Case reportSelective response to rituximab in a young child with MuSK-associated myasthenia gravis
Introduction
Neuromuscular junction disorders in children are either genetic, such as congenital myasthenic syndrome, or autoimmune with circulating antibodies most commonly against acetylcholine receptors. There is limited experience in both recognizing as well as treating myasthenia in children associated with antibodies to muscle-specific tyrosine kinase (MuSK). We report a child with MuSK myasthenia and highlight the young age of onset and successful treatment with rituximab despite failure of acetylcholinesterase inhibitors, corticosteroids and intravenous immunoglobulin (IVIg).
Section snippets
Case report
A seven-year-old girl presented with longstanding abnormal eye movements beginning at three months of age with intermittent bilateral esotropia. At five years of age she developed worsening diplopia, more severe bilateral esotropia with impaired lateral extra ocular movements, and nocturnal dysphagia (cough and gagging). She underwent strabismus surgery (bilateral medial rectus recession) and tonsil and adenoidectomy at age 6 years. Disconjugate gaze, esotropia, and nocturnal dysphagia
Discussion
We describe the successful use of rituximab (a human–mouse chimeric monoclonal CD20 antibody) in a child with longstanding, refractory MuSK antibody associated myasthenia gravis.
Reports of children with MuSK antibody associated myasthenia gravis are scarce [1], [2], [3], [4]. Skjei et al. recently reported 9 children with MuSK-associated myasthenia with age of onset from 2 to 16 years and with predominantly ocular and bulbar symptoms [4]. Our patient also had predominant ocular and bulbar
Conclusion
This case suggests that children with MuSK myasthenia, like adults, can respond to rituximab despite failure to improve on other immunosuppressant medications or pyridostigmine even after several years of symptoms. MuSK antibody testing should be performed in children with signs and symptoms of myasthenia gravis if AChR antibody levels are normal.
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Cited by (13)
Rituximab in juvenile myasthenia gravis-an international cohort study and literature review
2022, European Journal of Paediatric NeurologyCitation Excerpt :Stefano et al. reported 165 patients with AChR positive MG and concluded that significant clinical improvement was seen in 68%, with 36% achieving complete remission. The rituximab experience in children and adolescents with JMG literature is mainly based on case reports or small case series [7–17], consistently reporting a beneficial effect. Here we describe our experience of rituximab in JMG based on the collective experience of a large international multicentre study.
Rituximab as Adjunct Maintenance Therapy for Refractory Juvenile Myasthenia Gravis
2020, Pediatric NeurologyCitation Excerpt :Autoreactive B cells have demonstrated pathogenicity in the development of autoimmune myasthenia gravis.3 Rituximab has been well-studied for the treatment of adult myasthenia gravis,3-6 but its use has been documented sparsely in JMG.7-9 The objective of our study was to assess the tolerability and efficacy of rituximab use in children with refractory JMG.
AChR myasthenia gravis switching to MuSK or double antibody positive myasthenia gravis in two children and literature review
2020, Neuromuscular DisordersCitation Excerpt :Most pediatric MG cases initially manifest extraocular muscle paresis. Muscle tyrosine–specific kinase antibody (MuSK–Ab), discovered in 2001 by Hoch [2], is the second most frequent antibody detected in MG after acetylcholine receptor antibody (AChR–Ab) [3]. AChR–Ab and MuSK–Ab coexistence in the same patient is rare, and only a few double antibody positive MG cases (DP–MG) have been reported [4–9].
Therapeutic target of memory B cells depletion helps to tailor administration frequency of rituximab in myasthenia gravis
2016, Journal of NeuroimmunologyCitation Excerpt :B lymphocyte recovery CD19 + CD27 + but not total CD19 + was associated with relapse of clinical symptoms in all patients. Similar to previous reports, our 3 patients with MuSK positive myasthenia responded very well to RTX, with ongoing remissions of more than 1 year after therapy (Yi et al., 2013; Govindarajan et al., 2015). Over the 5 years, no case of progressive multifocal leukoencephalopathy or malignancy was observed, and there were no serious adverse events leading to discontinuation of treatment.
Rituximab treatment in myasthenia gravis
2023, Frontiers in Neurology