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

## TL;DR

A 70-year-old woman's spinal cord symptoms were initially mistaken for a rare antibody disease but were later found to be caused by herpes zoster.

## Contribution

This case highlights the diagnostic challenge of distinguishing herpes zoster myelitis from MOG antibody disease using MRI and clinical features.

## Key findings

- Herpes zoster myelitis can mimic MOG antibody disease with similar MRI findings like the H-sign.
- Repeated cerebrospinal fluid testing was necessary to confirm herpes zoster as the cause.
- Treatment with acyclovir improved symptoms after steroid treatment failed.

## Abstract

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.