What is the safe observation period for seizure recurrence in pediatric emergency departments?

Background: Afebrile seizures are the common causes of emergency department (ED) admissions in childhood, and there is limited data on the observation period in emergency service follow-up of these patients in terms of seizure recurrence in the literature. This study aims to determine the seizure recurrence time in afebrile seizures and the risk factors that determine it.

Methods: Patients aged between 1 month and 18 years with afebrile seizures were included in the study. Seizure recurrence times, demographic data, diagnosis of epilepsy, use of antiseizure medications, Electroencephalography (EEG) and imaging results, structural abnormalities, hospitalizations, and treatments were recorded.

Results: The median age of 623 patients included in the study was 42 months (16.0-94.0 months) and 59.9% were male. Epilepsy was diagnosed in 372 (59.7%) of the patients. Short-acting benzodiazepine was administered in 249 of the cases. The mean observation time of the patients was 36 hours (24-98 hours). Electroencephalography (EEG) was applied in 437 (70.1%) of the patients and abnormality was detected in 53.5%. Seizure recurrence was observed in 149 patients (23.9%). The median time of seizure recurrence was 1.0 hour (0.5-4.0 hours). Eighty-six percent of the seizure recurrences (n = 129) occurred within the first six hours and 95.3% (n = 142) within the first 12 hours. Risk factors included a history of febrile seizures (p = 0.001, OR = 2.7), not receiving short-acting benzodiazepine therapy (p = 0.026, OR 1.7), previous structural abnormalities (p = 0.018, OR 1.8), and cluster seizures (p = 0.001, OR 6.7) for all patients and also EEG abnormalities in pediatric ED for first seizure (p = 0.012, OR 2.4).

Conclusion: Patients with a history of febrile seizure, previous structural abnormalities, cluster seizures, EEG abnormalities in pediatric ED, and patients who didn't receive BZD treatment were at risk for seizure recurrence in the early period. Since most seizure recurrences occur within the first 6 hours, this period is the most critical time for recurrence risk.