Let us talk about transient ischemic attacks or TIA’s here. What does it mean when your doctor tells you that you had a TIA?
TIA or transient ischemic attack as the name suggests means that one has an episode of transient ischemia to the brain. Kind of like a mini-stroke except that for it to be called a TIA, the neurological deficits should reverse completely. Let me explain this further. Suppose you have an episode of sudden weakness of the right side of the body (arm and leg) and at the same time, your speech is off. This presentation is mostly likely due to ischemia (lack of blood flow) in the left middle cerebral artery of the brain. Now this can act out in 2 ways. One you are recover completely, often within a few minutes to an hour at most. That means the ischemia was transient and that you are not left behind with any neurological deficits (no weakness and speech is back to normal). This would then be called a TIA involving the left middle cerebral artery.
The second possibility is that you do not recover at all, or do recover to some extent (after been treated in the hospital for acute stroke). Here the patient has stroked out. If you do an MRI of the brain, you shall see evidence of acute stroke. In a TIA, the imaging shall be normal as the recovery is complete.
So now that we understand what a TIA means, let us talk about the different types of TIA’s. One of the most common TIA is what we call transient monocular blindess or Amaurosis Fugax. This is a special type of TIA in which there is sudden lack of blood flow into the ophthalmic artery (branch of the internal carotid artery in the neck). As there is lack of blood flow in the artery which supplies the retina, patients notice sudden onset of loss of vision in one eye (remember I said monocular). Ususally they describe it as if a curtain suddenly descended in front of that eye. This monocular blindness lasts for a few seconds to minutes and then goes away.
One can have other types of TIA’s depending upon which blood vessel in the brain has a sudden episode of ischemia. So you have patients who present with history of transient weakness in an arm or leg, transient speech difficulties, transient numbness in an arm or leg, transient episode of dizziness or unsteady gait etc etc.
So are TIA’s important and do they need to be treated is the next question? Usually a TIA shall affect the patient and make him or her visit the ER. Some patients though may ignore the episode, since now they are back to normal and just go on with their lives.
A TIA is a warning sign for stroke. It usually is a sign that a stroke is imminent. The brain has suffered an episode of dysfunction even though transient. Here in lies the importance of recognizing a TIA and seeking medical attention for it. Studies have shown that major strokes may soon follow a TIA.
What to do if you have a TIA?
1) well first things first it is important to recognize a TIA and give it its due importance. If you are having stroke like symptoms call for help and dial 911 and be taken to the nearest hospital for evaluation. You do not know at the onset whether this is going to be a TIA and that you shall recover completely without any intervention or that you are going to stroke out. Remember time is brain, the more time you waste, the more likely you shall suffer damage to the brain from a stroke.
2) If you are having a TIA, it is likely that the symptoms shall have abated by the time you reach the ER. Well and good, as you rather have a TIA than a stroke. When patient’s present to the ER with a TIA, doctors usually admit them for a thorough stroke evaluation. We have a unique opportunity to try to identify your risk factors for stroke and modify them, so that you do not have a future stroke. Your doctor may run many tests on your brain (MRI, carotid dopplers to look to see if your neck vessels are patent) as well as on your heart ( as some strokes and TIA’s come from the heart. Tests like holter monitor and ECHO).
We can also prescribe you medications to make your blood thin, medications like aspirin which may reduce the risk of a future stroke.
So remember to recognize a TIA and seek help promptly. A stroke prevented is a brain saved.