Flanagan, Eoin P.

Background: Myelitis accompanied by a negative spinal cord MRI may lead to diagnostic uncertainty. Objective and Methods: We retrospectively investigated the frequency of negative spinal cord MRI (performed <6 weeks from onset) in Mayo Clinic patients with myelin oligodendrocyte glycoprotein (MOG)-IgG-associated myelitis (2000–2019). Results: The initial spinal cord MRI was negative in 7/73 (10%) patients, despite severe acute disability (median EDSS, 7 (range, 4.5–8)); myelitis symptoms/signs were frequent (paraparesis, neurogenic bladder, sensory level, Lhermitte’s phenomenon). Myelitis lesions became overt at follow-up MRI in three patients. Conclusions: A negative spinal cord MRI should not dissuade from MOG-IgG testing in patients with acute/subacute myelitis.

Background: Longitudinally extensive transverse myelitis (LETM) accompanying systemic lupus erythematosus (SLE) is often due to coexisting aquaporin-4-IgG seropositive neuromyelitis optica spectrum disorder but has not been associated with myelin oligodendrocyte glycoprotein-IgG (MOG-IgG). Objective and methods: Case report at an academic medical center. Results: A 32-year-old woman developed severe transverse myelitis (paraplegia) shortly after SLE onset in the post-partum period. Magnetic resonance imaging (MRI) revealed an LETM, cerebrospinal fluid showed marked inflammation, and testing for infections was negative. Serum live-cell-based assay for MOG-IgG was positive but aquaporin-4-IgG was negative. Conclusion: In patients with SLE and LETM, MOG-IgG testing should be considered, in addition to AQP4-IgG.

Introduction: Glial fibrillary acidic protein (GFAP) immunoglobulin G is a recently discovered biomarker of an autoimmune central nervous system disorder characterized by a steroid-responsive meningoencephalomyelitis. Case Report: A 63-year-old man with rheumatoid arthritis on etanercept presented with steroid-responsive subacute encephalopathy and foot drop. Brain and sural nerve biopsies demonstrated a T-cell perivascular infiltrate. Cerebrospinal fluid studies 18 months into the course of the illness demonstrated a GFAP antibody on mouse tissue immunofluorescence confirmed by cell-based assay. The patient was treated with steroids and cyclophosphamide leading to resolution of his symptoms. Conclusion: This case expands on the previously reported cases of GFAP immunoglobulin G autoimmunity by describing an associated inflammatory large fiber peripheral neuropathy.