Pathogenesis and treatment of hyponatremia

Reduced plasma sodium concentration (hyponatremia), the most common electrolyte abnormality in hospitalized patients, is the subject of a recently published review. Disordered secretion of the pituitary hormone vasopressin (alternative name, antidiuretic hormone ADH) is central to the pathogenesis of hyponatremia for many patients, and this is the main focus of the article.

After discussion of the physiological role of vasopressin in regulating water balance and thereby plasma sodium concentration, attention turns to the pathological role of vasopressin in the pathogenesis of (euvolemic) hyponatremia. 

The syndrome of inappropriate antidiuretic hormone (SIADH), a common cause of hyponatremia in patients suffering malignant disease as well as a range of respiratory and CNS disorders, is, justifiably, a major focus of the article. Discussion of treatment options for hyponatremic patients includes description of a new class of drugs that correct plasma sodium by blocking the action of vasopressin. 

Clinical trials of these vasopressin antagonist drugs, the results of which are described in some detail, promise an effective and fresh approach to the management of patients suffering significant hyponatremia.