[Hyponatremia and its etiology in pediatric patients admitted to the emergency room].

BACKGROUND: The importance of hyponatremia is underestimated despite it is a frequent alteration in a hospital environment. Usually no cause is investigated and it is treated as an isolated data. The aim was to determine the prevalence and etiology of hyponatremia in pediatric patients.

METHODS: Cross-sectional study of 72 patients from 1-month to 15-years of age admitted to the emergency room, from May to September, 2015, with lower serum determination of Na < 135 mEq/L at admission. For statistical analysis, frequencies and percentages, as well as medians and ranges were used.

RESULTS: 72 patients (3%) out of 2400 admissions to the emergency room were detected. 42 were male (58%), 28 infant (30.5%), and 46 eutrophic (68.5%). The diagnosis at admission was sepsis in 13 (18%), mild hyponatremia in 41 (56.9%), real hyponatremia in 71 (98.6%) and dilutional in 1 (1.4%). The median serum sodium was 130 mEq/L (range 112-134), and the median serum osmolality 266 mOsm/L (range 236-288). The most usual management was the increase of sodium in solutions in 21 cases (29%), and the use of diuretics (n = 21, 29%). The median of sodium input per m2 (BSA) per day was 45 mEq (range 0-158).

CONCLUSIONS: Mild and real hyponatremia were the most frequent diagnoses. The infection at admission was the more common etiology. The increase in sodium input in solution was the most common management. The use of intravenous solutions 2:1 (isotonic) did not produce hypernatremia and avoided administration of hypotonic solutions.