2026 American Academy of Neurology Autoimmune Abstract Website

Objective:

To describe a challenging case of longitudinally extensive transverse myelitis (LETM) in the setting of per/post-viral infection, illustrating application of the 2023 International MOGAD diagnostic criteria and the TRUE‑MOGAD score in a low‑titer MOG‑IgG presentation with an incomplete immunotherapy response.

Background:

Myelin oligodendrocyte glycoprotein antibody–associated disease (MOGAD) is an uncommon inflammatory disorder of the central nervous system, distinct from MS and NMOSD. Diagnosis is particularly challenging with low MOG‑IgG titers, prompting reliance on clinical and imaging features per 2023 criteria. Viral infections, including EBV and HSV, often act as immune triggers.

Design/Methods:

Case report

Results:

A previously healthy 21‑year‑old man developed rapidly progressive bilateral lower‑extremity numbness, pain, and weakness one week following a recent trip to Mexico preceded by febrile illness and oral ulcers. Initial evaluation suggested painful Guillain–Barré syndrome, and he received IVIG with clinical deterioration. MRI of the spine revealed a longitudinally extensive T2/STIR hyperintense lesion extending from C7/T1 to the conus, with minimal enhancement and cord swelling along with bilateral enhancement of the trigeminal nerve nuclei. CSF showed lymphocytic pleocytosis and elevated protein. Infectious testing demonstrated EBV serologies consistent with recent infection and PCR HSV‑1 positivity; serum autoimmune testing revealed a low‑positive MOG‑IgG titer (1:40). Despite the low titer, the presence of LETM with conus involvement, bilateral Trigeminal nuclei involvement and a high TRUE‑MOGAD score, support MOGAD with myelobomencephalitis likely triggered by recent viral infection. Treatment with high‑dose corticosteroids and plasmapheresis led to stabilization but limited neurologic recovery, with persistent sensory deficits and paraplegia at discharge.

Conclusions:

Low‑titer MOGAD following EBV/HSV infection can present with severe LETM, conus and trigeminal involvement, fulfilling 2023 criteria via characteristic imaging and high TRUE‑MOGAD score. Parainfectious context and poor steroid/PLEX response complicate diagnosis and management, underscoring reliance on integrated clinical, radiographic, and serologic assessment in challenging low‑titer scenarios after viral triggers occur.