A transient ischemic attack, called a TIA for short, is often a warning signal of an impending stroke. Pieces of fat or blood clots can block an artery leading to the brain. When this happens, a part of the brain does not get enough oxygen and the symptoms of a TIA appear. With a TIA, the artery is only blocked for a short time. However, the Science Daily just reported 5 days ago (February 24, 2010), that nearly 4 in 10 transient ischemic attack and minor ischemic stroke patients may experience mental impairment. This was just revealed following a study presented at the American Stroke Association’s International Stroke Conference this year.
Unlike a stroke, a TIA is an episode in which a person has stroke-like symptoms, but they last less than 24 hours and usually less than 1-2 hours. A TIA is also different than a small stroke in that it does not show any changes on CT or MRI scans. Small strokes do show changes on such tests. The cause of a TIA is a temporary disturbance of blood supply to an area of the brain. This results in a sudden, brief decrease in brain function. A decrease in brain function is also called a neurologic deficit. Atherosclerosis (hardening of the arteries) 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, migraine headaches, smoking, heavy use of alcohol, diabetes and increasing age.
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. Even though a TIA is different than a small stroke, the signs of TIA are the same as a stroke and include the sudden development of:
- Muscle weakness of the face, arm or leg (usually only on one side of the body)
- Numbness or tingling on one side of the body
- Trouble speaking or understanding others who are speaking
- Problems with eyesight (double vision, loss of all or part of vision)
- Changes in sensation, involving touch, pain, temperature, pressure, hearing and taste
- Change in alertness (sleepiness, less responsive, unconscious or coma)
- Personality, mood or emotional changes
- Confusion or loss of memory
- Difficulty swallowing
- Difficulty writing or reading
- Lack of coordination and balance, clumsiness or trouble walking
- Abnormal sensation of movement (vertigo) or dizziness
- Lack of control over the bladder or bowels
- Inability to recognize or identify sensory stimuli (agnosia)
The treatment goal is to 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. Other blood thinners include dipyridamole, clopidogrel, Aggrenox, 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 transient ischemic attack 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. Risk for future stroke depends on the cause of TIA and management of risk factors.