What Is a Transient Ischemic Attack?

A transient ischemic attack (TIA), also called a ministroke or warning stroke, causes symptoms similar to those of a stroke. The difference is that TIAs don’t cause permanent brain damage, and they usually last less than one hour but can last up to 24 hours. Approximately one-third of people will suffer a stroke in the year following a TIA.

TIAs happen when a blood clot or artery spasm suddenly blocks or closes off an artery briefly. This stops blood from reaching a part of the brain for a short period of time. Different parts of the brain do different things, so TIA symptoms depend on what part of the brain is affected. For example, a person can have weakness in his or her arm without the real problem being in the arm. The problem can be a lack of blood flow to the part of the brain that is responsible for arm strength.

Here are symptoms to watch for:

• Sudden numbness in your face, arm or leg, especially on one side of the body

• Sudden confusion

• Sudden trouble seeing, talking or understanding

• Sudden trouble with balance or walking

• Sudden dizziness or loss of coordination 

• Sudden severe headache you can’t explain

• Loss of consciousness or seizure

If you suspect you are having a TIA, get medical help immediately. Recognizing symptoms of a TIA and seeking immediate treatment will reduce the risk of a major stroke.