Myelin Oligodendrocyte Glycoprotein Antibody-Positive Optic Neuritis: Clinical Characteristics, Radiologic Clues, and Outcome

Orbital Inflammation in Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease: A Case Report and Review of the Literature

BACKGROUND

To present 2 patients with myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease with unilateral orbital inflammation, optic nerve head edema, and abnormalities of the optic nerve and nerve sheath on imaging. We review the most current literature on this important and uncommon clinical phenotype.

METHODS

A case report of 2 patients and a comprehensive review of the relevant literature on orbital inflammation in MOG antibody-associated disease (MOG-AD).

RESULTS

Two patients presented with decreased vision and unilateral orbital inflammation. Both had optic nerve head edema and abnormalities of the optic nerve and nerve sheath on imaging. The patients were treated with immunosuppressants and had improvement of vision changes as well as their orbital inflammatory signs. MOG antibody was positive in high titers in both patients. Only 3 other cases of orbital inflammation associated with MOG antibody have been described. In all cases, orbital signs responded rapidly to intravenous methylprednisolone, but the improvement in visual acuity was variable and less robust.

CONCLUSION

Orbital inflammation is a unique and underrecognized phenotype of MOG-AD with only a few reports in the literature. In patients who present with vision loss and orbital inflammation, MOG-AD should be considered in the differential.

The Pediatric Optic Neuritis Prospective Outcomes Study – Two-Year Results

PURPOSE

Pediatric optic neuritis (ON) is a rare disease that has not been well characterized. The Pediatric ON Prospective Outcomes Study (PON1) was the first prospective study to our knowledge aiming to evaluate visual acuity (VA) outcomes, including VA, recurrence risk, and final diagnosis 2 years after enrollment.

DESIGN

Nonrandomized observational study at 23 pediatric ophthalmology or neuro-ophthalmology clinics in the United States and Canada.

PARTICIPANTS

A total of 28 (64%) of 44 children initially enrolled in PON1 (age 3-<16 years) who completed their 2-year study visit.

METHODS

Participants were treated at the investigator's discretion.

MAIN OUTCOMES MEASURES

Age-normal monocular high-contrast VA (HCVA). Secondary outcomes included low-contrast VA (LCVA), neuroimaging findings, and final diagnoses.

RESULTS

A total of 28 participants completed the 2-year outcome with a median enrollment age of 10.3 years (range, 5-15); 46% were female, and 68% had unilateral ON at presentation. Final 2-year diagnoses included isolated ON (n = 11, 39%), myelin oligodendrocyte glycoprotein-associated demyelination (n = 8, 29%), multiple sclerosis (MS) (n = 4,14%), neuromyelitis optica spectrum disease (NMOSD) (n = 3, 11%), and acute disseminated encephalomyelitis (n = 2, 7%). Two participants (7%; 95% confidence interval [CI], 1-24) had subsequent recurrent ON (plus 1 participant who did not complete the 2-year visit); all had MS. Two other participants (7%) had a new episode in their unaffected eye. Mean presenting HCVA was 0.81 logarithm of the minimum angle of resolution (logMAR) (∼20/125), improving to 0.14 logMAR (∼20/25^-2) at 6 months, 0.12 logMAR (∼20/25^-2) at 1 year, and 0.11 logMAR (20/25^-1) at 2 years (95% CI, -0.08 to 0.3 [20/20⁺¹-20/40^-1]). Twenty-four participants (79%) had age-normal VA at 2 years (95% CI, 60-90); 21 participants (66%) had 20/20 vision or better. The 6 participants without age-normal VA had 2-year diagnoses of NMOSD (n = 2 participants, 3 eyes), MS (n = 2 participants, 2 eyes), and isolated ON (n = 2 participants, 3 eyes). Mean presenting LCVA was 1.45 logMAR (∼20/500^-2), improving to 0.78 logMAR (∼20/125⁺²) at 6 months, 0.69 logMAR (∼20/100⁺¹) at 1 year, and 0.68 logMAR (∼20/100⁺²) at 2 years (95% CI, 0.48-0.88 [20/50⁺¹-20/150^-1]).

CONCLUSIONS

Despite poor VA at presentation, most children had marked improvement in VA by 6 months that was maintained over 2 years. Associated neurologic autoimmune diagnoses were common. Additional episodes of ON occurred in 5 (18%) of the participants (3 relapses and 2 new episodes).

Optomyelitis associated with the presence of antibodies to myelin oligodendrocyte glycoprotein. Case report

Antibodies to myelin-oligodendrocyte glycoprotein (anti-MOG-IgG) is a specific biomarker that has been detected in peripheral blood from children with acute multiple encephalomyelitis (ADEM) as well as in adults with aquaporin-4 (AQP4), associated with seronegative opticoneuromyelitis spectrum disease (NMOSD), brainstem encephalitis, longitudinally disseminated transverse myelitis, and optic neuritis. Most experts now consider MOG-IgG-associated disorder (MOG-AD) an independent disease immunopathogenetically distinct from classical multiple sclerosis (MS) and aquaporin-4 (AQP4)-IgG-positive optomyelitis. Isolated, bilateral, and less frequently unilateral OH, with simultaneous or sequential involvement of the eyes, is the most frequent clinical manifestation of MOG-AD. Because of the significant overlap in the clinical and radiological picture, MOG-AD is often misdiagnosed as MS. Timely diagnosis is critical to ensure appropriate treatment. This article describes a clinical case of anti-MOG-IgG encephalomyelitis with late-onset ON initially diagnosed as MS.

OCT retinal nerve fiber layer thickness differentiates acute optic neuritis from MOG antibody-associated disease and Multiple Sclerosis: RNFL thickening in acute optic neuritis from MOGAD vs MS

BACKGROUND

Optic neuritis (ON) is the most common manifestation of myelin oligodendrocyte glycoprotein antibody associated disorder (MOGAD) and multiple sclerosis (MS). Acute ON in MOGAD is thought to be associated with more severe optic disk edema than in other demyelinating diseases, but this has not been quantitatively confirmed. The goal of this study was to determine whether optical coherence tomography (OCT) can distinguish acute ON in MOGAD from MS, and establish the sensitivity of OCT as a confirmatory biomarker of ON in these entities.

METHODS

This was a multicenter cross-sectional study of MOGAD and MS patients with peripapillary retinal nerve fiber layer (pRNFL) thickness measured with OCT within two weeks of acute ON symptom. Cirrus HD-OCT (Carl Zeiss Meditec, Inc. Dublin, CA, USA) was used to measure the pRNFL during acute ON. Eyes with prior ON or disk pallor were excluded. A receiver operating characteristic (ROC) curve analysis was performed to assess the ability of pRNFL thickness to distinguish MOGAD from MS.

