Prodromal Infection Trigger Acute Onset Anti-DPPX Encephalitis without CNS Hyperexcitability Symptoms: A Case Report

Dipeptidylpeptidase-like protein-6 (DPPX) antibody associated encephalitis can present with protracted encephalitis, symptoms of central nervous system(CNS) hyperexcitability, and cerebellar signs. Most of these patients onset subacutely and have diarrhea in the initial phase. We report a 26-year-old Chinese female, who had ten days history of upper respiratory tract infection, followed by headache, dizziness, gait instability suddenly. Neurological examination demonstrated prominent vertical nystagmus, astasia and cognitive impairment. CSF testing for neuronal autoantibodies revealed DPPX antibody IgG titer of 1:1. After treatment with IV methylprednisolone combined with IV immunoglobulin, her neurological symptoms improved markedly. This case illustrated that anti-DPPX autoimmune encephalitis could be triggered by prodromal infection and onset acutely. Patients may only show cerebellar signs and cognitive impairment without CNS hyperexcitability. Performing an auto-antibody examination might aid differential diagnosis.