Dexamethasone, Intravenous Immunoglobulin, and Rituximab Combination Immunotherapy for Pediatric Opsoclonus-Myoclonus Syndrome

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.

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.

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.

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.

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.

Surgical considerations for neuroblastoma-associated opsoclonus-myoclonus-ataxia syndrome: a series of 14 patients from a single institution

INTRODUCTION

Neuroblastoma is a childhood cancer of neural crest cells occasionally associated with opsoclonus-myoclonus-ataxia syndrome (OMAS), a paraneoplastic process characterized by ataxia, rapid eye movements, and muscle twitching. OMAS treatment and outcomes are well studied, but prior reports do not detail how the presence of OMAS should impact surgical approach, particularly for tumors with image defined risk factors (IDRF).

METHODS

We reviewed patients with neuroblastoma and OMAS at our institution from January 2009 to December 2020 and recorded tumor characteristics, operative details, OMAS therapies, and outcomes.

RESULTS

We identified 14 patients with neuroblastoma and OMAS out of 212 patients referred for surgery. There were 11 gross total resections and three partial resections. Two patients with partial resections developed OMAS after initial resection. One patient with gross total resection developed tumor recurrence 10 years later with OMAS redevelopment signaling recurrence. Three patients were positive for IDRFs and the one receiving neoadjuvant therapy achieved a gross total resection.

CONCLUSIONS

OMAS development after partial resection and OMAS recurrence following tumor recurrence indicates a correlation between tumor bulk and the paraneoplastic process. This justifies an aggressive resection even for low-risk tumors. Neoadjuvant therapy should be considered for potentially unresectable tumors with image defined risk factors.

LEVEL OF EVIDENCE

IV.

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.

Neuroblastoma With Opsoclonus-Myoclonus-Ataxia Syndrome: Role of Chemotherapy in the Management: Experience From a Tertiary Care Center in a Resource-limited Setting

Children with neuroblastoma (NB) and opsoclonus-myoclonus-ataxia syndrome (OMAS) have a favorable oncologic outcome and overall survival. In contrast, despite intensive multidrug immunomodulation, the neurologic outcome is complicated by the relapsing nature of the neurologic symptoms and long-term neurobehavioral sequelae. Being associated with low-risk NB, there exists an ambiguity in the current literature regarding the administration of chemotherapy in these children. We reviewed our archives for children with NB-OMAS over a 22-year (January 1996 to January 2018) period. Eighteen children (10 female) with a median age at diagnosis of 23 months had NB-OMAS and were included. They had stage 1 (9/18; 50%), 2 (1/18; 5.5%), 3 (7/18; 39%), and 4 (1/18; 5.5%) disease according to the International Neuroblastoma Staging System. Multimodality therapy included surgery (16/18; 89%), chemotherapy (11/18; 61%), and immunomodulatory therapy (10/18; 55%). Complete oncologic remission was achieved in all children. Relapse of OMAS and presence of neurologic sequelae were observed in 1 (5.5%) and 5 (28%) cases, respectively. Presence of neurologic sequelae was significantly associated with low-tumor stage (P=0.036) and treatment without chemotherapy (P=0.003). Chemotherapy administration was the only variable significantly predicting a favorable neurologic outcome (95% confidence interval: 0.26-1.40, P=0.01). To conclude, our study including a limited cohort of patients highlights a favorable neurologic outcome associated with chemotherapy administration in children with NB-OMAS. However, further studies with larger sample size need to be conducted before drawing any definite conclusions.

Inflammatory Diseases of the Central Nervous System

Pediatric neuroinflammatory conditions are a complex group of disorders with a wide range of clinical presentations. Patients can present with a combination of focal neurologic deficits, encephalopathy, seizures, movement disorders, or psychiatric manifestations. There are several ways that pediatric neuroinflammatory conditions can be classified, including clinical presentation, pathophysiologic mechanism, and imaging and laboratory findings. In this article, we group these conditions into acquired demyelinating diseases, immune-mediated epilepsies/encephalopathies, primary rheumatologic conditions with central nervous system (CNS) manifestations, CNS vasculitis, and neurodegenerative/genetic conditions with immune-mediated pathophysiology and discuss epidemiology, pathophysiology, clinical presentation, treatment, and prognosis of each disorder.

