Optic neuropathy: A 15-year retrospective observational study

Background: Optic neuropathies (ON) have several aetiologies and sometimes the diagnosis established ab initio is redefined after further investigations and/or new neurological events. We aim with this study to report clinical, paraclinical findings, treatment choices and disease course in patients admitted with a suspicion of acute or subacute optic neuropathy and to explore the diagnosis redefinition during follow-up and evaluate possible predictive factors that may influence that change. Methods: We retrospectively reviewed the medical records of 156 patients with ON admitted to the ward of our Neurology Department, between January 2004 and August 2019. Clinical, laboratory and imaging data, as well as treatment protocols and follow-up were analysed. Results: At the time of discharge from the ward, our cohort comprised 83 idiopathic ON (53.2%), 38 multiple sclerosis-related ON (24.4%), 23 ischemic ON (14.7%), 5 neuromyelitis optica spectrum disorder-related ON (3.2%), 1 Chronic relapsing inflammatory optic neuropathy (0.6%), 1 Leber hereditary optic neuropathy (0.6%), 1 vitamin B12 deficiency ON (0.6%), 2 Behcet ON (1.3%), 1 systemic lupus erythematosus - associated ON (0.6%), 1 syphilitic ON (0.6%). During follow-up, 129 patients retained the ward's discharge diagnosis (82.7%) while in 27 it was redefined (17.3%). The median time between admission and change in diagnosis was 12.3 (5.4 - 42.9) months. 67.1% of valid patients manifested atypical characteristics of optic neuritis (presence of one of the following clinical findings: bilateral eye involvement, visual acuity <= 0.1 at admission, worsening or non-substantial recovery of visual acuity during hospitalization), while only 32.9% presented with ON typical for optic neuritis. Idiopathic ON was the "etiology" at discharge that changed the most during follow-up both in ON typical and atypical for optic neuritis. More than a half of the individuals with MS-RON in our study presented visual acuity at admission <= 0.1. Multivariate Cox regression analysis demonstrated that the patients with ON atypical for optic neuritis had lower risk of having the initial diagnosis changed (HR = 0.320, 95% CI = 0.138-0.743, p = 0.008). Conclusion: Our study illustrates that some patients admitted with ON may have their diagnosis redefined during follow-up and it demonstrates that patients with ON atypical for optic neuritis are those in which the diagnosis is more likely to remain during follow-up. Furthermore, our population has clinical and paraclinical characteristics that reinforce conclusions from previous international studies.