Demyelinating disease in patients with myasthenia gravis

Clinical characteristics of autoimmune disorders in the central nervous system associated with myasthenia gravis

Myasthenia gravis (MG) is occasionally associated with autoimmune diseases in the central nervous system (CNS), such as neuromyelitis optica spectrum disorder (NMOSD), multiple sclerosis (MS), Morvan syndrome, and anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis. Here, we report five original cases associated with autoimmune disorders in the CNS among 42 patients with MG in a single tertiary hospital in Japan (11.9%). In four of these five cases, the second disease developed when the preceding disease was unstable. Accurate diagnosis of the newly developing disease may be difficult in such cases, because some neurological symptoms can be seen in both disorders. This implies the great importance of recognizing the possible co-occurrence of MG and disorders in the CNS. In addition, a comprehensive review of the literature revealed distinct clinical characteristics depending on the associated disease in the CNS, including thymic pathology and temporal relationship between MG and associated CNS disorders. Notably, NMOSD usually develops after the onset of MG and thymectomy, in clear contrast to MS. Thymoma is highly prevalent among patients with Morvan syndrome, in contract to cases with NMOSD and MS. The analysis of clinical characteristics, representing the first such investigation to the best of our knowledge, suggests different pathogeneses of these autoimmune diseases in the CNS, and provides significant implications for clinical practice.

Autoimmune diseases associated with Neuromyelitis Optica Spectrum Disorders: A literature review

INTRODUCTION

Neuromyelitis Optica (NMO) is an autoimmune inflammatory demyelinating disease of the central nervous system (CNS) which predominantly involves optic nerves and spinal cord. Since the introduction of Neuromyelitis Optica Spectrum Disorders (NMOSD) as a separate entity, there have been many reports on its association with other disorders including systemic and organ-specific autoimmune diseases. Here, we reviewed other immune-mediated diseases associated with NMOSD and tried to categorize them.

METHODS

The present review was conducted using the PUBMED database based on papers from 1976 (i.e., since the first NMO comorbidity with SLE was reported) to 2017. We included all articles published in English. The keywords utilized included Neuromyelitis optica, Neuromyelitis Optica Spectrum Disorders, Devic's disease, in combination with comorbidity or comorbidities.

RESULTS

Diseases with immune-based pathogenesis are the most frequently reported co-morbidities associated with NMOSD, most of which are antibody-mediated diseases. According to literature, Sjogren's Syndrome (SS) and Systemic Lupus Erythematosus (SLE) are the most frequently reported diseases associated with NMOSD among systemic autoimmune diseases. Further, myasthenia gravis in neurological and autoimmune thyroid diseases in non-neurological organ-specific autoimmune diseases are the most reported comorbidities associated with NMOSD in the literature.

CONCLUSIONS

NMOSD may be associated with a variety of different types of autoimmune diseases. Therefore, systemic or laboratory signs which are not typical for NMOSD should be properly investigated to exclude other associated comorbidities. These comorbidities may affect the treatment strategy and may improve the patients' care and management.

A review of the current literature and a guide to the early diagnosis of autoimmune disorders associated with neuromyelitis optica

