title: Management of hyponatremia in various clinical situations.
abstract: Hyponatremia is the most common electrolyte abnormality in both inpatient and outpatient settings. The condition primarily results from the combination of impaired free water excretion due to elevated vasopressin levels in conjunction with a source of free water intake. Recent studies have revealed that even mild and asymptomatic hyponatremia is associated with deleterious consequences. It is an independent risk factor for mortality and is also associated with increased length of hospitalization and hospital costs. Even mild chronic hyponatremia can result in subtle neurologic impairment and bone demineralization, leading to falls and associated bone fractures in the elderly. Hyponatremia can be a difficult condition to treat, with varying therapeutic strategies based on the etiology, severity, duration, and extent of neurologic symptoms. The ideal magnitude of correction is also controversial, as both inadequate therapy and overly aggressive therapy can result in neurologic injury. Formulas that have been devised to aid in the treatment of hyponatremia can be inaccurate in that they fail to adequately account for the renal response to therapy. Hyponatremic encephalopathy is the most serious complication of hyponatremia, and can result in permanent neurologic impairment or death if left untreated. Individuals most at risk for developing hyponatremic encephalopathy are postmenarchal women, children under 16 years of age, patients with central nervous system disease or hypoxemia, and patients in the postoperative setting. The preferred therapy for hyponatremic encephalopathy is a 100-ml bolus of 3 % sodium chloride (513 mEq/L) administered in repeated doses until symptoms reverse, with the goal of increasing the serum sodium 5-6 mEq/L. Vasopressin (V2) antagonists (vaptans) are not appropriate for the management of acute hyponatremic encephalopathy, as the onset of action is not sufficiently rapid and the increase in sodium is not predictable. Vaptans are primarily indicated for the treatment of asymptomatic hyponatremia due to SIAD that is refractory to conventional measures.
authors.affiliation: Department of Pediatrics, Children's Hospital of Pittsburgh of UPMC, The University of Pittsburgh School of Medicine, Pittsburgh, PA, USA, moritzml@upmc.edu.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Moritz
authors.forename: Juan C
authors.initials: JC
authors.lastname: Ayus
references.citation: Ann Intern Med. 1992 Dec 1;117(11):891-7
references.pmid: 1443949
references.citation: Am J Kidney Dis. 2000 Aug;36(2):E12
references.pmid: 10922333
references.citation: Clin J Am Soc Nephrol. 2007 Nov;2(6):1110-7
references.pmid: 17913972
references.citation: Am J Med. 1967 May;42(5):790-806
references.pmid: 5337379
references.citation: Pediatrics. 2003 Feb;111(2):227-30
references.pmid: 12563043
references.citation: Brain Res. 2000 Jan 3;852(1):167-72
references.pmid: 10661508
references.citation: Ann Neurol. 1984 Jun;15(6):544-7
references.pmid: 6742788
references.citation: J Physiol. 1996 Apr 1;492 ( Pt 1):243-55
references.pmid: 8730599
references.citation: Clin Nephrol. 2014 Dec;82(6):397-401
references.pmid: 23816479
references.citation: BMC Nephrol. 2013 Dec 19;14:276
references.pmid: 24354674
references.citation: J Neurol Sci. 1996 Oct;142(1-2):134-9
references.pmid: 8902733
references.citation: Am J Physiol. 1995 May;268(5 Pt 2):R1143-52
references.pmid: 7771574
references.citation: Am J Med. 1957 Oct;23(4):529-42
references.pmid: 13469824
