The use of OCT in good visual acuity MOGAD and AQP4-NMOSD patients; with and without optic neuritis

Myelin oligodendrocyte-antibody-associated disease (MOGAD) often presents with severe optic neuritis (ON) but tends to recover better than in aquaporin-4 antibody neuromyelitis optica spectrum disorder (AQP4-NMOSD). We measured OCT and VEP in MOGAD and AQP4-NMOSD eyes with good visual function, with or without previous ON episodes. Surprisingly, OCT and/or VEPs were abnormal in 84% MOGAD-ON versus 38% AQP4-NMOSD-ON eyes (p = 0.009) with good vision, compared with 18% and 17% respectively of eyes with no previous ON. A sub-group with macular OCT performed as part of a research study confirmed both retinal and macular defects in visually-recovered MOGAD eyes. These findings have implications for investigation and management of MOGAD patients.

A challenging case of hypercapnic respiratory failure during pregnancy

We describe a 40-year-old female who presented with progressive breathlessness and hypercapnic respiratory failure during pregnancy secondary to undiagnosed muscle-specific kinase myasthenia gravis. Her presentation was progressive and protracted, having over five contacts with healthcare professionals over nine months, many of these predating her pregnancy. Her atypical presentation for myasthenia with minimal limb weakness led to consideration of other causes of hypercapnic respiratory failure. Once diagnosed, she was treated with intravenous immunoglobulin and non-invasive ventilation. She gave birth to a pre-term infant by planned caesarean section. Her insidious presentation and the progressive nature of her breathlessness were unusual and our report highlights the predominant involvement of respiratory muscles in muscle-specific kinase myasthenia. Her pregnancy may have further delayed her diagnosis due the attribution of some symptoms to normal pregnancy. Early recognition and treatment of myasthenia gravis are important to prevent life-threatening complications.

Demographic and clinical features of neuromyelitis optica: A review

The comparative clinical and demographic features of neuromyelitis optica (NMO) are not well known. In this review we analyzed peer-reviewed publications for incidence and prevalence, clinical phenotypes, and demographic features of NMO. Population-based studies from Europe, South East and Southern Asia, the Caribbean, and Cuba suggest that the incidence and prevalence of NMO ranges from 0.05-0.4 and 0.52-4.4 per 100,000, respectively. Mean age at onset (32.6-45.7) and median time to first relapse (8-12 months) was similar. Most studies reported an excess of disease in women and a relapsing course, particularly in anti-aquaporin 4 antibody (anti AQP4-IgG)-positive patients. Ethnicity may have a bearing on disease phenotype and clinical outcome. Despite limitations inherent to the review process, themes noted in clinical and demographic features of NMO among different populations promote a more global understanding of NMO and strategies to address it.

Characterization of neuromyelitis optica and neuromyelitis optica spectrum disorder patients with a late onset

BACKGROUND

Few data are available for patients with a late onset (≥ 50 years) of neuromyelitis optica (LONMO) or neuromyelitis optica spectrum disease (LONMOSD), defined by an optic neuritis/longitudinally extensive transverse myelitis with aquaporin-4 antibodies (AQP4-Ab).

OBJECTIVE

To characterize LONMO and LONMOSD, and to analyze their predictive factors of disability and death.

METHODS

We identified 430 patients from four cohorts of NMO/NMOSD in France, Germany, Turkey and UK. We extracted the late onset patients and analyzed them for predictive factors of disability and death, using the Cox proportional model.

RESULTS

We followed up on 63 patients with LONMO and 45 with LONMOSD during a mean of 4.6 years. This LONMO/LONMOSD cohort was mainly of Caucasian origin (93%), women (80%), seropositive for AQP4-Ab (85%) and from 50 to 82.5 years of age at onset. No progressive course was noted. At last follow-up, the median Expanded Disability Status Scale (EDSS) scores were 5.5 and 6 in the LONMO and LONMOSD groups, respectively. Outcome was mainly characterized by motor disability and relatively good visual function. At last follow-up, 14 patients had died, including seven (50%) due to acute myelitis and six (43%) because of opportunistic infections. The EDSS 4 score was independently predicted by an older age at onset, as a continuous variable after 50 years of age. Death was predicted by two independent factors: an older age at onset and a high annualized relapse rate.

CONCLUSION

LONMO/LONMOSD is particularly severe, with a high rate of motor impairment and death.

Myasthenia gravis and neuromyelitis optica spectrum disorder: a multicenter study of 16 patients

OBJECTIVE

To describe 16 patients with a coincidence of 2 rare diseases: aquaporin-4 antibody (AQP4-Ab)-mediated neuromyelitis optica spectrum disorder (AQP4-NMOSD) and acetylcholine receptor antibody (AChR-Ab)-mediated myasthenia gravis (AChR-MG).

METHODS

The clinical details and antibody results of 16 patients with AChR-MG and AQP4-NMOSD were analyzed retrospectively.

RESULTS

All had early-onset AChR-MG, the majority with mild generalized disease, and a high proportion achieved remission. Fifteen were female; 11 were Caucasian. In 14/16, the MG preceded NMOSD (median interval: 16 years) and 11 of these had had a thymectomy although 1 only after NMOSD onset. In 4/5 patients tested, AQP4-Abs were detectable between 4 and 16 years prior to disease onset, including 2 patients with detectable AQP4-Abs prior to thymectomy. AChR-Abs decreased and the AQP4-Ab levels increased over time in concordance with the relevant disease. AChR-Abs were detectable at NMOSD onset in the one sample available from 1 of the 2 patients with NMOSD before MG.

