Home > Causes of dementia, Dementia risk, Early recognition, Medical issues > What Is a Transient Ischemic Attack?

What Is a Transient Ischemic Attack?

Image courtesy puttsk @http://www.freedigitalphotos.netWe often hear about someone having a TIA, or a transient ischemic attack.  It is sometimes also called a “mini-stroke,” but should rather be called a “warning stroke.”  A transient ischemic attack is a neurological disorder caused by ischemia, or loss of blood flow, similar to that which causes a stroke.  However, unlike a stroke, a TIA does not cause an infarction, or tissue death.  “Transient” means not lasting, or enduring only a short time, and a TIA does just that.  It may last a few minutes or up to 24 hours. 

The warning signs for a TIA are the same as those for a stroke (Courtesy American Heart Association):

  • sudden numbness, weakness, or paralysis of the face, arm or leg — especially on one side of the body
  • sudden confusion, or trouble speaking or understanding
  • sudden trouble seeing in one or both eyes
  • sudden trouble walking, dizziness, loss of balance, or coordination
  • sudden, severe headache with no known cause

(One easy way to remember these warning signs is by the acronym F.A.S.T. — Face drooping, Arm weakness, Speech difficulty, Time to call 911.)

The mechanism that causes a TIA is the same as that which causes a stroke.  The two disorders can also result in similar symptoms:  paralysis or weakness/numbness occurring on the opposite side of the body from the affected brain hemisphere, sudden dimming or loss of vision, aphasia, slurred speech, and/or mental confusion.  Often a person presenting with one or more of these symptoms will present themselves at the emergency room (rightly so), and be admitted to the hospital under suspicion of having had a stroke.  However, by the time he/she is evaluated and processed, and admitted to the hospital (sometimes hours later), the symptoms may have actually begun to resolve themselves.  Most TIA symptoms will vanish after about one hour, but the person may be left with a vague feeling that something has happened to them.  This does not mean, however, that it is alright to wait at home for a while to see if the symptoms go away. 

Having a TIA can place a person at risk for having an actual stroke.  Or, it may be a signal for the person’s physician to look for other factors that can place him at significant risk.  It is not uncommon for a person to have something called a silent stroke (“silent cerebral infarct”), either before or shortly after a TIA.  A silent stroke is differentiated from a TIA by the fact that there are usually no immediately observable symptoms.  That said, it may still cause long-lasting neurologically-based difficulties, including changes in mood, personality, or cognition.   The most common form of vascular dementia is caused by a series of TIAs, which over time can produce an accumulation of symptoms that negatively affect cognitive functioning.

It is not unusual for a person to be admitted to a rehabilitation facility with a diagnosis of TIA.  However, had she experienced a true TIA, her symptoms would most likely have resolved themselves and she could have gone home from the hospital.  Often what has happened is that she has experienced a silent stroke during the same general time frame, which will explain the symptoms that she continues to exhibit.  It is also possible that she has experienced something called a reversible ischemic neurological deficit (RIND), which is an infarct lasting typically between 24 and 72 hours.  And a third possibility is that her physician wishes to investigate possible medical conditions that caused her to have the TIA in the first place. 

Most TIAs are caused by a small embolus (blood clot or gas bubble) that blocks the flow of blood through an artery in the brain.  This is usually derived from tissue that came from the carotid arteries in the neck or from the heart.  However, unlike a stroke, the blockage is only temporary — the unwanted material either dissolves or is pushed on through the circulatory system.  As a result, there is no permanent damage.  With time, and with repeated similar blockages, there may eventually be a build-up of material on the walls of the artery sufficient enough to cause a full-blown stroke. 

Medical conditions that can place a person at risk for TIAs include hypertension, heart disease (especially atrial fibrillation), migraines, hypercholesterolemia (high blood cholesterol), and diabetes mellitus.  Other factors that can place a person at risk for TIAs include having a family history of stroke or TIA, being 55 years or age or older, and smoking.  Males are somewhat more likely than females to have TIAs, but females are at greater risk of dying as a result of a stroke.  African Americans are also at a greater risk of having a stroke, primarily related to high blood pressure and uncontrolled diabetes.

There are a number of other conditions that can present with symptoms that are similar to a TIA.  These include an atypical migraine (especially if visual symptoms are present), a partial seizure in the parietal area of the brain, glucose abnormalities characterized by diabetes and a loss of consciousness, electrolyte imbalances, hypertensive encephalopathy, subdural hematoma, brain tumor, demyelinating disease, and a conversion disorder.  An accurate diagnosis is usually made after a physical examination (including a medical history), as well as radiological tests (possibly including a CT scan or MRI, ultrasound of the neck, or an echocardiogram of the heart).  Other tests may be performed as well.

Most sources report that TIAs can be prevented through a change in lifestyle, although there is no firm research-based evidence to support this.  Some of these changes include cessation of smoking, eating a healthy diet (including eating plenty of fruits and vegetables, cutting down on fats and cholesterol, and limiting sodium intake), regular exercise, moderate alcohol, and controlling blood pressure and blood sugar. 

Usually, treatment of a TIA consists of identifying and controlling the contributory factors involved.  A person may be admitted to the hospital for a short period, as it is almost impossible initially to differentiate a TIA from a stroke, however a person may also be discharged from the emergency room with instructions to contact her personal physician. 

Some consider a TIA to be the last warning, so to speak, that stringent measures should be undertaken to correct factors which may soon cause the person to experience what may be a severe stroke.  It has been shown that one third of people who have a TIA later experience recurrent TIAs, and one third will experience a stroke.  One source suggests that 10% of those who experience a TIA will have a major stroke within 90 days (half of theses occurring within the first two days after the TIA).

Sources:

Wikipedia

American Heart Association

 

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  1. July 12, 2013 at 12:17 AM

    You’ve provided us with a great deal of valuable information. Thank you.

  2. findingmyinnercourage
    July 15, 2013 at 5:31 PM

    Valuable information for my husband who has had many TIAs – thank you!

    • July 15, 2013 at 6:46 PM

      I’m glad you found it helpful. Best of luck to you and your husband!

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