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Hypernatremia (High Level of Sodium in the Blood)


James L. Lewis III

, MD, Brookwood Baptist Health and Saint Vincent’s Ascension Health, Birmingham

Last full review/revision Sep 2021| Content last modified Oct 2021

In hypernatremia, the level of sodium in blood is too high.

  • Hypernatremia involves dehydration, which can have many causes, including not drinking enough fluids, diarrhea, kidney dysfunction, and diuretics.

  • Mainly, people are thirsty, and if hypernatremia worsens, they may become confused or have muscle twitches and seizures.

  • Blood tests are done to measure the sodium level.

  • Usually, fluids are given intravenously to slowly reduce the sodium level in the blood.

  • Drinking too little

  • Vomiting

  • Having diarrhea

  • Using diuretics (drugs that increase urination)

  • Sweating excessively

Insufficient water intake usually plays an important role.

Rarely, adrenal gland disorders Overview of the Adrenal Glands The body has two adrenal glands, one near the top of each kidney. They are endocrine glands, which secrete hormones into the bloodstream. Each adrenal gland has two parts. Medulla: The inner... read more can cause mild hypernatremia without dehydration. Excessive administration of salt (usually in hospitalized people) is another rare cause of hypernatremia. Hypernatremia is most common among older people.

Symptoms of Hypernatremia

Hypernatremia typically causes thirst. The most serious symptoms of hypernatremia result from brain dysfunction. Severe hypernatremia can lead to confusion, muscle twitching, seizures, coma, and death.

Diagnosis of Hypernatremia

  • Measurement of sodium level in the blood

The diagnosis is based on blood tests indicating that the sodium level is high.

Doctors may do further testing to identify the cause of the hypernatremia, including measurements of urine volume and concentration. A special test called the water deprivation test Diagnosis Central diabetes insipidus is a lack of the hormone vasopressin (antidiuretic hormone) that causes excessive production of very dilute urine (polyuria). Central diabetes insipidus has several... read more is useful in identifying some causes, such as diabetes insipidus. The doctor monitors a person carefully during the 12-hour course of this test, because it is potentially dangerous.

Treatment of Hypernatremia

  • Fluid replacement

Hypernatremia is treated by replacing fluids. In all but the mildest cases, dilute fluids (containing water and a small amount of sodium in carefully adjusted concentrations) are given intravenously. The sodium level in blood is reduced slowly because reducing the level too rapidly can cause permanent brain damage.

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