[Hyponatremia - causes, diagnostic evaluation and treatment].

Intact osmoregulation prevents osmotic gradients thereby limiting cell swelling and shrinking. Hyponatremia is a state of an osmole-free water excess compared to the amounts of solutes and clinical management of hyponatremic patients requires pathophysiology-oriented approaches to select appropriate treatments. Clinicians need to assess the patient's volume status to differentiate hyponatremia with volume depletion, expansion or normovolemia, respectively. In addition, work-up includes differentiation between acute and chronic and asymptomatic and symptomatic hyponatremia. Estimation of free water-clearance helps predicting Serum-Na changes and is important to prevent overcorrection of hyponatremia. Water restriction, hypertonic salt, urea, V2-receptor-blockers and recently sodium glucose cotransporter 2 (SGLT2) inhibitors were employed to treat patients with hyponatremia.