The case of a 12-year-old girl with anti-methyl-D-aspartate receptor (NMDAR) encephalitis is reported by researchers from Augsburg and Bonn, Germany, and Oxford, UK. She was admitted with an episode of paresthesia and hypotonia of the left leg, and rare episodes of head turning with clonic movements of the left and all extremities. The symptoms were preceded by a 2-day episode of diarrhea 3 weeks before. The EEG, brain MRI, and CSF were normal, and she was discharged with a suspected diagnosis of psychogenic seizures. She was readmitted 2 days later with agitation, hyperventilation and intermittent ocular deviation, followed by intermittent catatonic postures with fever, hyperidrosis, chewing movements and tongue protrusion. She required tube feeding and intermittent oxygen. EEG now showed continuous slowing. The MRI was unremarkable. IgM antibodies against Campylobacter jejuni were elevated. Prednisolone was ineffective. At 6 weeks after admission, CSF showed IgG antibody reactivity with hippocampal neurophil, and subsequently, serum antibodies to NMDAR were demonstrated. Plasmapheresis was followed within 2 weeks by speaking words, walking and almost full recovery in 4 weeks. CSF antibody reactivity was no longer detected, and ultrasound and CT were negative for teratoma in the pelvis and mediastinum. 
COMMENT. This 12-year-old girl appears to be the youngest patient reported with anti-NMDAR encephalitis. Her presentation with neuropsychiatric symptoms progressing to seizures, catatonia, autonomic dysfunction, hypoventilation, orofacial dyskinesia and dysphagia is typical. Teratoma, absent in this child, may occur in 65% of patients, and sometimes develops 7 years following encephalitis [2, 3]. An apparent response to plasmapheresis and the association with Campylobacter infection are of interest.