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.

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.

Brain Volumes in Opsoclonus-Myoclonus Ataxia Syndrome: A Longitudinal Study.

INTRODUCTION: Little is known about the longitudinal trajectory of brain growth in children with opsoclonus-myoclonus ataxia syndrome. We performed a longitudinal evaluation of brain volumes in pediatric opsoclonus-myoclonus ataxia syndrome patients compared with age- and sex-matched healthy children. PATIENTS AND METHODS: This longitudinal case-control study included brain magnetic resonance imaging (MRI) scans from consecutive pediatric opsoclonus-myoclonus ataxia syndrome patients (2009-2020) and age- and sex-matched healthy control children. FreeSurfer analysis provided automatic volumetry of the brain. Paired t tests were performed on the curvature of growth trajectories, with Bonferroni correction. RESULTS: A total of 14 opsoclonus-myoclonus ataxia syndrome patients (12 female) and 474 healthy control children (406 female) were included. Curvature of the growth trajectories of the cerebral white and gray matter, cerebellar white and gray matter, and brainstem differed significantly between opsoclonus-myoclonus ataxia syndrome patients and healthy control children (cerebral white matter, P = .01; cerebral gray matter, P = .01; cerebellar white matter, P < .001; cerebellar gray matter, P = .049; brainstem, P < .01). DISCUSSION/CONCLUSION: We found abnormal brain maturation in the supratentorial brain, brainstem, and cerebellum in children with opsoclonus-myoclonus ataxia syndrome.

A rare clinical presentation of COVID 19: opsoclonus-myoclonus ataxia syndrome.

INTRODUCTION: Coronavirus disease 2019 (COVID-19) can have symptoms like many neurological diseases, and one of the rare forms of these presentations is opsoclonus-myoclonus ataxia syndrome (OMAS). The pathogenesis of OMAS in adults has not been clearly elucidated and OMAS can be fatal. CASE PRESENTATION: We present a 71-year-old male patient who was admitted to the emergency department with complaints of involuntary tremor-like movements in his hands, feet and mouth, and speech impediment for three days, and was followed up with COVID-19. The patient was diagnosed with OMAS and clonazepam treatment was started. He died three days later due to respiratory arrest. Our case is the first case diagnosed with COVID-19-associated OMAS in Turkey. DISCUSSION: OMAS has no definitive treatment. Early diagnosis and initiation of corticosteroids and intravenous immunoglobulin (IVIG) therapy, if necessary, can be life-saving. In COVID-19 patients with unexplained clinical findings, awareness of different and rare diseases and a multidisciplinary approach has vital importance.

[Clinical and prognostic analysis of opsoclonus-myoclonus-ataxia syndrome in children].

Objective: To summarize the clinical and prognostic features of children with opsoclonus-myoclonus-ataxia syndrome (OMAS). Methods: A total of 46 patients who met the diagnostic criteria of OMAS in the Department of Neurology, Beijing Children's Hospital from June 2015 to June 2023 were retrospectively analyzed. Centralized online consultations or telephone visits were conducted between June and August 2023. The data of the children during hospitalization and follow-up were collected, including clinical manifestations, assistant examination, treatment and prognosis. According to the presence or absence of tumor, the patients were divided into two groups. The chi-square test or Mann-Whitney U test was used to compare the differences between the two groups. Univariate Logistic regression was used to analyze the factors related to OMAS recurrence and prognosis. Results: There were 46 patients, with 25 males and the onset age of 1.5 (1.2, 2.4) years. Twenty-six (57%) patients were diagnosed with neuroblastoma during the course of the disease, and no patients were categorized into the high-risk group. A total of 36 patients (78%) were followed up for≥6 months, and all of them were treated with first-line therapy with glucocorticoids, gammaglobulin and (or) adrenocorticotrophic hormone. Among the 36 patients, 9 patients (25%) were treated with second-line therapy for ≥3 months, including rituximab or cyclophosphamide, and 17 patients (47%) received chemotherapy related to neuroblastoma. At the follow-up time of 4.2 (2.2, 5.5) years, 10 patients (28%) had relapsed of OMAS. The Mitchell and Pike OMS rating scale score at the final follow-up was 0.5 (0, 2.0). Seven patients (19%) were mildly cognitively behind their peers and 6 patients (17%) were severely behind. Only 1 patient had tumor recurrence during follow-up. The history of vaccination or infection before onset was more common in the non-tumor group than in the tumor group (55%(11/20) vs. 23%(6/26), χ²=4.95, P=0.026). Myoclonus occurred more frequently in the non-tumor group (40%(8/20) vs. 4%(1/26), χ²=7.23, P=0.007) as the onset symptom. Univariate Logistic regression analysis showed that the tumor group had less recurrence (OR=0.19 (0.04-0.93), P=0.041). The use of second-line therapy or chemotherapy within 6 months of the disease course had a better prognosis (OR=11.64 (1.27-106.72), P=0.030). Conclusions: OMAS in children mostly starts in early childhood, and about half are combined with neuroblastoma. Neuroblastoma in combination with OMAS usually has a low risk classification and good prognosis. When comparing patients with OMAS with and without tumors, the latter have a more common infection or vaccination triggers, and myoclonus, as the onset symptom, is more common. Early addition of second-line therapy is associated with better prognosis in OMAS.

