Opsoclonus-myoclonus in children associated or not with neuroblastoma

Late cognitive and adaptive outcomes of patients with neuroblastoma-associated opsoclonus-myoclonus-ataxia-syndrome: A report from the Children's Oncology Group

BACKGROUND

Opsoclonus-myoclonus-ataxia syndrome (OMAS) is a rare autoimmune disorder of the nervous system presenting with abnormal eye and limb movements, altered gait, and increased irritability. Two to four percent of children diagnosed with neuroblastoma have neuroblastoma-associated OMAS (NA-OMAS). These children typically present with non-high-risk neuroblastoma that is cured with surgery, with or without chemotherapy. Despite excellent overall survival, patients with NA-OMAS can have significant persistent neurological and developmental issues.

OBJECTIVE

This study aimed to describe long-term neurocognitive and adaptive functioning of patients with NA-OMAS treated with multimodal therapy, including intravenous immunoglobulin (IVIG) on Children's Oncology Group (COG) protocol ANBL00P3.

METHODS

Of 53 children enrolled on ANBL00P3, 25 submitted evaluable neurocognitive data at diagnosis and at least one additional time point within 2 years and were included in the analyses. Adaptive development was assessed via the Vineland Adaptive Behavior Scale, and validated, age-appropriate measures of intellectual function were also administered.

RESULTS

Twenty-one of the 25 patients in this cohort ultimately received IVIG. Descriptive spaghetti plots suggest that this cohort demonstrated stable long-term cognitive functioning and adaptive development over time. This cohort also demonstrated decreased OMAS scores over time consistent with improved OMAS symptoms.

CONCLUSIONS

While statistical significance is limited by small sample size and loss to follow-up over 10 years, findings suggest stable long-term cognitive and adaptive functioning over time in this treated cohort.

Characteristics of Opsoclonus-Myoclonus Syndrome in Patients of the Largest Pediatric Hospital in Latin America

BACKGROUND

Opsoclonus-myoclonus syndrome (OMS) is a rare neuroinflammatory disorder characterized by ataxia, opsoclonus, and myoclonus. Clinical diagnosis of OMS has been challenging; therefore, we sought to determine the clinical and treatment profiles of patients with OMS at the largest pediatric hospital in Latin America.

METHODS

We analyzed the data of patients diagnosed with OMS between 2010 and 2020 at Pequeno Principe Hospital (Brazil) to determine the corresponding clinical profile more accurately.

RESULTS

Of the approximately 50,000 visitors to our pediatric neurology department from 2010 to 2020, 10 patients with OMS were observed. Five nontumor cases included three parainfectious and two idiopathic cases. The median time from symptom onset to diagnosis was 34 days. All patients with diagnostic OMS criteria in the idiopathic, nontumor group underwent whole-exome sequencing, with potentially pathogenic mutations identified in two cases. Nine patients were treated with methylprednisolone pulse, followed by oral steroids; eight received one or more intravenous immunoglobulin treatments; and six received azathioprine and cyclophosphamide. Complete symptomatic recovery was observed in only one patient.

CONCLUSIONS

OMS diagnosis remains challenging. Diagnostic suspicion is necessary to improve the management of these patients and allow early immunosuppressive treatment. Paraneoplastic etiology is the most prevalent. In idiopathic patients who do not respond to immunosuppressive treatment, tests, such as whole-exome sequencing, may reveal a differential diagnosis. Genetic alterations that increase the risk of tumors may be an important clue to the pathophysiology of OMS.

Paraneoplastic cerebellar and brainstem disorders

Paraneoplastic cerebellar and brainstem disorders are a heterogeneous group that requires prompt recognition and treatment to help prevent irreversible neurologic injury. Paraneoplastic cerebellar degeneration is best characterized by Yo antibodies in patients with breast or ovarian cancer. Tr (DNER) antibodies in patients with Hodgkin lymphoma can also present with a pure cerebellar syndrome and is one of the few paraneoplastic syndromes found with hematological malignancy. Opsoclonus-myoclonus-ataxia syndrome presents in both pediatric and adult patients with characteristic clinical findings. Other paraneoplastic brainstem syndromes are associated with Ma2 and Hu antibodies, which can cause widespread neurologic dysfunction. The differential for these disorders is broad and also includes pharmacological side effects, infection or postinfectious processes, and neurodegenerative diseases. Although these immune-mediated disorders have been known for many years, mechanisms of pathogenesis are still unclear, and optimal treatment has not been established.

Paraneoplastic Neurological Syndromes of the Central Nervous System: Pathophysiology, Diagnosis, and Treatment

Paraneoplastic neurological syndromes (PNS) include any symptomatic and non-metastatic neurological manifestations associated with a neoplasm. PNS associated with antibodies against intracellular antigens, known as "high-risk" antibodies, show frequent association with underlying cancer. PNS associated with antibodies against neural surface antigens, known as "intermediate- or low-risk" antibodies, are less frequently associated with cancer. In this narrative review, we will focus on PNS of the central nervous system (CNS). Clinicians should have a high index of suspicion with acute/subacute encephalopathies to achieve a prompt diagnosis and treatment. PNS of the CNS exhibit a range of overlapping "high-risk" clinical syndromes, including but not limited to latent and overt rapidly progressive cerebellar syndrome, opsoclonus-myoclonus-ataxia syndrome, paraneoplastic (and limbic) encephalitis/encephalomyelitis, and stiff-person spectrum disorders. Some of these phenotypes may also arise from recent anti-cancer treatments, namely immune-checkpoint inhibitors and CAR T-cell therapies, as a consequence of boosting of the immune system against cancer cells. Here, we highlight the clinical features of PNS of the CNS, their associated tumors and antibodies, and the diagnostic and therapeutic strategies. The potential and the advance of this review consists on a broad description on how the field of PNS of the CNS is constantly expanding with newly discovered antibodies and syndromes. Standardized diagnostic criteria and disease biomarkers are fundamental to quickly recognize PNS to allow prompt treatment initiation, thus improving the long-term outcome of these conditions.

Indications and Safety of Rituximab in Pediatric Neurology: A 10-Year Retrospective Study

BACKGROUND

RTX is used off-label in several neurological inflammatory diseases in adults children patients. We conducted a study to assess indications and safety of rituximab (RTX) for children and to identify risk factors for early B-cell repopulation.

METHODS

A single-center retrospective study of children treated with RTX for a neurological disease between May 31, 2010, and May 31, 2020, was performed.

