Causes of Low Sodium Levels in the Elderly

Low sodium levels in the blood, medically known as hyponatraemia, are a common electrolyte imbalance, especially in older adults. Sodium is an essential mineral that helps regulate fluid balance, nerve function and muscle contractions. When sodium levels drop too low, it can lead to symptoms ranging from mild confusion and weakness to severe neurological problems. Understanding the causes of low sodium levels in the elderly is important for effective management and prevention.

What Is Hyponatraemia?

Hyponatraemia occurs when the concentration of sodium in the blood falls below the normal range, typically less than 135 millimoles per litre (mmol/L). This condition causes water to move into cells, leading to swelling and affecting brain function among other complications.

Why Are Elderly People More at Risk?

As people age, changes in kidney function, hormone regulation and body water balance make it harder to maintain proper sodium levels. Older adults are also more likely to have chronic illnesses or take medications that influence sodium and water balance, increasing their risk of hyponatraemia.

Common Causes of Low Sodium in the Elderly

Low sodium in older adults can result from various causes. One common cause is the use of certain medications such as diuretics, which increase urine production and sodium loss. Other drugs like antidepressants, antiepileptics and some pain medications can also affect sodium balance.

Chronic conditions like heart failure, liver disease or kidney disease often lead to fluid retention and dilution of sodium in the blood. Infections or severe illnesses can trigger inappropriate release of antidiuretic hormone (ADH), causing the body to retain water and lower sodium levels, a condition called syndrome of inappropriate antidiuretic hormone secretion (SIADH).

Dehydration due to poor fluid intake, vomiting or diarrhoea can disrupt sodium balance as well. Conversely, drinking excessive amounts of water without adequate sodium intake can dilute blood sodium, a situation sometimes seen in elderly individuals with cognitive impairments.

Symptoms to Watch For

Symptoms of low sodium may include headache, nausea, confusion, weakness, seizures or even coma in severe cases. In the elderly, subtle symptoms like lethargy, balance problems or increased falls should prompt consideration of hyponatraemia.

Diagnosis and Treatment

Diagnosis is made through blood tests measuring sodium levels, often alongside assessments of kidney function and fluid status. Treatment depends on the severity and cause. Mild cases may be managed by adjusting medications or fluid intake. More severe cases might require careful sodium replacement under medical supervision.

Preventing Low Sodium

Preventing hyponatraemia in older adults involves regular monitoring, cautious use of medications that affect fluid balance and ensuring adequate but not excessive fluid intake. Managing underlying health conditions and seeking prompt medical care for infections or illnesses also help reduce risk.

When to Seek Medical Advice

If an elderly person shows signs of confusion, weakness or unusual behaviour, especially if accompanied by symptoms like headache or seizures, medical attention should be sought immediately as severe hyponatraemia is a medical emergency.

Summary

Low sodium levels in the elderly are caused by a combination of factors including medications, chronic diseases, hormonal imbalances and fluid disturbances. Awareness and careful management are essential to prevent complications and maintain overall health in older adults.