Atypical Optic Neuritis: The Potential Red Flags.

Background: Many potential causes of optic nerve inflammation exist, including typical and atypical causes, which require different management strategies. Objective: The objective of this study is to identify red flags that help differentiate typical from atypical optic neuritis (ON). Materials and Methods: This prospective study included 66 patients (100 eyes) with immune-mediated ON from January 2016 to June 2019, carefully excluding the nonimmune causes. The clinico-radiological features, investigations, therapy, and outcome were analyzed. Results: We evaluated 33 cases each of typical and atypical ON. The typical group included 29 idiopathic ON and four associated with multiple sclerosis. Atypical ON included 19 neuromyelitis optica (NMO), seven MOG-associated ON (MOG-ON), and others due to Sjogren's syndrome, granulomatous polyangiitis, sarcoidosis, and IgG4 disease. Atypical ON occurred significantly and more frequently with extremes of ages (<10 or >70 years), bilateral simultaneous or severe vision loss with early disc pallor, multiple attacks, symptoms/neuro-imaging indicating non-MS disease e.g., long segment ON/myelitis, large confluent lesions, the involvement of optic tract, chiasma, area postrema or diencephalon, and (pachy) meningitis. Systemic involvement and poor outcomes despite steroids and second-line immunosuppression were observed more often in the atypical ON. Conclusions: The red flags indicating atypical ON are onset at extremes of age, multiple attacks, bilateral simultaneous or severe to very severe vision loss, early disc pallor, neurological symptoms, or imaging abnormalities suggesting non-MS disease, systemic involvement, and poor steroid responsiveness. The awareness might help the clinician promptly identify and escalate therapy to ensure a better outcome.

Myelin Oligodendrocyte Glycoprotein (MOG)-IgG Associated Demyelinating Disease: Our Experience with this Distinct Syndrome.

BACKGROUND: Discovery of serum myelin oligodendrocyte glycoprotein (MOG) antibody testing in demyelination segregated MOG-IgG disease from AQ-4-IgG positive NMOSD. AIMS: To study clinico-radiological manifestations, pattern of laboratory and electrophysiological investigations and response to treatment through follow up in MOG-IgG positive patients. METHOD: Retrospective data of MOG-IgG positive patients was collected. Demographics, clinical manifestations at onset and at follow up and relapses, anti AQ-4-IgG status, imaging and all investigations were performed, treatment of relapses and further immunomodulatory therapy were captured. RESULTS: In our 30 patients, F: M ratio was 2.75:1 and adult: child ratio 4:1. Relapses at presentation were optic neuritis {ON}(60%), longitudinally extensive transverse myelitis {LETM}(20%), acute disseminated encephalomyelitis {ADEM}(13.4%), simultaneous ON with myelitis (3.3%) and diencephalic Syndrome (3.3%). Salient MRI features were ADEM-like lesions, middle cerebellar peduncle fluffy infiltrates, thalamic and pontine lesions and longitudinally extensive ON {LEON} as well as non-LEON. Totally, 50% patients had a relapsing course. Plasma exchange and intravenous immunoglobulin worked in patients who showed a poor response to intravenous methylprednisolone. Prednisolone, Azathioprine, Mycophenolate and Rituximab were effective attack preventing agents. CONCLUSIONS: MOG-IgG related manifestations in our cohort were monophasic/recurrent/simultaneous ON, myelitis, recurrent ADEM, brainstem encephalitis and diencephalic Syndrome. MRI features suggestive of MOG-IgG disease were confluent ADEM-like lesions, middle cerebellar peduncle fluffy lesions, LETM, LEON and non-LEON. Where indicated, patients need to go on immunomodulation as it has a relapsing course and can accumulate significant disability. Because of its unique manifestations, it needs to be considered as a distinct entity. To the best of our knowledge, this is the largest series of MOG-IgG disease reported from India.

Myelin Oligodendrocyte Glycoprotein (MOG) Antibody-Associated CNS Demyelination: Clinical Spectrum and Comparison with Aquaporin-4 Antibody Positive Neuromyelitis Optica Spectrum Disorder.

BACKGROUND: The clinical phenotypes of myelin oligodendrocyte glycoprotein (MOG) antibody disease, its disease course, and treatment are poorly understood and much work needs to be done towards this. OBJECTIVE: To characterize the clinico-radiologic spectrum and treatment outcomes of MOG antibody disease and differentiate it from aquaporin-4 (AQP-4) antibody positive neuromyelitis optica spectrum disorders (NMO-SD). METHODS: A single-center, observational study from Western India during 2017-2019, of 48 patients with either MOG antibody positive (21 patients) or AQP-4 antibody positive (27 patients) central nervous system demyelination. RESULTS: MOG antibody group had median age 32.2 years, no gender bias, median disease duration 40 months, relapses in 9 patients (43%), and median 2.5 (1-16) episodes per patient. Onset phenotypes included isolated bilateral optic neuritis (ON) (43%), isolated unilateral ON (19%), acute brainstem syndrome (19%), simultaneous ON with myelitis (9%), isolated myelitis (5%), and acute disseminated encephalomyelitis optic neuritis (ADEM-ON) (5%). Characteristic neuroimaging abnormalities were anterior segment longitudinally extensive ON, upper brainstem, and thoracic cord involvement (both short and long segment lesions). Most patients (86%) responded well to steroids, only 3/21 required rescue immunotherapy. In total, 6 out of 46 eyes affected developed permanent visual disability, while one patient had motor disability. The features differentiating MOG from AQP-4 antibody group were: no female predilection, preferential optic nerve involvement, characteristic neuroimaging abnormalities, and favorable therapeutic response and outcome. CONCLUSIONS: MOG disease commonly presents as severe ON, myelitis, acute brainstem syndrome, ADEM or their combinations. Early identification, treatment, and maintenance immunosuppression are necessary. It can easily be differentiated from NMO-SD using clinico-radiological features and therapeutic response.