Hyponatremia is a common condition affecting hospitalized and ambulatory patients as well. The clinical spectrum of hyponatremia can range from asymptomatic laboratory findings to severely symptomatic conditions such as acute epileptic seizures. Etiologies of hyponatremia include excessive intake of solute-free fluids, side-effects of medication, diseases associated with hypervolemic states such as congestive heart failure, and the syndrome of inappropriate antidiuretic hormone secretion (SIADH).As hyponatremia can be a potentially life-threatening condition, it requires an efficient management with the goal of identifying the etiology and to subsequently provide adequate treatment, while avoiding treatment-related adverse effects such as overcorrection and pontine myelinolysis. This article summarizes the pathophysiology and differential diagnosis, as well as useful diagnostic tests and therapy of hyponatremia in a practice-oriented manner.