Dexamethasone-induced activation of heat shock response ameliorates seizure susceptibility and neuroinflammation in mouse models of Lafora disease

Heat shock response (HSR) is a conserved cytoprotective pathway controlled by the master transcriptional regulator, the heat shock factor 1 (HSF1), that activates the expression of heat shock proteins (HSPs). HSPs, as chaperones, play essential roles in minimizing stress-induced damages and restoring proteostasis. Therefore, compromised HSR is thought to contribute to neurodegenerative disorders. Lafora disease (LD) is a fatal form of neurodegenerative disorder characterized by the accumulation of abnormal glycogen as Lafora bodies in neurons and other tissues. The symptoms of LD include progressive myoclonus epilepsy, dementia, and cognitive deficits. LD is caused by the defects in the gene coding laforin phosphatase or the malin ubiquitin ligase. Laforin and malin are known to work upstream of HSF1 and are essential for the activation of HSR. Herein, we show that mice deficient for laforin or malin show reduced levels of HSF1 and their targets in their brain tissues, suggesting compromised HSR; this could contribute to the neuropathology in LD. Intriguingly, treatment of LD animals with dexamethasone, a synthetic glucocorticoid analogue, partially restored the levels of HSF1 and its targets. Dexamethasone treatment was also able to ameliorate the neuroinflammation and susceptibility to induced seizures in the LD animals. However, dexamethasone treatment did not show a significant effect on Lafora bodies or autophagy defects. Taken together, the present study establishes a role for HSR in seizure susceptibility and neuroinflammation and dexamethasone as a potential antiepileptic agent, suitable for further studies in LD.

Paraneoplastic opsoclonus myoclonus syndrome associated with inflammatory myofibroblastic tumor in a pediatric patient

Opsoclonus myoclonus syndrome (OMS) is a rare neurological syndrome caused by a paraneoplastic autoimmune process that affects children with neuroblastic tumors. Treatment includes corticosteroids, intravenous gamma globulin (IVIG), rituximab, and other immunosuppressive therapies. Here, we describe a patient diagnosed with OMS associated with a localized inflammatory myofibroblastic tumor. The patient has no evidence of tumor recurrence following surgical resection with 8-month follow-up. The neurologic symptoms resolved with corticosteroids and IVIG. This case demonstrates that in children, neoplasms other than neuroblastoma may be associated with this paraneoplastic syndrome, and highlights the importance of evaluating patients with OMS for underlying malignancies.

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.

An upfront immunomodulatory therapy protocol for pediatric opsoclonus-myoclonus syndrome

BACKGROUND

Treatment of opsoclonus-myoclonus syndrome (OMS) has historically involved corticosteroids and intravenous immunoglobulin (IVIG) for a duration of 6-12 months or longer. This study evaluated whether a brief upfront immunomodulatory therapy protocol with rituximab reduces the duration of OMS therapy without adversely affecting OMS outcomes.

PROCEDURE

Retrospective chart review was performed for consecutive children diagnosed with OMS from 2006 to 2019 at The Hospital for Sick Children (Toronto, Canada). Children treated within 3 months of diagnosis with a treatment protocol involving pulse methylprednisolone (3-5 days, followed by an oral steroid taper), IVIG and/or plasma exchange, and rituximab (protocol group, n = 7) were compared to a historical group treated primarily with prednisone and IVIG (n = 8).

