Psychiatric Manifestation of NMDA Receptor Autoimmune Encephalitis

Miss A, a 13-year-old female was admitted with complaints of sub-acute and continuous course of low mood and being lost in her own thoughts (on and off); odd behaviour in the form of seeing things not seen by others and two episodes of abnormal body movements, forgetfulness, decreased sleep and decreased food intake and restlessness for a period of 1 week. Initially her psychiatric symptoms led to a provisional diagnosis of a primary psychiatric disorder as stressor in the form of decreased academic decline was present.  However, over the next few days, it was noticed that the patient’s condition deteriorated as she kept lying on the bed staring blankly onto the roof.  Even though the eyes were opened, she not aware of her surroundings and was very restless. She started producing low tone sounds as if humming which alternated with shouting incoherent sounds. Hand movements in the form of twisting and writhing which seemed that she was dancing as well as bizarre facial movements started manifesting. The patient also started having difficulty in breathing with sudden drop in SpO2 upto 86%. Two episodes of seizure also developed. Neurological consultation was sought and she was immediately shifted to Neuro ICU, where necessary investigations were performed. Even though brain MRI came out normal and CSF Analysis did not show other abnormalities, except for increased sugar level. AE panel report showed “strong positive” against NMDA receptor autoantibodies. She was treated with Inj. Methylprednisolone 750 mg in 500ml NS over 4 hours (for 5 days) which was followed by Inj. Prednisolone 50mg for 10 days, then 40mg for 10 days, and then 30 mg  for another three months). Patient improved after about 15 days.