Recurrent Optic Neuritis as the Initial Symptom in Demyelinating Diseases

Abstract

Background and purpose: Optic neuritis (ON) is an inflammation of the optic nerve that can be recurrent, with unilateral or bilateral presentation. Diagnosing recurrent cases may be challenging. We aimed to compare patients with recurrent ON as their initial symptom according to their following final diagnoses: multiple sclerosis (MS), neuromyelitis optica spectrum disorders (NMOSD), or chronic relapsing inflammatory optic neuropathy (CRION).

Methods: The medical records of patients with initial recurrent ON who were followed at the Neuroimmunology Clinic of the Federal University of São Paulo between 2004 and 2016 were analyzed retrospectively. Patients were classified according to their final diagnosis into MS, NMOSD, or CRION, and the characteristics of these groups were compared to identify predictive factors.

Results: Thirty-three patients with recurrent ON were included, and 6, 14, and 13 had final diagnoses of MS, NMOSD, and CRION, respectively. Most of the patients were female with unilateral and severe ON in their first episode, and the initial Visual Functional System Score (VFSS) was ≥5 in 63.6%, 85.7%, and 16.7% of the patients with CRION, NMOSD, and MS, respectively. Anti-aquaporin-4 antibodies were detected in 9 of 21 (42.8%) tested patients. Seven of nine (77.8%) seropositive NMOSD patients experienced transverse myelitis episodes during the follow-up period. A multivariate regression analysis showed that the VFSS at the last medical appointment predicted the final diagnosis.

Conclusions: A lower VFSS at the last medical appointment was predictive of MS. Patients with NMOSD and CRION have similar clinical characteristics, whereas NMOSD patients tend to have worse visual acuity.

Keywords: aquaporin 4; multiple sclerosis; neuromyelitis optica; optic neuritis; recurrence.

Fig. 1. Diagram of the selection and inclusion criteria for the study. AION: anterior ischemic optic neuropathy, CRION: chronic relapsing inflammatory optic neuropathy, IDS: isolated demyelinating syndrome, MS: multiple sclerosis, NMOSD: neuromyelitis optica spectrum disorders, ON: optic neuritis, Others: other diseases, RION: relapsing isolated optic neuritis.

Fig. 2. A: Initial VFSS according to the diagnosis: p=0.05 for CRION vs. MS, p=0.002 for NMOSD vs. MS, and p=0.52 for CRION vs. NMOSD. B: Final VFSS according to the diagnosis. p=0.035 for CRION vs. MS and p=0.011 for NMOSD vs. MS. p<0.05, statistically significant difference between the groups. CRION: chronic relapsing inflammatory optic neuropathy, MS: multiple sclerosis, NMOSD: neuromyelitis optica spectrum disorders, VFSS: Visual Functional System Score.

Fig. 3. A: Kaplan-Meier curve for unilateral VA ≤20/200 according to the diagnosis. B: Kaplan-Meier curve for bilateral VA ≤20/200 according to the diagnosis. p<0.05, statistically significant difference between the groups. CRION: chronic relapsing inflammatory optic neuropathy, NMOSD: neuromyelitis optica spectrum disorders, VA: visual acuity.

Fig. 4. Comparison between brain white-matter abnormalities in patients with final diagnoses of chronic relapsing inflammatory optic neuropathy (A) and multiple sclerosis (B).