RESULTS

Sixty-four MOGAD and 50 MS patients met study inclusion criteria. Median age was 46.5 years (interquartile range [IQR]: 34.3-57.0) for the MOGAD group and 30.4 years (IQR: 25.7-38.4) for the MS group (p<0.001). Thirty-nine (61%) of MOGAD patients were female compared to 42 (84%) for MS (p = 0.007). The median pRNFL thickness was 164 µm (IQR: 116-212) in 96 acute MOGAD ON eyes compared to 103 µm (IQR: 93-113) in 51 acute MS ON eyes (p<0.001). The ROC area under the curve for pRNFL thickness was 0.81 (95% confidence interval 0.74-0.88) to discriminate MOGAD from MS. The pRNFL cutoff that maximized Youden's index was 118 µm, which provided a sensitivity of 74% and specificity of 82% for MOGAD. Among 31 MOGAD and 48 MS eyes with an unaffected contralateral eye or a prior baseline, the symptomatic eye had a median estimated pRNFL thickening of 45 µm (IQR: 17-105) and 7.5 µm (IQR: 1-18), respectively (p<0.001). All MOGAD affected eyes had a ≥ 5 µm pRNFL thickening, whereas 26 (54%) MS affected eyes had a ≥ 5 µm thickening.

CONCLUSION

OCT-derived pRNFL thickness in acute ON can help differentiate MOGAD from MS. This can aid with early diagnosis and guide disease-specific therapy in the acute setting before antibody testing returns, and help differentiate borderline cases. In addition, pRNFL thickening is a sensitive biomarker for confirming acute ON in MOGAD, which is clinically helpful and could be used for adjudication of attacks in future MOGAD clinical trials.

Comparative study of AQP4-NMOSD, MOGAD and seronegative NMOSD: a single-center Belgian cohort

PURPOSE

To emphasize physio-pathological, clinical and prognosis differences between conditions causing serious and sometimes very similar clinical manifestations: anti-aquaporin-4 (AQP4) and anti-myelin oligodendrocyte glycoprotein (MOG) antibodies related diseases, and seronegative NMOSD (neuromyelitis optica spectrum disorders).

METHODS

Based on Wingerchuk et al. (Neurology 85:177-189, 2015) criteria for NMOSD and on those more recently proposed by Jarius et al. (J Neuroinflammation 15:134, 2018) for MOGAD (MOG associated disorders), we retrospectively surveyed 10 AQP4-NMOSD, 8 MOGAD and 2 seronegative NMOSD, followed at the specialized neuroimmunology unit of the CHU Liège.

RESULTS

Female predominance was only observed in AQP4 group. Age at onset was 37.8 and 27.7 years old for AQP4-NMOSD and MOGAD respectively. In both groups, the first clinical event most often consisted of optic neuritis (ON), followed by isolated myelitis. Fifteen of our 20 patients encountered a relapsing course with 90% relapses in AQP4-NMOSD, 62.5% in MOGAD and 50% in seronegative group, and a mean period between first and second clinical event of 7.1 and 4.8 months for AQP4-NMOSD and MOGAD, respectively. In total we counted 54 ON, with more ON per patient in MOGAD. MOG-associated ON mainly affected the anterior part of the optic nerve with a papilledema in 79.2% of cases. Despite a fairly good visual outcome after MOG-associated ON, retinal nerve fibre layer (RNFL) thickness decreased, suggesting a fragility of the optic nerve toward further attacks.

CONCLUSION

As observed in larger cohorts, our MOGAD and AQP4-NMOSD cases differ by clinical and prognostic features. A better understanding of these diseases should encourage prompt biological screening and hasten proper diagnosis and treatment.

Pain in Multiple Sclerosis: Understanding Pathophysiology, Diagnosis, and Management Through Clinical Vignettes

Neuropathic pain and other pain syndromes occur in the vast majority of patients with multiple sclerosis at some time during their disease course. Pain can become chronic and paroxysmal. In this review, we will utilize clinical vignettes to describe various pain syndromes associated with multiple sclerosis and their pathophysiology. These syndromes vary from central neuropathic pain or Lhermitte's phenomenon associated with central nervous system lesions to trigeminal neuralgia and optic neuritis pain associated with nerve lesions. Muscular pain can also arise due to spasticity. In addition, we will discuss strategies utilized to help patients manage these symptoms.

The changing landscape of optic neuritis: a narrative review

Optic neuritis (ON) is an inflammatory optic neuropathy that is often a harbinger of central nervous system (CNS) demyelinating disorders. ON is frequently misdiagnosed in the clinical arena, leading to either inappropriate management or diagnostic delays. As a result, patients may fail to achieve optimal recovery. The treatment response to corticosteroids and long term risk of multiple sclerosis was established in the first clinical trials conducted roughly 30 years ago. Spontaneous resolution was observed in the vast majority of patients and intravenous high-dose corticosteroids hastened recovery; half of the patients eventually developed multiple sclerosis. Over the ensuing decades, the number of inflammatory conditions associated with ON has significantly expanded exposing substantial variability in the prognosis, treatment, and management of ON patients. ON subtypes can frequently be distinguished by distinct clinical, serological, and radiological profiles allowing expedited and specialized treatment. Guided by an increased understanding of the immunopathology underlying optic nerve and associated CNS injuries, novel disease management strategies are emerging to minimize vision loss, improve long-term surveillance strategies, and minimize CNS injury and disability. Knowledge regarding the clinical signs and symptoms of different ON subtypes is essential to guide acute therapy, prognosticate recovery, accurately identify underlying CNS inflammatory disorders, and facilitate study design for the next generation of clinical and translational trials.

Pain Symptoms in Optic Neuritis

Signs and symptoms of optic neuritis (ON), an autoimmune disorder of the central nervous system (CNS), differ between patients. Pain, which is commonly reported by ON patients, may be the major reason for some patients to visit the clinic. This article reviews the presence of pain related to ON with respect to underlying disorders, including multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), and myelin oligodendrocyte glycoprotein associated disease (MOGAD). The aim of this review is to provide an overview of pain symptoms in accordance with the context of various pathophysiological explanations, assist in differential diagnosis of ON patients, especially at the onset of disease, and make recommendations to aid physicians make decisions for follow up diagnostic examinations.

Uncommon inflammatory/immune-related myelopathies

The differential diagnosis for immune-mediated myelopathies is broad. Although clinical manifestations overlap, certain presentations are suggestive of a particular myelopathy etiology. Spine MRI lesion characteristics including the length and location, and the pattern of gadolinium enhancement, help narrow the differential diagnosis and exclude an extrinsic compressive cause. The discovery of specific antibodies that serve as biomarkers of myelitis such as aquaporin-4-IgG and myelin-oligodendrocyte -glycoprotein-IgG (MOG-IgG), has improved our understanding of myelitis pathophysiology and facilitated diagnosis. In this review we will focus on the pathophysiology, clinical presentation, imaging findings and treatment and outcomes of uncommon immune-mediated myelopathies.

Emerging concepts in the treatment of optic neuritis: mesenchymal stem cell-derived extracellular vesicles

BACKGROUND

Optic neuritis (ON) is frequently encountered in multiple sclerosis, neuromyelitis optica spectrum disorder, anti-myelin oligodendrocyte glycoprotein associated disease, and other systemic autoimmune disorders. The hallmarks are an abnormal optic nerve and inflammatory demyelination; episodes of optic neuritis tend to be recurrent, and particularly for neuromyelitis optica spectrum disorder, may result in permanent vision loss.