RESULTS

A total of 77 children (median age, 8.9 years) were included. RTX was mostly used as second-line therapy in all groups of diseases (68%). Median dose was 1500 mg/m² for each patient. There were 13 clinical relapses (17%), 5 when B-cell depletion was complete. Adverse events were present in 6% of the cases. The factors influencing early B-cell repopulation were the recent infusion of intravenous Ig (P < 0.01) and the administration of less than 1500 mg/m² during the first RTX treatment (P = 0.04). The median time to B-cell repopulation seemed to be shorter (160 vs 186 days) when patients had plasmapheresis even when a 48-hour delay was observed with RTX infusions.

CONCLUSIONS

This study confirms the good tolerance of RTX in the treatment of specific neurological disorders in a pediatric population. It also highlights risk factors for early B-cell repopulation and underlines the importance of B-cell monitoring.

Opsoclonus-myoclonus syndrome associated with neuroblastoma: Insights into antitumor immunity

Opsoclonus-myoclonus syndrome (OMS) is a rare neurological disorder. Half of these cases occur in children with neuroblastoma. Neuroblastoma patients with OMS usually have better oncological outcomes than those without OMS even after stratification by tumor stage and age, indicating that factors mediating OMS may also inhibit tumor cell proliferation. Although the mechanisms underlying OMS remain undefined, the cytokines and lymphocytes alterations in the cerebrospinal fluid support the concept that it is a pattern of neuroinflammation due to an autoimmune effect. The presence of lymphoid follicles consisting of follicular dendritic cells, CD20⁺ B lymphocytes, CD3⁺ T lymphocytes, and CD68⁺ macrophages in the tumor microenvironment in OMS-associated neuroblastoma support the autoimmune nature of this disorder. This review focuses on the clinical and genetic features of OMS-associated neuroblastoma, and we update readers on immune features of neuroblastoma with or without OMS to gain insights into antitumor immunity as it relates to tumor biology and prognosis.

Clinical features and outcomes of opsoclonus myoclonus ataxia syndrome

OBJECTIVES AND METHODS

Opsoclonus myoclonus ataxia syndrome (OMAS) is a rare neuroinflammatory disorder. We aimed to retrospectively evaluate clinical and laboratory data and outcomes of 23 children diagnosed with OMAS in two children's hospitals between 2010 and 2021.

RESULTS

There were 14 boys and 9 girls aged 4-113 months, median 24 months. Ten (43.5%) children had paraneoplastic causes: neuroblastoma/ganglioneuroblastoma (n = 9), acute lymphoblastic leukemia (n = 1). Three children had a postinfectious cause (upper respiratory tract infection in 2, EBV infection in 1) and two had a history of vaccination (varicella in 1, hepatitis A and meningococcal in 1). No underlying factor was identified in 8 (34.8%) children. Speech disorders were more frequent in patients with neural tumors than in those without (p = 0.017). Intravenous immunoglobulin and steroids were effective as initial treatment in most children. Rituximab resulted in at least mild improvement in all 6 children with persistent or recurrent symptoms. Nine (39%) children experienced at least one relapse. Neurological sequelae were detected in 13 (57%) children. There was no significant correlation between clinical characteristics and outcome, except for higher risk of relapse in case of incomplete recovery after first attack (p = 0.001).

CONCLUSIONS

Acute lymphoblastic leukemia, vaccines against hepatitis A and meningococci can be included among antecedent factors in OMAS. Among clinical symptoms, speech problems might point to the likelihood of an underlying neoplasm in OMAS. Intravenous immunoglobulin and steroids may be chosen for initial treatment while rituximab can increase the chance of recovery in case of persistent or recurrent symptoms. The presence of relapse was associated with poor outcome.

Monocentric retrospective clinical outcome in a group of 13 patients with opsoclonus myoclonus syndrome, proposal of diagnostic algorithm and review of the literature

BACKGROUND

Dancing eye syndrome or opsoclonus-myoclonus syndrome (OMS) is a very rare disease (incidence <1/5,000,000 per year), which is more prevalent in young children. Although it is not usually a cause of mortality, the aftermaths are not rare.

METHODS

We performed an observational retrospective review of children diagnosed with OMS in our neuropediatric department from 1996 to 2020, with the objective of assessing the prognostic value of initial clinical features. All medical data from diagnosis to last follow-up were reviewed. We defined unfavorable evolution of OMS as persistence or worsening of symptoms. Subsequently, based on a literature review, our results and experience, a diagnostic algorithm was developed.

RESULTS

A total of 13 OMS patients were included: 61.5% were male (n = 8), median age at diagnosis was 18 months (IR = 76), median treatment delay was 14 days (IR = 146) and OMS score at onset was 8 (IR = 11). The most frequent etiologies were neuroblastoma-associated and idiopathic OMS (38.46%; n = 5) of the patients, followed by post-infectious OMS (n = 3). All the patients were treated with corticosteroids, five required a surgical intervention (neuroblastoma group), and three required adjunctive immune therapy (immunoglobulins, cyclophosphamide and/or rituximab). We detected neurodevelopmental disorders in 38.46% (n = 5) of the patients, mainly attention deficit (n = 4), and persistent sleep disturbances (n = 4). The median OMS score at the end of follow-up was 1 (IR = 3). An important diagnostic delay, OMS score of ≥10 and age >1 year at onset may correlate with a higher risk of aftermaths. We detected a better prognosis in the post-infectious OMS, with full recovery occurring in 2/3 of patients.

CONCLUSIONS

Early clinical suspicion is key to guarantee maximum response of treatment.

Long-term neurological outcomes of children with neuroblastoma with opsoclonus-myoclonus syndrome

BACKGROUND

Neuroblastoma with opsoclonus-myoclonus syndrome (OMS-NB) is a rare disease in children. Few studies of long-term outcome of children with OMS-NB were conducted. This study aimed to review the rate of recovery of neurological symptoms and the long-term neurological outcomes of children with OMS-NB.

METHODS

This study retrospectively assessed 14 children with OMS-NB diagnosed at Peking University First Hospital from May 2011 to November 2019. Demographic data, neurological symptoms, oncological status and treatments were retrospectively reviewed from the records. Neurological sequelae were recorded by clinical and remote follow-up.

RESULTS

During the acute stage, myoclonus and ataxia were observed in all children while opsoclonus was observed in 10/14 children. The median durations of neurological symptoms were 15 months (range, 5-48 months). Approximately 93% (13/14) children revealed neurological sequelae. Significant correlations were as follows: motor retardation with female gender (P<0.001) and residual tumors (P<0.05); language impairment with non-adrenal-gland-located tumors (P<0.05). There were no obvious factors that had a statistical relationship with cognitive disorder or behavioral changes.

