A Rare Case of Osmotic Demyelination Syndrome in Advanced Pancreatic Adenocarcinoma Without Hyponatremia

Osmotic demyelination syndrome (ODS) is a rare neurological disease involving myelin loss in the central nervous system and is traditionally linked with abrupt correction of hyponatremia. In the absence of hyponatremia, ODS can occur if there are other risk factors such as malignancy, malnutrition, and metabolic disturbances. We describe a 52-year-old male with advanced pancreatic adenocarcinoma and liver metastases who presented with confusion, falls, bilateral leg oedema, hyperglycemia and hypokalemia. Initial imaging was negative for intracranial pathology but positive for pancreatic and hepatic malignancy. The patient's condition deteriorated despite intravenous insulin and potassium, and a brain MRI was positive for central pontine ODS without evidence of metastatic disease. Sodium levels were within normal limits on hospitalisation. A multi-disciplinary team deemed the malignancy inoperable, and the patient was transferred to palliative care and died three weeks post-discharge. This case illustrates the multifactorial aetiology of ODS in cancer patients, with a contribution from malignancy-related nutrient deficiencies, hypokalemia, and hyperglycemia despite normal sodium. Current literature identifies oligodendrocyte susceptibility to energy deficiency in cancer as a predisposition to ODS. This report highlights the significance of heightened awareness of ODS in malignancy, even in the absence of hyponatremia, and calls for further research into its pathophysiological basis as well as management.