Hyponatremia As Observed in a Chronic Disease Facility

ABSTRACT: A random sampling of 160 patients in a chronic disease facility showed that 36 patients (22.5 percent) had chronic hyponatremia. Their mean age was 72 years (range, 42–94 years); 75 percent of the patients were more than 65 years old. Women comprised 57 percent of the group. The mean serum sodium level was 120 mEq/L (range, 109–135 mEq/L). The mean serum osmolarity was 270 mOsm/L (range, 251–294 mOsm/L). Of the 36 patients, 9 were asymptomatic. Symptoms were associated with underlying disorders rather than with hyponatremia, although in 9 patients the hyponatremia appeared to have intensified existing symptoms. The most common cause of hyponatremia (in 41.6 percent of 20 overhydrated patients) was inappropriate secretion of antidiuretic hormone ( IADH syndrome). Factors accounting for the high incidence of IADH were the age of the patient and the nature of the underlying disorders, particularly diseases associated with aging. Simple measures were used to manage the hyponatremia, e.g., water restriction for patients who were overhydrated; replacement of sodium chloride for patients who were losing salt excessively and had a low sodium intake; and control of hyperglycemia in the pseudohyponatremic patients with hyperglycemia. No treatment was required for pseudohyponatremia associated with hyperlipidemia. When hyponatremia was due to drug‐induced ADH excess, the involved drug was discontinued. Emphasis on management of the patients' primary disorders also ameliorated the hyponatremic state.