RESULTS

The duration of corticosteroid treatment was shorter in the protocol (median 4.5 [range 3-12] months) compared to that in the historical group (median 21.5 [range 6-70] months, P = .005), and subjects in the protocol group received fewer cycles of IVIG (median 1 [range 0-7] cycle vs 7 [range 1-70] cycles, P = .01). The proportion of children with OMS relapse was similar between the protocol and historic groups (2/6 vs 5/8, P = .59). OMS symptom rating scales at 12-month follow-up were similar in the protocol group (median 2.5, range 0-3) compared to that in the historical group (median 1, range 0-7; P = .66).

CONCLUSIONS

An upfront immunomodulatory therapy protocol with rituximab permits reduction in the duration of corticosteroid and IVIG therapy without a detrimental effect on OMS outcomes. Future studies with longer follow-up will have to determine whether neurocognitive and psychosocial outcomes are improved by this approach.

Clinical Profile, Prognostic Indicators, and Therapeutic Outcomes of Pediatric Opsoclonus-Myoclonus-Ataxia Syndrome: A Single-Center Experience from South India

Background:

Opsoclonus myoclonus syndrome (OMS) is a neuroinflammatory disorder. Indian literature on its clinical profile and outcome is sparse.

Objectives:

The objective of this study is to describe the clinical profile and analyze outcomes and prognostic predictors in a cohort of children with OMS.

Materials and Methods:

This was a retrospective study of children with OMS between 2007 and 2017.

Results:

Twenty-two children were included in the study. The mean age at onset of symptom was 20.9 months (standard deviation [SD]: 7.5). The mean duration of delay in diagnosis was 8.4 months (SD 1.26) with acute cerebellitis being the most common misdiagnosis. Eleven children (50%) were diagnosed with tumor during evaluation and follow-up and 11 children (50%) belonged to idiopathic/postinfectious group. Magnetic resonance imaging brain was normal in all children except for one revealing cerebellar atrophy on follow-up. One child in the paraneoplastic group (neuroblastoma) had a positive PNMA2/Ta onconeural antibody. Children in the tumor group had an earlier age of onset (mean 15.5 vs. 26.3 months), shorter time to onset of opsoclonus from initial symptom (2.54 vs. 7.27 weeks), and higher severity score at presentation (13.7 vs. 11.3) compared to the nontumor group. Children in the nontumor group attained their first remission with treatment earlier (10.9 weeks, SD: 4.5) than the children with tumor (18.72 weeks, SD: 5.8). There was no significant difference in the outcome between the groups. Children with multiple relapses (>3) and late surgical intervention for tumor (>6 months after symptom onset) had a poor outcome.

Discussion:

A high index of suspicion coupled with early diagnosis and periodic tumor surveillance (even in the initially negative cases) along with aggressive combined multimechanistic immunotherapies is the key in improving outcomes.

Conclusion:

A high index of suspicion in appropriate clinical circumstances and early aggressive immunomodulation might lead to a better outcome.

Intensive Combination Immunotherapy and Neuroinflammation Resolution in a Child With Anti-PCA-1 (Yo) Paraneoplastic Syndrome and 2 Malignancies

Paraneoplastic cerebellar degeneration is rare and noteworthy in children. In this 7-year-old, it was documented to have occurred within a year of ataxia presentation. The instigating cancer was stage III adrenal adenocarcinoma, remitted after surgical resection at age 2. When her severe ataxia progressed, neuroinflammation was characterized by high cerebrospinal fluid Purkinje cell cytoplasmic antibody type 1 titers, oligoclonal bands, and neurofilament light chain. The immunotherapy strategy was to replace IV methylprednisolone, which lowered Purkinje cell cytoplasmic antibody type 1 titers without clinical improvement, with induction of adrenocorticotropic hormone/intravenous immunoglobulin/rituximab (ACTH/IVIG/rituximab) combination immunotherapy, ACTH/dexamethasone transition, and intravenous immunoglobulin maintenance. She became self-ambulatory and cerebrospinal fluid inflammatory markers regressed. Down syndrome predisposed her to a second cancer, pre-B acute lymphoblastic leukemia, 4 years later. Despite reversible cytosine arabinoside-provoked cerebellar toxicity, the ataxia is stable on monthly intravenous immunoglobulin without relapse, now 5 years after initial diagnosis. This report illustrates the use of cerebrospinal fluid biomarkers to detect, target, and monitor neuroinflammation, and successful combinations of immunotherapy to better the quality of life.

