Clinical characteristics and outcome of double-AQP4/MOG-seronegative and not MS-associated monophasic and relapsing demyelinating transverse myelitis: A monocenter study.

Background: Demyelinating acute transverse myelitis (ATM) may occur as part of the clinical presentation in multiple sclerosis (MS) as well as neuromyelitis optica spectrum disorder (NMOSD) and myelin-oligodendrocyte-glycoprotein antibody associated disease (MOGAD). However, some patients with demyelinating ATM do not fulfill diagnostic criteria of MS, NMOSD or MOGAD and some of these even experience more than one spinal relapse. As double-AQP4/MOG-seronegative demyelinating ATM (DSD-ATM) is poorly investigated so far and treatment recommendations for these patients are lacking, we aimed to investigate clinical features and outcome of these patients.

Methods: This is a retrospective chart-review study conducted at the Medical University of Innsbruck, using the Innsbruck MS database as well as medical charts to comprise a comprehensive cohort of people with DSD-ATM. We describe clinical and paraclinical characteristics as well as clinical outcome, comparing monophasic and relapsing DSD-ATM.

Results: Thirteen patients with relapsing and 19 with monophasic DSD-ATM were eligible for this study, of those 11 (34.4) female, with a mean age of 40.8 ± 15.5 years at first relapse and EDSS between 0 and 7.5 at last follow-up. While there was no difference in clinical outcome between these two groups, motor symptoms (p = 0.042, Z = -2.032) and higher age at first relapse (p = 0.024, ρ = 0.399) were predictors for poor outcome. No demographical or clinical variable, including magnetic resonance imaging and cerebrospinal fluid findings, was able to predict whether patients relapse or not after the first attack of ATM.

Conclusion: DSD-ATM is a rare and heterogenic entity of demyelinating disorders which may result in a relapsing disease course. Prediction of outcome and, thus, treatment choice remain challenging, requiring further studies.