CONCLUSIONS

Although both conditions are rare, the association of MG and NMOSD occurs much more frequently than by chance and the MG appears to follow a benign course. AChR-Abs or AQP4-Abs may be present years before onset of the relevant disease and the antibody titers against AQP4 and AChR tend to change in opposite directions. Although most cases had MG prior to NMOSD onset, and had undergone thymectomy, NMOSD can occur first and in patients who have not had their thymus removed.

Serologic diagnosis of NMO: a multicenter comparison of aquaporin-4-IgG assays

OBJECTIVES

Neuromyelitis optica (NMO) immunoglobulin G (IgG) (aquaporin-4 [AQP4] IgG) is highly specific for NMO and related disorders, and autoantibody detection has become an essential investigation in patients with demyelinating disease. However, although different techniques are now used, no multicenter comparisons have been performed. This study compares the sensitivity and specificity of different assays, including an in-house flow cytometric assay and 2 commercial assays (ELISA and transfected cell-based assay [CBA]).

METHODS

Six assay methods (in-house or commercial) were performed in 2 international centers using coded serum from patients with NMO (35 patients), NMO spectrum disorders (25 patients), relapsing-remitting multiple sclerosis (39 patients), miscellaneous autoimmune diseases (25 patients), and healthy subjects (22 subjects).

RESULTS

The highest sensitivities were yielded by assays detecting IgG binding to cells expressing recombinant AQP4 with quantitative flow cytometry (77; 46 of 60) or visual observation (CBA, 73%; 44 of 60). The fluorescence immunoprecipitation assay and tissue-based immunofluorescence assay were least sensitive (48%-53%). The CBA and ELISA commercial assays (100% specific) yielded sensitivities of 68% (41 of 60) and 60% (36 of 60), respectively, and sensitivity of 72% (43 of 60) when used in combination.

CONCLUSIONS

The greater sensitivity and excellent specificity of second-generation recombinant antigen-based assays for detection of NMO-IgG in a clinical setting should enable earlier diagnosis of NMO spectrum disorders and prompt initiation of disease-appropriate therapies.

Progressive encephalomyelitis with rigidity and myoclonus: glycine and NMDA receptor antibodies

BACKGROUND

The syndrome of progressive encephalopathy with limb rigidity has been historically termed progressive encephalomyelitis with rigidity and myoclonus (PERM) or stiff-person syndrome plus.

METHODS

The case is presented of a previously healthy 28-year-old man with a rapidly fatal form of PERM developing over 2 months.

RESULTS

Serum antibodies to both NMDA receptors (NMDAR) and glycine receptors (GlyR) were detected postmortem, and examination of the brain confirmed an autoimmune encephalomyelitis, with particular involvement of hippocampal pyramidal and cerebellar Purkinje cells and relative sparing of the neocortex. No evidence for an underlying systemic neoplasm was found.

CONCLUSION

This case displayed not only the clinical features of PERM, previously associated with GlyR antibodies, but also some of the features associated with NMDAR antibodies. This unusual combination of antibodies may be responsible for the particularly progressive course and sudden death.

The differential diagnosis of longitudinally extensive transverse myelitis

Longitudinally extensive transverse myelitis refers to florid and widespread inflammation of the spinal cord causing T2 hyperintensity on spinal magnetic resonance imaging that is seen to extend over three or more vertebral segments. Whilst rare, longitudinally extensive transverse myelitis is clinically important as it can lead to catastrophic morbidity, and a group of these patients are at risk of further attacks. Early identification and establishment of the underlying aetiology is vital in order to initiate appropriate therapy and optimize outcomes. Whilst longitudinally extensive transverse myelitis is classically associated with neuromyelitis optica, there are many other causes. These include other inflammatory aetiologies, infection, malignancy and metabolic disturbance. Some of these are readily treatable. Laboratory and radiological investigations can help to differentiate these causes. Treatment of longitudinally extensive transverse myelitis hinges on distinguishing inflammatory and non-inflammatory aetiologies and identifying patients who are at high risk of a recurrent course.

Thymoma and paraneoplastic myasthenia gravis

Paraneoplastic autoimmune diseases associate occasionally with small cell lung cancers and gynecologic tumors. However, myasthenia gravis (MG) occurs in at least 30% of all patients with thymomas (usually present at MG diagnosis). These epithelial neoplasms almost always have numerous admixed maturing polyclonal T cells (thymocytes). This thymopoiesis-and export of mature CD4(+)T cells-particularly associates with MG, though there are rare/puzzling exceptions in apparently pure epithelial WHO type A thymomas. Other features potentially leading to inefficient self-tolerance induction include defective epithelial expression of the autoimmune regulator (AIRE) gene and/or of major histocompatibility complex class II molecules in thymomas, absence of myoid cells, failure to generate FOXP3(+) regulatory T cells, and genetic polymorphisms affecting T-cell signaling. However, the strong focus on MG/neuromuscular targets remains unexplained and suggests some biased autoantigen expression, T-cell selection, or autoimmunization within thymomas. There must be further clues in the intriguing serological and cellular parallels in some patients with late-onset MG but without thymomas-and in others with AIRE mutations-and in the contrasts with early-onset MG, as discussed here.

Symptomatic, radiological and pathological involvement of the hypothalamus in neuromyelitis optica

This study describes a young girl who presented with involuntary weight loss, spontaneous vomiting and behavioural change. Imaging confirmed hypothalamic and brainstem involvement. Routine investigations (including cerebrospinal fluid analysis and neuromyelitis optica IgG) were unhelpful. Biopsy of the hypothalamic lesion implicated an aggressive inflammatory aetiology. There was a response to conventional immunosuppression, while a further relapse responded to plasma exchange. She died 21 months after presentation. Postmortem examination was highly suggestive of neuromyelitis optica, which was subsequently confirmed following the identification of aquaporin 4 antibodies.