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

Pediatric Opsoclonus-Myoclonus-Ataxia Syndrome can Lead to Long-Term Neurological, Neuropsychological, and Cognitive Sequelae Associated with Cerebellar Atrophy

To outline the long-term neuropsychological profile of a pediatric cohort with Opsoclonus-Myoclonus-Ataxia Syndrome (OMAS), and evaluate whether volumetric brain abnormalities correlate with clinical findings years after onset. Twelve patients diagnosed with OMAS between 2008 and 2020 (6 males, mean age 9.6 years, median follow-up 5.4 years) underwent a videorecorded neurological examination and a standardized cognitive and neuropsychological assessment. Patients and 12 age-matched controls underwent advanced 3-Tesla brain MRI studies. Voxel-Based Morphometry (VBM) and targeted cerebellar evaluation using ACAPULCO and ENIGMA pipelines were performed. The results were correlated with neuropsychological scores. Nine subjects (75%) had abnormal neurological findings (dysmetria n = 7, balance deficit n = 7, and speech impairment n = 6). The mean Full-Scale IQ was 76, with borderline IQ in 2 cases, intellectual disability in 5, visuospatial processing impairments in 6, and affective and internalizing issues in 7. Brain MRI and VBM showed mild cerebellar atrophy (41.6%), especially in Crus I-II, IV, VIIIa and VIIb lobules. Reduced gray matter volumes were noted in the precentral, inferior-occipital and middle orbitofrontal gyrus, while larger volumes were found in the ventral diencephalon fusiform and inferior temporal gyri. Lower white matter volumes were found in the cerebellum, superior frontal gyrus, midbrain, postcentral and precentral gyri. Patients with lower cognitive scores, especially in Working Memory and Processing Speed, had smaller volumes in several cerebellar lobules (p = 0.001). Smaller cerebellar volumes correlate with lower cognitive scores at long-term follow-up, confirming not only the role of the cerebellum in the pathogenesis of OMAS, but also its role in cognitive functioning.

The utilization of the multimodal immunotherapy for the opsoclonus-myoclonus syndrome can reduce relapses and permanent neurological sequelae

BACKGROUND

There is no known effective treatment strategy to prevent relapses and avert permanent neurological sequelae in opsoclonus-myoclonus syndrome (OMS). To describe the treatment strategy that reduced relapses and led to remission of OMS without permanent neurological sequelae.

METHODS

This cross-sectional study was conducted at the Department of Pediatrics, Xiangya Hospital, Central South University. Patients diagnosed with OMS from January 2014 to July 2022 were enrolled. Exposures included treatment with multimodal immunotherapy. Main outcomes and measures included the OMS severity grading scale and DQ/IQ scores. The clinical data was collected and analysed.

RESULTS

Of the six recruited patients, three were (50.00%) males. The median age of onset was 15.50 months. Preceding manifestation was present in one patient and two cases had neuroblastoma. The mean duration from disease onset to the initiation of therapies was 1.86 months. The combinations of ≥ two therapies were used: combination of the intravenous immunoglobulin (IVIG) plus intravenous dexamethasone plus rituximab was used for three (50.00%) patients and the combination of the IVIG plus intravenous dexamethasone plus rituximab plus mycophenolate mofetil for one (16.67%) case. Besides, the combination of the intravenous methylprednisolone (IVMP, which was switched to intravenous dexamethasone later) plus rituximab was utilized for one (16.67%) case and the combination of the IVIG and IVMP for one (16.67%) patient. Total numbers of the therapies used comprised of dual therapy (33.33%), triple therapy (50.00%), and other multiple agents (16.67%). Besides, surgical resections were done for the cases with tumors. The disease course was monophasic for five cases and five cases achieved remission. OMS scores improved significantly at the end of follow up. Five (83.33%) patients did not have permanent neurological sequelae.

CONCLUSIONS

The combination of the intravenous dexamethasone plus IVIG plus rituximab for the OMS can reduce relapses and permanent neurological sequelae.

