Osmotic demyelination syndrome in cancer patients: Risk even without rapid sodium correction - a scoping review.

Objective: To describe the clinical characteristics, therapeutic approaches, and prognostic outcomes of osmotic demyelination syndrome (ODS) in cancer patients.

Methods: A comprehensive literature search (January 1950-March 2024) using PubMed, Embase, Cochrane Library, and Web of Science. Keywords included "osmotic demyelination and cancer", "central pontine myelinolysis and cancer", and "extrapontine myelinolysis and cancer", "Osmotic demyelination and malignancy," "Central pontine myelinolysis and malignancy," and "Extrapontine myelinolysis and malignancy." References from selected articles were manually reviewed for inclusion. Studies involving benign lesions, surgical interventions, non-malignant ODS, and ODS of unknown etiology without malignancy were excluded.

Results: A total of 22 cases of cancer-complicated ODS were identified in the literature. The median age of onset was 55 years, with no observed gender differences. Clinical presentations ranged from completely asymptomatic (4.5 %,1/22) to disorders of consciousness (27.3 %, 6/22). Notably, 22.7 % (5/22) of patients initially presented with either no symptoms or non-specific symptoms (seizures, abnormal mental behavior) that could be mistaken for hyponatremia itself. Furthermore, 90 % of patients did not experience rapid sodium correction, and 59.1 % received only symptomatic therapy or treatment of the primary cancer. Only 9.1 % of patients received immunoglobulin or plasma exchange, which may improve outcomes.

Conclusions: Osmotic demyelination syndrome represents a potential complication in cancer patients, potentially arising from complex interactions. Clinical manifestations are highly variable and often under-recognized, particularly by non-neurologists. Traditional sodium correction protocols may still induce ODS in cancer patients, suggesting a need for cautious sodium management. Timely diagnosis and appropriate intervention are crucial for determining patient prognosis.