MAIN BODY

Mesenchymal stem cell (MSC) therapy is a promising approach that results in remyelination, neuroprotection of axons, and has demonstrated success in clinical studies in other neuro-degenerative diseases and in animal models of ON. However, cell transplantation has significant disadvantages and complications. Cell-free approaches utilizing extracellular vesicles (EVs) produced by MSCs exhibit anti-inflammatory and neuroprotective effects in multiple animal models of neuro-degenerative diseases and in rodent models of multiple sclerosis (MS). EVs have potential to be an effective cell-free therapy in optic neuritis because of their anti-inflammatory and remyelination stimulating properties, ability to cross the blood brain barrier, and ability to be safely administered without immunosuppression.

CONCLUSION

We review the potential application of MSC EVs as an emerging treatment strategy for optic neuritis by reviewing studies in multiple sclerosis and related disorders, and in neurodegeneration, and discuss the challenges and potential rewards of clinical translation of EVs including cell targeting, carrying of therapeutic microRNAs, and prolonging delivery for treatment of optic neuritis.

Myelin Oligodendrocyte Glycoprotein Antibody-Associated Optic Neuritis-A Review

ABSTRACT

Our understanding of demyelinating optic neuritis has substantially evolved over the past 2 decades. With advancements in serological testing, antibodies against myelin oligodendrocyte glycoprotein (MOG) have been recently discovered in a distinct subset of demyelinating neuroinflammatory disease. Although MOG-immunoglobulin G (IgG)-associated disorder (MOGAD) has previously been seen as a component of neuromyelitis optica spectrum disorder (NMOSD), evidence increasingly suggests that it should be distinguished as a separate condition. The distinction of MOGAD from aquaporin-4 IgG NMOSD is imperative as treatment plans need to be tailored to its unique disease course and prognosis. The purpose of this review is to explore the nature and outcomes of MOGAD optic neuritis to help guide acute and long-term immunosuppressive treatment decisions.

Clinical and neuroimaging findings in MOGAD-MRI and OCT

Myelin oligodendrocyte glycoprotein antibody-associated disorders (MOGAD) are rare in both children and adults, and have been recently suggested to be an autoimmune neuroinflammatory group of disorders that are different from aquaporin-4 autoantibody-associated neuromyelitis optica spectrum disorder and from classic multiple sclerosis. In-vivo imaging of the MOGAD patient central nervous system has shown some distinguishing features when evaluating magnetic resonance imaging of the brain, spinal cord and optic nerves, as well as retinal imaging using optical coherence tomography. In this review, we discuss key clinical and neuroimaging characteristics of paediatric and adult MOGAD. We describe how these imaging techniques may be used to study this group of disorders and discuss how image analysis methods have led to recent insights for consideration in future studies.

Differences in the involved sites among different types of demyelinating optic neuritis in traditional MRI examination: A systematic review and meta-analysis

Background

Magnetic resonance imaging (MRI) plays a significant role in assessing optic neuropathy and providing more detailed information about the lesion of the visual pathway to help differentiate optic neuritis from other visual disorders. This study aims to systematically review the literature and verify if there is a real difference in lesion location among different demyelinating optic neuritis (DON) subtypes.

Methods

A systematic search was conducted including 8 electronic databases and related resources from the establishment of the database to August 25th, 2020. We classified DON into 5 subtypes and divided the visual pathways into five segments mainly comparing the differences in the involved visual pathway sites of different subtypes.

Results

Fifty-five studies were included in the analysis, and the abnormal rate was as high as 92% during the acute phase (within 4 weeks of symptom onset). With respect to lesion location, the orbital segment of the optic nerve was the most frequently involved (87%), whereas optic tract involvement was very rare. Involvement of the orbital segment was more common in myelin oligodendrocyte glycoprotein antibody-related optic neuritis (MOG-ON) (78%) and chronic relapsing inflammatory optic neuropathy (CRION) (81%), while the lesion was found to be located more posteriorly in neuromyelitis optica spectrum disorder-related optic neuritis (NMOSD-ON). With respect to lesion length, approximately 77% of MOG-ON patients had lesions involving more than half of the optic nerve length.

Conclusions

MRI examination is recommended for DON patients in the acute phase. In MOG-ON, anterior involvement is more common and the involved length is mostly more than 1/2 of the optic nerve length, whereas posterior involvement, intracranial segment, optic chiasm, or optic tract, is more common in NMOSD-ON.

Prospero registration number

CRD42020222430 (25-11-2020).

Variation in Evolving Optic Neuritis

BACKGROUND

The typical natural history of optic neuritis is subjected to important exceptions. Recognition of these exceptions has led to valuable insights regarding specific etiologies of optic neuritis. Exceptions to the natural history of recovering optic neuritis are well-defined (e.g., chronic relapsing inflammatory optic neuropathy), but exceptions to the natural history of evolving optic neuritis are less so.

METHODS

Medical records of patients illustrating an atypical course of evolving optic neuritis were reviewed in a retrospective manner. Each patient was treated by at least one of the authors.

RESULTS

Four patients were identified who illustrated an atypical natural history of incipient optic neuritis. Diagnoses included idiopathic optic neuritis, seropositive neuromyelitis optica spectrum disease, anti-myelin oligodendrocyte glycoprotein antibody disease, and multiple sclerosis in 1 patient each. Features of interest included an atypical temporal relationship between development of pain and onset of clinical optic neuropathy, an unusually protracted duration of pain, and an unusually long duration of worsening optic neuropathy before stabilization.

CONCLUSIONS

This case series illustrates the substantial clinical heterogeneity which may be observed in the evolution of optic neuritis. The temporal relationship between development of pain and onset of clinical optic neuropathy, the duration of pain, and duration of worsening optic neuropathy before stabilization are all subjected to significant variability. Although most patients with optic neuritis present with painful vision loss which progresses over 1 week or less, careful attention to the exceptions described herein may facilitate earlier recognition of diagnostically challenging cases.

Approach to Common Visual Complaints Presenting to the Outpatient Neurologist

Visual complaints are commonly encountered by the practicing neurologist. We review assessment of vision loss, diplopia, and positive visual phenomena, all of which require a thoughtful evaluation to localize disease and refine management. While many causative entities are unlikely to cause poor visual outcomes, including dry eyes, migraine, and congenital strabismus, others may threaten vision, life, or both, such as posterior communicating artery aneurysms, pituitary apoplexy, or temporal arteritis. A systematic approach to vision loss and diplopia is reviewed along with focused differential diagnoses.

Multidisciplinary Rehabilitation for Relapsing Myelin Oligodendrocyte Glycoprotein Antibody-associated Disease: A Case Report

Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is an inflammatory central nervous system disease that is driven by antibodies of the immunoglobulin G1 class. MOGAD has recently been recognized as an autoimmune disease; therefore, little is known about its rehabilitation. Here, we present a case of MOGAD that showed significant recovery after rehabilitation. A 58-year-old woman developed weakness in all extremities, dysarthria, and dysphagia. She visited the neurology department, and early brain and spine magnetic resonance imaging showed multifocal high intensity in the subcortical and periventricular white matter and the cervical cord. The patient's serum tested positive for anti-MOG antibodies. She was diagnosed with MOGAD and received intravenous steroid pulse therapy. After pharmacologic therapy, the patient was transferred to the rehabilitation department. Initially, her Functional Independence Measure (FIM) motor score was 26, allowing her to stand independently for only a few seconds. After 5 weeks of rehabilitation involving physical therapy, occupational therapy, and balance training, her FIM motor score improved to 60. However, 4 months after discharge, the disease relapsed with symptoms of motor weakness in all extremities, and steroid treatment was initiated. On the second admission, her FIM motor score was 42, but after continuous multidisciplinary rehabilitation, it improved to 76. Computerized cognitive therapy improved her cognitive function, from a Korean version of the Mini-Mental State Examination score of 23 on the first admission to 30 on final discharge. Since MOGAD is a relapsing disease, a favorable outcome can be achieved with continuous monitoring and multidisciplinary, symptom-specific rehabilitation.

