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Update On Opsoclonus Myoclonus Ataxia Syndrome
Tuesday, 7 May 2024
07:15 - 08:15
Diagnosis of Opsoclonus Myoclonus Ataxia Syndrome – can we make it early?
Vrajesh Udani
Opsoclonus Myoclonus Ataxia (OMA) is a rare orphan disease, often missed in the early stages because of non-specific and atypical symptoms. This may lead to sometimes irreversible morbidity. Most of the literature on OMA consists of small single-center case series emphasizing the three cardinal symptoms in varying severity as the most important criteria for diagnosis. There are diagnostic scales that have been proposed for early diagnosis but these have been found wanting in at least a third of cases. This suggests a significant gap in early diagnosis.
A large cross-sectional multi-center study with most patients from a single US center has studied this problem in some detail and will be discussed at length in this presentation. Our own personal experience with ~ 30 children highlighting differences in presentations and diagnostic delays in a developing country will also be shared along with video-based case studies.
In at least half of OMA patients, neuroblastic tumors are associated making this the most common paraneoplastic syndrome in children. These are mostly neuroblastomas though other neurogenic tumors become more prominent in later ages. The characteristics of neuroblastomas with and without OMA are very different and will be discussed. The sensitivity and specificity of different imaging techniques will be compared to help make the right choice early. Lastly the usefulness of other laboratory dia.
Understanding the neuroimmunology of Opsoclonus Myoclonus Ataxia Syndrome.
Shekeeb Mohammad
Opsoclonus Myoclonus Ataxia Syndrome (OMAS) in children is a distinct clinical syndrome. It is the one of few recognized paraneoplastic neurological syndromes in children with a known association in more than half of affected children with neuroblastoma. OMAS is believed to be caused by cross-reactive autoimmunity between neuroblastoma cells and Purkinje cells and granular neurons in the cerebellum and brain stem, plausibly mediated by autoantibodies. Other associations described include preceding viral infections, including SARS-COV2 as well as rarer cases with autoantibody associations. This segment will summarise current knowledge of tumor profile, biomarkers, and evidence of B-cell, T-cell, and chemokine-mediated immune responses in OMAS. Recent antibody associations with glutamate receptor antibodies and overlap syndromes will be discussed. Overall, the segment will summarise what is currently understood about the immune pathogenesis of OMAS to explain well-known clinical observations at onset and progression as well as what can be learned about the use of current and emerging therapies.
Management strategies of Opsoclonus Myoclonus Ataxia Syndrome over the years: new consensus guidelines.
Ming Lim
Opsoclonus-myoclonus-ataxia syndrome (OMAS) can leave children with significant neurological and long-term cognitive impairment. Although the evidence base for treatment recommendations is limited, emergent data suggests that earlier and more optimal escalation favors better outcomes in a range of neuroinflammatory conditions. Within this construct, 2 approaches will be discussed. The first is an up-front approach often termed the “aggressive” approach using multiple agents, typically adrenocorticotropic hormone (ACTH) or corticosteroids, plasmapheresis, IV immunoglobulin, and rituximab or cyclophosphamide. A second is a stepwise approach starting with pulse oral dexamethasone (20 mg/m2/d for 3 consecutive days monthly) and escalating to rituximab or cyclophosphamide for patients who do not respond adequately. A recent international consensus proposing how both these approaches could be integrated would be discussed; alongside exploring management strategies for chronic relapsing children and when pragmatic (sometimes empirical) strategies may be employed to manage the child with chronic symptoms.
Long-term Neurological outcome in Opsoclonus Myoclonus Ataxia Syndrome
Anaita Hegde
Opsoclonus Myoclonus Ataxia Syndrome is a rare neuroimmunological disorder with a strong association with neuroblastoma. Neurodevelopmental sequelae are relatively frequent in these children. Neuropsychological deficits were considered significant, in more than 60% of the children in the past with impairments most frequently noted in speech and language. Also noted were deficits in cognitive scores, phonology, attention, and memory. Behavioral problems such as obsessive-compulsive, rage, and oppositional defiant were noted in a high percentage.
With a better understanding of the immunology of the condition over the last decade, and thus improved aggressive, combination treatment protocols, we need to review the immediate and long-term neurological outcomes for these children. In spite of the newer more aggressive treatment, most still show at least some neuropsychological deficits.
In this session, we will define the long-term neuropsychological outcomes of OMAS over the years. Identifying those risk factors such as neuroblastoma, time to treatment, and treatment protocols, MRI changes of cerebellar atrophy associated with varying degrees of neurological deficits. Try to understand those areas of cognition most affected. With this knowledge, we can focus on early diagnosis, and treatment protocols with improved outcomes. Early intervention in the areas of concern, may lead to an improved long-term outcome.