CONCLUSIONS

Children with OMS-NB have favorable outcomes in terms of neurological symptoms. Neurological sequelae occurred in almost all children. Children with different features tend to reveal different sequalae. Features of female gender and residual tumors tend to reveal motor retardation while that of non-adrenal-gland-located tumors tend to reveal language impairment.

Clinical Analysis of Pediatric Opsoclonus-Myoclonus Syndrome in One of the National Children's Medical Center in China

Objective: To study the clinical characteristics and treatment of pediatric opsoclonus-myoclonus syndrome (OMS).

Methods: We analyzed the clinical data of nine children OMS between June 2017 and Nov 2020.

Results: Nine children (M/F = 3:6, median onset age was 18 months) diagnosed with OMS were included in the study. Before onset, human rhinovirus and respiratory syncytial virus were seen in one patient, respectively. And one patient received Japanese encephalitis vaccination. Three patients had neuroblastoma, and one patient had ganglioneuroblastoma. All patients' symptoms were improved after receiving surgery (for four patients with tumor), intravenous human immunoglobulin and pulsed methylprednisolone. However, four patients without mass relapsed and became relapse free after rituximab treatment. The relapse rate was 44.4% (4/9). The OMS severity score at the last follow-up was significantly lower than the OMS severity score at onset (3.0 ± 1.0 vs. 11.0 ± 2.2, paired-samples t-test, P < 0.001). All patients had at least one item of neurological symptoms or neuropsychological disturbances.

Conclusion: For pediatric OMS, human rhinovirus infection and respiratory syncytial virus infection can be seen before onset. Rituximab is effective in reducing relapse. Improving recognition and long-term prognosis in OMS is urgent.

Opsoclonus-Myoclonus Syndrome in Children and Adolescents: A Therapeutic Challenge

Opsoclonus-myoclonus syndrome (OMS) is a neurological non-fatal disease that usually responds to immunotherapies. However, the real challenge is to counteract the high frequency of relapses and long-term developmental sequelae. Since the OMS is extremely rare, a common consensus regarding therapeutic guidelines is still lacking. The goals of this study were to test whether ACTH was superior to other immunotherapies and to investigate whether an early treatment could improve the outcome. Sixteen children affected by OMS were retrospectively reviewed. Eight children had a neuroblastic tumor. The other eight patients were affected by non-paraneoplastic OMS. Overall, the most commonly used treatment was corticotherapy (n = 11). However, ACTH (n = 10), rituximab (n = 7), immunoglobulins (n = 4), cyclophosphamide (n = 3), and mycophenolate (n = 2) were also administered. ACTH was associated with a high percentage of patients who healed (80%) and, as a first-line therapy, was associated with a lower incidence of relapses. An early treatment was associated with a favorable long-term outcome. Long-term sequelae occurred in 42% of patients who were treated early and in all of those who were treated late. It is advisable for the affected children to be identified at an early time, as they may benefit from an early treatment. ACTH represents an effective treatment with a high probability of recovery and low rate of relapses.

IQ predictors in pediatric opsoclonus myoclonus syndrome: a large international cohort study

AIM

To determine predictors of full-scale IQ (FSIQ) in an international pediatric opsoclonus myoclonus syndrome (OMS) cohort.

METHOD

In this retrospective and prospective cohort study at three academic medical centers (2006-2013), the primary outcome measure, FSIQ, was categorized based on z-score: above average (≥+1), average (+1 to -1), mildly impaired (-1 to -2), and impaired (<-2). Univariate analysis and multivariable linear regression modeling using stepwise selection with Akaike's information criterion was performed to understand the relationship between exposures and FSIQ.

RESULTS

Of 81 participants, 37 with sufficient data had mean FSIQ 84.38 (SD 20.55) and median 90 (40-114) at latest available evaluation (mean age 8y 5mo). Twenty (54%), nine (24.3%), and eight (21.6%) had normal, mildly impaired, and impaired FSIQ respectively. The final multivariable linear regression model included 34 participants with evaluable data: number of relapses occurring before neuropsychological testing (p<0.001) and OMS severity score at last follow-up (p<0.001) predicted FSIQ (adjusted R² =0.64). There was a mean decrease of 2.4 FSIQ points per OMS relapse.

INTERPRETATION

Number of relapses negatively correlates with FSIQ in pediatric OMS. Demographic and clinical measures available at OMS onset did not predict FSIQ. Strategies to reduce OMS relapses may improve intellectual outcomes.

The Treatment of Opsoclonus-Myoclonus Syndrome Secondary to Neuroblastic Tumours-Single-Centre Experience and Literature Review

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.

Opsoclonus-myoclonus syndrome: clinical characteristics, therapeutic considerations, and prognostic factors in a Spanish paediatric cohort

INTRODUCTION

Opsoclonus-myoclonus-ataxia syndrome is a rare neuroinflammatory disorder with onset during childhood; aetiology may be paraneoplastic, para-infectious, or idiopathic. No biomarkers have yet been identified, and diagnosis is clinical. Better cognitive prognosis appears to be related to early onset of immunomodulatory therapy.

METHODS

We describe the epidemiological, clinical, therapeutic, and long-term prognostic characteristics of a cohort of 20 Spanish patients.

RESULTS

The mean age of onset was 21 months (range, 2-59). Ataxia and opsoclonus were the most frequent symptoms both at disease onset and throughout disease progression. The mean time from onset to diagnosis was 1.1 months. Neuroblast lineage tumours were detected in 45% of patients; these were treated with surgical resection in 7 cases and chemotherapy in 2. Cerebrospinal fluid analysis revealed pleocytosis in 4 cases (25%) and neither antineuronal antibodies nor oligoclonal bands were detected in any patient. Immunomodulatory drugs were used in all cases. Nine patients started combined immunomodulatory treatment at the time of diagnosis, and 5 patients after a mean of 2.2 months. In the long term, 6 of the 10 patients followed up for more than 5 years presented mild or moderate cognitive sequelae. Four patients presented relapses, generally coinciding with the decrease of corticosteroid doses.

CONCLUSIONS

Early initiation of immunotherapy, as well as triple combination therapy, where needed, was associated with a lower frequency of cognitive impairment 2 years after onset.

