A transient ischemic attack (TIA) is an episode in which a person has stroke -like symptoms for less than 24 hours, usually less than 1-2 hours.

A TIA is often considered a warning sign that a true stroke may happen in the future if something is not done to prevent it.

A transient ischemic attack (TIA) is caused by temporary disturbance of blood supply to an area of the brain, which results in a sudden, brief decrease in brain function. (A decrease in brain function is called a neurologic deficit.)

A TIA is different than a small stroke. The symptoms of TIAs do not last as long as a stroke and do not show changes on CT or MRI scans. (Small strokes do show changes on such tests.)

The temporary loss of blood flow to the brain can be caused by:

• Blood clot within an artery of the brain
• Blood clot that travels to the brain from somewhere else in the body (for example, the heart)
• Injury to blood vessels
• Narrowing of a blood vessel in the brain or leading to the brain

For instance, the temporary disruption in blood flow could be due to a blood clot that occurs and then dissolves.

Less common causes of TIA include:

• An irregular heart rhythm called atrial fibrillation
• Certain blood disorders, including polycythemia, sickle cell anemia, and syndromes where the blood is very thick
• Conditions that cause blood vessels problems such as fibromuscular dysplasia, systemic lupus erythematosus, and syphilis
• Inflammation of the arteries such as arteritis, polyarteritis, and granulomatous angiitis
• Spasm of the small arteries in the brain

Atherosclerosis ("hardening of the arteries") is a condition where fatty deposits occur on the inner lining of the arteries. This condition dramatically increases the risk for both TIAs and stroke. Approximately 80-90% of people who have a stroke due to atherosclerosis had a TIA episode before.

Other risks for TIA include high blood pressure, heart disease, migraine headaches, smoking, diabetes, and increasing age.

About a third of those diagnosed with TIA will later have a stroke. TIAs are more common among men and black people.

A TIA is different than a small stroke. The symptoms of TIAs do not last as long as a stroke. However, the symptoms of TIA are the same as a stroke and include the sudden development of:

• Confusion
• Eye pain
• Facial paralysis
• Falling (caused by weakness in the legs)
• Gait changes, staggering
• Lack of coordination
• Loss of balance
• Numbness, tingling, changes in sensation
• Sensation that the person or the room is moving (vertigo)
• Speech difficulty (garbled speech; slurred speech)
• Weakness, heavy feeling of in the arms or legs
• Vision changes
  • Loss of vision in one eye
  • Decreased vision
  • Double vision

Symptoms begin suddenly, last only a short time (from a few minutes to 24 hours), and disappear completely. They may occur again at a later time. Symptoms usually occur on the same side of the body if more than one body part is involved.

TIAs do not show changes on CT or MRI scans. (Small strokes do show changes on such tests.)Because symptoms and signs may have completely disappeared by the time one gets to the hospital, a diagnosis of a TIA may be made on a person's medical history alone.

A physical examination should include a neurological exam, which may be abnormal during an episode but normal after the episode has passed.

Blood pressure may be high. The doctor will use a stethoscope to listen to your heart and arteries. An abnormal sound called a bruit may be heard when listening to the carotid artery in the neck or other artery. A bruit is caused by irregular blood flow. In some cases, low blood pressure may be seen before symptoms of a TIA occur.

Tests will be done to rule out a stroke or other disorders that may cause the symptoms. Tests to diagnose a TIA may include:

• Blood clotting tests, including PT, to rule out a blood disorder
• Carotid duplex (ultrasound)
• Cerebral arteriogram
• Complete blood count (CBC)
• Echocardiogram
• Head CT scan or cranial MRI

Additional tests and procedures may include:

• Blood glucose
• Blood chemistry
• Chest x-ray
• ECG
• ESR (Sedimentation rate)
• Serum lipids
• Tests for syphilis

Your doctor may use these tests to check high blood pressure, heart disease, diabetes, high cholesterol, and peripheral vascular disease.

The goal is to improve the blood supply to the brain and prevent a stroke from occurring.

If you have had a TIA within the last 48 hours, you will likely be admitted to the hospital so that doctors can determine the cause and treatment.

Underlying disorders such as high blood pressure, heart disease, diabetes, and blood disorders, should be treated appropriately.

Blood thinners, such as aspirin, may be prescribed to reduce blood clotting. Others include dipyridamole, clopidogrel, Aggrenox or heparin, Coumadin, or other similar medications. Treatment may be continued for an indefinite time period.

Surgery (carotid endarterectomy) may be appropriate for some people who have clogged neck arteries.

Smoking should be stopped.

Your health care provider may recommend a low-fat and low-salt diet. Other dietary changes may be recommended.

By definition, an episode of TIA is brief and recovery is complete. It may recur later that same day or at a later time. Some people have only a single episode, some have recurrent episodes, and some will have a stroke. A TIA needs to be treated as aggressively as a stroke would, as any given TIA could develop into a stroke.

Complications of TIA include:

• Death of brain cells due to too little blood flow to the brain
• Injury that occurs from falls
• Stroke

TIA is a medical emergency. Call 911 or other local emergency number immediately. Do not ignore symptoms just because they go away. They may be a warning of a future stroke.

Prevention of TIA includes controlling the risk factors such as high blood pressure, diabetes, heart disease, and other associated disorders. Smoking should be stopped.

The use of blood thinners may prevent strokes in some patients who have blood clots or atrial fibrillation.

Aspirin therapy (81mg a day or 100mg every other day) is now recommended for stroke prevention in women under 65 as long as the benefits outweigh the risks. Women over age 65 should take aspirin to prevent heart attack and stroke only if their blood pressure is controlled and the benefit is greater than the risk of gastrointestinal bleeding and brain hemorrhage.

Carotid endarterectomy in select patients may prevent stroke.

Mosca L, Banka CL, Benjamin EJ, et al. Evidence-Based Guidelines for Cardiovascular Disease Prevention in Women: 2007 Update. Circulation. 2007; Published online before print February 19, 2007.

Goldstein LB. Prevention and management of stroke. In: Libby P, Bonow RO, Mann DL, Zipes DP, eds. Libby: Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 8th ed. Saunders;2007:chap 58.