Dangers of low sodium levels

Arun Prabhahar & HS Kohli

Sodium (Na) ions are essential for the functioning of body cells. The elderly (65 years and above) are more prone to changes in the body’s sodium levels. Low sodium concentration or hyponatremia (< 135 mEq/L) is a relatively frequent electrolyte disorder in the elderly population because of:

1 Impaired water excretory capacity of the kidneys.

2 Many drugs such as diuretics normally prescribed for heart and kidney ailments as well as hypertension.

3 ‘Tea and toast’ syndrome: Many old people prefer light meals and often opt for tea and toast. Such meals don’t have any protein and contain very less salt.

Sodium levels in the body are dependent on the total body fluid or water content in the body. Kidneys regulate the body’s water and sodium levels through urine excretion. In the elderly, sometimes more water is retained, diluting the blood and leading to low sodium levels. Even a tiny fluctuation in body’s water levels can lead to alteration in sodium level in them as the total body water content decreases with age.

Common risk factors for hyponatremia in older people include medical conditions such as diabetes, hypertension, heart and kidney problems, and some cancers. These patients are often advised a low-sodium diet. Diuretic drugs (for example, Lasix), painkillers and anti-depressants can all predispose the elderly to hyponatremia, if not appropriately monitored.

Many elderly are on multiple drugs. This is also a major risk factor for low sodium levels. Less protein consumption also plays a role in the development of hyponatremia. It occurs more during the summer because of increased salt loss and water intake.

Symptoms of hyponatremia usually depend on sodium levels. The severity can be divided into mild (Na 130-135 mEq/L), moderate (125-129 mEq/L) and severe (