Background: Anti-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) encephalitis is a rare autoimmune synaptic encephalitis associated with autoantibodies that cause a selective decrease in surface expression and changes in receptor localization. Anti-AMPAR encephalitis is poorly recognized, especially in children, and its clinical phenotype is incompletely described.
Case presentation: We report a case of anti-AMPAR GluR1 antibody-mediated autoimmune encephalitis in a 12-year-old male. The patient manifested as a fulminant course, with ataxia, cerebellar degeneration at the onset, and rapidly evolved into hyperthermia, coma and rhabdomyolysis. Antibodies against AMPAR GluR1 receptors were detected in the cerebrospinal fluid by cell-based assay. Diffuse slow waves were found by electroencephalograph, and the left cerebellar vermis and hemisphere were affected on brain magnetic resonance imaging (MRI). The patient was treated with intravenous immunoglobulin (IVIG), methylprednisolone combined with plasma exchange. Symptoms were alleviated after immunotherapy and the patient sustained clinical improvement. This is the first time that acute rhabdomyolysis symptom has been identified in a pediatric patient with anti-AMPAR encephalitis.
Conclusions: This case expands the clinical spectrum of anti-AMPAR encephalitis and highlights that despite poor clinical manifestation at the outset, recovery remains possible.
Keywords: AMPAR encephalitis; Autoimmune encephalitis; GluR1 receptor; Rhabdomyolysis.
© 2022. The Author(s).