Hypernatremia is a high level of sodium in the blood that occurs with excessive fluid loss. When fluid is lost and not replaced, sodium is not adequately excreted from the body.

The following are causes of hypernatremia:

  • Diabetes insipidus (caused by deficiency of or insensitivity to ADH)
  • Diarrhea
  • Diuretic medication
  • Excessive salt intake
  • Excessive vomiting
  • Heavy respiration (e.g., exercise, exertion)
  • Severe burn
  • Sweating

Hypernatremia is associated with the same symptoms as hyponatremia, and also causes the following:

  • Delerium
  • Irritability
  • Muscle twitching

Hypernatremia commonly affects older hospitalized people, 50 percent of whom have underlying diseases that, when combined with excessive sodium and fluid loss, are fatal.


Treating hypernatremia involves slowly replenishing water loss, usually over 48 hours, through drinking or intravenous (IV) solution. In cases of diabetes, the imbalance is treated with adequate water intake and nonsteroidal anti-inflammatory drugs or with synthesized hormones (e.g., desmopressin) that aid in fluid retention and decrease urination.

Some drugs used to treat electrolyte imbalance may be unsafe for pregnant women and should not be taken before consulting a physician.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 30 Apr 2001

Last Modified: 14 Sep 2015