Neuromyelitis optica (NMO) is an immune-mediated neurological disorder characterised by recurrent episodes of optic neuritis and longitudinally extensive transverse myelitis. A serum biomarker, aquaporin-4 IgG, the autoantibody against aquaporin-4 water channel, has been specifically associated with NMO and has assisted early recognition and prediction of relapses. Less commonly, a monophasic course, associated with antibodies to myelin oligodendrocyte glycoprotein has been reported. Specific diagnostic criteria have been defined; however, some cases that do not fulfil these criteria (but are nevertheless associated with aquaporin-4 IgG) are classified as NMO spectrum disorder and follow the same relapsing course. An ever-growing list of autoimmune disorders, both organ-specific and non-organ-specific, have been associated in up to 20-30% of patients with NMO. These disorders, which may become symptomatic before or after the development of NMO, are often diagnosed long after the diagnosis of NMO, as symptoms may be wrongly attributed to NMO, its residual effects or medication side effects. In addition, autoantibodies can be found in patients with NMO without coexisting disease (up to 40% in some series) and maybe suggestive of a heightened humoral immune response. We present a comprehensive review of the current literature on autoimmune disorders co-existing with NMO and identified 22 autoimmune conditions (myasthenia gravis, coeliac disease, ulcerative colitis, sclerosing cholangitis, systemic lupus erythematosus, rheumatoid arthritis, antiphospholipid antibody syndrome, Sjogren's syndrome, autoimmune hypothyroidism, immune thrombocytopenic purpura, pernicious anaemia, narcolepsy, pemphigus foliaceus, alopecia areata, psoriasis, scleroderma, dermatitis herpetiformis, polymyositis, chronic inflammatory demyelinating polyneuropathy, paraneoplastic disorders, insulin dependent diabetes mellitus and autoimmune encephalitis).

Myasthenia gravis and neuromyelitis opica: A causal link

Neuromyelitis Optica (NMO) and Myasthenia Gravis (MG) are rare antibody mediated disorders of the central nervous system (CNS) and neuromuscular junction (NMJ) respectively. Both diseases are predominantly mediated by IgG1 antibodies that activate complement. There have been increasing reports of patients who develop both disorders. Given the rarity of both diseases it would seem that these occurrences are not purely coincidental. There is heterogeneity between the cases described in the literature but common trends are observed in patients who develop both disorders. Most patients described are female. Typically the MG precedes the NMO and the majority of patients have undergone thymectomy. Generally, the symptoms of MG are mild but the NMO tends to follow a more aggressive clinical course. The pathogenesis of NMO in combination with MG is unknown, but thymectomy has been implicated in a subset of patients. We present the case of a female patient who developed NMO on a background of sero-positive MG and discuss the relevant literature.

Disfonia como principal queixa num quadro de miastenia grave: diagnóstico e fonoterapia

Miastenia grave é uma doença autoimune que se manifesta por fraqueza e fadiga muscular progressivas. São frequentes os sintomas oculares e bulbares, dentre eles, a disfonia. Este artigo relata um caso de disfonia, cuja avaliação fonoaudiológica contribuiu com o diagnóstico de miastenia grave e seu tratamento. A paciente em questão procurou o atendimento fonoaudiológico com diagnóstico otorrinolaringológico de presbifonia. A avaliação perceptivo-auditiva e acústica da voz identificou alterações em respiração, fonte glótica e filtro/ressonância. Como alguns dados obtidos com a anamnese e observados nas provas vocais não se relacionavam diretamente com a presença de presbifonia, houve a necessidade de discussão do caso com o médico, quando ambos concluíram a necessidade de encaminhar a paciente para avaliação neurológica. O neurologista consultado levantou a hipótese diagnóstica de miastenia grave e solicitou exames. A paciente seguiu em acompanhamento fonoaudiológico e medicamentoso. Na reavaliação vocal, ocorrida cerca de dois meses após o início do tratamento, foi constatada melhora na qualidade vocal, com grande impacto na qualidade de vida. Este trabalho evidencia a importância da avaliação fonoaudiológica detalhada e da participação do fonoaudiólogo na equipe interdisciplinar.

Anti-aquaporin-4 antibody-positive definite neuromyelitis optica in a patient with thymectomy for myasthenia gravis

BACKGROUND

Since serum anti-aquaporin-4 (AQP4) antibody/neuromyelitis optica (NMO)-IgG has been detected as a specific biomarker for NMO), new diagnostic criteria have been proposed. Recently, a rare coexistence of NMO and myasthenia gravis (MG) has been documented. Here, we provide further evidence of the association of these 2 immunologic disorders and review the literature.

