Transient ischaemic attack

A transient ischaemic attack is a temporary disruption of blood flow to the brain that causes stroke-like symptoms lasting from a few minutes to hours. While the effects resolve without lasting damage, a TIA serves as a critical warning sign that a full stroke may follow, making immediate medical attention essential even after symptoms disappear.

Table of contents

• What is a transient ischaemic attack?
• Recognizing the symptoms
• What causes a TIA?
• Risk factors
• Why immediate medical attention is critical
• How TIAs are diagnosed
• Treatment and prevention
• Lifestyle changes to reduce risk

What is a transient ischaemic attack?

A transient ischaemic attack (TIA), sometimes called a “mini-stroke,” occurs when blood flow to part of the brain is temporarily blocked^[1]. This blockage is usually caused by a blood clot that forms elsewhere in the body and travels to the blood vessels supplying the brain, or by pieces of fatty material^[4].

The key difference between a TIA and a stroke is that a TIA stops on its own, typically within minutes to hours, and does not cause permanent brain damage^[3]. The disruption in blood supply results in a temporary lack of oxygen to the brain, which causes sudden symptoms similar to a stroke^[4].

The term “mini-stroke” is actually misleading. A TIA is not necessarily smaller or less serious than a stroke. The symptoms are identical to those of a stroke, and a TIA can affect large areas of the brain^[3]. Most importantly, having a TIA means you are at much higher risk of having a full stroke in the near future.

Recognizing the symptoms

The symptoms of a TIA appear suddenly and are the same as those of a stroke. You can remember the main warning signs using the word FAST^[4]:

• Face – the face may droop on one side, the person may not be able to smile, or their mouth or eye may have dropped
• Arms – the person may not be able to lift both arms and keep them raised because of weakness or numbness in one arm
• Speech – speech may be slurred or garbled, or the person may not be able to talk at all despite appearing awake; they may also have problems understanding what you’re saying to them
• Time – it’s time to call 999 immediately if you see any of these signs or symptoms

Other symptoms can include sudden weakness or paralysis (inability to move) on one side of the body, difficulty walking, loss of coordination or clumsiness, dizziness, confusion, vision changes including blindness in one or both eyes or double vision, difficulty swallowing, numbness or tingling on one side of the body, and severe headache^[1][3].

TIA symptoms typically last only a few minutes, though they can persist for up to 24 hours before fully resolving^[2][7]. However, even if symptoms disappear quickly, this does not mean the episode was unimportant.

What causes a TIA?

A TIA happens when one of the blood vessels that supply oxygen-rich blood to your brain becomes blocked^[4]. The blockage can occur in several ways:

A blood clot may form directly in the brain (thrombosis), or a fragment of a clot that formed elsewhere in the body may break free and travel through blood vessels until it becomes stuck in the brain (thromboembolism)^[3]. The blockage can also be caused by a narrowed blood vessel in the brain or leading to the brain^[6].

When the blockage is temporary and the blood clot dissolves or moves away on its own, blood flow is restored and the symptoms stop. This is what distinguishes a TIA from a full stroke, where the blockage persists and causes lasting brain damage^[2].

Risk factors

Certain health conditions and lifestyle factors increase the chances of having a TIA. The most significant risk factor is high blood pressure, also called hypertension^[3].

Other major risk factors include^[1][4][6]:

• Diabetes – a condition where blood sugar levels are too high
• High cholesterol levels
• Heart disease and atrial fibrillation – an irregular heartbeat
• Smoking
• Being overweight or obese
• Physical inactivity
• Regularly drinking excessive amounts of alcohol

The risk of TIA increases with age, particularly for people over 55 years old. Stroke rates double every 10 years after age 55^[2]. Men are more likely to have a TIA than women, and people of Asian, African, or Caribbean descent are at higher risk^[4].

If you have previously had a TIA or stroke, you are at increased risk of having another one^[2].

Why immediate medical attention is critical

A TIA is a medical emergency, even though the symptoms are temporary. You should call 999 (or your local emergency number) immediately if you or someone else experiences symptoms, even if they go away after a few minutes^[1][4].

There are several important reasons why urgent medical attention is essential. First, when symptoms first appear, there is no way to tell whether you are having a TIA or a full stroke. Both conditions have identical symptoms, and only medical assessment can determine which is occurring^[3].

Second, a TIA is a serious warning sign that you are at high risk of having a full stroke in the near future. About 1 in 3 people who have a TIA will eventually have a stroke, with about half occurring within a year after the TIA^[1]. The risk is highest in the first 48 hours following a TIA, with up to 10% of people having an actual stroke within a couple of days^[2][11].

Getting assessed quickly means healthcare professionals can identify what caused the TIA and start treatment to prevent a future stroke. Studies show that when patients receive urgent evaluation and treatment, up to 80% of strokes after TIA can be prevented^[5][11].

You should be referred to see a specialist within 24 hours of the onset of your symptoms^[4]. If you think you may have had a TIA previously but did not seek medical advice at the time, you should still make an urgent appointment with your doctor^[4].

