Hyponatremia in patients with cancer

Hyponatremia is seen commonly in patients with cancer and is associated with increased mortality and morbidity. Understanding the proper diagnosis and therapy of cancer-associated hyponatremia is critical to ensure improved outcomes.

The most common cancers associated with hyponatremia are the various forms of lung cancer with incidences approaching 25-45%. The most common causes of hyponatremia in cancer patients are the syndrome of inappropriate antidiuretic hormone secretion [syndrome of inappropriate antidiuretic hormone (ADH)] and volume depletion. Proper diagnosis rests on clinical information supplemented by laboratory studies and is critical to ensure appropriate therapy. In recent years, the development of drugs that specifically antagonize the vasopressin type 2 receptor in the distal tubule have offered targeted and highly effective therapies for syndrome of inappropriate ADH.

Hyponatremia in cancer patients generally indicates advanced or severe disease but proper therapy that targets the underlying process can improve outcomes.