In this retrospective cohort study, researchers characterized the outcomes of patients who initially presented with optic neuritis (ON) based on their final diagnoses.
Researchers reviewed medical records of 33 patients with recurrent ON who, between 2004 and 2016, were observed at the Neuroimmunology Clinic of the Federal University of São Paulo. All patients experienced at least 2 or more clinical relapse episodes, a minimum of 4 weeks apart.
The final diagnoses of these patients were multiple sclerosis (MS; n=6), neuromyelitis optica spectrum disorder (NMOSD; n=14) or chronic relapsing inflammatory optic neuropathay (CRION; n=13).
A visual functional system score (VFSS) of 5 or more indicated significant clinical disability. Severe visual outcomes were visual acuity less than or equal to 20/200. Laboratory measurements included anti-AQP-4 antibody detection using a commercially available method.
During the first episode, most patients had unilateral presentation. Visual disability was recorded in 63.6%, 85.7% and 16.7% of patients with CRION, NMOSD and MS, respectively. The NMOSD group had the longest interval between first episode and final diagnosis, whereas MS had the shortest (90.3 vs 14.7 months; P=0.039). The median number of relapses were highest in the NMOSD arm.
Brain white-matter abnormalities were detected in all 6 MS patients but in only 23.1% and 42.9% of CRION and NMOSD patients, respectively. Of the 21 patients who were tested for anti-AQP-antibody, all 9 positive patients were in the NMOSD arm. Seven of those patients developed transverse myelitis.
Multivariate regression analysis demonstrated final appointment VFSS scores could predict the final diagnosis.
This study was limited by its retrospective design.
This is an important paper to highlight that NMOSD and CRION should be considered as a relatively common differential diagnosis for demyelinating optic neuritis.