A Case Report of Rare MOG Antibody-Associated Optic Neuritis Related to Hepatitis E Virus Infection.

Hepatitis E infection is a highly prevalent viral infection, with neurological manifestations being the most common extrahepatic symptoms. However, cases of hepatitis E virus (HEV) infection presenting with optic neuropathy symptoms remain scarce. We reported a case of a 49-year-old male who presented with fatigue, poor appetite, slightly yellowish urine, and fever. The patient had no significant past medical history. Upon admission, liver and kidney function tests were abnormal, and serological testing was positive for HEV IgM antibodies. After targeted therapy for liver protection and jaundice reduction, liver and kidney function indices returned to normal. However, after discharge, the patient gradually developed blurred vision. Cranial magnetic resonance imaging (MRI) revealed bilateral optic nerve swelling with abnormal signals and slight accumulation of fluid in the optic nerve sheath. Cerebrospinal fluid (CSF) testing was positive for HEV antibodies and Myelin oligodendrocyte glycoprotein (MOG) antibody IgG, after confirm no other related factors causing optic neuritis present, so it is considered as MOG antibody-associated optic neuritis, and this was confirmed through effective treatment. After five days of immunoglobulin therapy, along with corticosteroids and neurotrophic drugs, the bilateral optic nerve swelling improved, and the fluid accumulation in the optic nerve sheath reduced. This case indicates that HEV infection may lead to MOG antibody-associated optic neuritis. Although there are currently no specific drugs for treating HEV infection, immunotherapy can play a crucial role.