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Transient Ischemic Attacks (TIAs)


Andrei V. Alexandrov

, MD, The University of Tennessee Health Science Center;

Balaji Krishnaiah

, MD, The University of Tennessee Health Science Center

Reviewed/Revised Jun 2023 | Modified Aug 2023
Topic Resources

A transient ischemic attack (TIA) is a disturbance in brain function that typically lasts less than 1 hour and results from a temporary blockage of the brain’s blood supply.

  • The cause and symptoms of a TIA are the same as those of an ischemic stroke.

  • TIAs differ from ischemic strokes because symptoms usually resolve within 1 hour and no permanent brain damage occurs.

  • Symptoms suggest the diagnosis, but brain imaging is also done.

  • Other imaging tests and blood tests are done to diagnose the cause of the TIA.

  • Controlling high blood pressure, high cholesterol levels, and high blood sugar levels and stopping smoking are recommended.

  • Medications to make blood less likely to clot and sometimes surgery (carotid endarterectomy) or angioplasty plus stenting are used to reduce the risk of stroke after a TIA.

TIAs may be a warning sign of an impending ischemic stroke. People who have had a TIA are much more likely to have a stroke than those who have not had a TIA. The risk of stroke is highest during the first 24 to 48 hours after the TIA. Recognizing a TIA and having the cause identified and treated can help prevent a stroke.

TIAs are most common among middle-aged and older people.

TIAs differ from ischemic strokes because TIAs do not seem to cause permanent brain damage. That is, TIA symptoms resolve completely and quickly, and few or no brain cells die—at least not enough to cause any changes that can be detected by brain imaging or a neurologic examination Neurologic Examination When a neurologic disorder is suspected, doctors usually evaluate all of the body systems during the physical examination, but they focus on the different parts of the nervous system. Examination... read more .

Causes of TIAs

Causes of TIAs and ischemic strokes Causes An ischemic stroke is death of an area of brain tissue (cerebral infarction) resulting from an inadequate supply of blood and oxygen to the brain due to blockage of an artery. Ischemic stroke... read more Causes are mostly the same. Most TIAs occur when a piece of a blood clot (thrombus) or of fatty material (atheroma, or plaque) due to atherosclerosis breaks off from the heart or from the wall of an artery (usually in the neck), travels through the bloodstream (becoming an embolus), and lodges in an artery that supplies the brain.

Risk factors

Some of these risk factors can be controlled or modified to some extent—for example, by treating the disorder that increases risk.

The major modifiable risk factors for TIAs are

Risk factors that cannot be modified include

  • Having had a stroke previously

  • Being male

  • Being older

  • Having relatives who have had a stroke

Symptoms of TIAs

Symptoms of a TIA develop suddenly. They are identical to those of an ischemic stroke Symptoms An ischemic stroke is death of an area of brain tissue (cerebral infarction) resulting from an inadequate supply of blood and oxygen to the brain due to blockage of an artery. Ischemic stroke... read more Symptoms but are temporary and reversible. They usually last 2 to 30 minutes, then resolve completely.

People may have several TIAs in 1 day or only two or three in several years.

Symptoms may include

  • Sudden weakness or paralysis on one side of the body (for example, half of the face, one arm or leg, or all of one side)

  • Sudden loss of sensation or abnormal sensations on one side of the body

  • Sudden difficulty speaking (such as slurred speech)

  • Sudden confusion, with difficulty understanding speech

  • Sudden dimness, blurring, or loss of vision, particularly in one eye

  • Sudden dizziness or loss of balance and coordination

Diagnosis of TIAs

  • Rapid resolution of symptoms

  • Computed tomography and, when available, magnetic resonance imaging

  • Tests to determine the cause

Doctors suspect a TIA if symptoms of a stroke develop, particularly if they resolve in less than 1 hour. Doctors may be unable to tell a stroke from a TIA before symptoms resolve. They evaluate people who have symptoms of a TIA or stroke rapidly. People who have had a TIA are usually admitted in the hospital, at least for a short time, to do tests and to be able to treat them rapidly if a stroke occurs soon after the TIA. Risk of a stroke is highest during the first 24 to 48 hours after a TIA.

