[A Patient with Acute Limbic Encephalitis Associated with Anti-Glutamate Receptor Antibodies and Subsequent Optic Neuritis].

A 19-year-old woman presented with headache and fever. Cerebrospinal fluid (CSF) analysis revealed increased pressure (>200 mmH2O) and pleocytosis. Brain MRI showed high intensity in the medial part of the right temporal lobe, insular regions, and basal ganglia of the right hemisphere on fluid attenuated inversion recovery images. Based on a tentative diagnosis of limbic encephalitis caused by viral infection, acyclovir therapy was started. However, 10 days after admission, a right superior temporal quadrantanopia developed in the left eye. MRI detected abnormal intensity in the left optic nerve on short tau inversion recovery images. After three courses of steroid pulse therapy, the optic neuritis quickly improved and the patient was maintained on subsequent oral administration of prednisolone, without relapse for one year. The CSF was positive for anti-glutamate receptor (GluR) antibodies (GluN2B, GluN1, and GluD2); however, anti-N-methyl-D-aspartate receptor antibody was not detected in both serum and CSF with cell-based asseys. Compared to previously reported anti-GluR positive cases combined with optic neuritis, the clinical outcome of our patient was short, with good prognosis. Our results indicate that an autoimmune mechanism involving anti-GluR antibodies contributes to the pathogenesis of optic neuritis as well as limbic encephalitis.