Approach to hyponatremia according to the clinical setting. Consensus statement from the Italian Society of Endocrinology (SIE), Italian Society of Nephrology (SIN), and Italian Association of Medical Oncology (AIOM)
Hyponatremia (hypoNa, serum sodium levels < 135 mEq/L)is the most frequently observed electrolyte disorder in clinical practice, affecting up to 15–30% of hospitalized patients. HypoNa is characterized by an excess of waterrelative to exchangeable total body sodium that can be normal, increased, or decreased. As a consequence, hypoNa can be classified by the fluid volume status of the patient (euvolemic, hypovolemic, and hypervolemic hypoNa) or by plasma tonicity, i.e., the effective osmolality (isotonic, hypertonic, and hypotonic hypoNa).