Successful use of tacrolimus for treatment-refractory neuroblastoma-associated opsoclonus-myoclonus-ataxia syndrome: A case series.

Opsoclonus-myoclonus-ataxia syndrome (OMAS) is an autoimmune central nervous system disorder, primarily manifesting as a paraneoplastic sequalae to neuroblastoma, and characterized by motor disorders and behavioral disturbances. OMAS is typified by aberrant B-cell and T-cell activation. Current treatment involves immunosuppression using corticosteroids, intravenous immunoglobulin, and rituximab. However, these approaches often lead to treatment-related toxicities and symptomatic recurrences with chronic neurocognitive impairment. We treated three children with refractory neuroblastoma-associated OMAS with tacrolimus, a T-cell-targeting calcineurin inhibitor, effectively controlling symptoms within a month and enabling the discontinuation of immunosuppression with minimal side effects. Tacrolimus shows promise as a therapeutic option for refractory OMAS.

Benign paraspinal ganglioneuroma with paraneoplastic opsoclonus myoclonus syndrome.

Opsoclonus-myoclonus-ataxia syndrome (OMAS) is a rare immune-mediated movement disorder occurring as a paraneoplastic manifestation of neuroblastic tumours (NTs), especially neuroblastoma in infancy. Ganglioneuroma (GN), the benign tumour in the spectrum, is rarely associated with OMAS. We report the case of a child in her second year of life presenting with acute onset of progressive paraplegia and OMAS. MRI showed diffuse and infiltrating left paraspinal mass from T3-T9 levels with differentials of neuroblastoma or ganglioneuroblastoma. Histopathological and immunohistochemistry examination of the excised tumour showed maturing GN. The OMAS was managed with intravenous immunoglobulin and steroids. In the 6-month follow-up, the child has a residual motor weakness with myelomalacia in neuroimaging. The case report substantiates the occurrence of OMAS as paraneoplastic manifestation in NTs, including benign, in children younger than 2 years with a female predilection.

Five Years Follow-up of Opsoclonus-Myoclonus-Ataxia Syndrome-Associated Neurogenic Tumors in Children.

AIM: Opsoclonus-myoclonus-ataxia syndrome (OMAS) is a rare autoimmune disorder. Approximately half of the cases are associated with neuroblastoma in children. This study's aim is to review management of our cases with OMAS-associated neuroblastoma for treatment approach as well as long-term follow-up. METHODS: Age at onset of symptoms and tumor diagnosis, tumor location, histopathology, stage, chemotherapy, OMAS protocol, surgery, and follow-up period were evaluated retrospectively in six patients between 2007 and 2022. RESULTS: Mean age of onset of OMAS findings was 13.5 months and mean age at tumor diagnosis was 15.1 months. Tumor was located at thorax in three patients and surrenal in others. Four patients underwent primary surgery. Histopathological diagnosis was ganglioneuroblastoma in three, neuroblastoma in two, and undifferentiated neuroblastoma in one. One patient was considered as stage 1 and rest of them as stage 2. Chemotherapy was provided in five cases. The OMAS protocol was applied to five patients. Our protocol is intravenous immunoglobulin (IVIG) 1 g/kg/d for 2 consecutive days once a month and dexamethasone for 5 days (20 mg/m2/d for 1-2 days, 10 mg/m2/d for 3-4 days, and 5 mg/m2/d for the fifth day) once a month, alternatively by 2-week intervals. Patients were followed up for a mean of 8.1 years. Neuropsychiatric sequelae were detected in two patients. CONCLUSION: In tumor-related cases, alternating use of corticosteroid and IVIG for suppression of autoimmunity as the OMAS protocol, total excision of the tumor as soon as possible, and chemotherapeutics in selected patients seem to be related to resolution of acute problems, long-term sequelae, and severity.

