This episode of Epilepsy Explained focuses on how epilepsy is diagnosed and features Dr. David E. Burdette, MD, Epilepsy Section Chief at Corewell West Health System.
Video Transcript
How can you tell if you or someone around you is having or has had a seizure?
Dr. David Burdette: Whether or not someone has a seizure may be obvious, it may be subtle. And it goes back to the basic crux of the matter, which is how our brain works by networks. That’s how we think our lofty thoughts. That’s how we chill. But if a network develops a life of its own and fires in an excessively synchronous fashion, we have a seizure. And that seizure may or may not cause symptoms to us. If we have symptoms from that seizure, and a lot of times we do, then we will have symptoms that are related to the part of the brain that is seizing.
So we may hear a funny sound that isn’t there. We may see something that isn’t there or have visual distortion. We may smell an unpleasant smell. All of these related to the part of the brain that is involved. To the outside observer, they may not even know that this is occurring. Oh my goodness, I’m hearing that sound again, that oncoming train, but I’m going to finesse it and no one knows. Once that seizure though spreads to broader areas of the brain, I can no longer finesse it, and a person who knows me well may see a change in my face or my behavior if that seizure spreads enough.
From my perspective, the lights go out and I don’t know what is occurring around me. I have no recollection for this because I’m not forming memories, and people may see me having lip-smacking movements or other automatic movements of which I’m not aware. And finally, God forbid, if it spreads to the entire brain, I will convulse.
QUESTION: Do you have to experience more than one seizure before you can be diagnosed with epilepsy?
Dr. David Burdette: We can be diagnosed with epilepsy even after one seizure. The International League Against Epilepsy, who helps us define these criteria, for many years had a very nice definition of epilepsy, whereby if we had at least two seizures separated by 24 hours and they were unprovoked, then that person had epilepsy. So we would say one seizure does not epilepsy make. A few years ago, however, the ILAE, this governing body, made an astute observation that there is a subset of people who are prone to seizures and maybe we are doing them a disservice by waiting for that second seizure.
So now we have a second criterion. We still have two seizures separated by at least 24 hours. But additionally, if you have one seizure and a greater than 60% chance of having another one, it is in everyone’s best interest if we proceed with treatment.
How are we going to determine this? Well, we’re going to get a series of tests in order to ascertain are you in that 60% risk group or are you not? Tests include a brain MRI scan because we’re looking for any abnormality, any issue that is going to predispose you to seizures.
We’ll get an EEG to see if there is epileptic form activity. When we see findings of this type, we know that you are in the 60% and that you do meet the diagnosis or criteria for epilepsy.
QUESTION: What type of doctor should I see to diagnose epilepsy?
Dr. David Burdette: Epilepsy at its very core is a brain issue. So if someone has a brain issue, who are you going to see to diagnose epilepsy, to ascertain that these funky spells that you’re having are in fact epilepsy or maybe there’s something else. We’re going to go to a neurologist. Neurologists are brain specialists.
Now, in any specialty, you have people who are more specialized in an area and less specialized. So we’ll start with a neurologist. You may actually have your primary care provider who gives you a suspicion that maybe these episodes are seizures, but they will send you to a neurologist to try to confirm that diagnosis. And many times that diagnosis is confirmed, appropriate tests are performed, and appropriate medications started.
There are times, however, when the presentation, the symptoms are more subtle, or God forbid, the seizures are not responding to one of the first few medications, then we’re going to kick it up another level and we’re going to be referred to an epileptologist, a neurologist who specializes in the treatment of epilepsy. And if surgical considerations are on the table, we’re going to see an epileptologist at an NAEC, National Association of Epilepsy Centers, Level 4 Center.
QUESTION: What medical tests are used to diagnose epilepsy?
Dr. David Burdette: The first tests that we are going to use to diagnose epilepsy are frankly quite straightforward. Your neurologist will obtain a history. They will learn about you, about your family history to see if maybe there’s a genetic reason why you may be predisposed to epilepsy. They will also do a physical examination to see if there are any clues there as to why these seizures may have occurred. Once this is done, then we’re going to use that information to guide what tests we want to obtain. Two of the most common tests are brain imaging studies, most likely an MRI scan. That gives us the best, most detailed picture of the brain.
But if for some reason you can’t have a brain MRI, then we’ll get a CAT scan, because we get a pretty good picture with a CAT scan as well. We will also, of course, get an EEG, electroencephalogram. We will look at the electrical activity of the brain that will help us both make the diagnosis and guide treatment. Ideally and frankly, about 63% of the time, that alone is going to be enough. We’ll make a good choice of medication, start you on it, and that or perhaps the second medication that you’re started on, you will do well.
If, however, your seizures are more difficult to control, then we will want to get more testing. We don’t always get this, but this includes an MEG. Remember an EEG, electroencephalogram? This is a magnetoencephalography. A little more detailed, a little more difficult test. We will get a PET scan, a SPECT scan, and a variety of tests to determine are you a candidate for epilepsy surgery?
QUESTION: What is the difference between a seizure type and an epilepsy syndrome?
Dr. David Burdette: Seizure types are, as we have discussed, determined by the part or parts of the brain that are involved in the seizure, but this is just one minute part of the puzzle.
The bigger picture is the entire individual. And within epilepsy, we can group many epilepsies into what we would call a syndrome. And this syndrome has specific seizures, maybe even multiple types of seizures that occur associated with it. It has specific findings on EEG. And in our increasingly genetically aware world, there may well be a genetic marker for this. So if we can put all of this together, then your epileptologist can come up with a better way of treating your epilepsy, not just the seizures, but the entire person.
Let me throw an example. Dravet syndrome, a genetic disorder that affects a subtype of sodium channels. Our brain works by electricity and sodium channels play a role in the generation of electricity. These individuals have very difficult to control seizures of multiple types. At least one of those types, a prominent type, are convulsive, bilateral tonic-clonic seizures. We have a bunch, a plethora of medications that work for bilateral tonic-clonic seizures. Some of those medications work at the sodium channel.
Turns out with Dravet syndrome, it’s a bad idea. We do not use most of our typical sodium channel modulators in that setting because they can make things worse. Ultimately, the syndrome is going to affect the overall treatment.