Serum IgG-induced microglial activation enhances neuronal cytolysis via the NO/sGC/PKG pathway in children with opsoclonus-myoclonus syndrome and neuroblastoma

Background

Opsoclonus-myoclonus syndrome (OMS) is a rare neurological disease. Some children with OMS also have neuroblastoma (NB). We and others have previously documented that serum IgG from children with OMS and NB induces neuronal cytolysis and activates several signaling pathways. However, the mechanisms underlying OMS remain unclear. Here, we investigated whether nitric oxide (NO) from activated microglias and its cascade contribute to neuronal cytolysis in pediatric OMS.

Methods

The activation of cultured cerebral cortical and cerebellar microglias incubated with sera or IgG isolated from sera of children with OMS and NB was measured by the expression of the activation marker, cytokines, and NO. Neuronal cytolysis was determined after exposing to IgG-treated microglia-conditioned media. Using inhibitors and activators, the effects of NO synthesis and its intracellular cascade, namely soluble guanylyl cyclase (sGC) and protein kinase G (PKG), on neuronal cytolysis were evaluated.

Results

Incubation with sera or IgG from children with OMS and NB increased the activation of cerebral cortical and cerebellar microglias, but not the activation of astrocytes or the cytolysis of glial cells. Moreover, the cytolysis of neurons was elevated by conditioned media from microglias incubated with IgG from children with OMS and NB. Furthermore, the expression of NO, sGC, and PKG was increased. Neuronal cytolysis was relieved by the inhibitors of NO signaling, while neuronal cytolysis was exacerbated by the activators of NO signaling but not proinflammatory cytokines. The cytolysis of neurons was suppressed by pretreatment with the microglial inhibitor minocycline, a clinically tested drug. Finally, increased microglial activation did not depend on the Fab fragment of serum IgG.

Conclusions

Serum IgG from children with OMS and NB potentiates microglial activation, which induces neuronal cytolysis through the NO/sGC/PKG pathway, suggesting an applicability of microglial inhibitor as a therapeutic candidate.

Tremor and myoclonus

Tremor and myoclonus are two common hyperkinetic movement disorders. Tremor is characterized by rhythmic oscillatory movements while myoclonic jerks are usually arrhythmic. Tremor can be classified into subtypes including the most common types: essential, enhanced physiological, and parkinsonian tremor. Myoclonus classification is based on its anatomic origin: cortical, subcortical, spinal, and peripheral myoclonus. The clinical presentations are unfortunately not always classic and electrophysiologic investigations can be helpful in making a phenotypic diagnosis. Video-polymyography is the main technique to (sub)classify the involuntary movements. In myoclonus, advanced electrophysiologic testing, such as back-averaging, coherence analysis, somatosensory-evoked potentials, and the C-reflex can be of additional value. Recent developments in tremor point toward a role for intermuscular coherence analysis to differentiate between tremor subtypes. Classification of the movement disorder based on clinical and electrophysiologic features is important, as it enables the search for an etiological diagnosis and guides tailored treatment.

Update on opsoclonus-myoclonus syndrome in adults

Opsoclonus-myoclonus syndrome in adults is a rare and heterogeneous disorder with the clinical features of opsoclonus, myoclonus, ataxia, and behavioral and sleep disturbances. The pathophysiology is thought to be immunological on the basis of paraneoplastic or infectious etiologies. Immunomodulatory therapies should be performed although the response may be incomplete. A number of autoantibodies have been identified against a variety of antigens, but no diagnostic immunological marker has yet been identified. This review focuses on underlying mechanisms of opsoclonus-myoclonus syndrome, including findings that have been identified recently, and provides an update on the clinical features and treatments of this condition.

Multifactorial analysis of opsoclonus-myoclonus syndrome etiology ("Tumor" vs. "No tumor") in a cohort of 356 US children

BACKGROUND

Pediatric opsoclonus-myoclonus syndrome (OMS) presents a paradox of etiopathogenesis: A neuroblastic tumor (NB) is found in only one half of the cases, the others are ascribed to infections or designated as idiopathic.

METHOD

From an IRB-approved observational study of 356 US children with OMS, secondary analysis of "etiology" and related factors was performed on a well-characterized cohort. The "Tumor" (n = 173) and "No Tumor" groups (n = 183), as defined radiologically, were compared according to multiple factors considered potentially differentiating. Data were analyzed retrospectively using parametric and nonparametric tests as indicated.

RESULTS

Patients with NB were not distinguishable by prodromal symptoms, OMS onset age, gender, race/ethnicity, OMS severity, rank order of neurological sign appearance, or geographic distribution. Various CSF immunologic biomarker abnormalities of OMS did not vary in the presence or absence of a detectable tumor: frequency of six lymphocyte subsets, or concentrations of 18 cytokines/chemokines, cytokine antagonists, chemokine receptors, cell adhesion molecules, or neuronal/glial markers. Prior responsiveness to conventional immunotherapy was not contingent on tumor/no tumor designation.

CONCLUSIONS

Multiple convergent factors provide compelling empirical evidence and rationalize the concept that OMS is one neurological disorder, regardless of apparent etiology. Limitations to the current clinical etiologic classifications as paraneoplastic, parainfectious/post-infectious, and idiopathic etiology require antigen-based biological solutions to tease out the molecular pathophysiology of viral/tumoral mechanisms. Systematic studies, regardless of presumed etiology, will be necessary to find the highest-yield combination of imaging approaches, screening for infectious agents, and new biomarkers. Two testable hypotheses for future research are presented.

Autoimmune Movement Disorders in Children

Over the last decade, there have been significant advances in the identification, characterization, and treatment of autoimmune neurologic disorders in children. Many of these diseases include a typical movement disorder that can be a powerful aid to diagnosis. Frequently, movement disorders in autoimmune conditions are the sole or among a few presenting symptoms, allowing for earlier diagnosis of an underlying malignancy or systemic autoimmune disease. Given that early detection and treatment with immunotherapy may confer improved outcomes, recognizing these patterns of abnormal movements is essential for child neurologists. The purpose of this review is to summarize the clinical characteristics, diagnosis, and treatment of movement disorders that occur in pediatric autoimmune disorders.