Opsoclonus-Myoclonus-Ataxia Syndrome: A Rare Outcome Following Routine Vaccinations

Opsoclonus-myoclonus-ataxia syndrome (OMAS) is a rare neurological disorder, affecting approximately 0.18 per million individuals annually. It presents with a triad of opsoclonus, myoclonus, and ataxia, often including cognitive dysfunction and behavioral disturbances. Even though OMAS is non-fatal, it frequently follows a chronic-relapsing course, resulting in long-term neuropsychological sequelae in over 50% of patients. Diagnosis is challenging due to variable symptom presentation and the lack of specific diagnostic markers. We report a case of a two-month-old infant who developed OMAS after routine vaccinations, a rare post-vaccination occurrence. Initial treatment with high-dose corticosteroids successfully resolved symptoms, but the patient experienced a relapse during medication tapering. The relapse occurred following another vaccination, suggesting a potential link between the immune response triggered by vaccination and OMAS symptoms. Despite the early relapse, the patient had a favorable recovery, with normal neurodevelopment at 24 months and no further relapses. This case raises awareness of the rare autoimmune post-vaccine reaction as a possible etiology of OMAS, which is infrequently reported in the literature. With this report, we aimed to underscore the importance of early recognition of OMAS, particularly in infants, and highlight the potential for a positive outcome with timely diagnosis and treatment.

An unusual case of early onset opsoclonus-myoclonus syndrome: Case report and literature review

Opsoclonus-myoclonus syndrome is a rare neurological condition characterized by opsoclonus, myoclonus, ataxia, irritability, and sleep disturbances. In pediatric patients, symptoms usually start between 16 and 18 months of age; opsoclonus-myoclonus syndrome presentation in children under 6 months is rare. Approximately 50% of cases are associated with neuroblastoma. We report an early onset presentation of opsoclonus-myoclonus syndrome in a previously healthy, 3-month-old female infant. The diagnostic workup revealed no abnormalities. The patient underwent monthly cycles of dexamethasone pulses and intravenous immunoglobulin with a favorable response. After a few months, the patient presented intermittent opsoclonus before the next scheduled pulse so from the 9th cycle onwards, the intravenous immunoglobulin dose was increased to 2 g/kg. After 9 months of treatment, she was diagnosed with a latent Mycobacterium tuberculosis infection. Due to this infection, dexamethasone pulses were discontinued, and intravenous immunoglobulin treatment was maintained with clinical improvement The patient received 18 intravenous immunoglobulin cycles, leaving her with a score of one on the Mitchell-Pike scale. Developmental milestones have been attained according to age. Despite the range of therapeutic options for managing opsoclonus-myoclonus syndrome described in the literature, the efficacy of these available therapies needs to be better established. A modified upfront approach with dexamethasone and intravenous immunoglobulin could be an option in settings where rituximab is unavailable.

Inaugural Patient-Reported Registry of Pediatric Opsoclonus-Myoclonus-Ataxia Syndrome: Presentation, Diagnosis, and Treatment of 194 Patients

BACKGROUND

Opsoclonus-myoclonus-ataxia syndrome (OMAS) is a rare neuroimmune disease with peak onset at 18 months, associated with neural crest tumors in 50% of patients. In part due to its rarity, misdiagnosis at onset is common, can delay treatment, and may contribute to adverse outcomes. Patient-reported registries may overcome some of these challenges in rare disease research. In this context, the OMSLife Foundation collaborated with the National Organization of Rare Diseases to create a patient-reported registry in OMAS.

METHODS

Retrospective analysis was performed of data entered by parents of patients with OMAS into nine online surveys assessing demographics, symptoms at onset, triggers, time of diagnosis, treatment, and additional therapies.

RESULTS

A total of 194 patients were enrolled. There was a female predominance (54%) and high rate of parental autoimmunity (31%). Age at onset peaked between 12 and 18 months overall. The age of onset was older in female patients (median [interquartile range]: females 22 [15 to 31] vs males 18 [14 to 23], P = 0.0223, P = 0.0223). Symptoms at onset most commonly included ataxia (84%) and were typically severe. Initial misdiagnosis occurred in nearly 50% and tumor discovery was delayed in 18 patients, but overall median time to correct diagnosis was 25 days. Most patients (56%) received combination immunomodulatory therapies, and nearly all underwent supportive therapies.

