Low blood sodium, known as hyponatremia, occurs when you have an irregularly low amount of sodium in your blood or when you have too much water in your blood. Low blood sodium is common in older adults, especially those who are hospitalized or have long-term health problems such as heart disease, kidney disease or cancer, among others.

Symptoms of hyponatremia can include nausea and vomiting, loss of energy and confusion. Serious hyponatremia can cause seizures, coma and even death.

Hyponatremia is more common in older adults because they're more likely to take medicines or have medical problems that put them at risk of the disorder. These include:

• Drugs that cause the body to make more urine, called diuretics.
• Some types of antidepressants.
• Carbamazepine, an anti-seizure medication.
• Underactive thyroid or adrenal glands.
• Decreased function of the kidneys, liver or heart.
• Certain cancers, including lung cancer.
• Certain illnesses, such as pneumonia or urinary tract infections, that can cause dehydration.

Hyponatremia treatments may include changing a medicine that affects sodium level, treating an underlying disease, changing the amount of water you drink or changing the amount of salt in your diet.