Genomic Profiles of Neuroblastoma Associated With Opsoclonus Myoclonus Syndrome

Opsoclonus myoclonus syndrome (OMS), often called "dancing eyed syndrome," is a rare neurological condition associated with neuroblastoma in the majority of all childhood cases. Genomic copy number profiles have shown to be of prognostic significance for neuroblastoma patients. The aim of this retrospective multicenter study was to analyze the genomic copy number profiles of tumors from children with neuroblastoma presenting with OMS at diagnosis. In 44 cases of neuroblastoma associated with OMS, overall genomic profiling by either array-comparative genomic hybridization or single nucleotide polymorphism array proved successful in 91% of the cases, distinguishing tumors harboring segmental chromosome alterations from those with numerical chromosome alterations only. A total of 23/44 (52%) tumors showed an segmental chromosome alterations genomic profile, 16/44 (36%) an numerical chromosome alterations genomic profile, and 1 case displayed an atypical profile (12q amplicon). No recurrently small interstitial copy number alterations were identified. With no tumor relapse nor disease-related deaths, the overall genomic profile was not of prognostic impact with regard to the oncological outcome in this series of patients. Thus, the observation of an excellent oncological outcome, even for those with an unfavorable genomic profile of neuroblastoma, supports the hypothesis that an immune response might be involved in tumor control in these patients with OMS.

Intravenous immunoglobulin with prednisone and risk-adapted chemotherapy for children with opsoclonus myoclonus ataxia syndrome associated with neuroblastoma (ANBL00P3): a randomised, open-label, phase 3 trial

Purpose

No previous clinical trial has been conducted for patients with neuroblastoma associated opsoclonus myoclonus ataxia syndrome (OMA), and current treatment is based on case reports. To evaluate the OMA response to prednisone and risk-adapted chemotherapy and determine if the addition of intravenous gammaglobulin (IVIG) further improves response, the Children’s Oncology Group designed a randomized therapeutic trial.

Patient and Methods

Eligible subjects were randomized to receive twelve cycles of IVIG (IVIG+) or no IVIG (NO-IVIG) in addition to prednisone and neuroblastoma risk-adapted chemotherapy. All low-risk patients were treated with cyclophosphamide. The severity of OMA symptoms was evaluated at 2, 6, and 12 months using a scale developed by Mitchell and Pike and baseline versus best response scores were compared. A single patient who did not undergo neurologic assessment was excluded from OMA response analysis. This study is registered with Clinical Trials.gov (identifier NCT00033293).

Results

Of the 53 patients enrolled in the study, 62% (33/53) were female. There were 44 low-risk, 7 intermediate-risk, and 2 high-risk neuroblastoma patients. Twenty-six subjects were randomized to receive IVIG+ and 27 were randomized to NO-IVIG. The neuroblastoma 3-year event-free survival (95% confidence interval (CI)) was 94.1% (87.3%, 100%) and overall survival was 98.0% (94.1%, 100%). Significantly higher rates of OMA response were observed in patients randomized to IVIG+ compared to NO-IVIG [21/26=80.8% for IVIG+; 11/27=40.7% for NO-IVIG (odds ratio=6.1; 95% CI: (1.5, 25.9), p=0.0029)]. For the majority of patients, the IVIG+ OMA regimen combined with cytoxan or other risk-based chemotherapy was well tolerated, although there was one toxic death in a high-risk subject.

Conclusion

This is the only randomized prospective therapeutic clinical trial in children with neuroblastoma-associated OMA. The addition of IVIG to prednisone and risk-adapted chemotherapy significantly improves OMA response rate. IVIG+ constitutes a back-bone upon which to build additional therapy.

Childhood opsoclonus-myoclonus syndrome: A case series from Tunisia

INTRODUCTION

Opsoclonus myoclonus syndrome (OMS) is a rare immune-mediated disorder characterized by opsoclonus, myoclonus, ataxia and behavioral changes. The aim of our study was to investigate the epidemiology, clinical features, etiological aspects and outcome of OMS in Tunisian children.

METHODS

We conducted a retrospective study over 11years (2005-2016) including all patients aged under 18years who were managed for newly diagnosed OMS in a tertiary care research centre for children with neurological symptoms. Epidemiological and clinical data were analyzed.

RESULTS

Fifteen patients were included. The male-female ratio was 7:8. Median age of onset was 4.32years (range: 14months-16years). Time to diagnosis ranged between 2days and 10months. Median follow-up period was 3.8years (range: 2-6years). Acute ataxia was the preponderant inaugural feature. Mean severity score was 9 (range: 3-14). In "Tumor group" (n=7), the main underlying malignancy was neuroblastoma identified in 5 patient. In "No tumor group" (n=8), parainfectious and idiopathic OMS were identified in 5 and 3 patients, respectively. All patients received immunomodulatory treatment. Complete recovery of OMS symptoms was obtained in 12 children. Comparing the "Tumor group" and the "No tumor group", there were no differences in age of onset, sex ratio, main presenting symptom, median OMS severity score or responsiveness to treatment. However, sleep and behavioral disturbances were more frequent in the "No tumor group" (p=0.04). Neurological sequelae were equally found in both groups.

CONCLUSION

Annual incidence of OMS in Tunisia could be estimated as 0.6 patients in children per million per year. Diagnosis may be challenging especially when the triad is incomplete. Although behavioral disturbances seem to be more frequent in the "No tumor group", our study suggests that there is no specific features differentiating paraneoplastic OMS from non paraneoplastic OMS. Acute symptoms are responsive to immunomodulatory treatment but long term follow up can reveal neurological (mainly cognitive) sequelae.

Demographic, Clinical, and Immunologic Features of 389 Children with Opsoclonus-Myoclonus Syndrome: A Cross-sectional Study

Pediatric-onset opsoclonus-myoclonus syndrome (OMS) is a devastating neuroinflammatory, often paraneoplastic, disorder. The objective was to characterize demographic, clinical, and immunologic aspects in the largest cohort reported to date. Cross-sectional data were collected on 389 children in an IRB-approved, observational study at the National Pediatric Myoclonus Center. Non-parametric statistical analysis was used. OMS manifested in major racial/ethnic groups, paralleling US population densities. Median onset age was 1.5 years (1.2–2 interquartile range), inclusive of infants (14%), toddlers (61%), and youngsters (25%). The higher female sex ratio of 1.2 was already evident in toddlers. Time to diagnosis was 1.2 months (0.7–3); to treatment, 1.4 months (0.4–4). Irritability/crying dominated prodromal symptomatology (60%); overt infections in <35%. Acute cerebellar ataxia was the most common misdiagnosis; staggering appeared earliest among 10 ranked neurological signs (P < 0.0001). Some untreated youngsters had no words (33%) or sentences (73%). Remote neuroblastic tumors were detected in 50%; resection was insufficient OMS treatment (58%). Age at tumor diagnosis related to tumor type (P = 0.004) and stage (P = 0.002). A novel observation was that paraneoplastic frequency varied with patient age—not a mere function of the frequency of neuroblastoma, which was lowest in the first 6 months of life, when that of neuroblastoma without OMS was highest. The cerebrospinal fluid (CSF) leukocyte count was minimally elevated in 14% (≤11/mm³) with normal differential, and commercially screened serum autoantibodies were negative, but CSF oligoclonal bands (OCB) and B cells frequency were positive (58 and 93%). Analysis of patients presenting on immunotherapy revealed a shift in physician treatment practice patterns from monotherapy toward multi-agent immunotherapy (P < 0.001); the number of agents/sequences varied. In sum, a major clinical challenge is to increase OMS recognition, prevent initial misdiagnosis, and shorten time to diagnosis/treatment. The index of suspicion for an underlying tumor must remain high despite symptoms of infection. The disparity in onset age of neuroblastoma frequency with that of neuroblastoma with OMS warrants further studies of potential host/tumor factors. OMS neuroinflammation is best diagnosed by CSF OCB and B cells, not by routine CSF or commercial antibody studies.

