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people will have a seizure in their lifetime. Many times they’re told “everyone is allowed one seizure” and meds aren’t started until a second seizure. But why is this?#neurotwitter #tweetorial
Recurrence risk after a first seizure has been examined in numerous studies. This review by Dr Anne Berg is an outstanding summary. https://www.ncbi.nlm.nih.gov/pubmed/18184149
large-scale randomized trials provide recurrence risk after untreated first unprovoked seizure.A multicenter study from Italy randomized 193 people to deferred treatment after second seizure. Recurrence risks were 18%,28%,41%,51% at 3,6,12,24 months after first sz
The reference for this first study is found here https://www.ncbi.nlm.nih.gov/pubmed/8450987
The European Multicenter Epilepsy & Single Seizure study randomized 408 with first unprovoked seizure to deferred treatment.
Recurrence risk was 26%,39%,51%,52% at 6m, 2y,5y,8y. https://www.ncbi.nlm.nih.gov/pubmed/15950714
Recurrence risk was 26%,39%,51%,52% at 6m, 2y,5y,8y. https://www.ncbi.nlm.nih.gov/pubmed/15950714
These trials suggest risk of a second seizure at approximately 40% within 2 y of first unprovoked seizure. Nearly 90% of those that will recur will do so in those 2 years. (See Berg 2008 for refs)
Many choose not to commit someone to daily meds after first seizure based on these numbers. However, risk of more seizures after a second seizure is much higher - 57%,61%,73% at 1,2, and 5 y after recurrence. Thus meds are often started here. https://www.ncbi.nlm.nih.gov/pubmed/9459646
Recurrence risk in children is similar after the second seizure - 57%,63%, and 72% at 1,2, and 5 years after first recurrence. https://www.ncbi.nlm.nih.gov/pubmed/10939563
Now, many factors may increase the risk of recurrence after a first seizure and thus prompt starting meds after the first event.
Epileptiform abnormalities on eeg and symptomatic cause (for example brain injury, malformation, etc) routinely are noted to increase recurrence risk
Epileptiform abnormalities on eeg and symptomatic cause (for example brain injury, malformation, etc) routinely are noted to increase recurrence risk
So, you weigh the risk of recurrence with risk of side effects from the treatment. Both randomized studies mentioned above showed reduced recurrence risks in those treated after the first seizure - 60% reduction in rate of relapse in the first and 30% in the second.
The @AANMember guideline on therapy after first seizure in adults provides useful summary of data in adults treated vs untreated.
Since treating after first seizure reduces risk (for those that would recur), does it impact outcome (vs waiting) enough to warrant starting therapy early?
The AAN guideline summarized data that shows likelihood of long term remission does not improve by treating early.
The AAN guideline summarized data that shows likelihood of long term remission does not improve by treating early.
Risk of side effects of therapy ranged from 7-31% in the studies included in the guideline. https://www.ncbi.nlm.nih.gov/pubmed/25901057
So, after a first seizure you must take into consideration the recurrence risk which is modified by results of EEG, MRI, and potentially other factors. You weigh that against risk of adverse effects of therapy and ultimate long term outcome to determine a treatment decision.
You consider the overall circumstances as well- recurrent seizure in adult versus a child for example- and impact on quality of life. Many opt to wait for second seizure defining a much higher recurrence risk before committing to daily meds.
