By Dr. Katie E. Golden, MD
A transient ischemic attack (TIA) is the medical term for a temporary lack of blood flow to the brain. You may have heard people refer to this as a ‘mini-stroke’ because it results in stroke-like symptoms that resolve themselves, in a matter of minutes to hours. But labeling this as a ‘mini’ event does not do it justice, and perhaps minimizes the seriousness of the condition. The same causes and risk factors that lead to a TIA also lead to larger strokes that can leave people with permanent disability. And about 1 in 3 people who have a TIA will have a more severe stroke within 1 year. So a TIA is not as harmless as some people make it out to be.
When medical experts first coined the term TIA several decades ago, they defined it as stroke symptoms that resolve within 24 hours. But since the time of its original conception, experts have dropped the ‘24 hour’ part of the definition. Instead, they defined a TIA as a stroke-like event that did not result in any permanent brain damage. In other words, they defined a TIA by its effect on the brain (or lack thereof), rather than how long the symptoms lasted.
But it seems our understanding of the TIA needs to be redefined yet again. With advanced MRI technology, experts are now realizing the ‘no permanent brain damage’ may not be so true either. Even when someone’s stroke symptoms resolve in minutes, MRIs can still pick up areas of damaged brain tissue (aka dead neurons) that result from the brief event. And so instead of thinking of a TIA as a mini-stroke, it is more accurate to think of it as a mild stroke – and one that is on the same spectrum as a severe stroke.
So let’s take some time to review the symptoms and causes of TIA, and what you can expect if it happens to you or a loved one.
The symptoms of a TIA
TIA symptoms are identical to stroke symptoms. This makes sense now that you understand TIAs and strokes are more alike – and in fact the same disease – rather than separate conditions. The main difference is that TIA symptoms tend to resolve within minutes to hours.
The symptoms of a TIA include:
- Facial drooping, which often becomes more obvious when someone tries to smile, talk, eat or drink
- Weakness in the hand, arm, or leg (especially if it is only present on one half of the body)
- Numbness in one half of the face, hand, arm, or leg
- Sudden confusion, disorientation, or amnesia-like memory loss
- Difficulty speaking, which can look like difficulty finding or getting words out, difficulty articulating words or slurred speech, or even stringing words together that don’t make sense
- Difficulty walking or coordinating movements
- Sudden loss of vision
The causes of a TIA
A TIA occurs when there is a sudden loss of blood flow to one part of the brain. In other words, there is a temporary blockage in one of the arteries (blood vessels) that supplies blood to the brain. These blockages can happen for several different reasons:
- A blood clot can travel from another part of the body into the brain
- A blood clot can form within the blood vessels in the brain
- Plaque (cholesterol) build-up within the arteries in the brain
- A spasm in the artery, similar to the way a muscle gets a temporary cramp
A TIA can also happen when there is a sudden drop in blood pressure, which affects the body’s ability to get blood up into the brain. This is not a ‘blockage’ in an artery per se, but results in a sudden lack of blood flow just the same.
What happens when you go to the ER for TIA symptoms
Whenever you or a loved one develops stroke symptoms like the ones listed above, you should call 911 to get to the nearest ER as soon as possible. There is no way to tell when the symptoms first start if it is a mild stroke and will resolve (like a TIA), or a more severe stroke. Even if your symptoms resolve quickly, or before the ambulance gets there, it is still best to be evaluated to figure out what happened. And if it was a TIA, to prevent a more serious stroke from happening.
When you arrive at the ER, you will soon be evaluated by an emergency or neurology provider. This will include a quick physical exam to look for any neurologic signs of stroke. This will then be followed by some tests that will be done right away:
- A CT scan of your brain. If your symptoms are due to a TIA, this will most likely appear normal. The main goal of this initial scan is to rule out any bleeding, or signs of a more serious stroke.
- The initial CT scan may be followed by a second CT scan that is designed to take a closer look at the arteries in the head and neck. This requires placement of an IV in order to administer IV contrast, which lights up the blood vessels. This special CT scan looks for blockages in the arteries.
- These CT scans will likely be followed by additional tests, like blood tests and an EKG.
Even if all your testing is normal —and your symptoms have fully resolved—your ER or neurology provider will likely recommend a short stay in the hospital. This is not only so they can continue to monitor you for any new or returning symptoms, but also to run additional testing:
- An MRI on your brain, to look for smaller or more subtle signs of a stroke.
- Tests to look for reasons you may have had a TIA. These can vary from ultrasounds to look for blood clots in the heart or legs, tests to look for signs of plaque in the arteries, or more blood tests like measurements of cholesterol levels.
In addition to these tests, a short stay in the hospital allows your providers to make sure you are on the right medicines to decrease your risk of stroke in the future. The right treatment is different for everyone, but can include medicines to keep your blood pressure in normal range, lower your cholesterol level, or even aspirin or anticoagulants to prevent blood clots.
A TIA is not a mini stroke, but a major warning sign. But the good news is that it is a warning sign you can do something about. So if you or someone you care about has stroke symptoms, no matter how brief or mild they may seem, seek emergency medical care. This is a critical step in preventing a more serious stroke in the future.