Diagnosis and Management of Central Nervous System Demyelinating Disorders

The spectrum of demyelinating diseases affecting the central nervous system is broad. Although many have a chronic course, neuroinflammatory conditions often present with acute to subacute onset symptoms requiring hospitalization when severe. This article reviews the acute phase assessment and management of these disorders, with a particular focus on multiple sclerosis, neuromyelitis optica spectrum disorder, myelin oligodendrocyte glycoprotein antibody disorder, and several atypical demyelinating diseases.

Chiasmatic lesions on conventional magnetic resonance imaging during the first event of optic neuritis in patients with neuromyelitis optica spectrum disorder and myelin oligodendrocyte glycoprotein-associated disease in a Latin American cohort

BACKGROUND AND PURPOSE

Optic neuritis (ON) is often the initial symptom of neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein-associated disease (MOGAD). We aimed to compare the frequency and pattern of chiasmatic lesions in MOGAD-related ON (MOGAD-ON) and NMOSD-related ON (NMOSD-ON) using conventional brain imaging (magnetic resonance imaging [MRI]) in Latin America (LATAM).

METHODS

We reviewed the medical records and brain MRI (≤30 days from ON onset) of patients with a first event of MOGAD-ON and NMOSD-ON. Patients from Argentina (n = 72), Chile (n = 21), Ecuador (n = 31), Brazil (n = 30), Venezuela (n = 10) and Mexico (n = 82) were included. Antibody status was tested using a cell-based assay. Demographic, clinical, imaging and prognostic (as measured by the Visual Functional System Score [VFSS] of the Expanded Disability Status Scale) data were compared.

RESULTS

A total of 246 patients (208 NMOSD and 38 MOGAD) were included. No differences were found in gender and ethnicity between the groups. We observed chiasmatic lesions in 66/208 (31.7%) NMOSD-ON and in 5/38 (13.1%) MOGAD-ON patients (p = 0.01). Of these patients with chiasmatic lesions, 54/66 (81.8%) and 4/5 had associated longitudinally extensive optic nerve lesions, 45/66 (68%) and 4/5 had bilateral lesions, and 31/66 (47%) and 4/5 showed gadolinium-enhancing chiasmatic lesions, respectively. A positive correlation was observed between VFSS and presence of bilateral (r = 0,28, p < 0.0001), chiasmatic (r = 0.27, p = 0.0001) and longitudinally extensive lesions (r = 0,25, p = 0.0009) in the NMOSD-ON group, but no correlations were observed in the MOGAD-ON group.

CONCLUSIONS

Chiasmatic lesions were significantly more common in NMOSD than in MOGAD during an ON attack in this LATAM cohort. Further studies are needed to assess the generalizability of these results.

Evidence for and against subclinical disease activity and progressive disease in MOG antibody disease and neuromyelitis optica spectrum disorder

Myelin oligodendrocyte glycoprotein antibody disease (MOGAD) and aquaporin-4 IgG seropositive neuromyelitis optica spectrum disorder (AQP4-IgG+ NMOSD) are generally considered to be relapsing disorders, without clinical progression or subclinical disease activity outside of clinical relapses, in contrast to multiple sclerosis (MS). With advances in the diagnosis and treatment of these conditions, prolonged periods of remission without relapses can be achieved, and the question of whether progressive disease courses can occur has re-emerged. In this review, we focus on studies exploring evidence for and against relapse-independent clinical progression and/or subclinical disease activity in patients with MOGAD and AQP4-IgG+ NMOSD.

Recurrent ataxia and dysarthria in myelin oligodendrocyte glycoprotein antibody-associated disorder

The spectrum of central nervous system demyelinating disorders is vast and heterogeneous and, often, with overlapping clinical presentations. Misdiagnosis might occur in some cases with serious therapeutic repercussions. However, introduction of several new biomarkers such as aquaporin-4 IgG and myelin oligodendrocyte glycoprotein IgG has made distinction between diseases such as multiple sclerosis and myelin oligodendrocyte glycoprotein antibody-associated disorder easier. Here, we report a case of a 15-year-old male patient with subacute multifocal neurological presentation without encephalopathy, eventually diagnosed as myelin oligodendrocyte glycoprotein antibody-associated disorder.

Chronic Relapsing Inflammatory Optic Neuropathy (CRION)

Purpose of review

This review highlights the epidemiology, clinical and radiologic characteristics of chronic relapsing inflammatory optic neuropathy (CRION) and treatment modalities.

Recent findings

Summary

CRION is an inflammatory optic neuropathy that is characterized by a chronic and relapsing course, that is characterized by pain associated with subacute vision loss. It is favorably responsive but highly dependent on corticosteroids with frequent relapses in the setting of steroid tapering. Additional diagnostic biomarkers and further studies are required to better diagnose and treat this rare but potentially debilitating condition.

Validation of a Flow Cytometry Live Cell-Based Assay to Detect Myelin Oligodendrocyte Glycoprotein Antibodies for Clinical Diagnostics

BACKGROUND

Myelin oligodendrocyte glycoprotein antibodies (MOG Ab) are essential in the diagnosis of MOG Ab-associated disease (MOGAD). Live cell-based assays (CBAs) are the gold standard for MOG Ab detection with improved sensitivity and specificity over fixed CBAs. A number of testing centers have used flow cytometry for its high throughput and quantitative utility. Presently, there is increasing demand to translate these research-based methods into an accredited routine diagnostic setting.

METHODS

A flow cytometry live CBA was used to detect MOG Ab in patients with demyelination. Serostatuses were compared between a research-based assay and a streamlined diagnostic assay. Inter-laboratory validation of the streamlined assay was performed in an accredited diagnostic laboratory. Further streamlining was performed by introducing a borderline serostatus range and reducing the number of controls used to determine the positivity threshold.

RESULTS

High serostatus agreement (98%-100%) was observed between streamlined and research-based assays. Intra- and inter-assay imprecision was improved in the streamlined assay (mean intra- and inter-assay CV = 7.3% and 27.8%, respectively) compared to the research-based assay (mean intra- and inter-assay CV = 11.8% and 33.6%, respectively). Borderline positive and clear positive serostatuses were associated with confirmed phenotypes typical of MOGAD. Compared to using 24 controls, robust serostatus classification was observed when using 13 controls without compromising analytical performance (93%-98.5% agreement).

CONCLUSIONS

Flow cytometry live CBAs show robust utility in determining MOG Ab serostatus. Streamlining and standardizing use of this assay for diagnostics would improve the accuracy and reliability of routine testing to aid diagnosis and treatment of patients with demyelination.

