Hypercholesterolemia due to lipoprotein-X manifesting as pseudohyponatremia in a patient with cholestasis.

Pseudohyponatremia is an often misdiagnosed condition that needs to be managed by addressing the underlying cause. Treatment of hyponatremic patients with intravenous fluids without ruling out pseudohyponatremia may aggravate a patient's hyponatremia and result in adverse outcomes. In a patient whose sodium is deteriorating, it is critical to diagnose pseudohyponatremia early in the course and acquire necessary consultations, even if the patient is asymptomatic. We discuss a case of a man in his 20s with a history of liver transplantation who presented with unexplained dangerously low sodium while being asymptomatic. The case illustrates an uncommon cause of pseudohyponatremia due to lipoprotein-X hypercholesterolemia in a patient with cholestatic liver disease.