Abstracts

Rationale: To date, there are no data on the proportion of children in whom electrographic seizures persist after convulsive status epilepticus (CSE) terminates. We aimed to describe the occurrence and characteristics of electrographic seizures following CSE in children.Methods: This was a multi-center (11 centers) retrospective study. We describe the clinical and electroencephalographic features of all consecutive children (1 month to 21 years) who presented with CSE and underwent continuous electroencephalographic monitoring in pediatric intensive care units.Results: Ninety-eight children (53 males) with a median age of 5 years underwent continuous electroencephalographic monitoring after CSE. Electrographic seizures were identified in 32 subjects (33%). Eleven (34.4%) had electroencephalographic-only seizures, 17 (53.1%) had electro-clinical seizures, and four (12.5%) did not have data about clinical correlate. Of the 32 subjects with electrographic seizures, 15 (46.9%) had electrographic status epilepticus, of which six (40%) were classified as continuous status epilepticus (electrographic seizures lasting more than 30 minutes) and nine (60%) as intermittent status epilepticus (recurring electrographic seizures totaling more than 50% of a one hour epoch). Factors associated with the development of electrographic seizures after CSE were a prior diagnosis of epilepsy and the presence of interictal epileptiform discharges (Table 1). When comparing patients who developed electrographic status epilepticus with patients who developed electrographic seizures without status epilepticus or who did not developed electrographic seizures, we found that the presence of an abnormal initial background category on continuous electroencephalogram (Pearson chi-square= 9.7346, p= 0.045) and the presence of sporadic interictal epileptiform discharges (Pearson chi-square= 11.7072, p= 0.001) were associated with electrographic status epilepticus. The median (interquartile range) duration of stay in the pediatric intensive care unit was 3 (2-10) days, being longer for children with electrographic seizures at 9.5 (3-22.5) days than for children without electrographic seizures at 2 (2-5) days (Wilcoxon test, Z=3.916, p=0.0001). Four children (4.1%) died before leaving the hospital.Conclusions: Electrographic seizures occurred in approximately one third of children after control of CSE, and approximately one third of these children (11% of the total) did not have any clinical correlate associated with their electrographic seizures. A prior diagnosis of epilepsy and the presence of interictal epileptiform discharges were associated with the occurrence of electrographic seizures. Electrographic seizures were associated with a longer stay in the intensive care unit.