Visual fields and optical coherence tomography (OCT) in neuro-ophthalmology: Structure-function correlation

Visual field (VF) testing is an essential component of the neurological examination. The differential diagnosis of VF defects depends on relating this measure of afferent visual function to the structure of the visual pathway and optical coherence tomography (OCT) is an invaluable tool for detailed structural evaluation of the optic nerve and retina. This review describes the ways in which interpretation of VF and OCT can be used together to increase the accuracy of the localization of lesions along the visual pathway. Lesions of the anterior visual pathway (originating in ganglion cells or nerve fibre layer of the retina or optic nerve) will typically produce defects that respect the horizontal midline, reflecting the arcuate path of the ganglion cell axons as they travel to the optic nerve. OCT of peripapillary retinal nerve fibre layer and ganglion cell complex (GCC) will typically demonstrate irreversible thinning in compressive and demyelinating lesions affecting anterior visual pathway. Chiasmal lesions produce highly localizable VF defects (junctional scotoma and bitemporal hemianopia) which correspond to the thinning of nasal portion of GCC. Lesions of the optic tract result in incongruous homonymous hemianopia on VF with corresponding hemianopic thinning on GCC developing within months. Lesions affecting optic radiations usually produce more congruous homonymous VF defects and can also produce homonymous thinning on GCC, however, this takes much longer to develop as trans-synaptic degeneration at the lateral geniculate body must occur.

Retinal optical coherence tomography and magnetic resonance imaging in neuromyelitis optica spectrum disorders and MOG-antibody associated disorders: an updated review

INTRODUCTION

Neuromyelitis optica spectrum disorders (NMOSD) and myelin oligodendrocyte glycoprotein IgG antibody-associated disorders (MOGAD) comprise two groups of rare neuroinflammatory diseases that cause attack-related damage to the central nervous system (CNS). Clinical attacks are often characterized by optic neuritis, transverse myelitis, and to a lesser extent, brainstem encephalitis/area postrema syndrome. Retinal optical coherence tomography (OCT) is a non-invasive technique that allows for in vivo thickness quantification of the retinal layers. Apart from OCT, magnetic resonance imaging (MRI) plays an increasingly important role in NMOSD and MOGAD diagnosis based on the current international diagnostic criteria. Retinal OCT and brain/spinal cord/optic nerve MRI can help to distinguish NMOSD and MOGAD from other neuroinflammatory diseases, particularly from multiple sclerosis, and to monitor disease-associated CNS-damage.

AREAS COVERED

This article summarizes the current status of imaging research in NMOSD and MOGAD, and reviews the clinical relevance of OCT, MRI and other relevant imaging techniques for differential diagnosis, screening and monitoring of the disease course.

EXPERT OPINION

Retinal OCT and MRI can visualize and quantify CNS damage in vivo, improving our understanding of NMOSD and MOGAD pathology. Further efforts on the standardization of these imaging techniques are essential for implementation into clinical practice and as outcome parameters in clinical trials.

Facial Nerve Involvement Accompanying Optic Neuritis Secondary to Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disorder

ABSTRACT

We present the first reported case of facial nerve involvement accompanying an optic neuritis in myelin oligodendrocyte glycoprotein antibody-associated disorder.

Approach to optic neuritis: An update

Over the past few years, there has been remarkable development in the area of optic neuritis. The discovery of new antibodies has improved our understanding of the pathology of the disease. Antiaquaporin4 antibodies and antimyelin oligodendrocytes antibodies are now considered as distinct entities of optic neuritis with their specific clinical presentation, neuroimaging characteristics, treatment options, and course of the disease. Similarly, there has been a substantial change in the treatment of optic neuritis which was earlier limited to steroids and interferons. The development of new immunosuppressant drugs and monoclonal antibodies has reduced the relapses and improved the prognosis of optic neuritis as well as an associated systemic disease. This review article tends to provide an update on the approach and management of optic neuritis.

Five-year visual outcomes after optic neuritis in anti-MOG antibody-associated disease

INTRODUCTION

Optic neuritis (ON) is a major phenotype of clinical attack related to demyelinating neurological diseases of the central nervous system, including multiple sclerosis (MS), anti-aquaporin-4 (AQP4) antibody-positive neuromyelitis optica spectrum disorder (NMOSD), and anti-myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). As the concept of MOGAD is relatively new, the long-term visual outcomes after ON in MOGAD remains unclear.

METHODS

To elucidate the long-term visual prognosis after ON in MOGAD, patients with MOGAD whose visual acuity were regularly followed for more than 5 years from the onset of ON were enrolled. Best-corrected visual acuity (BCVA) at nadir in the acute phase and at 1 and 5 years from onset was evaluated. The data from patients with MOGAD were compared with those from patients with MS or anti-AQP4-positive NMOSD.

RESULTS

Twenty-three patients (31 ON-involved eyes) with MOGAD, 20 patients (24 ON-involved eyes) with MS, and 22 patients (24 ON-involved eyes) with anti-AQP4-positive NMOSD were evaluated. All BCVA at nadir, 1 year, and 5 years from the onset of ON were much worse in anti-AQP4-positive NMOSD than in MS (p = 0.0024) and MOGAD (p = 0.0014) patients. In MOGAD and anti-AQP4-positive NMOSD, the serum disease-specific antibody titer was not associated with the subsequent visual prognosis. Visual acuity had almost fully recovered spontaneously or shortly after initiating acute treatment in 22 of the 23 patients with MOGAD-ON. The administration of high-dose intravenous steroid therapy further facilitated early recovery of visual acuity. Meanwhile, a small fraction of patients with extensive optic nerve lesions involving the chiasma irreversibly experienced severe visual impairment despite appropriate acute treatment.

CONCLUSION

Although a small fraction of patients with MOGAD who presented with extensive optic nerve lesions experienced irreversible severe visual impairment, the long-term visual outcomes after 5 years from ON in patients with MOGAD were generally as good as that in patients with MS and much better than that in patients with anti-AQP4-positive NMOSD.

Myelin-oligodendrocyte glycoprotein antibody-associated disease

Myelin-oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is a recently identified autoimmune disorder that presents in both adults and children as CNS demyelination. Although there are clinical phenotypic overlaps between MOGAD, multiple sclerosis, and aquaporin-4 antibody-associated neuromyelitis optica spectrum disorder (NMOSD) cumulative biological, clinical, and pathological evidence discriminates between these conditions. Patients should not be diagnosed with multiple sclerosis or NMOSD if they have anti-MOG antibodies in their serum. However, many questions related to the clinical characterisation of MOGAD and pathogenetic role of MOG antibodies are still unanswered. Furthermore, therapy is mainly based on standard protocols for aquaporin-4 antibody-associated NMOSD and multiple sclerosis, and more evidence is needed regarding how and when to treat patients with MOGAD.

At this Junction…

An 81-year-old woman developed painful vision loss to hand motions in the right eye over a several-day period. Dilated fundus examination revealed no acute pathology, but automated perimetry showed a superotemporal visual field defect in the asymptomatic left eye, suggestive of a junctional scotoma. Magnetic resonance imaging demonstrated enhancement of the right optic nerve extending to its junction with the optic chiasm. The patient's vision failed to improve with intravenous corticosteroids, but demonstrated significant improvement with therapeutic plasma exchange. She was subsequently found to be seropositive for aquaporin-4 autoantibodies, confirming the diagnosis of neuromyelitis optic spectrum disorder.

