Proceedings of the 25th BCTRIMS Annual Meeting

Background: Neuromyelitis Optica Spectrum Disorder (MMOSD) represents an important cause of optic neuritis (ON) with a high risk of sequelae and recurrence. Early diagnosis is crucial, but its recognition in acute phase ON may be difficult. Anti-aquaporin-4 antibody (anti-AQP4) testing is not easily available in limited-resource scenarios, and different methods offer variable sensitivity profiles. These limitations represent a challenge for early diagnosis of NMOSD and emphasize the important prognostic role of clinical aspects in acute phase ON for suspicion of the disease.

Objectives: We aimed to develop an easily appliable prognostic model for suspicion of NMOSD in patients with ON.

Methods: Patients admitted to our emergency department between 2015 and 2020 with a 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; 6 anti-AQP4 negative) and 45 with other demyelinating disease. Our prognostic model included four variables and 1 point attributed to each of them: female gender, bilateral ON, painless, and chiasmal involvement in MRI. Application of our score in our sample provided the following distribution of NMOSD patients: 0: 0/7 (0%); 1: 5/23 (22%); 2: 6/23 (26%); 3: 6/9 (67%); 4: 1/1 (100%).

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