Hypernatremia refers to sodium levels in the blood being too high. Common causes include inadequate fluid intake, or fluid loss.

Sodium plays an essential role in functions such as muscle contraction, nerve impulse generation, and fluid balance.

Hypernatremia is often mild and does not usually require treatment. But moderate to severe cases can sometimes cause health issues without medical attention.

Keep reading for more information about the causes, symptoms, and treatments of hypernatremia.

Doctors diagnose hypernatremia when the concentration of sodium in blood serum is higher than 145 milliequivalents per liter (mEq/l).

Two common causes of hypernatremia are not enough fluid intake and too much water loss. In rare cases, consuming too much sodium can cause hypernatremia.

The opposite of hypernatremia is hyponatremia. This refers to a serum sodium level of less than 135 mEq/l. Hyponatremia refers to sodium levels that are too low.

Sodium is an electrolyte that plays an essential role in regulating levels of water and other substances in the body. The kidneys and adrenal glands are responsible for regulating sodium levels.

The adrenal glands produce a hormone called aldosterone. This hormone and the kidneys work together to maintain the balance of sodium in the blood.

Changes in water loss or water intake change the concentration of sodium in the blood. Receptors in the brain then recognize the need for level corrections.

The body responds by either increasing thirst to boost water intake or passing more sodium out of the body via urine.

The primary causes of hypernatremia are not enough fluid intake or too much loss of fluids, leading to insufficient liquid in the blood.

Several health factors can cause hypernatremia or increase its likelihood. These include:

Taking certain medications or having large areas of burned skin can also lead to too much sodium in the blood.

Certain people are more likely to develop hypernatremia, including:

  • infants
  • older adults
  • people with an altered mental state
  • people receiving IV treatments
  • people receiving nutrients through a tube that runs through the nose and into the stomach, known as nasogastric feeding

Sodium is crucial for several functions in the body. It exists mostly in the fluid outside of cells, called extracellular fluid.

Its main role is to maintain fluid balance in the body. It also plays key roles in:

  • regulating the movement of materials through cell membranes, known as cellular transport
  • maintaining the volume of plasma in blood
  • controlling nerve impulses
  • stimulating muscle contractions

Changes in levels of sodium in the blood can lead to alterations in fluid balance, which can cause several serious symptoms.

Having too much sodium in the blood may cause no symptoms, and a person may be unaware of it.

However, it can cause symptoms and complications such as:

In most cases, an underlying health condition such as kidney disease or diabetes is behind hypernatremia.

A doctor may start the diagnostic process by asking about a person’s medical history and doing a physical examination.

If they suspect hypernatremia, they may run blood or urine tests. Both can show an increased presence of sodium.

All treatment for hypernatremia involves correcting the fluid and sodium balance in the body. This usually means treating the underlying health condition.

The best approach varies, depending on the underlying cause. For example, if a person is finding it difficult to manage their diabetes, the doctor will recommend ways to help.

The treatment may involve:

  • the person drinking more water
  • a healthcare professional administering IV fluids
  • a doctor monitoring sodium levels and adjusting the amount of fluids accordingly

Without treatment, hypernatremia can lead to serious complications. One of the most dangerous is a brain hemorrhage, which stems from veins in the brain rupturing.

Untreated hypernatremia has a mortality rate of 20–60%.

Hypernatremia may stem from a different health issue that requires treating.

To prevent hypernatremia, a person can also:

  • Drink plenty of water to stay hydrated.
  • Increase their fluid intake as needed, in hot climates or during physical activity.
  • Have a balanced, healthy diet.
  • Make sure other health conditions, such as such as diabetes or kidney disease, are well-managed.

A high sodium intake does not typically cause hypernatremia, unless the intake is excessive or the person has certain other underlying health issues.

Still, a high sodium diet may cause other negative effects, including increased blood pressure.

If a person has unexplained fatigue, irritability, or other mood changes, they should speak with a doctor, as these may be symptoms of hypernatremia or other health conditions.

Often, a person will not realize that they have the condition until a doctor performs an examination or runs a blood or urine test.

When a doctor diagnoses and treats hypernatremia early, the outlook is generally good, and people usually recover with minimal intervention.

Often, a person can treat their condition by increasing their fluid intake. In other cases, they may need medical care in a hospital setting.

The success of treatment often relies on controlling the underlying condition, which then resolves the hypernatremia.

Below, find answers to some common questions about an excess of sodium in the blood.

What is the main cause of hypernatremia?

This condition is often caused by insufficient fluid intake or excessive water loss. Certain health conditions may also increase the risk of hypernatremia, including kidney disease, uncontrolled diabetes, diabetes insipidus, and dementia.

What happens during hypernatremia?

Hypernatremia causes water to move from the tissues into the bloodstream, which can cause the cells to shrink. It also causes changes in hormone levels to regulate the amount of sodium, which results in increased thirst and concentrated urine.

What are the symptoms of high sodium levels?

In some cases, hypernatremia causes symptoms such as excessive thirst, fatigue, muscle weakness, irritability, and confusion. However, it may not cause any symptoms.

Hypernatremia refers to levels of sodium in the blood being too high. It typically occurs when a person has a reduced fluid intake or excessive fluid loss.

Certain people have a higher risk, including older people, infants, and people in long-term care facilities.

Treatment usually involves increasing the fluid intake and managing any underlying health condition that is causing the high sodium levels.