Longitudinally extensive transverse myelitis: Impact on functional prognosis and mortality in a 10-year follow-up...

Neuromyelitis optica spectrum disorder (NMOSD) with positivity for aquaporin-4 antibody (AQP4-IgG) represents one of the mains etiologies of longitudinally extensive transverse myelitis (LETM). Advancements in early diagnosis and treatment have led to a decline in NMOSD-related mortality. However, long-term prognostic data for patients experiencing their first episode of LETM remain scarce, especially in Brazil. This study aims to evaluate the final diagnosis and long-term prognosis of patients with first episode of LETM and investigate factors associated with worse prognosis.

This is an observational retrospective study involving all consecutive patients diagnosed with longitudinally extensive myelopathy who were sequentially referred to the clinical neurology department of a brazilian tertiary hospital between January 2005 and December 2011. Only patients meeting the criteria for the first episode of idiopathic LETM were included. Data were retrieved from electronic medical records from October 2023 to January 2024.

39 patients met the inclusion criteria. After a median follow-up of 12 years, 51% patients remained with isolated monophasic seronegative LETM, 28% were diagnosed with NMOSD AQP4-IgG positive, 7.7% with NMOSD AQP4-IgG negative, 5% with MOGAD, 5% experienced recurrent seronegative LETM, and only 1 (2.6%) developed multiple sclerosis. The mortality rate was 10% at last follow-up, with a median time to death of 3 years. Deceased patients had a higher age at onset of LETM (OR 1.09, 95% CI 1.01-1.21). Among survivors, 17% had an Expanded Disability Status Scale (EDSS) ≥7 at last follow-up. Predictors of severe sequelae included higher EDSS at nadir (OR 5.29; 95% CI 1.38-39), pain as an initial myelitis symptom (OR 11.1; 95% CI 1.51-230) and spinal shock during the first myelitis (p < 0.001).

In this cohort, after a median 12-year follow-up, half of the patients remained as isolated monophasic seronegative LETM, mortality reached 10% and 83% of survivors were ambulatory. Predictors of poor prognosis included older age, presence of pain as an initial symptom and higher initial severity.