Pathogenesis of autoimmune demyelination: from multiple sclerosis to neuromyelitis optica spectrum disorders and myelin oligodendrocyte glycoprotein antibody-associated disease

Autoimmunity plays a significant role in the pathogenesis of demyelination. Multiple sclerosis (MS), neuromyelitis optica spectrum disorders (NMOSD) and myelin oligodendrocyte glycoprotein antibody‐associated disease (MOGAD) are now recognised as separate disease entities under the amalgam of human central nervous system demyelinating disorders. While these disorders share inherent similarities, investigations into their distinct clinical presentations and lesion pathologies have aided in differential diagnoses and understanding of disease pathogenesis. An interplay of various genetic and environmental factors contributes to each disease, many of which implicate an autoimmune response. The pivotal role of the adaptive immune system has been highlighted by the diagnostic autoantibodies in NMOSD and MOGAD, and the presence of autoreactive lymphocytes in MS lesions. While a number of autoantigens have been proposed in MS, recent emphasis on the contribution of B cells has shed new light on the well‐established understanding of T cell involvement in pathogenesis. This review aims to synthesise the clinical characteristics and pathological findings, discuss existing and emerging hypotheses regarding the aetiology of demyelination and evaluate recent pathogenicity studies involving T cells, B cells, and autoantibodies and their implications in human demyelination.

Antibody-Mediated Autoimmune Diseases of the CNS: Challenges and Approaches to Diagnosis and Management

Antibody-mediated disorders of the central nervous system (CNS) are increasingly recognized as neurologic disorders that can be severe and even life-threatening but with the potential for reversibility with appropriate treatment. The expanding spectrum of newly identified autoantibodies targeting glial or neuronal (neural) antigens and associated clinical syndromes (ranging from autoimmune encephalitis to CNS demyelination) has increased diagnostic precision, and allowed critical reinterpretation of non-specific neurological syndromes historically associated with systemic disorders (e.g., Hashimoto encephalopathy). The intracellular vs. cell-surface or synaptic location of the different neural autoantibody targets often helps to predict the clinical characteristics, potential cancer association, and treatment response of the associated syndromes. In particular, autoantibodies targeting intracellular antigens (traditionally termed onconeural autoantibodies) are often associated with cancers, rarely respond well to immunosuppression and have a poor outcome, although exceptions exist. Detection of neural autoantibodies with accurate laboratory assays in patients with compatible clinical-MRI phenotypes allows a definite diagnosis of antibody-mediated CNS disorders, with important therapeutic and prognostic implications. Antibody-mediated CNS disorders are rare, and reliable autoantibody identification is highly dependent on the technique used for detection and pre-test probability. As a consequence, indiscriminate neural autoantibody testing among patients with more common neurologic disorders (e.g., epilepsy, dementia) will necessarily increase the risk of false positivity, so that recognition of high-risk clinical-MRI phenotypes is crucial. A number of emerging clinical settings have recently been recognized to favor development of CNS autoimmunity. These include antibody-mediated CNS disorders following herpes simplex virus encephalitis or occurring in a post-transplant setting, and neurological autoimmunity triggered by TNFα inhibitors or immune checkpoint inhibitors for cancer treatment. Awareness of the range of clinical and radiological manifestations associated with different neural autoantibodies, and the specific settings where autoimmune CNS disorders may occur is crucial to allow rapid diagnosis and early initiation of treatment.

Optic neuritis classification in 2021

Optic neuritis (ON) can be associated with inflammatory disease of the central nervous system or can be isolated, with or without relapse. It can also be associated with infectious or systemic disease. These multiple associations based on a variety of clinical, radiological, and biological criteria that have changed over time have led to overlapping phenotypes: a single ON case can be classified in several ways simultaneously or over time. As early, intensive treatment is often required, its diagnosis should be rapid and precise. In this review, we present the current state of knowledge about diagnostic criteria for ON aetiologies in adults and children, we discuss overlapping phenotypes, and we propose a homogeneous classification scheme. Even if distinctions between typical and atypical ON are relevant, their phenotypes are largely overlapping, and clinical criteria are neither sensitive enough, nor specific enough, to assure a diagnosis. For initial cases of ON, clinicians should perform contrast enhanced MRI of the brain and orbits, cerebral spinal fluid analysis, and biological analyses to exclude secondary infectious or inflammatory ON. Systematic screening for MOG-IgG and AQP4-IgG IgG is recommended in children but is still a matter of debate in adults. Early recognition of neuromyelitis optica spectrum disorder, MOG-IgG-associated disorder, and chronic relapsing idiopathic optic neuritis is required, as these diagnoses require therapies for relapse prevention that are different from those used to treat multiple sclerosis.

Past, present and future role of retinal imaging in neurodegenerative disease

Retinal imaging technology is rapidly advancing and can provide ever-increasing amounts of information about the structure, function and molecular composition of retinal tissue in humans in vivo. Most importantly, this information can be obtained rapidly, non-invasively and in many cases using Food and Drug Administration-approved devices that are commercially available. Technologies such as optical coherence tomography have dramatically changed our understanding of retinal disease and in many cases have significantly improved their clinical management. Since the retina is an extension of the brain and shares a common embryological origin with the central nervous system, there has also been intense interest in leveraging the expanding armamentarium of retinal imaging technology to understand, diagnose and monitor neurological diseases. This is particularly appealing because of the high spatial resolution, relatively low-cost and wide availability of retinal imaging modalities such as fundus photography or OCT compared to brain imaging modalities such as magnetic resonance imaging or positron emission tomography. The purpose of this article is to review and synthesize current research about retinal imaging in neurodegenerative disease by providing examples from the literature and elaborating on limitations, challenges and future directions. We begin by providing a general background of the most relevant retinal imaging modalities to ensure that the reader has a foundation on which to understand the clinical studies that are subsequently discussed. We then review the application and results of retinal imaging methodologies to several prevalent neurodegenerative diseases where extensive work has been done including sporadic late onset Alzheimer's Disease, Parkinson's Disease and Huntington's Disease. We also discuss Autosomal Dominant Alzheimer's Disease and cerebrovascular small vessel disease, where the application of retinal imaging holds promise but data is currently scarce. Although cerebrovascular disease is not generally considered a neurodegenerative process, it is both a confounder and contributor to neurodegenerative disease processes that requires more attention. Finally, we discuss ongoing efforts to overcome the limitations in the field and unmet clinical and scientific needs.

Working up a child with demyelinating optic neuritis: Striking a balance!

Pediatric optic neuritis (PON) is one of the commonest causes of acute vision loss in children. Although it might often be postinfectious or postvaccination, recent understanding and available evidence suggest that it can be the first manifestation of a neuro-inflammatory syndrome such as multiple sclerosis, neuromyelitis optica spectrum disorder, acute disseminated encephalomyelitis or myelin oligodendrocyte glycoprotein associated optic neuritis. Therefore, neuroimaging, serological testing, cerebrospinal fluid analysis, testing for various systemic autoimmune conditions become a part of the workup. However, this can be exhaustive and expensive, especially in countries with limited access to health insurance. Many recent studies suggest that neuroimaging and few clinical features can provide clues to the underlying etiology. However, serological tests can provide a confirmatory evidence. Therefore, in this mini-review, we propose a balanced approach to the evaluation of PON, based on the available literature emanating in the last decade.

