Recognition and treatment of hyponatremia in acutely ill hospitalized patients.
OBJECTIVE
The objective of this paper was to discuss the diagnosis, pathophysiology, and management of hyponatremia among critically ill, hospitalized patients (eg, after surgery or in the intensive care unit).


METHODS
English-language literature published between 1967 and 2006 was searched using several key words (AVP receptor antagonists, hyponatremia, SIADH, conivaptan, tolvaptan, and lixivaptan) and by accessing MEDLINE and ScienceDirect. Meeting abstracts from scientific sessions (American Society of Nephrology Renal Week 2004 and the Endocrine Society's 87th Annual Meeting [2005]) were reviewed. The package insert for conivaptan hydrochloride injection was referenced from . Clinical trials included in this review were randomized and placebo controlled.


RESULTS
Based on the literature we researched, hyponatremia is the most common electrolyte disorder encountered in critical care and is associated with a variety of conditions, including congestive heart failure and the syndrome of inappropriate antidiuretic hormone secretion. Because hyponatremia can arise in hypervolemic, euvolemic, and hypovolemic states, clinicians may not recognize its presence and cause. Incorrect management can lead to significant morbidity and mortality. Physicians need to recognize risk factors and symptoms and use appropriate treatment guidelines for hyponatremia. Traditionally, therapy for hyponatremia has been limited by efficacy and safety concerns. Arginine vasopressin (AVP) receptor antagonists, therapeutic agents that promote aquaresis in patients with hyponatremia by targeting V(1a) receptors in the vascular smooth muscle, V(2) receptors in the kidney, or both, are under development. A dual-receptor antagonist targeting both V(1a) and V(2) receptors is now approved for the treatment of euvolemic hyponatremia in hospitalized patients.


CONCLUSIONS
Hyponatremia, an electrolyte abnormality found in critically ill patients, can be associated with significant morbidity and mortality. AVP receptor antagonists show promise as effective and tolerable treatments for patients with hyponatremia.
Patel
Gourang P
GP
Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Rush University Medical Center and Rush Medical College, Chicago, Illinois 60612, USA.
Balk
Robert A
RA
D065092:Antidiuretic Hormone Receptor Antagonists; D001127:Arginine Vasopressin / Q000096:biosynthesis / Q000187:drug effects; D001381:Azepines / Q000494:pharmacology / Q000627:therapeutic use; D001549:Benzamides / Q000494:pharmacology / Q000627:therapeutic use; D001552:Benzazepines / Q000494:pharmacology / Q000627:therapeutic use; D016638:Critical Illness; D006801:Humans; D007010:Hyponatremia / Q000145:classification / Q000175:diagnosis* / Q000188:drug therapy* / Q000209:etiology / Q000401:mortality / Q000503:physiopathology; D007297:Inpatients; D017410:Practice Guidelines as Topic; D011758:Pyrroles; D016032:Randomized Controlled Trials as Topic; D000077602:Tolvaptan; D001569:Benzodiazepines
D065092:Antidiuretic Hormone Receptor Antagonists; D001127:Arginine Vasopressin; D001381:Azepines; D001549:Benzamides; D001552:Benzazepines; D011758:Pyrroles; D000077602:Tolvaptan; C106389:conivaptan; C409452:lixivaptan; D001569:Benzodiazepines