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Medically reviewed by Last updated on Sep 3, 2023.

What is hyponatremia?

Hyponatremia occurs when the amount of sodium (salt) in your blood is lower than normal. Sodium is an electrolyte (mineral) that helps your muscles, heart, and digestive system work properly. It helps control blood pressure and fluid balance.

What causes hyponatremia?

Hyponatremia happens when too much sodium leaves your body, or when more water than sodium stays in your blood. Any of the following conditions can lead to hyponatremia:

  • A diet that is low in sodium
  • Drinking too much water or receiving too much fluid through an IV
  • Intense and prolonged exercise that causes excessive sweating
  • Medical conditions, such as Addison disease, kidney disease, congestive heart failure, liver cirrhosis, or cancer
  • Medicines, such as diuretics, antidepressants, pain medicines, or illegal drugs such as ecstasy
  • Dehydration

What are the signs and symptoms of hyponatremia?

You may have no signs or symptoms. Symptoms may start to appear when the amount of sodium in your blood drops too low or too fast. You may have any of the following:

  • Abdominal cramps, nausea, or vomiting
  • Headache, confusion, hallucinations, or trouble staying awake
  • Muscle weakness or cramps
  • Seizures or coma

How is hyponatremia diagnosed?

Your healthcare provider will ask you about the medicines you take. Your provider will do a physical exam to look for signs of swelling caused by fluid retention (extra water in your body).

  • Blood tests will be done to check the level of sodium in your blood. They may also be done to find the cause of your hyponatremia.
  • Urine sodium is a test that checks the level of sodium in your urine. A sample of your urine is collected and is sent to a lab for tests.

How is hyponatremia treated?

Treatment depends on the cause of your hyponatremia and how severe it is. Healthcare providers may limit the amount of liquids you drink if you are retaining water. A salt solution may be given through an IV to increase the amount of sodium in your blood. Medicines may also be given to help get rid of extra fluid in your body. You may urinate more often while taking these medicines.

Treatment options

The following list of medications are in some way related to or used in the treatment of this condition.

When should I contact my healthcare provider?

  • You have muscle cramps or twitching.
  • You feel very weak or tired.
  • You have nausea or are vomiting.
  • You have questions or concerns about your condition or care.

When should I seek immediate care or call 911?

  • You have a seizure.
  • You have an irregular heartbeat.
  • You have trouble breathing.
  • You cannot move your arms and legs.
  • You are confused or cannot think clearly.

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your healthcare providers to decide what care you want to receive. You always have the right to refuse treatment. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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