references.citation: Clin J Am Soc Nephrol. 2014 Feb;9(2):229-37
references.pmid: 24262506
references.citation: N Engl J Med. 1986 Jun 12;314(24):1529-35
references.pmid: 3713746
references.citation: Ann Intern Med. 2000 May 2;132(9):711-4
references.pmid: 10787364
references.citation: Am J Physiol Renal Physiol. 2008 Sep;295(3):F619-24
references.pmid: 18448591
references.citation: Kidney Int. 2006 Apr;69(8):1319-25
references.pmid: 16614721
references.citation: J Clin Invest. 1953 Sep;32(9):868-78
references.pmid: 13084753
references.citation: N Engl J Med. 2013 Jun 27;368(26):2520-1
references.pmid: 23802520
references.citation: Nephrol Dial Transplant. 2003 Dec;18(12):2486-91
references.pmid: 14605269
references.citation: Am J Med. 2006 Jul;119(7 Suppl 1):S30-5
references.pmid: 16843082
references.citation: N Engl J Med. 2006 Nov 16;355(20):2099-112
references.pmid: 17105757
references.citation: Brain. 1972;95(3):495-504
references.pmid: 4655276
references.citation: Am J Kidney Dis. 1989 Sep;14(3):196-9
references.pmid: 2773922
references.citation: Clin J Am Soc Nephrol. 2008 Jul;3(4):1175-84
references.pmid: 18434618
references.citation: Nephrol Dial Transplant. 2006 Jan;21(1):70-6
references.pmid: 16141458
references.citation: Clin Nephrol. 2001 Mar;55(3):248-53
references.pmid: 11316247
references.citation: J Mol Med (Berl). 1998 Apr;76(5):326-37
references.pmid: 9587067
references.citation: J Am Soc Nephrol. 2010 Apr;21(4):705-12
references.pmid: 20185637
references.citation: Kidney Int. 1991 Jun;39(6):1274-82
references.pmid: 1895679
references.citation: N Engl J Med. 1981 Feb 5;304(6):329-30
references.pmid: 7442772
references.citation: Ann Neurol. 1990 Jan;27(1):61-6
references.pmid: 2301929
references.citation: Pediatrics. 2014 Jan;133(1):105-13
references.pmid: 24379232
references.citation: Kidney Int. 1992 Jun;41(6):1662-7
references.pmid: 1501423
references.citation: Kidney Int. 2007 Apr;71(8):822-6
references.pmid: 17311074
references.citation: Clin J Am Soc Nephrol. 2010 Feb;5(2):167-8
references.pmid: 20089487
references.citation: Nat Rev Endocrinol. 2011 Mar;7(3):151-61
references.pmid: 21283124
references.citation: Kidney Int. 2013 Apr;83(4):700-6
references.pmid: 23325088
references.citation: J Bone Miner Res. 2010 Mar;25(3):554-63
references.pmid: 19751154
references.citation: Intensive Care Med. 1997 Mar;23(3):309-16
references.pmid: 9083234
references.citation: Am J Med. 2013 Oct;126(10 Suppl 1):S1-42
references.pmid: 24074529
references.citation: N Engl J Med. 1987 Nov 5;317(19):1190-5
references.pmid: 3309659
references.citation: PLoS One. 2013 Dec 18;8(12):e80451
references.pmid: 24367479
references.citation: N Engl J Med. 1986 Jun 12;314(24):1535-42
references.pmid: 3713747
references.citation: Ann Neurol. 1982 Feb;11(2):128-35
references.pmid: 7073246
references.citation: Case Rep Endocrinol. 2014;2014:807054
references.pmid: 24511399
references.citation: Am J Med. 1994 May;96(5):408-13
references.pmid: 8192171
references.citation: JAMA. 1999 Jun 23-30;281(24):2299-304
references.pmid: 10386554
references.citation: N Engl J Med. 2005 Jul 28;353(4):427-8; author reply 427-8
references.pmid: 16050061
references.citation: Kidney Int. 2009 Sep;76(6):614-21
references.pmid: 19606078
references.citation: Am Heart J. 2003 Mar;145(3):459-66
references.pmid: 12660669
references.citation: Clin Neuropathol. 1987 Nov-Dec;6(6):262-70
references.pmid: 3322623
references.citation: QJM. 1998 Nov;91(11):749-53
references.pmid: 10024938
references.citation: J Card Fail. 2013 Jan;19(1):1-9
references.pmid: 23273588