[Clinical analysis of adult oculomoclonus-myoclonus syndrome with vertigo].

The clinical manifestation, physical and laboratory examination, electrophysiological, and imaging data of 2 female adult OMS patients with vertigo were analyzed at the Department of Neurology of the First Medical Center of Chinese PLA General Hospital from February 2021 to March 2022. The treatment strategy and clinical outcome were followed up. The two female patients were aged 42 and 66 years. Anti-NMDA receptor antibody and anti-GABAB receptor antibody were detected in serological screening, respectively. The two patients met the diagnostic criteria for OMS, and one was screened for breast tumor. The clinical symptoms of the two patients were relieved after immunomodulation therapy. OMS is a group of rare clinical syndromes; its clinical evaluation process should be standardized and the etiology should be actively searched for.

Immune-mediated ataxias: Guide to clinicians.

Immune-mediated cerebellar ataxias were initially described as a clinical entity in the 1980s, and since then, an expanding body of evidence has contributed to our understanding of this topic. These ataxias encompass various etiologies, including postinfectious cerebellar ataxia, gluten ataxia, paraneoplastic cerebellar degeneration, opsoclonus-myoclonus-ataxia syndrome and primary autoimmune cerebellar ataxia. The increased permeability of the brain-blood barrier could potentially explain the vulnerability of the cerebellum to autoimmune processes. In this manuscript, our objective is to provide a comprehensive review of the most prevalent diseases within this group, emphasizing clinical indicators, pathogenesis, and current treatment approaches.

Cervical Ganglioneuroblastoma Diagnosed by 68Ga-DOTATOC PET/CT in a Child with Opsoclonus Myoclonus Syndrome.

We performed a 68Ga-DOTATOC PET/CT scan on a 25-mo-old female patient who presented with opsoclonus myoclonus ataxia syndrome and had negative initial anatomic imaging. The scan showed a somatostatin receptor-overexpressing cervical tumor in favor of a cervical neuroendocrine tumor, with subsequent histopathologic findings of ganglioneuroblastoma.

Polyclonal lymphoid expansion drives paraneoplastic autoimmunity in neuroblastoma.

Neuroblastoma is a lethal childhood solid tumor of developing peripheral nerves. Two percent of children with neuroblastoma develop opsoclonus myoclonus ataxia syndrome (OMAS), a paraneoplastic disease characterized by cerebellar and brainstem-directed autoimmunity but typically with outstanding cancer-related outcomes. We compared tumor transcriptomes and tumor-infiltrating T and B cell repertoires from 38 OMAS subjects with neuroblastoma to 26 non-OMAS-associated neuroblastomas. We found greater B and T cell infiltration in OMAS-associated tumors compared to controls and showed that both were polyclonal expansions. Tertiary lymphoid structures (TLSs) were enriched in OMAS-associated tumors. We identified significant enrichment of the major histocompatibility complex (MHC) class II allele HLA-DOB∗01:01 in OMAS patients. OMAS severity scores were associated with the expression of several candidate autoimmune genes. We propose a model in which polyclonal auto-reactive B lymphocytes act as antigen-presenting cells and drive TLS formation, thereby supporting both sustained polyclonal T cell-mediated anti-tumor immunity and paraneoplastic OMAS neuropathology.

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.

Probable association between mRNA COVID-19 vaccine and opsoclonus-myoclonus-ataxia syndrome.

Opsoclonus-myoclonus-ataxia syndrome (OMAS) in children is most often of paraneoplastic origin, but it can also result from infectious processes, toxic and metabolic disorders, and organic events that cause damage to the brainstem or cerebellum. Post-vaccination OMAS has also been reported. We report the case of a 15-year-old girl who developed OMAS 24 hours after her first dose of mRNA COVID-19 (BioNTech) vaccine.

Opsoclonus-myoclonus syndrome caused by organophosphate poisoning.

Opsoclonus-myoclonus syndrome is a combination of involuntary, arrhythmic, conjugate saccadic eye movements with myoclonus. The most common cause in adults is paraneoplastic encephalitis. Rarer causes include infections such as scrub typhus, and toxins such as organophosphates and cocaine. Organophosphates are one of the common poisonings in tropical countries such as India, causing both central and peripheral nervous system manifestations. We describe a middle-aged male farmer with unexplained altered consciousness and respiratory depression. After 2 days, he developed opsoclonus-myoclonus, and then bronchorrhoea and bradycardia, raising suspicion of organophosphate poisoning. After we had identified a very low serum cholinesterase concentration, he disclosed having consumed organophosphates.

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.