A comprehensive review of the classification of seizure types by the ILAE in 2017 and how that has improved patient categorization.
Michael R. Sperling, MD; Trevor J. Resnick, MD; Jesus E. Pina-Garza, MD; and Kathryn A. Davis, MD, MS, FAES
PUBLISHED February 19, 2019
Michael R. Sperling, MD: Let’s move forward a little bit. The International League Against Epilepsy [ILAE] promulgated a new classification of both seizures and epilepsy in 2017. What are the advantages of these and when do you use it? Perhaps I’ll lead off with a case and ask Dr. Resnick to start this discussion. A 16-year-old comes into your office, and the story was he was sitting in class and suddenly he fell out of his chair and was observed to stiffen and shake all 4 limbs for a minute or 2. Although, of course, they said it lasted hours because it seems like it lasts hours. How do you classify someone with that sort of history? And where does the new classification help you?
Trevor J. Resnick, MD: Well, let’s start with the classification first. I think the classification is an improvement because it’s much less ambiguous. The definitions are much clearer, much simpler, much easier to define in terms of trying to classify specific seizure. In terms of the case that you ask me about, that, unfortunately, is a very common scenario where the history that you get is consistent with a patient who has a generalized seizure. However, first of all, the symptom that the parents see that freaks them out the most is the fact that the child is jerking all over. They don’t remember to tell you about the fact that the child may have been staring for a few seconds before they start jerking. And their reason is because it’s not as emotionally effective as the generalized jerking.
So I think it’s very important, first of all, when you get a history and that early history is the patient was jerking all over, to always go back and ask if anybody noticed anything else prior to the jerking occurring. Because that’s definitely very helpful and it’s suggestive of a seizure that may be focal at onset and then becomes generalized. But, frequently, even if you go through all that, you still don’t know. And, under those circumstances, you need other additional testing to help you out such as EEG [electroencephalogram] or imaging studies as to what the true etiology is and what the true seizure type is.
Michael R. Sperling, MD: Eric, do you think the classification makes it easier for the neurologist and the non-neurologist to understand what we mean when we talk about seizures? Do you find complex partial seizure different than focal impaired awareness in terms of conveying a message? And do you think over the long run there will be an advantage to something like that?
Jesus E. Pina-Garza, MD: I definitely applaud the effort to simplify the classification because definitely, like Trevor says … mistakes are less likely when we document and communicate. So, in the past, the classification was good, but unfortunately, many times we misinterpret or misuse the terms. So one term in medicine that is commonly used is idiopathic. In epilepsy it was more a term for genetic epilepsies where we didn’t know the genes. So we knew etiology, not exactly the gene. And then the term cryptogenic we applied more for the unknown causes, which in other areas of medicine, they use the term idiopathic. So that creates a lot of confusion.
So now it’s the same with complex or simple, using names to describe the seizure, or call them like they are. So, when you say someone has a focal onset, it’s very clear that it’s not generalized, still partial; and when you say there’s impairment of awareness or not is absolutely clear. So I think definitely the new classification is clearer, less likely to be misused, and it still leaves us the option—because not in every case we’ll have the answer—to say we don’t know. Hopefully, we won’t use that very often, but the option is there.
Michael R. Sperling, MD: Kate, how does this classification help in the real world in practice? Does it make a difference?
Kathryn A. Davis, MD, MS, FAES: I do think it makes it easier for patients to understand the different subtypes of epilepsy using the new classification. It is confusing for patients who have had longstanding epilepsy and we’re changing the names, but over time, I think it is an improvement.
Michael R. Sperling, MD: And it may help us decide upon treatment as well, right? Because with that fundamental distinction between an absent seizure, for example, and focal impaired awareness, the drugs may be somewhat different. Although with the advent of more broad-spectrum agents, it’s a little less challenging for nonabsence-type seizures I suppose.
Kathryn A. Davis, MD, MS, FAES: Right.
Michael R. Sperling, MD: And then when we classify the epilepsies, there are a number of domains that have been brought into it now as a way of thinking about it from the syndromic perspective. Does anybody have any comments about how that makes a difference and helps in the way of thinking about epilepsy, or was that something for the benefit of the panel that created the system and not for the rest of us?
Jesus E. Pina-Garza, MD: I wanted to take that, too. So the syndromic cases, even though it’s not the specific etiology, in many cases, it gives you an identity for the patient. The best example would be Lennox-Gastaut. So, when you have Lennox-Gastaut, any epilepsy may lead to that. There may be compounding factors, mainly having a childhood onset and refractoriness to treatment. You can develop that syndrome, but it’s very different the way you treat it compared to just an epilepsy refractory to treatment where you can have drugs that can make the epilepsy worse compared to specific treatments for that type of syndrome. It also, in this new era, may open the possibility to have a third payer for that medication compared to being rejected. So, clearly, the syndromes are a more specific way to define the condition of the patient. And many times they are matched with the specific therapies.
Michael R. Sperling, MD: Trevor?
Trevor J. Resnick, MD: Yes, I agree. I think for me, in terms of counseling patients, being able to have a label of a syndrome is most important from the standpoint of prognosis and outcome. So you really have a much more focused ability to talk about natural history and prognosis with the patient, and it provides a framework for them to understand it from a long-term standpoint. To Eric’s point, for some of the syndromes, very specific treatment paradigms are very relevant. So I think those 2 areas are very helpful when you’re able to discuss a syndrome with a family or a patient.