Long-term follow-up of neuroblastoma-associated opsoclonus-myoclonus-ataxia syndrome

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.

Another promising treatment option for neuroblastoma-associated opsoclonus-myoclonus syndrome by oral high-dose dexamethasone pulse: lymphocyte markers as disease activity

A one-year-old boy with neuroblastoma (NBoma)-associated opsoclonus-myoclonus syndrome (OMS) was treated by oral high-dose dexamethasone (DEX) pulses (20 mg/m(2)/day of DEX for three consecutive days) every 28 days for 6 months after resection of the tumor. All OMS symptoms improved after the first course of DEX pulse therapy and disappeared after the last course. No adverse effects were observed. Minor deterioration of his developmental quotient was noted 33 months after the onset of the disease. NBoma remission has been maintained since treatment. Before DEX pulse therapy, frequency of T lymphocyte, in particular CD4-positive cell decreased markedly resulted in low CD4/8 ratio in the peripheral blood (PB). The frequency of B lymphocyte increased, especially in cerebrospinal fluid. These aberrant values in PB were reversed by DEX pulse therapy and correlated well with the neurological symptoms. A prospective study that assesses the efficacy of this promising and inexpensive treatment for OMS is warranted.

Response to rituximab in 3 children with opsoclonus-myoclonus syndrome resistant to conventional treatments

We report the 1 year follow-up of 3 children affected by non-paraneoplastic Opsoclonus-Myoclonus Syndrome (OMS) resistant to conventional therapies (steroids, ACTH and intravenous immunoglobulins) who were treated with an anti CD20 monoclonal antibody (rituximab). Treatment response was recorded on the basis of an international score at 0, 3, 6, 9 and 12 months. Despite the long disease duration and the numerous previously administered treatments, all patients underwent rapid and persistent neurological recovery following rituximab administration, thus suggesting a potential role of this drug even in pre-treated patients.

Cognitive and psychiatric phenotypes of movement disorders in children: a systematic review

AIM

The cognitive and psychiatric aspects of adult movement disorders are well established, but specific behavioural profiles for paediatric movement disorders have not been delineated. Knowledge of non-motor phenotypes may guide treatment and determine which symptoms are suggestive of a specific movement disorder and which indicate medication effects.

METHOD

The goal of this review is to outline the known cognitive and psychiatric symptoms associated with paediatric movement disorders. We used a systematic approach, via PubMed, and reviewed over 400 abstracts of studies of selected disorders, of which 88 papers reporting paediatric non-motor symptoms are summarized.

RESULTS

Obsessive-compulsive disorder was manifest in children with paediatric autoimmune neuropsychiatric disorders associated with streptococcal infections and Sydenham chorea. Children with opsoclonus-myoclonus syndrome had, for the most part, cognitive and behavioural problems, and attention-deficit-hyperactivity disorder was reported as a major comorbidity in Tourette syndrome, stereotypies, and restless legs syndrome. Symptoms of depression and anxiety were more frequent in individuals with idiopathic dystonia. Affective disorders were suggestive of Wilson disease. Cognitive decline was common in children with juvenile Huntington disease. A limitation of this review was the lack of systematic assessment in paediatric movement disorders for evaluation and uniform definitions.

INTERPRETATION

Although the literature in non-motor phenomena is still emerging, recognition of salient cognitive and psychiatric phenomena may facilitate management of paediatric movement disorders.

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.

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.