CASE REPORT

A 60-year-old woman, who had a history of optic neuritis at age 43, developed longitudinally extended transverse myelitis (LETM). She had repeated optic neuritis and longitudinally extended transverse myelitis attacks, which have been treated by corticosteroid pulse therapy. She was diagnosed as having definite NMO, because serum anti-aquaporin-4 antibody was positive. She had also been suffering from generalized MG since age 30 and underwent thymectomy at age 40. There have been 14 patients with NMO associated with MG, most of whom developed NMO years after thymectomy. Our patient is the seventh patient with seropositive NMO who underwent thymectomy for MG.

CONCLUSIONS

The coexistence of MG with thymectomy and seropositive NMO suggests an etiopathogenic link between these 2 disorders but remains underrecognized by neurologists. Neurologists should consider this possible association when encountering atypical presentations of either MG or NMO.

Neuromyelitis optica spectrum disorders in patients with myasthenia gravis: ten new aquaporin-4 antibody positive cases and a review of the literature

BACKGROUND

Neuromyelitis optica (NMO, Devic syndrome) and myasthenia gravis (MG) are rare antibody-mediated autoimmune disorders. Concurrent incidence has been reported in only few patients, mostly non-Caucasians.

OBJECTIVE

To report on ten Caucasian patients with NMO spectrum disorders (NMOSD) and MG and to provide a comprehensive review of the literature.

METHOD

Retrospective study.

RESULTS

In total, 26 patients (m:f = 1:12; Caucasian in 12) with MG (generalized in 17) and NMOSD (NMO in 21, longitudinally extensive transverse myelitis in five) were identified from the authors' own files (n = 10) and the previous literature (n = 16). MG preceded NMOSD in 24/25 cases (96%). AQP4-Ab were tested in 20 patients and were positive in 17 (85%). Twenty out of 25 patients (80%) had been treated with thymectomy or thymic irradiation, which preceded NMOSD in all cases (median latency, 12 years; range, 0.3-32). At last follow-up, complete remission of MG was reported in 15/22 (68%), and MG was well controlled with pyridostigmine in three. Co-existing autoimmune disorders or autoimmune antibodies were reported in 17 patients.

CONCLUSION

Our study demonstrates that i) AQP4-Ab-positive NMOSD are more commonly associated with MG in Caucasians than previously thought; ii) MG precedes NMOSD in most cases, often by more than a decade; iii) NMOSD almost exclusively occur in females with juvenile or early-onset MG; and iv) MG frequently takes an unusually mild course in patients with NMOSD. A history of thymectomy could be a possible risk factor for the later development of NMOSD. We recommend testing for AQP4-Ab in MG patients presenting with atypical motor or optic symptoms.

Ophthalmologic manifestations commonly misdiagnosed as demyelinating events in multiple sclerosis patients

PURPOSE OF REVIEW

Multiple sclerosis may affect both afferent and efferent visual pathways, and sometimes physicians err on ordinary ophthalmologic diagnosis due to overlapping symptoms between demyelinating and nondemyelinating visual diseases. The present article highlights nondemyelinating ocular occurrences due to physiologic or other pathologic processes that may appear in some patients.

RECENT FINDINGS

Optic neuritis is representative of the most common and best-studied demyelinating visual occurrence in multiple sclerosis. However, other nondemyelinating visual disturbances also seen in the general population may be erroneously interpreted as being part of the underlying disease. This comparison has not been documented and may be helpful to overcome such difficulties.

SUMMARY

Based on clinical history and some strategies of ophthalmologic examination, physicians can achieve the correct diagnosis. Some clinical situations, however, may be challenging and a multidisciplinary approach in the care of multiple sclerosis is warranted.

Aquaporin-4 water channel expression by thymoma of patients with and without myasthenia gravis

BACKGROUND

Neuromyelitis optica (NMO) is a serious idiopathic inflammatory demyelinating disorder characterized by acute transverse myelitis and optic neuritis. A significant proportion of NMO patients are seropositive for NMO-IgG, an autoantibody targeting aquaporin-4 (AQP4) water channel. Paraneoplastic NMO associated various tumors were recently reported.