CONCLUSIONS

Patient- and parent-powered research is feasible in OMAS and created the second largest published cohort of pediatric patients with OMAS. Results were similar to other large cohorts and also validated findings from prior case reports and smaller case series.

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.

Clinical Presentation, Management, and Diagnostic Performance of 2021 Criteria for Paraneoplastic Neurologic Syndromes in Childhood

BACKGROUND AND OBJECTIVES

Paraneoplastic neurologic syndromes (PNSs) are remote neurologic immune-related effects of tumors. The clinical characteristics of pediatric PNSs remain unclear. We retrospectively examined the clinical characteristics of cases of pediatric PNSs and assessed the performance of the 2021 diagnostic criteria in children.

METHODS

Patients hospitalized in the Beijing Children's Hospital between June 2015 and June 2023 and fulfilling the description of definite by 2004 diagnostic criteria of PNSs were included. A retrospective analysis of clinical characteristics was conducted, and the 2021 diagnostic criteria were applied to rediagnostic stratification.

RESULTS

Among the 42 patients included, the most common neurologic syndrome was opsoclonus-myoclonus syndrome (OMS) (62%), followed by rapidly progressive cerebellar syndrome (26%). Most tumors were neuroblastomas (88%), with few being ovarian teratomas (10%). Approximately 71% (30/42) of patients were classified as definite and 24% (10/42) as probable according to the 2021 criteria. All cases judged as probable exhibited rapidly progressive cerebellar ataxia with neuroblastoma. For OMS, chemotherapy was administered based on the tumor's risk stage, accompanied by regular infusion of IV gamma globulin and oral steroids following tumor diagnosis. Twenty-one patients underwent regular follow-ups over 4.92 (0.58-7.58) years. The initial hospitalization recorded a median score of 12 (7-14) on the Mitchell and Pike OMS rating scale, decreasing to 0 (0-5) at the final follow-up. In cases of rapidly progressive cerebellar syndrome, a similar therapeutic regimen was used. Nine patients underwent regular follow-ups over 4.42 (1.17-7.50) years. The mean modified Rankin scale score at first hospitalization was 4 (3-4), reducing to 1 (0-4) at the final follow-up. Only 17% (5/30) of patients across both groups exhibited poor response to this regimen. Among these 5 patients, 4 belonged to the low-risk group (without chemotherapy).

DISCUSSION

OMS followed by rapidly progressive cerebellar ataxia are the most common forms of PNSs in children and are associated with neuroblastoma. An aggressive approach with multiple immunotherapies may improve the prognosis of neuroblastoma-associated PNSs. The 2021 criteria perform well in pediatric PNSs. However, we propose upgrading the classification of antibody-negative rapidly progressive cerebellar ataxia with neuroblastoma to definite diagnosis. This adjustment aims to further improve the diagnostic efficacy of this diagnostic criterion in childhood.

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.

Neuroblastic Tumor Recurrence Associated With Opsoclonus Myoclonus Ataxia Syndrome Relapse a Decade After Initial Resection and Treatments

Opsoclonus myoclonus ataxia syndrome (OMAS) is a rare disorder that causes significant neurodevelopmental sequelae in children. Approximately half of pediatric OMAS cases are paraneoplastic, typically associated with localized neuroblastic tumors. Since early persistence or relapse of OMAS symptoms is common even after tumor resection, OMAS relapses may not routinely prompt reevaluation for recurrent tumors. We report a 12-year-old girl with neuroblastic tumor recurrence associated with OMAS relapse a decade after initial treatment. Providers should be aware of tumor recurrence as a trigger for distant OMAS relapse, raising intriguing questions about the role of immune surveillance and control of neuroblastic tumors.