references.citation: J Neurol Neurosurg Psychiatry. 2011 Mar;82(3):326-31
references.pmid: 20826870
references.citation: Am J Kidney Dis. 2010 Aug;56(2):325-37
references.pmid: 20538391
references.citation: J Hosp Med. 2012 Oct;7(8):634-9
references.pmid: 22961813
references.citation: Nephrol Dial Transplant. 2012 Oct;27(10):3725-31
references.pmid: 23114899
references.citation: J Pediatr. 2013 Dec;163(6):1646-51
references.pmid: 23998517
references.citation: Am J Med. 2013 Dec;126(12):1127-37.e1
references.pmid: 24262726
references.citation: BMJ. 1992 May 9;304(6836):1218-22
references.pmid: 1515791
references.citation: Pediatr Nephrol. 2010 Jul;25(7):1225-38
references.pmid: 19894066
references.citation: Am J Med. 2006 Jan;119(1):71.e1-8
references.pmid: 16431193
references.citation: J Natl Cancer Inst. 1999 Sep 1;91(17):1513-4
references.pmid: 10469762
references.citation: Pediatr Nephrol. 2012 May;27(5):689-93
references.pmid: 22358189
references.citation: J Neurosurg Pediatr. 2014 Mar;13(3):283-90
references.pmid: 24410125
references.citation: Am J Physiol. 1985 May;248(5 Pt 2):F711-9
references.pmid: 3993796
references.citation: N Engl J Med. 2007 May 17;356(20):2064-72
references.pmid: 17507705
references.citation: Nat Clin Pract Nephrol. 2007 Jul;3(7):374-82
references.pmid: 17592470
references.citation: Am J Med. 2001 May;110(7):582-4
references.pmid: 11343672
references.citation: Brain. 1979 Jun;102(2):361-85
references.pmid: 455045
references.citation: Blood Purif. 2013;36(3-4):274-9
references.pmid: 24496199
references.citation: Eur J Intern Med. 2013 Mar;24(2):110-6
references.pmid: 23176963
references.citation: Nephron Clin Pract. 2012;120(3):c168-72
references.pmid: 22722264
references.citation: Pediatrics. 2011 Nov;128(5):980-3
references.pmid: 22007008
references.citation: Clin J Sport Med. 2008 Mar;18(2):111-21
references.pmid: 18332684
references.citation: Clin J Am Soc Nephrol. 2010 Feb;5(2):275-80
references.pmid: 20056759
references.citation: Am J Emerg Med. 2012 Oct;30(8):1659.e5-6
references.pmid: 22030189
references.citation: Metab Brain Dis. 2010 Mar;25(1):91-6
references.pmid: 20221678
references.citation: BMJ. 2013 Dec 10;347:f7073
references.pmid: 24326887
references.citation: Ann Intern Med. 1973 Jun;78(6):870-5
references.pmid: 4197370
references.citation: Q J Med. 1959 Apr;28(110):235-58
references.pmid: 13658352
references.citation: Endocr Pract. 2011 Jul-Aug;17(4):e97-100
references.pmid: 21613055
references.citation: J Neuropathol Exp Neurol. 1996 Jan;55(1):106-13
references.pmid: 8558165
references.citation: Acta Paediatr. 2013 Apr;102(4):e164-8
references.pmid: 23278861
references.citation: Arch Intern Med. 1986 Feb;146(2):333-6
references.pmid: 3947194
references.citation: Am J Kidney Dis. 2013 Jul;62(1):139-49
references.pmid: 23291150
references.citation: Indian J Pediatr. 2015 Jan;82(1):13-8
references.pmid: 24830423
references.citation: Clin Nephrol. 1999 Jun;51(6):383-6
references.pmid: 10404700
references.citation: Intern Med. 2008;47(5):431-5
references.pmid: 18310977
references.citation: J Clin Invest. 1973 Dec;52(12):3212-9
references.pmid: 4750450
references.citation: Neuroradiology. 2002 Aug;44(8):674-80
references.pmid: 12185545
references.citation: N Engl J Med. 2012 Dec 20;367(25):2407-18
references.pmid: 23121377
references.citation: Am J Med. 2006 Jul;119(7 Suppl 1):S36-42
references.pmid: 16843083
references.citation: JAMA. 1982 Jan 22-29;247(4):471-4
references.pmid: 7054549
references.citation: Indian J Crit Care Med. 2013 Jul;17(4):231-3
references.pmid: 24133331