Hyponatremia in children with lower respiratory tract infection: a cross-sectional study

Introduction: Lower respiratory tract infections (LRTIs) are a leading cause of pediatric mortality in Nepal. Hyponatremia is a common electrolyte imbalance in severe infections, but its prevalence and impact in high-altitude, resource-limited settings like Jumla are poorly characterized. This study aimed to determine the prevalence and clinical significance of hyponatremia in children hospitalized with LRTIs at a tertiary hospital in Jumla, Nepal. Methods: A hospital-based cross-sectional study was conducted from January 2024 to June 2025, including 80 children aged 1 month to 12 years with LRTIs. Serum sodium levels were measured, and hyponatremia was classified as mild (130-134 mEq/L), moderate (125-129 mEq/L), or severe (<125 mEq/L). Associations with clinical parameters and outcomes were analyzed. Results: The prevalence of hyponatremia was 56.3% (45/80), predominantly mild (77.8% of hyponatremic cases). Hyponatremia was significantly associated with clinical signs of severe respiratory distress, including chest indrawing (p=0.001), crackles (p<0.001), and nasal flaring (p=0.004). Children with hyponatremia had markedly higher needs for CPAP (48.9% vs. 2.9%, p<0.001) and ventilator support (22.2% vs. 5.7%, p=0.010). A longer duration of hospital stay was strongly correlated with lower sodium levels (r=-0.43, p<0.001). Furthermore, significant negative correlations were found between serum sodium and both absolute neutrophil count (r=-0.57, p<0.001) and white blood cell count (r=-0.42, p=0.0001). Conclusion: Hyponatremia is highly prevalent among children with LRTIs in Jumla and is a significant marker of disease severity, associated with increased respiratory support needs and prolonged hospitalization. Routine sodium screening can aid in risk stratification and guide fluid management in this vulnerable high-altitude population.