The patient was a 10-year-old previously healthy and developmentally normal girl who presented with intermittent left sided facial twitching with preserved awareness, then progressed to continuous facial twitching concerning for EPC. Otherwise, the initial neurological examination was unremarkable.
MRI brain with gadolinium revealed foci of cortical and subcortical T2 hyperintensities in the right frontal operculum, right inferior frontal gyrus, the right cingulate gyrus, and the cortex along the left superior frontal sulcus. EEG showed right frontal and central sharp waves as well as continuous slowing in the right frontal, central and temporal regions. CSF and serum analyses were remarkable for very high anti-GAD65 antibody titers.
Anti-seizure medications provided minimal and transient improvement. She subsequently developed ataxia and diplopia. Pulse steroids and therapeutic plasma exchange resulted in complete resolution of EPC, ataxia and diplopia. She was discharged with a plan to continue immunotherapy with rituximab.