Disorders of Water Balance: Hypernatremia

  • Alluru S. ReddiEmail author


Hypernatremia is defined as a serum or plasma [Na+] > 145 mEq/L and hyperosmolality (serum osmolality > 295 mOsm/kg H2O). Serum [Na+] is determined by total body Na+, K+, and water content: Serum [Na+] = (Nae + +Ke +)/TBW, where Nae + and Ke + are total exchangeable quantities of these cations, and TBW is total body water. Therefore, hypernatremia can develop by a deficit in total body water and/or a gain of Na+. In a healthy individual, an increase in serum [Na+] and associated hyperosmolality create thirst, and water intake lowers serum [Na+] to a normal level (Chap. 11). Hypernatremia develops when patients cannot experience or respond to thirst, and have no access to water.


Water balance disorders Hypernatremia Hyperosmolality Nephrogenic diabetes insipidus 


  1. 1.
    Miller M, et al. Recognition of partial defects in antidiuretic hormone secretion. Ann Intern Med. 1970;73:721–9.PubMedCrossRefGoogle Scholar
  2. 2.
    Sterns RH, Silver SM. Salt and water: read the package insert. QJM. 2003;96:549–52.PubMedCrossRefGoogle Scholar

Suggested Reading

  1. 4.
    Sands JM, Bichet DG. Nephrogenic diabetes insipidus. Ann Intern Med. 2006;144:186–94.PubMedCrossRefGoogle Scholar
  2. 5.
    Adroguè HJ, Madias NE. Hypernatremia. N Engl J Med. 2000;342:1493–9.PubMedCrossRefGoogle Scholar
  3. 7.
    Arieff AI, Ayus CJ. Strategies for diagnosing and managing hypernatremic encephalopathy. When to suspect and how to correct fluid deficits safely. J Crit Care. 1996;11:720–7.Google Scholar
  4. 8.
    Feig PU, McCurdy DK. The hypertonic state. N Engl J Med. 1977;297:1444–54.PubMedCrossRefGoogle Scholar
  5. 6.
    Oster JR, Singer I, Thatte L, et al. The polyuria of solute diuresis. Arch Intern Med. 1997;157:721–9.PubMedCrossRefGoogle Scholar
  6. 3.
    Thurman JM, Berl T. Disorders of water metabolism. In: Mount DB, Sayegh MH, Singh AJ, editors. Core concepts in the disorders of fluid, electrolytes and acid-base balance. New York: Springer; 2013. pp 29–48.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2014

Authors and Affiliations

  1. 1.Department of Medicine Division of Nephrology and HypertensionRutgers New Jersey Medical SchoolNewarkUSA

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