Transient Ischemic Attack (TIA)

What a TIA is

A TIA happens when a clot or narrowed artery briefly cuts off blood to part of the brain, retina or spinal cord. Blood flow returns before brain tissue is permanently damaged, so symptoms fade completely.

Doctors now define a TIA as a temporary episode without evidence of infarction (tissue death) on brain imaging. If an MRI shows damage even though symptoms resolved, it is classed as a minor stroke. About one-third of people with classic TIA symptoms lasting more than an hour have a small stroke visible on MRI.

TIA vs stroke

You cannot tell a TIA from a stroke while symptoms are happening, so always call for emergency help.

TIA symptoms: BE FAST

Symptoms come on suddenly:

• Balance: sudden loss of balance or coordination.
• Eyes: sudden loss of vision in one eye, or double vision.
• Face: drooping of one side of the face.
• Arm: weakness or numbness in one arm or leg.
• Speech: slurred speech, difficulty finding words or understanding.
• Time: call 911 immediately.

Other symptoms include numbness on one side of the body and sudden confusion. Temporary blindness in one eye, described as a shade coming down, is called amaurosis fugax and often signals a narrowed carotid artery.

Symptoms less likely to be a TIA on their own include dizziness without other signs, fainting, gradual spreading tingling (typical of migraine aura), confusion alone and memory lapses.

What causes a TIA

• Atherosclerosis of large arteries: fatty plaques in the carotid arteries in the neck or the arteries at the base of the brain. A piece of clot from a plaque travels into the brain. See carotid artery disease.
• Clots from the heart: atrial fibrillation is the most important; also recent heart attack, heart valve disease and heart failure.
• Small vessel disease: narrowing of tiny arteries deep in the brain, linked to high blood pressure and diabetes.
• Less common causes: tears in neck arteries (dissection, especially in younger people after neck strain), blood clotting disorders, vasculitis and a hole in the heart (patent foramen ovale).

Risk factors

• High blood pressure, the most important.
• Smoking.
• Diabetes.
• High LDL cholesterol.
• Atrial fibrillation.
• Older age, male sex, family history.
• Obesity, physical inactivity, heavy alcohol use.
• Previous stroke or TIA.

Conditions that can mimic a TIA

• Migraine with aura.
• Seizures and the weakness that can follow them.
• Low blood sugar (hypoglycemia).
• Fainting.
• Inner-ear vertigo.
• Bell's palsy, which affects the whole of one side of the face including the forehead.
• Transient global amnesia.

How a TIA is diagnosed

Guidelines recommend specialist assessment within 24 hours, often in an ER or rapid-access TIA clinic.

1. History and examination: what happened, how long it lasted, and a neurological exam.
2. Blood sugar: to exclude hypoglycemia.
3. Brain MRI with diffusion-weighted imaging: the preferred scan to look for small strokes. CT is used if MRI is not available quickly.
4. Imaging of neck and brain arteries: carotid ultrasound, CT angiography or MR angiography to find narrowing.
5. ECG and heart rhythm monitoring: to detect atrial fibrillation, sometimes with a wearable monitor for weeks.
6. Echocardiogram: heart ultrasound to look for clot sources.
7. Blood tests: blood count, kidney function, cholesterol, HbA1c and clotting tests.

TIA treatment and stroke prevention

Treatment begins immediately and is aimed at preventing a stroke.

Medicines

• Antiplatelet therapy: aspirin, clopidogrel or both. For many people with a higher-risk TIA, aspirin plus clopidogrel together for about 3 weeks, followed by a single antiplatelet, lowers early stroke risk more than aspirin alone.
• Anticoagulants: for atrial fibrillation, usually a direct oral anticoagulant such as apixaban or rivaroxaban, rather than antiplatelets.
• Statins: high-intensity statins to lower LDL cholesterol, with a common target below 70 mg/dL.
• Blood pressure medicines: most people should aim for under 130/80 mmHg long-term.
• Diabetes control.

Surgery and procedures

• Carotid endarterectomy: surgery to remove plaque from a significantly narrowed carotid artery (generally 50 to 99 percent, or 70 to 99 percent depending on the guideline). It is most effective when done within 2 weeks of the TIA.
• Carotid stenting: an alternative for some people.
• Patent foramen ovale closure: for selected people under 60 with no other cause found.

Lifestyle changes

• Stop smoking completely.
• Limit alcohol.
• Exercise at least 150 minutes a week, as able.
• Follow a Mediterranean-style diet, with less salt.
• Lose weight if overweight.

Driving

Many US states and other countries restrict driving for a short period after a TIA. Ask your doctor about local rules, especially if you drive commercially.

Outlook

Without treatment, roughly 1 in 3 people who have a TIA eventually have a stroke, and the risk is concentrated in the first days and weeks. With urgent assessment and modern prevention, the risk of stroke in the following year has fallen to around 5 percent in specialist centers. A TIA is also a marker of heart disease risk, so the same treatments reduce heart attacks.

Frequently asked questions

What are the warning signs of a mini-stroke?

The warning signs are the same as a stroke and come on suddenly: face drooping, arm or leg weakness or numbness on one side, slurred or confused speech, loss of vision in one eye, double vision, and sudden loss of balance. Use BE FAST and call 911 even if symptoms go away.

How long does a TIA last?

Most TIAs last less than 10 to 15 minutes, and symptoms fully resolve, by definition, within 24 hours. Symptoms lasting longer than an hour often show a small stroke on MRI. You cannot tell how long an episode will last when it starts, so seek emergency care immediately.

What causes a TIA?

A TIA is caused by a temporary blockage of blood flow to the brain, usually a small clot. The clot may come from fatty plaque in the neck arteries, from the heart in atrial fibrillation, or from narrowed small arteries in the brain. High blood pressure, smoking, diabetes and high cholesterol are the main risk factors.

Is a TIA a stroke?

A TIA is not a stroke because it does not cause permanent brain damage, but it uses the same mechanism and is a strong warning sign. Up to about 1 in 20 people have a stroke within days to weeks after a TIA without treatment, so it is treated as an emergency.

What should I do after a TIA?

Get assessed urgently, ideally within 24 hours, even if you feel normal. Take prescribed medicines such as antiplatelets or anticoagulants and statins, control blood pressure, stop smoking, and attend follow-up appointments. Call 911 immediately if any symptoms return.

Can a TIA be treated at home?

No. A TIA needs urgent medical assessment to find the cause and start treatment that prevents a stroke. Do not take aspirin at home before you are assessed unless a clinician tells you to, because some strokes are caused by bleeding.