MOG-IgG- versus AQP4-IgG-Positive Optic Neuritis in Thailand: Clinical Characteristics and Long-Term Visual Outcomes Comparison

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 spectrum of myelin oligodendrocyte glycoprotein antibody-associated disease in Brazil: a single-center experience

BACKGROUND

 Anti-myelin oligodendrocyte glycoprotein (anti-MOG) antibody-associated disease (MOGAD) is an immune-mediated neurological disorder with a broad spectrum of clinical presentation that is often difficult to distinguish from other demyelinating diseases, such as multiple sclerosis and neuromyelitis optica spectrum disorder.

OBJECTIVE

 To describe the clinical and paraclinical characteristics of MOGAD in a Brazilian tertiary center.

METHODS

 We retrospectively reviewed the records of adult and pediatric patients who tested positive for anti-MOG antibodies and presented with clinical and radiological diseases compatible with MOGAD.

RESULTS

 Forty-one patients (10 children) were included: 56% female, 58% Caucasian, mean age at onset 31 years (range 6-64), with a mean disease duration of 59.6 months (range 1-264 months). The most frequent onset presentation was optic neuritis (68%), acute disseminated encephalomyelitis (ADEM, 12%), and myelitis (10%). A monophasic disease course was observed in 49%. EDSS median was 2.1 at the last visit. Most patients (83%) were under continuous immunosuppressive treatment. Azathioprine was the first-line treatment in 59%. In all ADEM cases, conus, and root involvement was radiologically observed on MRI.

CONCLUSION

 Brazilian MOGAD patients presented with a similar spectrum of previously reported MOGAD phenotypes. Conus and spinal root involvement seems to be frequently present in MOGAD-ADEM and could serve as radiologic characteristics of this clinical entity.

Long-Term Visual Prognosis in Patients With Aquaporin-4-Immunoglobulin G-Positive Neuromyelitis Optica Spectrum Disorder

BACKGROUND

To identify the factors associated with visual prognosis for functional and structural outcomes of optic neuritis (ON) in patients with aquaporin-4-immunoglobulin (AQP4-IgG)-positive neuromyelitis optica spectrum disorder (NMOSD).

METHODS

We included the eyes that experienced at least 1 episode of ON and were followed for at least 2 years after the first attack of ON in patients with AQP4-IgG-positive NMOSD. We performed a retrospective review of clinical data, including ophthalmological examination and orbital MRI, of 34 eyes of 22 patients. Functional outcomes were measured as final visual acuity, visual field index, and mean deviation and structural outcomes as final retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GCIPL) thickness.

RESULTS

The mean age at onset of the first ON was 42.7 ± 13.7, and all patients were female. The poor visual acuity was significantly associated with the worse final visual acuity and thinner RNFL and GCIPL. Older age also showed a negative correlation with RNFL thickness. The number of attacks was not statistically significant for functional and structural outcomes. The lesion involving the intracanalicular optic nerve to the chiasm on orbital MRI showed worse visual acuity and a thinner GCIPL. Rapid high-dose intravenous methylprednisolone pulse therapy within 3 days was statistically significant, with better visual acuity and more preserved GCIPL thickness.

CONCLUSIONS

Our results indicate that the severity of ON rather than the number of recurrences might be critical for the visual prognosis of patients with AQP4-IgG-positive NMOSD. Rapid treatment within 3 days may improve visual outcomes, and a younger age at onset may have better visual outcomes.