Risk of seizure recurrence after a first unprovoked seizure in childhood

Objective: The aim of this study was to assess the risk of recurrence after a first unprovoked seizure in childhood and to explore the correlation between the first and second seizures in recurrent patients. Methods: In a prospective study, we included 467 children aged 1 month to 16 years, who were attended to between November 1, 2008 and October 31, 2016 following a first seizure. Children who had been started on treatment with antiepileptic drugs were excluded. Recurrence rates were calculated using Kaplan-Meier survival analyses. Univariate and multivariate analyses for recurrence risk were performed using the Cox proportional hazards model. The kappa coefficient of correlation for categorical data was calculated. Results: Recurrences occurred in 280 children (60.0%), of which 75 (26.8%) occurred in the first month, 184 (65.7%) within 6 months, and 256 (91.4%) within 2 years. None of the patients had new neurologic sequelae after their first or second seizure. The estimates of seizure recurrence risk were 39.5%, 48.1%, 55.1%, 60.8%, 61.8% and 61.8% at 0.5, 1, 2, 5, 8, and 10 years after the first seizure, respectively. Multivariate analysis showed that abnormal electroencephalogram and neuroimaging findings significantly increased the risk of recurrence. First and second seizures were significantly associated with state of arousal, status epilepticus, and multiple seizures in recurrent patients. Conclusion: Over half of untreated children had recurrence after a first unprovoked seizure, but prognosis was good overall. (c) 2021 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.