Development of a clinical score to estimate the probability of neuromyelitis optica in patients presenting with optic neuritis.

Background: Neuromyelitis Optica Spectrum Disorder (NMOSD) represents a significant etiology of optic neuritis (ON), primarily due to its severity and risk of sequelae. Early diagnosis is crucial to establish prompt treatment and avoid disability. However, its recognition in acute-phase ON can pose challenges. We aimed to develop a prognostic model for early suspicion of neuromyelitis optica (NMOSD) in patients presenting with ON.

Methods: Patients admitted to our emergency department between 2015 and 2020 with diagnosis of ON were enrolled in our study. We performed univariable analysis in our sample to identify variables associated with a final diagnosis of NMOSD. Based on our findings and previous literature, we selected four variables to develop a prognostic model to predict the risk of a diagnosis of NMOSD independent of anti-AQP4 status.

Results: We enrolled 63 participants with optic neuritis (45 women [71 %]; median age 34 years [interquartile range 29-47 years]), of which 18 were diagnosed with NMOSD (12 anti-AQP4 positive and 6 anti-AQP4 negative) and 45 with other demyelinating disease. Our final prognostic model included female gender, bilateral ON, absence of pain, and chiasmal involvement detected in orbit MRI into an NMOON risk score. This score aims to stratify patients into low, intermediate, and high-risk categories for NMOSD among those presenting with ON symptoms.

Conclusion: An easily accessible score with clinical and radiological information may early predict the risk of NMOSD to help in diagnostic and therapeutic decisions.