Sodium Balance and Imbalance: A Review Linking Physiology with Pathophysiology

Abstract

Sodium (Na+), one of the major extracellular cationsin the body, exerts a significant role in regulating body fluid compartments and generating action potentials. It represents one of the most important and readily available biomarkers of fluid status. Disturbances of Na+ homeostasis are frequently observed in outpatient and inpatient settings and can be challenging to clinicians attempting to decipher the underlying aetiologies. Various disorders involving the renal, endocrine, and central nervous systems can lead to dysnatremias and imbalance in volume status. Understanding the diverse physiological mechanisms involved in normal Na+ regulation and the expected pathological outcomes when the normal processes are disrupted is crucial in assisting clinicians with coming up with reasonable differential diagnoses and targeted management plans for Na+ disorders. This review summarises the pathophysiology of Na+ disorders by linking it closely with normal Na+ homeostasis.