Diagnosis and Management of Opsoclonus-Myoclonus-Ataxia Syndrome in Children: An International Perspective

BACKGROUND AND OBJECTIVES

Opsoclonus-myoclonus-ataxia syndrome (OMAS) is a rare disorder of the nervous system that classically presents with a combination of characteristic eye movement disorder and myoclonus, in addition to ataxia, irritability, and sleep disturbance. There is good evidence that OMAS is an immune-mediated condition that may be paraneoplastic in the context of neuroblastoma. This syndrome may be associated with long-term cognitive impairment, yet it remains unclear how this is influenced by disease course and treatment. Treatment is largely predicated on immune suppression, but there is limited evidence to indicate an optimal regimen.

METHODS

Following an international multiprofessional workshop in 2004, a body of clinicians and scientists comprising the International OMS Study group continued to meet biennially in a joint professionals and family workshop focusing on pediatric OMAS. Seventeen years after publication of the first report, a writing group was convened to provide a clinical update on the definitions and clinical presentation of OMAS, biomarkers and the role of investigations in a child presenting with OMAS, treatment and management strategies including identification and support of long-term sequelae.

RESULTS

The clinical criteria for diagnosis were reviewed, with a proposed approach to laboratory and radiologic investigation of a child presenting with possible OMAS. The evidence for an upfront vs escalating treatment regimen was reviewed, and a treatment algorithm proposed to recognize both these approaches. Importantly, recommendations on monitoring of immunotherapy response and longer-term follow-up based on an expert consensus are provided.

DISCUSSION

OMAS is a rare neurologic condition that can be associated with poor cognitive outcomes. This report proposes an approach to investigation and treatment of children presenting with OMAS, based on expert international opinion recognizing the limited data available.

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-ataxia syndrome in children

Opsoclonus-myoclonus-ataxia syndrome is a rare neuroimmunologic disorder typically presenting in previously healthy infants and toddlers. It is characterized by a clinical triad of (1) erratic saccadic intrusions; (2) myoclonus and/or ataxia; (3) behavioral features, typified by developmental plateauing, irritability and insomnia. About half of cases are associated with an underlying neuroblastoma and diagnostic imaging is essential once OMAS is suspected. A thorough workup, including serum, urine, and cerebrospinal fluid studies is critical to identify underlying biomarkers of OMAS itself or neuroblastoma. Historically, many children had relatively poor long-term outcomes, with residual neurologic and/or neuropsychiatry sequelae typical. More recent concepts have emphasized combined immunotherapy regimens that offer hope for better outcomes in children with this remarkable, challenging disease.

Tics, tremors and other movement disorders in childhood

Movement disorders presenting in childhood include tics, dystonia, chorea, tremor, stereotypy, myoclonus, and parkinsonism, each of which can be part of various clinical syndromes with distinct etiologies.  Some of these conditions are benign and require only reassurance; others are bothersome and require treatment, or may be clues that herald underlying pathology.  Answers lie in the inherent characteristics of the movements themselves, together with the clinical context provided in the history obtained by the examiner.  The aim of this review is to present an overview of the categories of involuntary movements, along with examples of common acquired and genetic causes, and an approach to history-taking, examination, and treatment.

Evolving Cognitive Dysfunction in Children with Neurologically Stable Opsoclonus-Myoclonus Syndrome

Cognitive and acquired neurodevelopmental deficits have been reported in children with opsoclonus-myoclonus syndrome (OMS) and are known to be associated with more severe and relapsing disease course. However, there is a paucity of data regarding cognitive dysfunction in children with stable neurological disease. We report three children with OMS and evolving cognitive dysfunction in the context of a mild disease course. The children's ages at disease onset were between 17 and 35 months and they were followed up for 4-10 years. Neuroblastoma was identified in one child. OMS severity scores ranged between 8 and 12/15 at presentation. They underwent immunotherapy and all were in remission by 7 months (range 4-13 months), with treatment maintained for 1 year. One child remained relapse-free, while two others had one clinical relapse each and were immunotherapy-responsive again. In all cases, evolving cognitive dysfunction was reported despite being in remission and stable off treatment for a median of 20 months (range of 12-31 months; two OMS scores of 0/15 and one of 2/15). In children with OMS who have completed treatment and have made full or near full neurological recovery, concerns remain regarding long-term outcome in terms of future learning and cognitive development.