New-Onset Refractory Status Epilepticus With Diffuse Cerebral Restricted Diffusion in Young Children: A Novel Clinical-Radiologic Presentation.

Background: New-onset refractory status epilepticus (NORSE) is a clinical presentation characterized by explosive-onset refractory status epilepticus (RSE) without evident etiology or active epilepsy, often leading to devastating epilepsy. There is heterogeneity in neuroradiographic findings for NORSE. We encountered a series of young patients with NORSE who had diffuse cerebral restriction in diffusion (DCRD) with similar radiographic appearances as acute encephalopathy with biphasic seizures and late restricted diffusion/acute leukoencephalopathy with restricted diffusion (AESD/ALERD). We explore clinical similarities and proposed pathophysiologic overlaps to highlight a novel clinical-radiologic presentation.

Methods: Retrospective review was completed for patients younger than five years meeting NORSE criteria and then screened for radiographic evidence of DCRD. Demographic, clinical, and outcome data were collected.

Results: Eleven patients met NORSE criteria, of whom seven displayed DCRD. Immunosuppressant management varied. All patients required multiple antiseizure medications and continuous infusions for RSE. Only one had an etiology identified (genetic). All but one patient developed diffuse, global, and progressive cerebral atrophy. Two patients died: one after prolonged seizure three years post-NORSE and another of unknown causes two months post-NORSE. Of five survivors, three have medically refractory epilepsy. Most survivors have severe disability.

Conclusions: We present a single-center case series of seven patients with NORSE and DCRD, akin to AESD/ALERD. Our patients differed clinically to AESD/ALERD in terms of seizure severity and poorer outcome. There is a need to develop biomarkers for specific NORSE phenotypes. The young child with NORSE and DCRD may represent a novel phenotype with a specific neuroradiographic signature that deserves further attention.