Objective: To describe the clinical features, diagnostic findings, and treatment outcomes of adult OMAS cases in Vietnam.

Background: Opsoclonus-myoclonus-ataxia syndrome (OMAS) is a rare neurological disorder characterized by opsoclonus, myoclonus, and cerebellar ataxia. While pediatric cases are more frequently reported, adult-onset OMAS remains uncommon and under-recognized.

Method: We conducted a descriptive study of four adult patients diagnosed with OMAS at the National Institute of Neuroscience, Bach Mai Hospital, Vietnam, between 2023 and 2025. Clinical presentation, laboratory results, imaging, and treatment responses were documented.

Results: Four patients (two female, two male; ages 17, 40, 55, and 66 years) presented with opsoclonus, myoclonus, cerebellar ataxia, dizziness, and nausea. Myoclonus severity varied: mild and intermittent in two cases, severe with limb and facial involvement in one, and neck involvement in one. Prodromal symptoms included mild fever and fatigue (two cases), high fever (one case), and none (one case). Brain MRI and systemic CT scans were normal. CSF analysis revealed mild lymphocytic pleocytosis and elevated protein levels; infectious and autoimmune panels were negative. All patients received high-dose methylprednisolone (1000 mg/day for 5 days) and rehabilitation; two with severe myoclonus also received levetiracetam and clonazepam. Four patients achieved partial recovery within 1–4 weeks and complete recovery within 2–4 months.

Conclusion: This initial case series highlights the clinical spectrum of adult OMAS in Vietnam, consistent with international reports. Early recognition and immunotherapy may improve outcomes.

Table 1: Data of four adult patients with OMAS

References: 1. Lino AMM, Spera RR, de Campos FPF, et al. Adult-onset opsoclonus-myoclonus-ataxia syndrome as a manifestation of brazilian lyme disease-like syndrome: a case report and review of literature. Autops Case Rep. Jan-Mar 2014;4(1):29-37. doi:10.4322/acr.2014.005
2. Jayasekara H, Wickramarathne JS, Liyanage DS, Jayasinghe PA. Opsoclonus-myoclonus-ataxia syndrome associated with bacterial urinary tract infection. BMJ Case Rep. Aug 22 2024;17(8)doi:10.1136/bcr-2024-261533
3. Wallace A, Thomas J, Boren J, Bryant C, Brewer J, Dhanani R. Opsoclonus-Myoclonus-Ataxia Syndrome in a Patient With West Nile Virus: Case Report and a Patient’s Experience. Neurohospitalist. Jul 15 2025:19418744251361303. doi:10.1177/19418744251361303
4. Oh SY, Kim JS, Dieterich M. Update on opsoclonus-myoclonus syndrome in adults. J Neurol. Jun 2019;266(6):1541-1548. doi:10.1007/s00415-018-9138-7

« Back to 2026 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/opsoclonus-myoclonus-ataxia-syndrome-in-adults-case-series-in-vietnam/