What causes low sodium in the elderly

In older adults, low sodium often results from certain medications, kidney issues, or infections. Because multiple factors may contribute, treatment depends on identifying the underlying cause.

Sodium is an important electrolyte that helps control water balance, muscle and nerve activity, and blood pressure.
When sodium levels are less than 135 milliequivalents per liter (mEq/L), a person can develop low sodium (hyponatremia).

This usually occurs when there is an excess of water relative to salt in the body, which may arise from too much water or insufficient sodium in the blood.

Hyponatremia is the most common electrolyte disorder in older adults, and some research has suggested that older women may develop it more commonly than older men. A 2019 study found that nearly half of all hospitalized older adults had hyponatremia.

This article addresses the causes, management strategies, and treatment options for low sodium in older adults.

In older adults, the most common causes of hyponatremia include diuretic medications, kidney failure, and infections.

However, there may be several simultaneous causes that contribute to the challenge of diagnosing low sodium in older adults. Additional reasons for hyponatremia include:

Hyponatremia can affect people in different ways. If sodium levels decrease gradually, symptoms may take longer to develop. General symptoms of hyponatremia include:

That said, for older adults in particular, hyponatremia can increase the risk of falls, which can lead to serious injury and hospitalization. For this reason, it is important to pay attention to symptoms.

If sodium levels decrease rapidly, these symptoms can become more severe and dangerous. In extreme cases, hyponatremia may result in death. Emergency signs that will require a person to call 911 immediately are:

Because the treatment for hypoantremia depends on the cause, accurately diagnosing the cause is crucial to help a person get the appropriate treatment.

Treatment for hyponatremia usually involves administering saline and fluids intravenously (via a vein), though this depends on the type of hyponatremia and the severity of symptoms. For this reason, it is important for the doctor to determine whether a person’s low sodium is hypovolemic, euvolemic, or hypervolemic.

A 2019 study of hospitalized older adults presenting with hyponatremia found that more than 40% of cases had a classification of hypovolemic. Hypovolemic refers to when there is a loss of both water and sodium, but more sodium is lost than water. In this case, doctors generally administer both saline and fluids.

In contrast, hypervolemic hyponatremia occurs when a person retains both water and sodium, but more water than sodium. In this case, doctors usually restrict salt and fluids and may prescribe diuretics to remove excess fluid.

Finally, euvolemic hyponatremia occurs when sodium volume is typical, but there is too much water. Doctors typically treat this with fluid restriction.

That said, if a person’s sodium level drops rapidly or symptoms are acute, doctors will typically choose to administer saline regardless of the type of hyponatremia. They will do this to rapidly correct sodium levels and reduce the risk of complications, such as seizures, stupor, or coma.

Additionally, a person’s doctor must also exercise caution when prescribing treatments for any co-occurring conditions, such as medications, in case these treatments lead to low sodium.

The doctor will usually do this by prescribing the lowest effective dose and using safe alternatives when available. They will also avoid multiple medications that may increase the risk of developing this condition even more.

Sodium is present naturally in a variety of foods, and manufacturers often add it during processing. Table salt comprises approximately 40% sodium and 60% chloride.

The body needs some sodium to maintain healthy functioning. Adults over the age of 51 generally need to consume up to 2,300 milligrams (mg) of sodium daily, and most people can naturally obtain sufficient sodium from a balanced diet without the need for additional salt.

It is important to understand that adding more salt to a person’s diet to correct hyponatremia is not usually appropriate unless a doctor recommends doing so. This is because it could lead to retaining too much sodium, which has links to other health problems, and because low sodium levels generally do not result from diet but from changes in bodily fluid levels.

Low sodium, or hyponatremia, is the most frequent electrolyte disorder in older adults, particularly in older females. It occurs when the fluid and sodium levels become unbalanced, which can commonly occur due to diuretic drugs, kidney failure, or an infection, but often involves multiple causes.

Symptoms of low sodium may include fatigue or confusion, but also seizures and even coma in severe cases. Treatment depends on the type of low sodium a person has, but may include saline or fluid restrictions.

Increasing salt directly in a person’s diet is inadvisable, as the issue usually involves fluid balance rather than the amount of sodium a person eats. Additionally, excess sodium intake can lead to other health problems.