The diagnostic dilemma of bilateral optic neuritis and idiopathic intracranial hypertension coexistence in a patient with recent COVID-19 infection

Owing to autoantibody production and thrombophilic disorders in COVID-19, physicians must have low threshold to investigate secondary IIH and demyelinating disorders in patients with headache and decreased vision following recent COVID-19 infection.

Age-dependent favorable visual recovery despite significant retinal atrophy in pediatric MOGAD: how much retina do you really need to see well?

Background

To investigate age-related severity, patterns of retinal structural damage, and functional visual recovery in pediatric and adult cohorts of myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) optic neuritis (ON).

Methods

All MOGAD patients from the 5 participating centers were included. Patients with initial manifestation <18 years were included in the pediatric (MOGAD^ped) cohort and patients with ≥18 years in the adult (MOGAD^adult) cohort. For patients with MOGAD ON, examinations at least ≥6 months after ON onset were included in the analyses. Using spectral domain optical coherence tomography (SD-OCT), we acquired peripapillary retinal nerve fiber layer thickness (pRNFL) and volumes of combined ganglion cell and inner plexiform layer (GCIPL). High- and 2.5% low-contrast visual acuity (HCVA, LCVA) and visual-evoked potentials (VEP) were obtained.

Results

Twenty MOGAD^ped (10.3±3.7 years, 30 MOGAD ON eyes) and 39 MOGAD^adult (34.9±11.6 years, 42 MOGAD ON eyes) patients were included. The average number of ON episodes per ON eye was similar in both groups (1.8±1.3 and 2.0±1.7). In both pediatric and adult MOGAD, ON led to pronounced neuroaxonal retinal atrophy (pRNFL: 63.1±18.7 and 64.3±22.9 μm; GCIPL: 0.42±0.09 and 0.44±0.13 mm³, respectively) and moderate delay of the VEP latencies (117.9±10.7 and 118.0±14.5 ms). In contrast, visual acuity was substantially better in children (HCVA: 51.4±9.3 vs. 35.0±20.6 raw letters, p=0.001; LCVA: 22.8±14.6 vs. 13.5±16.4, p=0.028). Complete visual recovery (HCVA-logMAR 0.0) occurred in 73.3% of MOGAD^ped and 31% MOGAD^adults ON eyes, while 3.3% and 31% demonstrated moderate to severe (logMAR > 0.5) visual impairment. Independent of retinal atrophy, age at ON onset significantly correlated with visual outcome.

Conclusion

Pediatric MOGAD ON showed better visual recovery than adult MOGAD ON despite profound and almost identical neuroaxonal retinal atrophy. Age-related cortical neuroplasticity may account for the substantial discrepancy between structural changes and functional outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-021-02160-9.

The occurrence of myelin oligodendrocyte glycoprotein antibodies in aquaporin-4-antibody seronegative Neuromyelitis Optica Spectrum Disorder: A systematic review and meta-analysis

BACKGROUND

Despite inclusion in neuromyelitis optica spectrum disorders (NMOSD), myelin oligodendrocyte glycoprotein antibody (MOG-Ab)-associated diseases are increasingly recognized as an independent disease entity. In this study, we conducted a systematic review and meta-analysis to comprehensively update the rate of occurrence of MOG-Ab in Aquaporin4 (AQP4)-antibody seronegative NMOSD.

METHODS

We searched PubMed, EMBASE, and Cochrane databases for studies reporting the rates of patients with MOG-Ab in NMOSD. Fixed or random-effects models were used to pool results across studies.

RESULTS

Fourteen studies met the inclusion criteria. Overall, MOG-Abs positive patients comprised 9.3% of all NMO/NMOSD (95% confidence interval [CI] 7.9%-10.8%, I² = 13.1%), 32.5% of all AQP4-Ab seronegative NMO/NMOSD (95% CI 25.7%-39.3%, I² = 45.8%), and 41.6% of AQP4-Ab seronegative NMOSD cases diagnosed by IPND 2015 criteria (95% CI 35.1%-48.2%, I² = 0.0%). The pooled prevalence of MOG-Ab was 31.0% among Asian AQP4-Ab seronegative NMO/NMOSD patients (95% CI 22.1%-39.9% I²=54.1%) and 34.3% in European seronegative NMO/NMOSD (95% CI 21.9%-46.7%, I² = 51.9%).

CONCLUSIONS

This study shows that MOG-Abs represent a substantial proportion of AQP4-Ab seronegative NMOSD patients despite different underlying mechanisms, clinical manifestations, and treatment response, suggesting MOG-Ab screening in AQP4-Ab seronegative NMOSD patients can facilitate accurate diagnoses and treatments.

Steroid-Resistant Double-Seronegative Optic Neuritis Responds Favorably to Plasma Exchange

The clinical presentation of optic neuritis is quite characteristic, and the epidemiology, differential diagnosis, and treatment protocol are well established. However, when the presentation of optic neuritis is atypical, bilateral, and intravenous steroid-resistant, the treatment guidelines are quite nebulous. We present a case of bilateral severe double-seronegative optic neuritis with catastrophic vision loss and intravenous steroid resistance. After an exhaustive investigation, we empirically treated our patient with plasma exchange therapy and obtained a dramatic recovery of vision. When an immune etiology is suspected, this case is instructive vis-a-vis the utility of plasma exchange in refractory cases of optic neuritis despite seronegativity.

Immune-Mediated Myelopathies: A Review of Etiologies, Diagnostic Approach, and Therapeutic Management

Myelopathy is a broad term used to describe a heterogeneous group of disorders that affects the spinal cord; the focus of this article will be a subgroup of these disorders with an autoimmune and inflammatory-based pathology. Symptoms typically develop over hours or days and then worsen over a matter of days to weeks, but sometimes can have a more insidious or subacute presentation, which can make the diagnosis more puzzling. Despite relatively low incidence rates, almost a third of affected patients are left with severely disabling symptoms. Prompt recognition of the underlying etiology is essential so that a specific targeted therapy can be implemented for optimal outcomes. The authors discuss a systematic approach to immune-mediated myelopathies, with a focus on the unique characteristics of each that may aid in diagnosis.

Current understanding of the epidemiologic and clinical characteristics of optic neuritis

Optic neuritis is an ocular disorder whose pathogenesis has not been fully determined, although autoimmune mechanisms have been suggested to be involved in its development. In recent years, anti-aquaporin-4 antibody (AQP4-Ab) and anti-myelin oligodendrocyte glycoprotein antibody (MOG-Ab) have been shown to play major roles in the development of optic neuritis. Because these two antibodies target different tissues, optic neuritis can be classified by the type of antibody. AQP4-Ab-positive optic neuritis responds poorly to steroid therapy and has a poor prognosis in terms of visual acuity. On the other hand, MOG-Ab-positive optic neuritis responds favorably to steroid therapy but is likely to recur when the dosage of steroids is reduced or discontinued. We first present the high incidence of idiopathic optic neuritis and discuss these relatively newer disease concepts of AQP4-Ab-positive optic neuritis and MOG-Ab-positive optic neuritis.

Optic chiasm involvement in AQP-4 antibody-positive NMO and MOG antibody-associated disorder

BACKGROUND

Optic neuritis (ON) is often the presenting symptom in inflammatory central nervous system demyelinating disorders.

