TRANSIENT ISCHEMIC ATTACK


Transient ischemic attacks (TIAs) are caused by the same processes that cause cerebrovascular attacks (CVA). They are the result of the temporary deprivation of oxygen and glucose to a region of the central nervous system, and occur when an artery supplying that region is transiently obstructed or occluded. The symptoms of TIAs are typically sudden in onset and quick to resolve, and can include paralysis, sensory loss, visual loss, difficulty verbalizing or understanding, double vision, dizziness, imbalance, or trouble swallowing.

By definition, TIAs do not cause permanent cerebral damage. TIAs were previously defined as neurological symptoms that lasted less then 1 day, but the definition has been recently changed to symptoms lasting less than 1 hour.1
This change was made based on radiological findings that symptoms lasting less than one hour did not result in a permanent lesion, whereas those lasting more than one hour tended to result in lesions that were visible on CT or MRI.1  Persons experiencing a TIA are at great risk of having a CVA in the following weeks. In one study, patients presenting with a TIA had a 5% chance of having a CVA within the next 2 days, and a 10% chance over the next 90 days.2   In addition, patients had a 13% chance of having a recurrent TIA, a 3% chance of having a cardiovascular event, and a 3% rate of mortality, during the next 90 days.2    These statistics underscore the importance of obtaining medical attention, and undergoing a complete cerebrovascular evaluation, whenever a person experiences a TIA.

The evaluations for patients with TIAs are similar to patients with CVAs, and include CT, MRI, ultrasound, and cardiac studies. Like CVAs, TIAs may be caused by occlusions of the small or large cerebral arteries, obstructions in the large neck arteries that ultimately supply the cerebral arteries, or by cardiac abnormalities that result in emboliazation. The treatment for TIA patients is also similar to CVA patients, and may include medications such as aspirin, Plavix, Aggrenox, or warfarin, depending on the specific cause of the TIA. If the symptoms are due to severe carotid artery disease, carotid endarterectomy surgery may be necessary.

Whenever a person experiences symptoms of a TIA, immediate admission to a hospital and examination by a cerebrovascular neurologist are essential.

2. Johnston S, Gress D, Browner W, Sidney S. Short-Term Prognosis After Emergency Department Diagnosis of TIA. JAMA 2000:284:2901-6.

Michael Moussouttas, MD

Assistant Professor of Neurology
Seton Hall University
Neuroscience Institute at JFK
65 James Street
Edison, NJ 08818