The incidence of dysnatremia in children with acute gastritis/gastroenteritis and the effects of various hypotonic intravenous fluids on subsequent serum sodium levels

Background: The incidence of early dysnatremia in children with acute gastritis/gastroenteritis varied, and factors associated with early dysnatremia have not been clearly identified. The optimal sodium (Na) content of intravenous (IV) fluid for children with acute gastritis/gastroenteritis is debatable. Methods This retrospective study included hospitalized patients aged 1 month-18 years with community-acquired acute gastritis/gastroenteritis from January to October 2016. Factors associated with early dysnatremia were identified using multivariable analysis. The effects of various types of hypotonic IV fluids on subsequent serum Na were analyzed and compared. Results Among the 304 children included, the median age was 2.2 (1.0, 4.2) years. The incidence of early dysnatremia was 17.1% (hyponatremia 15.8%; hypernatremia 1.3%). Moderate ( p  = 0.03) and severe dehydration ( p  = 0.04) and presenting of both vomiting and diarrhea ( p  = 0.03) were associated with early dysnatremia. Subgroup analysis was performed in initially eunatremia patients who subsequently underwent serum Na measurements. Among the D5-1/3 − 1/5NS group, 6.7% and 7.7% developed hyponatremia at 4–24 hours and 24–48 hours, respectively, while no one in the D5-1/2 NS group developed hyponatremia. The changes in serum Na at 24–48 hours were significantly higher in the D5-1/2 NS group (+ 2.0 (1.0–2.0) mmol/L) than in the D5-1/3 − 1/5NS group (0 (-0.25-2.0) mmol/L) ( p  = 0.04). Conclusions Dysnatremia was common in children with acute gastritis/gastroenteritis. Moderate to severe dehydration and presenting of both vomiting and diarrhea were significantly associated with early dysnatremia. Serum electrolytes should be monitored in patients with those conditions and IV fluid with at least the same Na content as D5-1/2NS is recommended.