三谷 忠宏

We report on an 8-year-old boy with non-paraneoplastic anti-NMDA receptor (NMDAR) encephalitis, who presented with psychotic symptoms and involuntary movement following an intractable seizure. His serum and CSF tested positive for anti-NMDAR antibodies. He received an initial immunotherapy consisting of methylprednisolone pulse therapy (mPSL) and intravenous immunoglobulin therapy (IVIg), without any clinical improvement. He had three cycles of monthly cyclophosphamide pulse therapy (500 mg/m2), and his clinical condition started to improve gradually two weeks after the first cycle, without any side effects. Six months after onset, he tested normal upon standard neurological examination. Cyclophosphamide therapy should be considered for children with anti-NMDAR encephalitis, as well as mPSL and IVIg.

The changes in the signals for brain metabolites in the left cerebellum of a 14-year-old boy with acute hemicerebellitis were monitored using proton magnetic resonance spectroscopy (MRS). From the onset of disease treatment to long-term follow-up, MRS data were serially acquired from the left and right cerebella, basal ganglia (BG), and centrum semiovale (CS). Large fluctuations in his MRS signals were observed in the left cerebellum. At onset (first day), his glutamate/glutamine complex signals were increased (>mean ± 2 standard deviations [SD] of the control), and those for N-acetylaspartate/N-acetylaspartylglutamate and myo-inositol were decreased (<2SD). By the 25th day, these signals had recovered to normal levels, while those for choline (Cho) were increased. In other locations, the signals for mIns in the BG and Cho in the CS were decreased on the seventh day. By the 201st day, the levels of all metabolites in all locations had recovered to within ± 2SD of the control levels. In vivo proton MRS monitoring demonstrated reversible metabolite changes associated with acute hemicerebellitis, which should contribute to its differential diagnosis from brain tumors.