Herpes Zoster Myelitis Mimicking Myelin Oligodendrocyte Glycoprotein (MOG) Antibody Disease: A Case Report

Identifying the cause of myelopathy is difficult because associated clinical and imaging findings are nonspecific. The onset pattern and magnetic resonance imaging (MRI) findings are important for the diagnosis. Herein, we present the case of a 70-year-old woman hospitalized with acute-onset weakness of the lower limbs. Blood and cerebrospinal fluid tests did not reveal any abnormalities that could have been the cause. Cerebrospinal fluid was negative for varicella-zoster virus (VZV)-DNA. Spinal cord MRI revealed an H-sign in the central gray matter of the conus medullaris, suggesting myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD)-induced spinal cord inflammation. Intravenous methylprednisolone (IVMP) was initiated; however, the patient's symptoms did not improve. No anti-MOG antibodies were detected. During hospitalization, shingles appeared on the skin at the same level as the spinal cord lesions. In the repeat cerebrospinal fluid test, VZV-DNA was negative the first time, but later turned positive. We subsequently initiated treatment with acyclovir, and paralysis and bladder-rectum disorders improved. This case study provides important insights for patients with myelopathy. First, it is difficult to distinguish herpes zoster myelopathy from MOGAD because herpes zoster myelopathy presents as an H-shaped lesion in the conical area. Second, when treating myelopathy, virological confirmation via cerebrospinal fluid examination should be repeated until other diseases are diagnosed.