Evaluating the late seizures of acute encephalopathy with biphasic seizures and late reduced diffusion via monitoring using continuous electroencephalogram.

Abstract

Background: Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) causes clustered seizures (late seizures; LS) 3-7 days after early seizure (ES); however, few reports provide continuous electroencephalogram (C-EEG) monitoring details. This study aimed to evaluate the initial/last detection date of LS using C-EEG and determine whether LS EEG features correlate with neurological sequelae.

Materials and methods: We analyzed 28 patients diagnosed with AESD who underwent C-EEG monitoring between 2015 and 2020. Multiple pediatric neurologists and epileptologists evaluated the LS detection timing, duration, and severity. Based on the evaluated data, we compared the clinical characteristics and LS-induced neurological sequelae between the ESEEG+LS (initiated C-EEG immediately after ES) and LSEEG+LS (initiated C-EEG after LS confirmation) groups. Additionally, we compared LS clinical characteristics and severity between severe and non-severe groups for 15 patients (baseline Pediatric Cerebral Performance Category Scale score <3).

Results: LS was detected in 17 of 28 patients. The earliest and latest LS detection dates were 2 and 11 days, respectively, and the longest LS duration was 7 days (median, 0.6 days). Regarding neurological sequelae, the LS duration was markedly longer in the severe group than that in the non-severe group during the distant period. However, LS severity was not associated with neurological sequelae.

Conclusion: This study highlights the importance of C-EEG as it could aid in the early detection of LS. Neurological sequelae correlated with LS duration but not severity.