TIA stands for Transient Ischemic Attack. That's "medicalese", but what it means is that you had a spell which is a warning that you are at increased risk for having a stroke. You might think of the warning spell that you just had as a "gift," because it gives us a chance to intervene and to try to prevent you from going on to have a major stroke.
A stroke is damage to the brain that occurs because the blood supply is cut-off, or because of bleeding into the brain or around the brain. It can give you permanent problems like inability to speak or understand what is being said, loss of vision in one eye or on one side, numbness, weakness, paralysis, loss of balance, problems walking.
Right now we need to figure out why you had this spell, so that we can try to prevent your having another spell or a stroke. You might be wondering how much risk you're really at. This will sound very scary, but you need to understand that your risk of having a stroke, a heart attack or dying would be about 8% a year over the next 5 years if we did nothing.
We're going to do a number of tests right away because the highest risk of your having a stroke is in the coming month. We will use the results to help figure out what caused your spell, and to select the most appropriate treatment. The aspirin that they started you on in the emergency department has been shown to reduce the chances of stroke for patients like you. However, there may be additional or other treatments that we can provide once we understand exactly why your spell occurred.