Never Too Late to Treat NMDAR Encephalitis: A Paediatric Case Report and Review of Literature

Abstract

Background: Anti-N-methyl-D-aspartate receptor antibody encephalitis is an immune-mediated disorder characterised by a complex neuropsychiatric syndrome that often can be initially misdiagnosed. A small subset of the population is refractory to both first- and second-line therapies. These reasons make delays to the correct therapy a major concern, as early treatment may lead to better outcomes in children. Nevertheless, there is still benefit in additional medication courses despite a prolonged refractory state. The authors provide an illustrative case report and review of literature. Case Presentation: The authors describe a 5-year-old female with 5 days of change in mental status; choreoathetoid movements were found to have positive anti-GluN1 antibodies in their cerebral spinal fluid. They failed first-line intravenous steroids and intravenous Ig and second-line rituximab, but then were discharged to rehabilitation without improvement over 3 months. Despite the time frame, they had a complete response to 12 sessions of plasma exchange with concomitant pulse steroids and subsequent intravenous Ig. Conclusion: The authors’ case report and review of literature supports practices that prompt additional therapy for incomplete or failure of response in anti-N-methyl-D-aspartate receptor encephalitis despite prolonged symptom duration. Extended plasma exchange therapy may be beneficial in some treatment refractory cases.