The changing pattern of hypernatremia in hospitalized children

Objectives. Past studies have revealed that hypernatremia occurs primarily in infants with diarrheal dehydration. With improved infant feeding practic es and the advent of pediatric critical care medicine, the pattern of hyper natremia in children has likely changed. The purpose of this study was to e valuate the current pattern of hypernatremia in hospitalized children. Methods. Medical records were reviewed for 68 patients admitted to a large urban children's hospital during a 3-year period, all with a serum sodium g reater than 150 mEq/L. The etiologies, predisposing factors, and morbidity and mortality associated with hypernatremia were evaluated. Results. The average patient age was 3.9 years (range, 1 day to 19.7 years) , and the peak serum sodium concentration was 159 mEq/L (range, 151-184 mEq /L). Hypernatremia was hospital acquired in 60% of children. The majority o f children (71%) were admitted for reasons other than hypernatremia. In 76% of the patients, inadequate fluid intake was the main cause of hypernatrem ia. Gastroenteritis contributed to the hypernatremia in only 20% (14 out of 68) of children. Eleven of these were infants <1 year of age with hypernat remia on admission. Eighty-eight percent of patients (60 out of 68) suffere d from neurologic impairment, critical illness, chronic disease, or prematu rity before developing hypernatremia. The overall mortality was 16%. Patien ts in whom hypernatremia was not corrected had a significantly higher morta lity than those in whom hypernatremia was corrected (4 out of 8 [50%] vs 7 out of 60 [12%]). Peak serum sodium was no different for survivors than non survivors. No deaths were attributable to cerebral edema caused by correcti on of hypernatremia. Neurologic complications related to hypernatremia occu rred in 15% of patients. Conclusions. Hypernatremia occurs in children of all ages, with the vast ma jority having significant underlying medical problems. Hypernatremia caused by gastroenteritis in infants has become much less common than previously reported. Hypernatremia is primarily a hospital-acquired disease, produced by the failure to administer sufficient free water to patients unable to ca re for themselves. Failure to correct hypernatremia may result in a high mo rtality rate.