Severe hyponatremia associated with unintended infusion of an unmixed neutral-pH peritoneal dialysis solution in an elderly patient with cognitive impairment.

Neutral-pH, low-glucose degradation product peritoneal dialysis (PD) solutions are widely used because of their favorable biocompatibility. These solutions are typically packaged in dual-chamber bags and must be mixed immediately before use. Although the mixing procedure is simple, improper preparation may occur, particularly in patients with cognitive impairment, potentially resulting in unintended electrolyte exposure. We report a case of severe hyponatremia with altered mental status associated with inadvertent infusion of an unmixed neutral-pH PD solution in an elderly patient undergoing automated peritoneal dialysis (APD). A man in his eighth decade with diabetic nephropathy and progressive cognitive decline presented with somnolence and severe hyponatremia after a dual-chamber PD bag with an unopened septum was connected. Based on the clinical course and the finding that a PD solution bag with an unopened inter-chamber septum had been connected, hyponatremia due to exposure to an unmixed dialysate compartment was diagnosed. Management consisted of immediate discontinuation of the improperly prepared dialysate and correction using appropriately mixed PD solutions, without administration of hypertonic saline. Serum sodium levels improved gradually without neurological complications, accompanied by recovery of mental status. This case highlights a rare but serious complication related to improper preparation of dual-chamber PD solutions. Increased awareness of this risk and careful monitoring of vulnerable patients, particularly those with cognitive impairment, are essential to ensure safe home PD therapy.