How TIAs are diagnosed

Diagnosing a TIA can be challenging because symptoms may have completely resolved by the time you reach the hospital. The diagnosis is often based on your medical history and description of what happened^[6].

Your healthcare professional will perform a physical examination and a neurological examination, testing your vision, eye movements, speech and language, strength, reflexes, and sensory system^[8]. They may use a stethoscope to listen to the carotid artery in your neck. An abnormal whooshing sound called a bruit may indicate narrowed arteries^[6].

Several tests and scans are typically performed to find the cause of the TIA and assess your risk of stroke^[8]:

A head CT scan or brain MRI uses imaging technology to create detailed pictures of your brain. While a stroke will show changes on these scans, a TIA typically will not, as there is no permanent tissue damage^[6].

Blood vessel imaging may include a carotid ultrasound (also called carotid Doppler), which uses sound waves to create images of the carotid arteries in your neck. This test can show narrowing or blockages in these important blood vessels^[8]. Other imaging tests such as CT angiography or MR angiography may be performed to see which blood vessels are blocked or narrowed^[6].

An echocardiogram is an ultrasound of the heart that may be performed if your doctor thinks a blood clot from your heart may have caused the TIA^[6]. An electrocardiogram (ECG) and heart rhythm monitoring tests check for an irregular heartbeat such as atrial fibrillation^[6].

Blood tests will check for risk factors such as high blood pressure, high cholesterol, diabetes, and sometimes blood clotting disorders^[6].

Treatment and prevention

Although TIA symptoms resolve on their own without specific treatment, you will need ongoing treatment to help prevent another TIA or a full stroke from happening in the future^[9]. Treatment focuses on managing the underlying cause and reducing risk factors.

Most people who have had a TIA will need to take one or more medicines every day on a long-term basis^[9]:

Antiplatelet medicines help prevent blood clots by reducing the ability of platelets (blood cells that help blood clot) to stick together. You will likely be given low-dose aspirin straight after a TIA^[9]. Other antiplatelet medicines include clopidogrel or dipyridamole. Sometimes two antiplatelet medications are used together for a short time, then you continue with only one^[1].

Anticoagulants are medicines that change the chemical composition of your blood to prevent clots from forming. They are usually offered to people whose TIA was caused by a blood clot in the heart, often due to atrial fibrillation^[9]. Examples include warfarin, apixaban, dabigatran, and rivaroxaban. All anticoagulants carry a risk of bleeding as a side effect.

Blood pressure medicines will be prescribed if you have high blood pressure. There are several types available, and some people may need a combination of medicines^[9].

Statins are medicines that reduce cholesterol levels in the blood. You may be offered a statin even if your cholesterol level is not particularly high, as statins can help reduce your risk of stroke regardless of cholesterol levels^[9].

In some cases, surgery may be recommended. A carotid endarterectomy is an operation to remove part of the lining of the carotid arteries plus any blockage inside the arteries^[9]. This procedure may be recommended if you have significant narrowing (stenosis) of the carotid artery. For people with 70 to 99 percent stenosis, this surgery is recommended if the risks of the operation are low^[1].

Lifestyle changes to reduce risk

Making healthy lifestyle changes is one of the most important ways to reduce your risk of having a stroke after a TIA. These changes can significantly lower your chances of future problems^[4][9]:

Stop smoking. If you smoke, stopping can significantly reduce your risk of having a stroke in the future. Smoking narrows your arteries and makes your blood more likely to clot^[17].

Eat a healthy diet. A low-fat, reduced-salt, high-fiber diet is usually recommended, including plenty of fresh fruit and vegetables and whole grains^[9][17]. Limit the amount of salt you eat to no more than 6 grams a day, as too much salt will increase your blood pressure.

Exercise regularly. For most people, at least 150 minutes of moderate-intensity activity (such as cycling or fast walking) or 75 minutes of vigorous-intensity activity (such as running or swimming) every week is recommended, plus strength exercises on two days every week^[9][17].

Maintain a healthy weight. Being overweight or obese increases stroke risk. Combining a healthy diet with regular exercise is the best way to maintain a healthy weight^[17].

Limit alcohol consumption. Excessive alcohol can lead to weight gain, high blood pressure, and irregular heartbeat, all of which increase stroke risk. Men and women are advised not to drink more than 14 units a week on a regular basis^[17].

Manage underlying health conditions. It is important to control conditions such as diabetes, high blood pressure, high cholesterol, and atrial fibrillation through medication and lifestyle changes^[9].

Taking your prescribed medications is crucial for reducing stroke risk. Many of the conditions linked to stroke have few or no symptoms, so when you start taking medication, it may not have a noticeable effect on how you feel physically. However, these medications could significantly reduce your chance of having a stroke^[18].

By following treatment plans and making healthy lifestyle changes, you can actively reduce your risk of stroke. Your risk decreases over time following a TIA, so looking after your health gives you the best possible chance of staying well in the long term^[18].