Clinical profile, imaging features and short term visual outcomes of Indian optic neuritis patients with and without seromarkers for myelin oligodendrocyte glycoprotein and neuromyelitis optica

MOG antibody-associated optic neuritis

Myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) is a demyelinating disorder, distinct from multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD). MOGAD most frequently presents with optic neuritis (MOG-ON), often with characteristic clinical and radiological features. Bilateral involvement, disc swelling clinically and radiologically, and longitudinally extensive optic nerve hyperintensity with associated optic perineuritis on MRI are key characteristics that can help distinguish MOG-ON from optic neuritis due to other aetiologies. The detection of serum MOG immunoglobulin G utilising a live cell-based assay in a patient with a compatible clinical phenotype is highly specific for the diagnosis of MOGAD. This review will highlight the key clinical and radiological features which expedite diagnosis, as well as ancillary investigations such as visual fields, visual evoked potentials and cerebrospinal fluid analysis, which may be less discriminatory. Optical coherence tomography can identify optic nerve swelling acutely, and atrophy chronically, and may transpire to have utility as a diagnostic and prognostic biomarker. MOG-ON appears to be largely responsive to corticosteroids, which are often the mainstay of acute management. However, relapses are common in patients in whom follow-up is prolonged, often in the context of early or rapid corticosteroid tapering. Establishing optimal acute therapy, the role of maintenance steroid-sparing immunotherapy for long-term relapse prevention, and identifying predictors of relapsing disease remain key research priorities in MOG-ON.

Clinical profile and challenges faced in the management of optic neuritis: the Indian scenario

PURPOSE

Optic neuritis (ON) is a relatively common ophthalmic disease that has recently received renewed attention owing to immunological breakthroughs. We studied the profile of patients with ON with special reference to antibody-mediated ON and the challenges faced in its management.

METHODS

Case records of patients with ON presenting to a tertiary eye-care center in South India were analyzed. Data on demographics, presenting visual acuity (VA), clinical features, seropositivity for aquaporin-4 immunoglobulin G (AQP4-IgG) and myelin oligodendrocyte glycoprotein immunoglobulin G (MOG-IgG), details of magnetic resonance imaging (MRI) of orbits and brain, and treatment were collected.

RESULTS

Among 138 cases with acute ON, male: female ratio was 1:2. Isolated ON was present in 41.3% of cases. Antibody testing of sera was performed in 68 patients only due to financial limitations. Among these, 48.5% were MOG-IgG-seropositive, 11.76% were AQP4-IgG-seropositive, and 30.88% samples were double seronegative. Other causes included multiple sclerosis (n = 4), lactational ON (n = 4), tuberculosis (n = 2), invasive perineuritis (n = 2), COVID-19 vaccination (n = 2), and COVID-19 (n = 1). The mean presenting best corrected visual acuity (BCVA) was 1.31 ± 1.16 logMAR (logarithm of the minimum angle of resolution). The mean BCVA at 3 months was 0.167 ± 0.46 logMAR. Only initial VA ≤ 'Counting fingers' (CF) had a significant association with the visual outcome for final VA worse than CF. The steep cost of investigations and treatment posed challenges for many patients in the management of ON.

CONCLUSION

MOG-IgG-associated ON is common in India. Unfortunately, financial constraints delay the diagnosis and timely management of ON, adversely affecting the outcome.

A 10-Year Single-Center Study of the Clinical Characteristics of Optic Neuritis-Related NMOSD, MS, and Double Seronegative Optic Neuritis, Together with Factors Predicting Visual Outcomes

The clinical characteristics of three types of optic neuritis (double seronegative optic neuritis; DN-ON, Neuromyelitis optica spectrum disorder-related optic neuritis; NMOSD-ON, and multiple sclerosis-related optic neuritis; MS-ON) were examined in order to identify factors that may affect good visual recovery in Thai patients. The study included patients diagnosed with three types of optic neuritis at Rajavithi Hospital between 2011 and 2020. Visual acuity at the end of 12 months was used as the treatment outcome. Multiple logistic regression analysis was used to evaluate potential predictors of good visual recovery. Of the 76 patients, 61 had optic neuritis, with DN-ON as the most common subtype (52.6%). MS-ON patients were significantly younger (28.3 ± 6.6 years, p = 0.002) and there was a female predominance in all subgroups (p = 0.076). NMOSD-ON patients had a significantly higher proportion of poor baseline VA (p < 0.001). None of the NMOSD-ON patients achieved 0.3 logMAR visual recovery in the 12-month period (p = 0.022). A delay in treatment with intravenous methylprednisolone (IVMP) for more than 7 days increased the risk of failure to gain 0.3 logMAR visual recovery by five times (OR 5.29, 95% CI 1.359–20.616, p = 0.016), with NMOSD-ON as the strongest predictor (OR 10.47, 95% CI; 1.095–99.993, p = 0.041). Early treatment with intravenous methylprednisolone may be important for achieving at least 0.3 logMAR visual recovery in Thai patients with optic neuritis.

[Typical and atypical optic neuritis]

Optic neuritis (ON) is one of the most common neuro-ophthalmic causes of vision loss worldwide. Demyelinating ON can be idiopathic or be one of the symptoms of autoimmune demyelinating diseases of the central nervous system (CNS) such as multiple sclerosis (MS), neuromyelitis optica spectrum disorders (NMOSD), myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). Demographic, clinical and radiological signs of ON in these CNS diseases have differences. In this regard, typical and atypical ON are currently distinguished. Recognizing the clinical features that differentiate typical MS-associated ON from atypical ON in NMOSD and MOGAD is important for choosing the correct disease management and treatment strategy. This review summarizes the data from clinical, laboratory, instrumental methods of management used for the differential diagnosis of optic neuritis.

Optic neuritis with potential for poor outcome

The Optic Neuritis Treatment Trial previously reported that corticosteroids accelerated visual recovery in optic neuritis (ON) without improving outcome. This finding related largely to multiple sclerosis (MS), and subsequently neurologists tended to await spontaneous recovery in ON. Since then, non-MS cases of ON have been identified with antibodies to aquaporin-4 (AQP4) or myelin oligodendrocyte glycoprotein (MOG). These disorders can closely mimic multiple sclerosis-associated or idiopathic demyelinating optic neuritis (MS/IDON) initially but risk a worse visual outcome. Scrutinising the clinical features and neuroimaging often enables differentiation between MS/IDON and other causes of ON. Early treatment with high-dose corticosteroids is an important determinant of visual outcome in non-MS/IDON. Prompt use of plasma exchange may also save sight. In this review, we contrast the presentations of myelin oligodendrocyte glycoprotein associated optic neuritis (MOG-ON) and aquaporin 4 associated optic neuritis (AQP4-ON) with MS/IDON and provide an approach to acute management while awaiting results of antibody testing.