Neuroblastoma (Peripheral neuroblastic tumours)

Peripheral neuroblastic tumours (PNTs), a family of tumours arising in the embryonal remnants of the sympathetic nervous system, account for 7-10% of all tumours in children. In two-thirds of cases, PNTs originate in the adrenal glands or the retroperitoneal ganglia. At least one third present metastases at onset, with bone and bone marrow being the most frequent metastatic sites. Disease extension, MYCN oncogene status and age are the most relevant prognostic factors, and their influence on outcome have been considered in the design of the recent treatment protocols. Consequently, the probability of cure has increased significantly in the last two decades. In children with localised operable disease, surgical resection alone is usually a sufficient treatment, with 3-year event-free survival (EFS) being greater than 85%. For locally advanced disease, primary chemotherapy followed by surgery and/or radiotherapy yields an EFS of around 75%. The greatest problem is posed by children with metastatic disease or amplified MYCN gene, who continue to do badly despite intensive treatments. Ongoing trials are exploring the efficacy of new drugs and novel immunological approaches in order to save a greater number of these patients.

Neuroblastoma presenting as opsoclonus-myoclonus: A series of six cases and review of literature

The opsoclonus-myoclonus ataxia syndrome (OMAS) also called “Kinsbourne syndrome” or “dancing eye syndrome” is a rare but serious disorder characterized by opsoclonus, myoclonus, and ataxia, along with extreme irritability and behavioural changes. Data on its epidemiology, clinical features, and outcome are limited worldwide. The aim of the study was to evaluate the clinical profile and outcome of children with OMAS. A retrospective data of all children presented to Pediatric oncology clinic with a diagnosis of opsoclonus-myoclonus from 2013 to 2016 were collected. 6 patients with a diagnosis of OMAS were presented over a 4-year period. All 6 cases had paraneoplastic etiology. All Children had good outcome without any relapse. Paraneoplastic opsoclonus myoclonus had a good outcome in our experience.

A novel diagnostic approach to patients with myoclonus

Myoclonus is a hyperkinetic movement disorder characterized by brief, involuntary muscular jerks. Recognition of myoclonus and determination of the underlying aetiology remains challenging given that both acquired and genetically determined disorders have varied manifestations. The diagnostic work-up in myoclonus is often time-consuming and costly, and a definitive diagnosis is reached in only a minority of patients. On the basis of a systematic literature review up to June 2015, we propose a novel diagnostic eight-step algorithm to help clinicians accurately, efficiently and cost-effectively diagnose myoclonus. The large number of genes implicated in myoclonus and the wide clinical variation of these genetic disorders emphasize the need for novel diagnostic techniques. Therefore, and for the first time, we incorporate next-generation sequencing (NGS) in a diagnostic algorithm for myoclonus. The initial step of the algorithm is to confirm whether the movement disorder phenotype is consistent with, myoclonus, and to define its anatomical subtype. The next steps are aimed at identification of both treatable acquired causes and those genetic causes of myoclonus that require a diagnostic approach other than NGS. Finally, other genetic diseases that could cause myoclonus can be investigated simultaneously by NGS techniques. To facilitate NGS diagnostics, we provide a comprehensive list of genes associated with myoclonus.

A nationwide survey of opsoclonus-myoclonus syndrome in Japanese children

BACKGROUND

Opsoclonus-myoclonus syndrome (OMS) is a rare neurological disease characterized by opsoclonus, myoclonus, ataxia, and behavioral changes. The aim of our study was to investigate the epidemiological characteristics of OMS in Japan and to clarify the association between therapy and prognosis.

METHODS

We retrospectively collected the data from 626 Japanese medical institutions from 2005 to 2010, and analyzed the clinical features of pediatric patients with OMS based on the data.

RESULTS

In this survey, there were 23 patients (10 males and 13 females). The median ages at the disease onset and the time of study were 16.5 months (range: 11-152 months) and 54 months (range: 24-160 months), respectively. The principal symptoms were opsoclonus (23 patients, 100%), myoclonus (21 patients, 91.3%), and ataxia (23 patients, 100%). The related factors were neuroblastoma (10, 43.5%), infection (9, 39.1%), and immunization (2, 8.7%). The treatments for OMS were included intravenous immunoglobulin (17, 73.9%), methylprednisolone pulse (13, 56.5%), oral prednisolone (12 patients, 52.2%), and chemotherapy and/or operation for the underlying tumors (6, 26.1%), and rituximab (2, 8.7%). Complete remissions were obtained in 35.3%, 23.1%, 33.3%, 66.7%, and 100% of these treatments, respectively. At the latest follow-up period, 8 (34.8%) and 17 patients (73.9%) showed neurological sequelae of motor and intellectual functions, respectively. Patients whose treatment was started more than 30 weeks after the disease onset suffered from the severest neurological sequelae (OMS severity 4) more frequently than those less than 30 weeks (p=0.022).

CONCLUSION

The annual incidence of OMS was estimated to be 0.27-0.40 cases per million in Japanese children. More than 70% of OMS patients had neurological sequelae, especially intellectual function. Early effective treatments within 30 weeks after the onset may be required to prevent the serious neurological outcome.

