Introduction: Autoimmune encephalitis associated with myelin oligodendrocyte glycoprotein antibodies is rare. Methods: Case report of a child immunocompetent male with combined Anti-NMDAR encephalitis and MOG antibody. Results: A previously healthy 6-year-old boy and normal psychomotor development presented acutely disorder movement characterized for choreic movements in the left lower and upper limb and 4 days after he had stopped walking by increase of choreic movements and generalized dystonia. Prenatal, perinatal, and family histories were unremarkable. Computed tomography scan on arrival to hospital was normal. Brain MRI scan was normal. Lumbar puncture was normal. Visual evoked potential was normal. EEG showed background activity associated with diffuse slow waves. Results routine blood count, biochemistry, and metabolic tests were normal. Subsequently was added psychomotor agitation, fever, tonic-clonic generalized seizures, dysarthria, headaches, drowsiness, swallowing disorders, and sleep disturbances. In the presence of marked symptoms, the diagnosis of autoimmune encephalitis was considered. Anti-NMDAR NR1/2 IgG in CSF was positive, and serum anti-MOG antibodies was positive. He received intravenous methylprednisolone 30 mg/kg for 5 days, and intravenous immunoglobulins 1 g/kg once daily for 2 days. Seizures and movement disorders stopped on the second day of the immunoglobulin. A reducing course of oral prednisone was then started, and antiepileptic was gradually withdrawn. One month after, the patient was discharged with mild cognitive difficulties. At follow-up 3 months later, the neurological examination was normal. Conclusion: In case of clinical suspicion of autoimmune encephalitis despite normal neuroimaging, treatment must be instituted early to avoid neurological sequelae or death.

LEIDI VILCHEZ FERNANDEZ
DANIEL ALCIDES CARRION HOSPITAL
Peru