What is hyponatremia?

Hyponatremia is usually discovered on laboratory tests as a lower than normal sodium level in the blood. It will appear as sodium or Na+ in your lab results. Actually, the main problem in the vast number of situations is too much water that dilutes the Na+ value rather than too much sodium. As a result, water moves into body cells, causing them to swell. This swelling causes the major problem, which is a change in mental status that can progress to seizures or coma.

Hyponatremia can result from multiple diseases that often are affecting the lungs, liver or brain, heart problems like congestive heart failure, or medications. Most people recover fully with their doctor’s help.

Who is most at risk for hyponatremia?

Anyone can develop hyponatremia. Hyponatremia is more likely in people living with certain diseases, like kidney failure, congestive heart failure, and diseases affecting the lungs, liver or brain. It often occurs with pain after surgery. Also, people taking medications like diuretics and some antidepressants are more at risk for this condition.

How common is hyponatremia?

Hyponatremia is very common. Hyponatremia is the most common chemical abnormality seen among patients in the hospital. Rates of hyponatremia are higher among people admitted to inpatient hospital care units or with the medical conditions mentioned above.

What causes hyponatremia?

In general, too much water in your body is usually the main problem and this dilutes the sodium levels. Much less frequently, hyponatremia is due to significant sodium loss from your body.

Too much water in your body causes your blood to become “watered down.” A good example is people who run in long races or run on hot days. They lose both salt and water in their sweat and often replace these losses with mostly water. This combination can be deadly because it dilutes the remaining sodium in the body.

It’s also possible to lose too much sodium from your body. Medications, like diuretics, can cause your kidneys to increase the amount of sodium excreted in urine. Medical problems like diarrhea may cause excessive sodium loss if left untreated. Chronic or binge alcohol consumption can cause people to lose too much sodium through increased urination and vomiting. You can have hyponatremia without feeling dehydrated or volume depleted. This is most often the case in hospitalized patients.

What are the symptoms of hyponatremia?

Hyponatremia causes neurologic symptoms ranging from confusion to seizures to coma. The severity of the symptoms depends on how low the sodium levels are in the bloodstream and how quickly they fall. In many cases, blood sodium levels fall gradually, producing only mild symptoms as the body has time to make adjustments. Symptoms are more serious when blood sodium levels fall quickly.

Other symptoms of moderate to severe hyponatremia include:

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