Hyponatremia in patients with respiratory syncytial virus bronchiolitis

Hiroaki Kanai,1 Yuko Sato,2 Ko Ichihashi21Department of Pediatrics, Faculty of Medicine, University of Yamanashi, Chuo, Yamanashi; 2Department of Pediatrics, Saitama Medical Center, Jichi Medical University, Saitama, JapanAbstract: Children with pulmonary diseases are at risk of developing hyponatremia (serum sodium concentrations <136 mEq/L). The aim of this study was to define the clinical and laboratory characteristics of respiratory syncytial virus (RSV) bronchiolitis in patients with hyponatremia and determine the associated risk factors. Medical data of 105 children (56 boys, 49 girls; mean age ± standard deviation: 9.1 ± 8.9 months) with RSV bronchiolitis were retrospectively analyzed. At admission, 35.2% of all patients, 13% of the <12-month-old patients, and 58.8% of the 12–35-month-old patients had hyponatremia. The results show that the development of hyponatremia in inpatients with RSV bronchiolitis is associated with age (12–35 months), body temperature, high fever (≥38.5°C), duration of fever until hospitalization, and high C-reactive protein level at admission. These results indicate that hyponatremia occurs in patients with RSV bronchiolitis exhibiting severe inflammation assessed by fever severity and C-reactive protein level. The use of isotonic fluids is recommended for parenteral therapy of patients with RSV bronchiolitis with risk of developing hyponatremia.Keywords: respiratory syncytial virus, bronchiolitis, hyponatremia, fever, C-reactive protein