocked, these clots are called emboli. Rarer cases of TIAs are when there is a small tear in the vessel wall, and this leads to bleeding.^1,2

With age, the narrowing of arteries is commonly seen and certain factors such as the following  can speed up this process: 

• Smoking
• High blood pressure (hypertension)
• Obesity
• High cholesterol
• Diabetes
• Excessive alcohol

Apart from these factors, another common condition that can also lead to a TIA or stroke, is an irregular heartbeat. This can lead to a clot, that forms near the valves of the heart, which can dislodge and make its way up to the carotid arteries and then cause a blockage.²

Signs and symptoms of transient ischaemic attack

The main symptoms of a transient ischaemic attack can be remembered with the acronym  F.A.S.T.:^1,2

1. F - Face: there may be a droop on one side of the face making it difficult to smile or lift your eyebrows
2. A - Arms: you may not be able to lift one arm, this usually presents on the opposite side to the side of the face that is affected
3. S - Speech: your speech may be slurred or distorted, or you might have a problem understanding what is being said
4. T - Time: this is of the essence, and you need to call your local emergency helpline number immediately if you experience any of these symptoms

Although rare, other signs and symptoms include muscle rigidity and spasticity, abnormal tongue movement, auditory dysfunction, and difficulty swallowing.²

Management and treatment for transient ischaemic attack

The main aim of management targets decreasing the risk of subsequent stroke or TIA. Therefore, management focuses on treating underlying causative agents which, over time, has led to the development of a polytherapeutic approach. These include a combination of:^2,3

• Diet: to eat a balanced diet, free of fats
• Smoking: to stop smoking and reduce the risk of vessel walls hardening
• Exercise: increased activity leads to the consumption of the body's fat sources for energy
• Blood “thinners”: these medications, that are commonly known as blood “thinners”, are used for up to 6 months or as long as required, especially in people who have rhythm problems of the heart
• Statins: these are medications that decrease the levels of cholesterol in your blood
• Antihypertensive therapy: medications that help manage your blood pressure in order for your vessels and heart to be able to continue functioning normally and not buckle under pressure

Sometimes, if the disease is quite severe and has progressed, a surgical procedure called a carotid endarterectomy may be required. This procedure entails removing part of the lining of the carotid artery along with any blockage inside the carotid artery. This is a decision that your consultant/ specialist will make and is usually reserved for more severe cases and therefore, is not implemented for everyone.^2,3

Diagnosis

In order for your doctor to pinpoint the source of the problem, they will need to do extensive testing. Some of the tests will determine how much the attack has affected you, while other tests will attempt to find the cause of the blockage.

Usually, when one suffers such an attack they are immediately taken to the emergency department, and in this situation, a non-contrast CT scan (NCCT) is usually the first imaging study obtained. A doctor may also suggest magnetic resonance imaging (MRI) since it is a better modality for examining the severity of the TIA.

Along with the above, a person will have cardiological tests conducted. For this, an electrocardiogram (ECG) and an echocardiogram (ultrasound scan of the heart) will be performed.

Last but not least, blood tests will also be taken. This is often one of the first things done since the results can take some time to come back. The blood tests are to check your blood cell counts, for anaemia or other blood components that can contribute to clot formation (for example, increased lipid levels can lead to clots as well, and increased or decreased sugar levels can mimic TIAs, etc.).³

Risk factors

When addressing TIA, doctors counsel patients on non-modifiable (one doesn't have control over) and modifiable (one has control over) risk factors, some of which have been mentioned above. They are further discussed as follows ^2,4,5:

Non-modifiable risk factors:

1. Age: TIAs can affect people of all ages, however, they are most commonly seen in people over 55
2. Ethnicity: people of South Asian, African, and Caribbean descent have a higher risk, due to the risk of other health conditions like diabetes and high blood pressure
3. Medical history: additional health conditions, such as diabetes also increase risk further

Modifiable:

1. Smoking and alcohol: excessive indulgence in both increases risk and therefore needs to be stopped or reduced
2. Eating: being overweight or having a diet heavy in salts and fats further increases risk
3. Exercise: lack of physical activity also increases risk. The bare minimum recommended routine is two 30 minute sessions a week

Addressing the modifiable factors will help decrease the risk of developing plaques that lead to atherosclerosis (hardened plaques in the vessel wall) and other processes that lead to the formation of blood clots. Making these lifestyle changes will reduce future risks of TIAs or strokes.

FAQs

How can I prevent transient ischaemic attacks?

The best way to prevent transient ischaemic attacks is by looking after your cardiovascular health (i.e., heart and vessels) This means:^2,4,5

1. Stop using tobacco
2. Healthy eating
3. Physical activity
4. Maintaining a healthy weight 
5. Sleeping well and avoiding stress and tiredness
6. Blood pressure < 140/90mmHg
7. Cholesterol < 5mmol/L

How common are transient ischaemic attacks?

It is estimated that around 50 per 100,000 people each year have their first-ever episode of TIA. About 1 in 5 who have had a stroke in the past have had a TIA.⁶

When should I see a doctor?

You should go to your nearest emergency department immediately. If you are alone, call your local emergency number and request an ambulance as driving can make this a more dangerous situation.

If you think you might have had a TIA in the past but did not go to the hospital as the symptoms had passed, you should make an urgent appointment with your GP so that they can do a proper assessment.

Summary

Transient ischaemic attacks (TIAs) are short stroke-like attacks that occur as a result of a temporary blockage of blood flow to the brain. Although the attacks often resolve within minutes to hours, immediate medical attention is needed to determine if the event was a TIA or a traditional stroke. Symptoms of TIAs are similar to a stroke including a drooping face, weakness on one side of the body, and slurred speech. People who smoke or have conditions such as high blood pressure, diabetes, or obesity are more susceptible to having a TIA. Maintaining a healthy lifestyle may reduce your chances of experiencing a transient ischaemic attack.