How to Say It: hahy-per-nuh-TREE-mee-uh


Hypernatremia is a high level of sodium in the blood. It can be deadly if it is not treated.


This problem happens when there is too little water for the amount of sodium in the body.

The main cause is having more water leave the body than enter it. This causes dehydration. A person can become dehydrated in different ways, such as:

Risk Factors

This problem is more common in older adults. Other things that may raise the risk are:

  • Fever
  • Losing too much fluid by sweating
  • Vomiting
  • Diarrhea
  • Using certain diuretics —medicines that increase urination
  • Severe burns
  • Having certain health problems, such as central diabetes insipidus or kidney disorder


Problems may be:

  • Dry mouth
  • Being very thirsty
  • Lightheadedness
  • Muscle weakness, cramps, or twitching
  • Irritability
  • Weight loss
  • Urinating less than usual
  • Confusion

Dry Mouth

Dry Mouth and Throat
Dry mouth is a symptom of hypernatremia.
Copyright © Nucleus Medical Media, Inc.


The doctor will ask about your symptoms and health history. You will be asked about your fluid intake and urine output. A physical exam will be done.

Blood and urine tests will be done to check sodium levels.


The goal of treatment is to balance the fluids in the body. Liquids will be given by mouth or IV. The fluid will contain specific amounts of water, sugar, and sodium. Reintroducing fluids slowly will lower the sodium to a normal level.

Medicine may also be given to ease nausea.


The risk of this problem may be lowered by staying hydrated by drinking plenty of fluids.


Family Doctor—American Academy of Family Physicians
National Institute of Diabetes and Digestive and Kidney Diseases


The College of Family Physicians of Canada


Central diabetes insipidus. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/central-diabetes-insipidus. Accessed August 18, 2021.
Dehydration and hypovolemia in adults. EBSCO DynaMed Plus website. Available at: https://www.dynamed.com/condition/dehydration-and-hypovolemia-in-adults. Accessed August 18, 2021.
Hypernatremia. Merck Manual Professional Edition website. Available at: https://www.merckmanuals.com/professional/endocrine-and-metabolic-disorders/electrolyte-disorders/hypernatremia. Accessed August 18, 2021.
Hypernatremia—approach to the patient. EBSCO DynaMed website. Available at: https://www.dynamed.com/approach-to/hypernatremia-approach-to-the-patient. Accessed August 18, 2021.
Nephrogenic diabetes insipidus. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/nephrogenic-diabetes-insipidus. Accessed August 18, 2021.
Last reviewed July 2021 by EBSCO Medical Review Board James Cornell, MD
Last Updated: 8/18/2021

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