Hyponatremia is a condition that occurs when the level of sodium in your blood is abnormally low. Sodium is an electrolyte, and it helps regulate the amount of water that's in and around your cells.

In hyponatremia, one or more factors — ranging from an underlying medical condition to drinking too much water during endurance sports — causes the sodium in your body to become diluted. When this happens, your body's water levels rise, and your cells begin to swell. This swelling can cause many health problems, from mild to life-threatening.

Hyponatremia treatment is aimed at resolving the underlying condition. Depending on the cause of hyponatremia, you may simply need to cut back on how much you drink. In other cases of hyponatremia, you may need intravenous fluids and medications.

Symptoms Causes Risk factors Complications Prevention

Hyponatremia signs and symptoms may include:

  • Nausea and vomiting
  • Headache
  • Confusion
  • Loss of energy and fatigue
  • Restlessness and irritability
  • Muscle weakness, spasms or cramps
  • Seizures
  • Coma

When to see a doctor

If you have a medical condition that increases your risk of hyponatremia, or you have other risk factors for hyponatremia, such as participating in high-intensity activities, and you have the signs and symptoms of low blood sodium, see your doctor.

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