Doctors check for risk factors for stroke by asking people questions, reviewing their medical history, and doing blood tests.

Imaging tests, such as computed tomography (CT) or magnetic resonance imaging (MRI), are done to check for evidence of a stroke, bleeding, and brain tumors. A specialized type of MRI, called diffusion-weighted MRI Diffusion-weighted MRI Magnetic resonance imaging (MRI) is a type of medical imaging that uses a strong magnetic field and very high frequency radio waves to produce highly detailed images. During an MRI, a computer... read more Diffusion-weighted MRI , can show areas of brain tissue that are severely damaged and not functioning. Diffusion-weighted MRI can often help doctors differentiate a TIA from an ischemic stroke. However, diffusion-weighted MRI is not always available.

Tests are done to determine what caused the TIA. Tests may include

Other imaging tests help determine whether an artery to the brain is blocked, which artery is blocked, and how complete the blockage is. These tests provide images of the arteries that carry blood through the neck to the brain (the internal carotid arteries and the vertebral arteries) and the arteries of the brain (such as the cerebral arteries). They include color Doppler ultrasonography Color Doppler ultrasonography Ultrasonography is a type of medical imaging that uses high-frequency sound (ultrasound) waves to produce images of internal organs and other tissues. During an ultrasound, a device called a... read more Color Doppler ultrasonography (used to evaluate blood flow through arteries), magnetic resonance angiography Magnetic resonance angiography (MRA) Magnetic resonance angiography (MRA) , and CT angiography CT angiography CT angiography (CT done after a contrast agent is injected into a vein).

Did You Know...

  • Even if symptoms of a stroke resolve within a few minutes, people should still go to the emergency department immediately.

Treatment of TIAs


People may be given a medication to make blood less likely to clot (an antiplatelet medication or an anticoagulant).

Taking an antiplatelet medication, such as aspirin, a combination tablet of low-dose aspirin plus dipyridamole, clopidogrel, or clopidogrel plus aspirin, reduces the chance that clots will form and cause TIAs or ischemic strokes. Antiplatelet medications make platelets less likely to clump and form clots. (Platelets are tiny cell-like particles in the blood that help it clot in response to damaged blood vessels.)

Taking clopidogrel plus aspirin appears to reduce the risk of future strokes more than taking aspirin alone, but only for the first 3 months after a stroke. After that, the combination has no advantage over taking aspirin alone. Also, taking clopidogrel plus aspirin increases the risk of bleeding by a small amount.

If a blood clot from the heart caused the TIA, anticoagulants, such as warfarin, are given to make blood less likely to clot. Dabigatran, apixaban, and rivaroxaban are newer anticoagulants that are often used instead of warfarin. These newer anticoagulants are more convenient to use because they, unlike warfarin, do not require regular monitoring with blood tests to measure how long it takes blood to clot. Also, they are not affected by foods and are unlikely to interact with other medications. But the new anticoagulants have some disadvantages. Dabigatran and apixaban must be taken twice a day. (Warfarin is taken once a day.) Also, people must not miss any doses of the newer medications for the medications to be effective, and these medications are significantly more expensive than warfarin.


The degree of narrowing in the carotid arteries helps doctors estimate the risk of a stroke or subsequent TIAs and thus determine the need for further treatment. If people are thought to be at high risk (for example, if the carotid artery is narrowed at least 70%), an operation to widen the artery (called carotid endarterectomy Carotid artery surgery Carotid artery surgery ) may be done to reduce the risk. Carotid endarterectomy usually involves removing fatty deposits (atheromas, or plaques) due to atherosclerosis and clots in the internal carotid artery. However, the operation can trigger a stroke because the operation may dislodge clots or other material that can then travel through the bloodstream and block an artery. After the operation, the risk of stroke is lower for several years than it is when medications are used. The procedure can result in a heart attack because people who have this procedure often have risk factors for coronary artery disease.

Angioplasty and stents placement

If people are not healthy enough to have surgery, angioplasty with stenting (see figure ) may be done. For this procedure, a catheter with a balloon at its tip is threaded into the narrowed artery. The balloon is then inflated for several seconds to widen the artery. To keep the artery open, doctors insert a tube made of wire mesh (a stent) into the artery.

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