Role of BAFF in Opsoclonus-Myoclonus syndrome, a bridge between cancer and autoimmunity

OMS is a rare paraneoplastic disorder that affects adults and children. Pediatric OMS is often associated with NB, a common, solid tumor of childhood, derived from the sympathetic nervous system. The detection of autoantibodies and lymphocytic infiltration in NB patients led to advance an autoimmune hypothesis for the pathogenesis of OMS-related NB. BAFF is a potent modulator of B cell growth and survival upon interaction with its receptors BAFF-R and BCMA. The aim of this study was to investigate mechanism(s) involved in ectopic lymphoid neogenesis in OMS-associated NB. We investigated BAFF, BAFF-R, and BCMA expression in NB tumors associated or not with OMS. Furthermore, we evaluated BAFF expression and secretion in NB cell lines, treated or untreated with differentiating agents. Immunohistochemically, lymphocytes infiltrating NB tumors from patients, with or without OMS, expressed BAFF, BAFF-R, and BCMA, whereas neuroblasts expressed BAFF and BCMA but not BAFF-R. By flow cytometry, BAFF was found to be consistently expressed in NB cell lines. Similarly to the results obtained in tissue lesions, BCMA but not BAFF-R was detected on the surface of all NB cell lines under basal conditions. De novo synthesis of BAFF-R and up-regulation of BCMA were observed in NB cell lines upon treatment with IFN-γ or 13-cis retinoic acid. This study provides new insights in the mechanisms driving the neogenesis of lymphoid follicles and in the functional interactions between tumor and immune cells in OMS-associated NB.

Clinical responses to rituximab in a case of neuroblastoma with refractory opsoclonus myoclonus ataxia syndrome

Opsoclonus myoclonus ataxia syndrome (OMS) is a rare neurologic syndrome. In a high proportion of children, it is associated with neuroblastoma. The etiology of this condition is thought to be immune mediated. In children, immunotherapy with conventional treatments such as corticosteroids, intravenous immunoglobulin, adrenocorticotropic hormone, and even antiepileptic drugs has been tried. Recently rituximab has been used safely for refractory OMS in children with neuroblastoma. Our patient was a 3.5-year-old girl referred for ataxia and dancing eye movements starting since 1.5 years ago. She was diagnosed with neuroblastoma on imaging studies on admission. The OMS was refractory to surgical resection, chemotherapy, corticosteroids, and intravenous immunoglobulin. Patient received rituximab simultaneously with chemotherapy. The total severity score decreased by 61.1% after rituximab. Patient's ataxia markedly improved that she was able to walk independently after 6 months. Our case confirmed the clinical efficacy and safety of rituximab in a refractory case of OMS.

Opsoclonus-myoclonus and anti-Hu positive limbic encephalitis in a patient with neuroblastoma

Opsoclonus-myoclonus syndrome (OMS) is seen in 2-3% of children with neuroblastoma and is believed to be caused by an autoimmune process elicited by the tumor. Although long-term neurologic sequelae are common in children with OMS, limbic encephalitis has not previously been reported. We report a child who developed limbic encephalitis associated with anti-Hu antibodies, 6 years after her initial diagnosis of neuroblastoma and OMS. This case demonstrates that patients with neuroblastoma and OMS are at risk for developing new paraneoplastic symptoms years after their original diagnosis and emphasizes the need for careful long-term follow-up.

Opsoclonus-myoclonus syndrome following influenza a infection

A 60-year-old woman developed opsoclonus-myoclonus syndrome (OMS) a week after being diagnosed with influenza A infection by a rapid antigen test. She had no loss of consciousness. Opsoclonus, myoclonus, and truncal ataxia were noted. Two weeks after treatment with intravenous immunoglobulin and corticosteroids, her opsoclonus, myoclonus, and truncal ataxia disappeared. No malignant tumors were detected during the 3-year follow-up period. There has been no previous report of postinfectious OMS following confirmed influenza A infection. OMS without a loss of consciousness has been reported to be statistically less common in cases of non-paraneoplastic OMS. This finding was consistent with the present patient's clinical manifestations.

Movement disorder emergencies in childhood

The literature on paediatric acute-onset movement disorders is scattered. In a prospective cohort of 52 children (21 male; age range 2mo-15y), the commonest were chorea, dystonia, tremor, myoclonus, and Parkinsonism in descending order of frequency. In this series of mainly previously well children with cryptogenic acute movement disorders, three groups were recognised: (1) Psychogenic disorders (n = 12), typically >10 years of age, more likely to be female and to have tremor and myoclonus (2) Inflammatory or autoimmune disorders (n = 22), including N-methyl-d-aspartate receptor encephalitis, opsoclonus-myoclonus, Sydenham chorea, systemic lupus erythematosus, acute necrotizing encephalopathy (which may be autosomal dominant), and other encephalitides and (3) Non-inflammatory disorders (n = 18), including drug-induced movement disorder, post-pump chorea, metabolic, e.g. glutaric aciduria, and vascular disease, e.g. moyamoya. Other important non-inflammatory movement disorders, typically seen in symptomatic children with underlying aetiologies such as trauma, severe cerebral palsy, epileptic encephalopathy, Down syndrome and Rett syndrome, include dystonic posturing secondary to gastro-oesophageal reflux (Sandifer syndrome) and Paroxysmal Autonomic Instability with Dystonia (PAID) or autonomic 'storming'. Status dystonicus may present in children with known extrapyramidal disorders, such as cerebral palsy or during changes in management e.g. introduction or withdrawal of neuroleptic drugs or failure of intrathecal baclofen infusion; the main risk in terms of mortality is renal failure from rhabdomyolysis. Although the evidence base is weak, as many of the inflammatory/autoimmune conditions are treatable with steroids, immunoglobulin, plasmapheresis, or cyclophosphamide, it is important to make an early diagnosis where possible. Outcome in survivors is variable. Using illustrative case histories, this review draws attention to the practical difficulties in diagnosis and management of this important group of patients.

Outcome and prognostic features in opsoclonus-myoclonus syndrome from infancy to adult life

OBJECTIVE

Opsoclonus-myoclonus syndrome (OMS) is a serious and often chronically disabling neurologic illness with onset in early childhood. Our aim was to identify long-term neurologic sequelae of OMS and predictors for disease outcome.

METHODS

We retrospectively assessed the case records of 101 patients diagnosed with OMS over a 53-year period. Clinical data were obtained from medical record review; we documented age at onset, severity of symptoms, response to treatment, and neurocognitive sequelae.

RESULTS

Overall, 21% of the patients had a neuroblastoma detected; however, in those born after 1990, this figure rose to 40%. Sixty-one percent of the patients had a chronic-relapsing course, 32% experienced several acute exacerbations, and 7% had a monophasic course. At the most recent review, 60% had residual motor problems, 66% speech abnormalities, 51% learning disability, and 46% behavior problems. One-third of the patients had normal intellectual outcome and cessation of symptoms. A severe initial presentation predicted a chronic disease course (odds ratio [OR]: 2.77 [95% confidence interval (CI): 1.47-5.23]; P = .002) and later learning disability (OR: 2.03 [95% CI: 1.08-3.79]; P = .026). Those with cognitive impairment were younger at disease onset (15.0 vs 19.5 months; P = .029). A chronic-relapsing disease course was associated with motor (P < .001), speech (P = .001), cognitive (P < .001), and behavior (P = .006) problems.

