The Role of Systemic Inflammatory Indices in Children with Parapneumonic Pleural Effusion

Background: Parapneumonic effusion (PPE) is a common complication of community-acquired pneumonia (CAP) in children, classified as complicated (CPPE) or uncomplicated (UPPE). Differentiating between these types aids in appropriate management and improves outcomes. This study evaluates the diagnostic utility of systemic inflammatory indices in distinguishing CPPE from UPPE in pediatric patients. Methods: A cross-sectional study of 90 children with PPE categorized into CPPE and UPPE groups based on laboratory and imaging findings. Systemic immune inflammatory index (SII), neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), derived neutrophil-to-lymphocyte ratio (dNLR), lymphocyte-monocyte ratio (LMR), and C-reactive protein/albumin (CRP/Alb) ratio were calculated. Results: The CRP/Alb ratio was significantly higher in the CPPE group (p = 0.013). ROC analysis identified a CRP/Alb ratio >113.46 as a predictor of CPPE with 85.71% specificity and 44.12% sensitivity. Multivariate regression analysis identified parainfluenza virus infection and the CRP/Alb ratio as significant predictors of CPPE (OR = 17.12, p = 0.009). Conclusions: Among the inflammatory indices analyzed, the CRP/Alb ratio was the most reliable marker for differentiating CPPE from UPPE.