Managing hyponatremia in patients with syndrome of inappropriate antidiuretic hormone secretion.

Disorders of sodium [Na+] and water metabolism are commonly encountered in the hospital setting due to the wide range of disease states that can disrupt the balanced control of water and solute intake and output. In particular, the prompt identification and appropriate management of abnormally low serum [Na+] is critical if we are to reduce the increased morbidity and mortality that accompany hyponatremia in hospitalized patients. Use of an algorithm that is based primarily on the symptomatology of hyponatremic patients, rather than the serum [Na+] or the chronicity of the hyponatremia, will help to choose the correct initial therapy in hospitalized hyponatremic patients. However, careful monitoring of serum [Na+] responses is required in all cases to adjust therapy appropriately in response to changing clinical conditions. Although this approach will enable efficacious and safe treatment of hyponatremic patients with syndrome of inappropriate antidiuretic hormone secretion (SIADH) at the present time, evolving knowledge of the consequences of chronic hyponatremia will likely alter treatment indications and guidelines in the future.