OBJECTIVE

To compare the frequency and pattern of optic chiasm involvement in patients with aquaporin-4-immunoglobulin G (AQP4-IgG)-associated ON to patients with myelin oligodendrocyte glycoprotein-immunoglobulin G (MOG-IgG)-associated ON.

METHODS

Retrospective review of all patients evaluated at Mayo Clinic, Stanford University and Ramathibodi Hospital who were found to have: (1) ON, (2) either MOG-IgG or AQP4-IgG by cell-based assay, and (3) magnetic resonance imaging (MRI) at the time of ON. MRI was reviewed for contrast enhancement of the optic chiasm and the pattern of involvement.

RESULTS

One hundred and fifty-four patients (74 AQP4-IgG and 80 MOG-IgG) were included. Among patients with AQP4-IgG-ON, 20% had chiasmal involvement, compared with 16% of patients with MOG-IgG-ON (p = 0.66). In patients with chiasmal involvement, longitudinally extensive optic nerve enhancement (from orbit extending to chiasm) was identified in 54% of MOG-IgG-ON patients, compared with 7% of AQP4-IgG-ON patients (p = 0.01).

CONCLUSION

Chiasmal involvement of MOG-IgG-ON and AQP4-IgG-ON occur at more similar frequencies than previously reported. Furthermore, MOG-IgG-ON chiasmal involvement is more likely to be part of a longitudinally extensive optic nerve lesion.

A window into the future? MRI for evaluation of neuromyelitis optica spectrum disorder throughout the disease course

Neuromyelitis optica spectrum disorder (NMOSD) is a relapsing, inflammatory disease of the central nervous system marked by relapses often associated with poor recovery and long-term disability. Magnetic resonance imaging (MRI) is recognized as an important tool for timely diagnosis of NMOSD as, in combination with serologic testing, it aids in distinguishing NMOSD from possible mimics. Although the role of MRI for disease monitoring after diagnosis is not as well established, MRI may provide important prognostic information and help differentiate between relapses and pseudorelapses. Increasing evidence of subclinical disease activity and the emergence of newly approved, highly effective immunotherapies for NMOSD adjure us to re-evaluate MRI as a tool to guide optimal treatment selection and escalation throughout the disease course. In this article we review the role of MRI in NMOSD diagnosis, prognostication, disease monitoring, and treatment selection.

Comparative analysis of immunosuppressive therapies for myelin oligodendrocyte glycoprotein antibody-associated optic neuritis: a cohort study

AIMS

The optimal immunosuppressive therapy (IST) in patients with myelin oligodendrocyte glycoprotein antibody-associated optic neuritis (MOG-ON) remains uncertain. This study aimed to observe the disease course of MOG-ON and evaluate the therapeutic efficacy and tolerability of conventional immunosuppressants through Chinese cohort analysis.

METHODS

This bidirectional cohort study included 121 patients with MOG-ON between January 2015 and December 2018. The clinical features and annualised relapse rate (ARR) of patients with and without IST were analysed.

RESULTS

The median age at onset was 17.5 years, and the sex ratio (F:M) was 1.24. Of 121 patients, 77 patients relapsed and 61 patients were younger than 18 years at disease onset. The overall median ARR of 63 patients in the non-IST group was 0.5, with 46.0% patients showing relapse at a median follow-up of 33.5 months. In the IST group, the ARR decreased from 1.75 pre-IST to 0.00 post-IST in 53 patients who received IST exceeding 6 months, with 20.8% patients showing relapse at a median follow-up of 23.8 months. The relapse rates of patients treated with rituximab (RTX) and mycophenolate mofetil (MMF) were not statistically different, but the rate of discontinuation was significantly lower in the RTX-treated group (18.2% vs 57.7%, p=0.0017).

CONCLUSION

This study provides Class III evidence that both MMF and RTX may lower disease activity in patients with MOG-ON, and RTX showed better tolerability than MMF. However, observation after a single attack remains a good option because less than half of patients not on treatment suffered a relapse.

Central vein sign and other radiographic features distinguishing myelin oligodendrocyte glycoprotein antibody disease from multiple sclerosis and aquaporin-4 antibody-positive neuromyelitis optica

BACKGROUND

Myelin oligodendrocyte glycoprotein antibody disease (MOGAD) can radiographically mimic multiple sclerosis (MS) and aquaporin-4 (AQP4) antibody-positive neuromyelitis optica spectrum disorder (NMOSD). Central vein sign (CVS) prevalence has not yet been well-established in MOGAD.

OBJECTIVE

Characterize the magnetic resonance imaging (MRI) appearance and CVS prevalence of MOGAD patients in comparison to matched cohorts of MS and AQP4+ NMOSD.

METHODS

Clinical MRIs from 26 MOGAD patients were compared to matched cohorts of MS and AQP4+ NMOSD. Brain MRIs were assessed for involvement within predefined regions of interest. CVS was assessed by overlaying fluid-attenuated inversion recovery (FLAIR) and susceptibility-weighted sequences. Topographic analyses were performed on spinal cord and orbital MRIs when available.

RESULTS

MOGAD patients had fewer brain lesions and average CVS+ rate of 12.1%, compared to 44.4% in MS patients (p = 0.0008). MOGAD spinal cord and optic nerve involvement was lengthier than MS (5.8 vs 1.0 vertebral segments, p = 0.020; 3.0 vs 0.5 cm, p < 0.0001). MOGAD patients tended to have bilateral/anterior optic nerve pathology with perineural contrast enhancement, contrasting with posterior optic nerve involvement in NMOSD.

CONCLUSION

CVS+ rate and longer segments of involvement in the spinal cord and optic nerve can differentiate MOGAD from MS, but do not discriminate as well between MOGAD and AQP4+ NMOSD.

Clinical characteristics of progressive nonarteritic anterior ischemic optic neuropathy

AIM

To study whether patients with progressive nonarteritic anterior ischemic optic neuropathy (NAION) present earlier than patients with stable NAION and to describe their clinical characteristics and visual outcome.

METHODS

This was a retrospective chart review. All patients with NAION seen during the acute stage from January 2012 to December 2018 were reviewed. Patients were included if they had documented disc edema and follow up of at least 3mo. Patients with progressive NAION were identified if they worsened in 2 out of 3 parameters: visual acuity ≥3 Snellen lines; Color vision ≥4 Ishihara plates; the visual field defect involved a new quadrant. The clinical characteristics, time from symptom onset to presentation, systemic risk factors and visual outcome were compared to patients with stable NAION.

RESULTS

Totally 122 NAION cases met the inclusion criteria. Mean age was 58.1y (range 22-74), 70% were men. Twenty cases (16.4%) had progressive NAION. Patients with progressive NAION did not differ from stable NAION in their demographics, systemic risk factors or in their initial visual deficit. At last follow up, median visual acuity was 1.0 logMAR (IQR 0.64-1.55) in patients with progressive NAION, vs 0.18 (IQR 0.1-0.63) in stable NAION (P<0.001). Median color vision testing was 0 plates correct (IQR 0-2.5%) vs 92% plates correct (IQR 50%-100%) in the stable NAION group (P<0.001). Patients with progressive NAION differed in the time from symptom onset to presentation (median 2d vs 5d, P=0.011).

CONCLUSION

We find no identifiable risk factors associated with progressive NAION. Progressors arrive earlier for ophthalmological evaluation.