Case Report Autoimmune autonomic ganglionopathy in a pediatric patient presenting with acute encephalitis

Autoimmune autonomic ganglionopathy (AAG) is an acquired immune-mediated disorder that leads to systemic autonomic failure. Autoantibodies to the ganglionic nicotinic acetylcholine receptor (gAChR) are detected in 50% of AAG patients. We report the first pediatric case of AAG presenting with acute encephalitis. The patient was a 13-year-old boy who presented with orthostatic hypotension, followed by rapidly progressing disturbance of consciousness. Cerebrospinal fluid analysis revealed significant pleocytosis and increased neopterin concentration. Head MRI showed hyperintensities in bilateral caudate nuclei, putamen, hippocampus, and insula cortex. Severe autonomic dysfunctions such as severe orthostatic hypotension, bradycardia, dysuria, prolonged constipation and vomiting appeared. These symptoms were successfully controlled by repeated immunomodulating therapy with intravenous methylprednisolone pulse therapy and intravenous immunoglobulin. Autoantibodies to the a3 subunit of gAChR were detected at neurological onset, but were undetectable five months later. This observation indicates that AAG should be suspected in patients manifesting acute encephalitis characterized by preceding and prolonged autonomic symptoms, and immunomodulating therapy from an early stage can be effective.