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Background and Objectives : The opsoclonus-myoclonus syndrome (OMS) is characterised by opsoclons, myoclons and impaired balance, often concomitant with sleep disorder and behavioural difficulties. The symptoms develop as a result of autoimmune response triggered by a neuroblastic tumour (NT). OMS can also develop secondarily to a viral infection or as an immune response triggered by an unknown agent. This leads to the activation of B- and T-cells, which produce and release autoantibodies or cytokines directly within the central nervous system (CNS), thus damaging the neurons within the cerebellum and the brain stem. The available OMS treatments aim at decreasing lymphocyte, cytokine and autoantibody production or accelerating the utilisation of the latter. Another treatment option for OMS involves using cytostatic agents, which damage T- and B-cells causing their depletion and impaired function, which reduces their ability to produce antibodies and cytokines. Materials and Methods : We present a single-centre experience in treating OMS secondary to NT in 7 children. Results : The combined treatment with cyclophosphamide plus dexamethasone resulted in a complete resolution of OMS symptoms in 4 children, and a significant improvement in the 3 children. Two of them periodically present hyperactivity, and one girl requires an additional support at school due to special educational needs (SEN). Conclusions : NT resection does not resolve OMS in children with OMS secondary to NT. The combined treatment with dexamethasone plus cyclophosphamide seems to be an effective treatment of OMS.

Background: Opsoclonus-myoclonus syndrome is an autoimmune neurological disorder characterized by opsoclonus, myoclonus, ataxia, and behavioral changes. Although long-term outcomes have historically been poor, including motor and cognitive disabilities, the advent of new and more aggressive immunotherapy regimens may be improving prognosis in opsoclonus-myoclonus syndrome., Methods: We retrospectively reviewed the records of all children diagnosed with opsoclonus-myoclonus syndrome at BC Children's Hospital from 2000 to 2010. Neurological outcomes were compared with those previously reported in the literature., Results: Twelve children with opsoclonus-myoclonus syndrome were identified, four of whom had an associated neuroblastoma. Two thirds of patients received initial treatment with a combination of corticosteroids, intravenous immunoglobulin (IVIG), and an additional immunosuppressant agent. After a median follow-up of three years from diagnosis, ten patients had no or minimal neurological abnormalities. Two patients had poor outcome with significant cognitive impairment., Conclusions: Most patients in this series were treated with early multimodal immunotherapy, and neurological outcomes were better than those in most historical reports. This finding is consistent with recent studies that suggest multimodal immunotherapy regimens may be improving the prognosis in this challenging disease. However, some individuals did well with less aggressive treatment, and further studies are required to determine optimal treatment approach., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Opsoclonus-myoclonus syndrome is characterized by abnormal lymphocyte trafficking into brain. The authors hypothesized that mycophenolate mofetil, a lymphocyte proliferation inhibitor, might be therapeutic. The cerebrospinal fluid and blood immunophenotypes of 15 children with predominantly chronic-relapsing opsoclonus-myoclonus syndrome were compared before and after treatment by flow cytometry. Mycophenolate mofetil reduced the cerebrospinal fluid expansion of HLA-DR+ activated T cells (-40%); the frequency of other T-cell or natural killer cell subsets remained unchanged, but cerebrospinal fluid B cells increased significantly. Adrenocorticotropic hormone dose was lowered by 64% over an average of 1.5 years, yet 73% eventually relapsed despite therapeutic drug levels. Prior treatment with rituximab prevented relapse-associated increase in cerebrospinal fluid B cells, without hindering mycophenolate mofetil-induced reduction in T-cell activation. These data demonstrate resistant immunologic problems in chronic-relapsing opsoclonus-myoclonus syndrome. Mycophenolate mofetil did not prevent relapse. The novel effect of mycophenolate mofetil on chronically activated T cells may contribute to its efficacy in T-cell mediated neurological disorders.

Opsoclonus-myoclonus-ataxia-syndrome (OMS) represents a rare neuroblastoma-associated paraneoplastic syndrome that commonly results in neurologic deficits despite tumor resection and immunosuppressive therapy. We describe the response of five such children to high-dose dexamethasone pulses including two patients in whom previous glucocorticoids, rituximab, and cytostatic drugs were not successful. All patients had MYCN non-amplified tumors that were detected 1 to 7 months after the onset of the OMS or ataxia. This treatment resulted in a good partial response in three and in complete remission in two patients. Our results show that dexamethasone pulses are likely to be useful for both, first-line- and salvage-therapy for OMS-patients., ((c) 2007 Wiley-Liss, Inc.)

Opsoclonus-myoclonus syndrome (OMS) is a rare and debilitating disorder of unknown etiology affecting children and adults. Outcome is unfavourable; approximately 80% of children with OMS suffer from mild to severe neurological handicaps, mainly cognitive impairment. A standard therapy does not exist. Due to the possible immune-mediated mechanisms, treatment with steroids, ACTH, plasmapheresis and immunoglobulins can be successful. However, some children become steroid dependent and symptoms may reoccur after treatment has been finished. We present two girls with OMS, who had a prolonged clinical course lasting 4 and 9 years with many relapses. Both children developed symptoms around the age of two years. Diagnostic work-up to exclude neuroblastoma was negative. Several treatment modalities including oral steroids, dexamethasone pulses, immunoglobulin and cyclosporine were used without lasting success. In addition, cognitive impairment developed in both children. In order to prevent further clinical and mental deterioration, 6 pulses of cyclophosphamide in combination with dexamethasone pulses every 4 weeks were administered. Both children showed significant improvement of OMS symptoms. One girl is still symptom free 18 months after treatment, mild ataxia developed in the other after 12 months. Both children are mentally handicapped and in special need schools. We conclude that combination of cyclophosphamide pulses and dexamethasone pulse therapy is a therapeutic option even after a long clinical course to improve symptoms of OMS.

Opsoclonus-myoclonus, a rare paraneoplastic syndrome that may occur in patients with neuroblastoma, is thought to be a humorally mediated immune reaction to malignant cells that cross-react with autoantigens. This report describes the case of an occult neuroblastoma diagnosed in a 4-year-old female 2 years after presentation of opsoclonus-myoclonus. Although no mass was evident on previous imaging at an interval of 10 months, a computed tomographic scan 4 months after rituximab treatment and 20 months after presentation revealed a new left adrenal mass. Although neuroblastomas can be identified months after presentation of opsoclonus-myoclonus without treatment with rituximab, this report describes one of the longest intervals using up-to-date imaging techniques. Therefore the case raises two concerns: (1) whether the same immune process that causes opsoclonus-myoclonus may suppress neuroblastomas, and (2) whether immunosuppressive therapy with rituximab may inhibit the immune reaction to occult neuroblastomas in patients with unexplained opsoclonus-myoclonus.