Utility of electrolyte-free water clearance in the analysis and treatment of the dysnatremias

Abstract

Understanding the pathogenesis and treatment of hyponatremia is a challenge for medical students and experts alike. Although hyponatremia has a wide range of causes, the pathogenesis of hyponatremia is largely characterized by disorders of urinary dilution. In evaluating the renal mechanisms responsible for the pathophysiology of hyponatremia, an analysis of free water clearance (FWC) and electrolyte-free water clearance (EFWC) is often utilized to quantify the renal diluting defect in this disorder. In this article, the utility of free water clearance (FWC) and electrolyte-free water clearance (EFWC) in the diagnostic and therapeutic approach to hyponatremia is discussed.