Objective: This paper aims to present a case of stereotypy as a unique manifestation of ODS in a Filipino adult female, along with the co-occurrence of other abnormal involuntary movements.

Background: Osmotic demyelinating syndrome (ODS) is an uncommon and serious neurological condition characterized by demyelination from oligodendrocyte loss, primarily caused by rapid serum sodium correction. Striatal involvement is associated with an array of hypokinetic and/or hyperkinetic movement disorders; however, stereotypy has never been recorded in ODS.

Method: Not applicable

Results: Case presentation: A 63-year-old Filipino woman had severe hyponatremia (99.7 mmol/L) due to inadequate oral intake during a COVID-19 infection. Unfortunately, this was rapidly corrected at a net increase of 16.3 mmol/L in 20 hours. Subsequently, dysarthria and dysphagia developed. ODS was confirmed by Cranial MRI findings of both central pontine myelinolysis (CPM) and extrapontine myelinolysis (EPM) of bilateral corpus striatum. Initially, symptoms improved; however, parkinsonian signs emerged six months later. Stereotypy followed after three months, exhibited as involuntary, repetitive and purposeless kicking and stomping movements while lying supine. Other movement disorders followed shortly, including dystonia, chorea, mild myoclonus and possible catalepsy.

Discussion: Dysarthria and dysphagia may be due to CPM of the corticobulbar tract in the basis pontis, or secondary to bradykinesia of orolingual movements. Meanwhile, EPM could lead to various movement disorders due to its effect on the basal ganglia; however, stereotypical movements have never been recorded in ODS. These involuntary movements can be diverse, appear late, evolve over time, and persist despite treatment. Adherence to safe correction rates of sodium (<8–10 mmol/L/day) is crucial to prevent iatrogenic complications.

Conclusion: This case highlights the occurrence of stereotypy as a novel manifestation of ODS in a Filipino adult female. The patient’s clinical progression underscores the complexity of ODS and its potential to elicit a diverse array of movement disorders, particularly following rapid sodium correction.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/stereotypy-and-other-movement-disorders-following-osmotic-demyelinating-syndrome-a-case-report/