AIM

We studied the expression of AQP4 by thymoma from patients with and without myasthenia gravis (MG).

METHODS

Thymoma obtained from thymomectomy in patients with and without MG were studied by immunohistochemistry and western blot.

RESULTS

Ten thymoma patients (9 with MG) and two control patients without thymoma or MG were studied. Immunohistochemistry revealed AQP4 immunoreactivity in cell membrane of thymoma cells from all ten thymoma specimens whereas thymic tissues from patients without thymoma or MG were negative for AQP4 immunoreactivity. Western blot revealed that lysates of nine of the ten thymoma specimens reacted with anti-human AQP4 antibody with a band of ~30 kDa compatible with the molecular weight of AQP4. Interestingly, immunofluorescence revealed that IgG isolated from 2 NMO patients seropositive for NMO-IgG bound to cell membrane of thymoma cells from all ten thymoma specimens while IgG from healthy control subject did not.

CONCLUSION

Thymoma cells of patients with and without MG express AQP4. AQP4 autoantibodies from serum of NMO patients bound to AQP4 expressed on thymoma cell membrane.

Association of anti-aquaporin-4 antibody-positive neuromyelitis optica with myasthenia gravis

We describe 2 patients who developed anti-aquaporin-4 antibody-positive neuromyelitis optica (NMO) following the development of anti-acetylcholine receptor antibody-positive myasthenia gravis (MG). A literature review of 13 similar cases in addition to the present 2 cases of NMO with MG showed predominance among Asian women and frequent development of NMO following thymectomy for MG. Moreover, in one of our patients, serial assays of anti-aquaporin-4 antibody and anti-acetylcholine receptor antibody were performed. Accumulating evidence for the coexistence of NMO and MG suggests that a common immunopathogenesis of NMO and MG may exist, and the association of NMO with MG may be more frequent than hitherto believed.

Neuromyelitis optica in Brazil: a study on clinical and prognostic factors

Objectives

To describe the clinical characteristics of patients with relapsing neuromyelitis optica (NMO) from a tertiary care center in Brazil and compare the groups with normal and abnormal brain magnetic resonance imaging (MRI).

Methods

Retrospective review of 41 patients followed at the Neuroimmunology Clinic of the Federal University of São Paulo, Brazil, from 1994 to 2007.

Results

All patients had relapsing-remitting optic-spinal disease, long extending spinal cord lesions, and brain MRI not meeting Barkhof criteria for multiple sclerosis (MS), thus fulfilling the 1999 and 2006 Wingerchuck criteria for NMO. Mean follow-up time was 52 months; mean age of onset was 32.6 years. The mean relapse rate (RR) and progression index (PI) were 1.0 and 0.9, respectively. Twenty-four patients had brain lesions not compatible with MS on MRI, and there were no statistical differences on PI and RR between patients who had brain lesions and patients who did not. Incomplete recovery, but not the type of first relapse, correlated with a worse prognosis. Seventeen patients were tested for NMO-IgG (anti-aquaporin-4 antibody) with 41% positivity.

Conclusions

In this series, we did not find a statistical difference of disease progression between patients with and without brain lesions, suggesting that the presence of brain abnormalities is not a marker of disease severity.

NMO-IgG positive neuromyelitis optica in a patient with myasthenia gravis but no thymectomy

Here we report on a 44-year old woman presenting with both myasthenia gravis (MG) and neuromyelitis optica (NMO). MRI showed transverse myelitis extending from C2 to T4, multifocal demyelinating lesions in the supratentorial white matter, and left optic neuritis. Serological analysis demonstrated antibodies to acetylcholine receptors as well as NMO-IgG. To our knowledge, this is the first case of NMO-IgG positive NMO in a patient with MG but no history of thymectomy or immunosuppression.