CONCLUSIONS

OMS is a chronic and debilitating illness; those with severe initial symptoms and those who are very young at disease onset are at increased risk of developing long-term sequelae. It is important for affected children to be identified early, because they might benefit from targeted immunomodulating therapy in specialist centers.

Progress in treatment and risk stratification of neuroblastoma: impact on future clinical and basic research

Close international collaboration between pediatric oncologists has led to marked improvements in the cure of patients, seen as a long-term overall survival rate of about 80%. Despite this progress, neuroblastoma remains a challenging disease for both clinicians and researchers. Major clinical problems include lack of acceptable cure rates in high-risk neuroblastoma and potential overtreatment of subsets of patients at low and intermediate risk of the disease. Many years of intensive international cooperation have recently led to a promising joint effort to further improve risk classification for treatment stratification, the new International Neuroblastoma Risk Group Classification System. This approach will facilitate comparison of the results of clinical trials performed by different international collaborative groups. This, in turn, should accelerate refinement of risk stratification and thereby aid selection of appropriate therapies for individual patients. To be able to identify new therapeutic modalities, it will be necessary to elucidate the pathogenesis of the different subtypes of neuroblastoma. Basic and translational research have provided new tools for molecular characterization of blood and tumor samples including high-throughput technologies for analysis of DNA, mRNAs, microRNAs and other non-coding RNAs, as well as proteins and epigenetic markers. Most of these studies are array-based in design. In neuroblastoma research they aim to refine risk group stratification through incorporation of molecular tumor fingerprints and also to enable personalized treatment modalities by describing the underlying pathogenesis and aberrant signaling pathways in individual tumors. To make optimal use of these new technologies for the benefit of the patient, it is crucial to have a systematic and detailed documentation of both clinical and molecular data from diagnosis through treatment to follow-up. Close collaboration between clinicians and basic scientists will provide access to combined clinical and molecular data sets and will create more efficient steps in response to the remaining treatment challenges. This review describes the current efforts and trends in neuroblastoma research from a clinical perspective in order to highlight the urgent clinical problems we must address together with basic researchers.

Síndrome de Kinsbourne manifestando-se com quadro de encefalite pós-viral

OBJETIVO: Descrever um caso de síndrome de Kinsbourne manifestando-se com quadro de encefalite pós-viral e rever a da literatura. DESCRIÇÃO DO CASO: Criança do sexo feminino, dois anos e seis meses, encaminhada de outro serviço com história de ataxia, irritabilidade e dificuldades articulatórias na fala após episódio prodrômico de febre, lesões de pele e mucosa. Com hipótese de encefalite pós-viral, a avaliação clínica evidenciou quadro de síndrome opsoclônus-mioclonia-ataxia ou síndrome de Kinsbourne. Foi afastada a associação de neuroblastoma oculto e iniciada terapêutica com corticosteroide. Durante internação e acompanhamento ambulatorial, houve regressão progressiva e normalização do quadro clínico e neurológico inicial. COMENTÁRIOS: Apesar de se tratar de uma doença rara, o diagnóstico de síndrome de Kinsbourne deve ser reconhecido pelos pediatras e intensivistas, com objetivo de instituir tratamento específico precoce, embora com resultados variáveis, sendo fundamental a exclusão de neuroblastoma oculto.

Therapies for multiple sclerosis: considerations in the pediatric patient

Current and emerging therapies for multiple sclerosis (MS) offer promise for improved disease control and long-term clinical outcome. To date, these therapies have been evaluated solely in the context of adult MS. However, onset of MS in children is being increasingly recognized, and recent studies have identified a significant impact of MS onset during childhood on cognitive and physical functioning. Optimization of pediatric MS care requires that promising new therapies be made available to children and adolescents, but also that safety and tolerability and potential influence of therapies on the developing immune and neural networks of pediatric patients be closely considered. We propose care algorithms illustrating models for therapy that detail careful monitoring of pediatric patients with MS, provide definitions for inadequate treatment response and treatment escalation, and foster multinational collaboration in future therapeutic trials.

Update on diagnosis, treatment, and prognosis in opsoclonus-myoclonus-ataxia syndrome

PURPOSE OF REVIEW

Opsoclonus-myoclonus-ataxia syndrome (OMS) is a severe autoimmune central nervous system disorder, which predominantly affects young children and causes lifelong neurological disability. Early recognition and treatment may yield better outcomes.

RECENT FINDINGS

Appreciation of the spectrum of clinical presentations of OMS, awareness of common misdiagnoses, and utilization of diagnostic criteria may facilitate the timely diagnosis of OMS. Approximately 50% of patients have an associated neuroblastoma, which may escape detection by traditional methods and require MRI or computed tomography of the torso for diagnosis. In nonparaneoplastic cases, many associated infections have been reported. Although there has been progress in autoantibody identification and cerebrospinal fluid B cell expansion is a common finding, there is no diagnostic biomarker for OMS currently. Approximately 80% of reported patients, typically treated with conventional therapies such as adrenocorticotropin hormone, corticosteroids, and/or intravenous immunoglobulin, develop long-term neurological morbidity. Newer treatment approaches using early, aggressive therapy with cyclophosphamide or rituximab are promising.

SUMMARY

The diagnosis of OMS requires a high level of suspicion and a systematic approach for diagnostic testing, particularly for neuroblastoma. Future collaborative studies are required to determine whether early, aggressive therapy will improve the typically poor long-term neurological outcome.

Management of patients with myoclonus: available therapies and the need for an evidence-based approach

Myoclonus is a hyperkinetic movement disorder characterised by quick and involuntary jerks. Therapy should focus on cure of an underlying disorder; however, symptomatic treatment is often needed when treatment of an underlying cause is impossible or ineffective. The appropriate treatment for a specific type of myoclonus is based on the classification of the anatomical origin of the myoclonus: cortical, subcortical, spinal, or peripheral. We outline criteria for classification and present an overview of the available therapeutic options for the different types of myoclonus. Because of a generally low level of evidence, therapeutic options mainly rely on small observational studies and expert opinion. For an evidence-based approach in the future, randomised controlled trials of symptomatic therapies for myoclonus in homogeneous patient groups are needed.