Hyponatremia: Evolving diagnostics and emerging therapeutics in clinical practice

Abstract

Hyponatremia remains the most common electrolyte disorder in clinical practice, with a wide range of causes ranging from endocrine dysregulation to iatrogenic causes. Recent developments in point-of-care ultrasonography, vasopressin physiology, and osmoregulation have transformed diagnostics by emphasizing accuracy above purely clinical judgment. Although traditional management based on fluid restriction and hypertonic solutions remain the cornerstone of treatment, a careful and cautious monitoring is required to avoid osmotic demyelination and overcorrection. The Furst equation, a validated predictor of response to fluid restriction, should be integrated into routine practice, together with objective tools such as point-of-care ultrasonography, to improve the accuracy of volume assessment and guide more precise therapeutic decisions. Likewise, different therapeutic options have been studied for non-responders to fluid restriction, including urea, desmopressin, and selective vasopressin receptor antagonists (vaptans), showing promising results. Ongoing developments in artificial intelligence and laboratory-based decision support tools are expected to improve personalized management and predictive accuracy, potentially reconciling the disparity between evidence and clinical practice.

Keywords: Hyponatremia; Fluid restriction; Furst equation; Point-of-care ultrasound; Hypertonic saline; Urea; Tolvaptan

Core Tip: Hyponatremia, defined as a low concentration of sodium in the blood, is the most frequent electrolyte disorder in clinical practice. Its causes are diverse and often overlap, from hormonal imbalances to medication effects or underlying heart, liver, and kidney conditions. Effective and safe correction depends on accurately identifying whether the body has too much or too little water, rather than simply restricting fluids. Bedside ultrasound (point-of-care ultrasonography) and simple laboratory tools such as the Furst equation allow clinicians to assess fluid status objectively, predict response to fluid restriction, and guide personalized treatment strategies that reduce complications and improve patient outcomes.