Autologous stem cell transplantation for refractory opsoclonus myoclonus ataxia syndrome

Opsoclonus, myoclonus, ataxia syndrome (OMA) is a severe neurologic disorder often associated with neuroblastoma. It is challenging to treat and can have long-term neurologic sequelae. Current recommended therapies include intravenous immunoglobulin, corticosteroids, rituximab, and chemotherapy (cyclophosphamide). We present two cases who were refractory to conventional therapy and underwent autologous stem cell transplantation (ASCT). One patient had complete resolution of symptoms following ASCT and the other patient had minimal change in symptoms with this therapy. These findings support consideration of ASCT as a therapeutic option for patients with refractory OMA after failure of known effective therapies.

Effect of low-dose cyclophosphamide, ACTH, and IVIG combination immunotherapy on neuroinflammation in pediatric-onset OMS: A retrospective pilot study

INTRODUCTION

Flow cytometric cerebrospinal fluid (CSF) lymphocyte subset analysis has improved the diagnosis of neuroinflammation and identified multiple markers of inflammation in opsoclonus-myoclonus syndrome (OMS). The aim of this exploratory, retrospective study was to analyze the effect of immunotherapy on these markers to determine which agents are disease modifying.

METHODS

Cross-sectional immunological observations were made in an IRB-approved case-control study, and patients were treated empirically. Ten different CSF lymphocyte subpopulations from 18 children with persistent OMS had been measured by flow cytometry before and after clinical treatment with cyclophosphamide/ACTH/IVIG combination (n = 7) or ACTH/IVIG alone (n = 11). Clinical severity of OMS was scored from videotapes by a blinded observer using the OMS Evaluation Scale.

RESULTS

Only cyclophosphamide combination therapy (mean dose 26 ± 3 mg/kg or 922 ± 176 mg/m² x 6 cycles) significantly decreased the percentage of CSF B cells. The mean reduction was 65%, with CSF B cell frequency normalized at 7-8 months in 70%. Other abnormalities of the CSF immunophenotype, such as the low CD4/CD8 T cell ratio, persisted, and there were no therapeutic changes in T cell activation/maturation markers. Effects on relative and absolute size of PBMC subsets were similar. Clinical improvement was 70% and 55% in respective treatment groups. The relapse rates of the two groups did not significantly differ.

DISCUSSION

The main effect of cyclophosphamide combination therapy on neuroinflammation in OMS was moderate reduction in CSF B cell expansion. Though exploratory, it may provide a steroid sparer option in partially-responsive OMS.

Principles and approaches to the treatment of immune-mediated movement disorders

Immune mediated movement disorders include movement disorders in the context of autoimmune encephalitis such as anti-NMDAR encephalitis, post-infectious autoimmune movement disorders such as Sydenham chorea, paraneoplastic autoimmune movement disorders such as opsoclonus myoclonus ataxia syndrome, and infection triggered conditions such as paediatric acute neuropsychiatric syndrome. This review focuses on the approach to treatment of immune mediated movement disorders, which requires an understanding of the immunopathogenesis, whether the disease is destructive or 'altering', and the natural history of disease. Factors that can influence outcome include the severity of disease, the delay before starting therapy, use of multimodal therapy and whether the course is monophasic or relapsing. Although the four main conditions listed above have different pathophysiological processes, there are general themes that broadly apply including: early diagnosis and treatment is better, minimise the severity of disease, escalate treatment if the patient is not responding to initial treatments, and minimise relapse.