Parapneumonic Effusion Versus Pulmonary Empyema in Children: Analysis of Risk Factors and Laboratory Predictors Through a Single Center Experience

<b>Background:</b> Parapneumonic effusion is a common complication of community-acquired pneumonia and can range from a simple inflammatory transudate to an organized purulent collection, known as empyema. Progression to empyema significantly worsens the prognosis, leading to increased morbidity, longer hospital stays, and a greater need for invasive interventions. Several risk factors for pleural effusion and progression to empyema have been identified, but the absence of standardized criteria underline the need for better risk stratification. We analyzed clinical and laboratory data from a cohort of children hospitalized with pneumonia associated with pleural effusion or empyema, to identify predictive risk factors associated with these complications. <b>Methods</b>: We retrospectively analyzed clinical and laboratory data from patients admitted to our Pediatric Emergency Department with pneumonia complicated by pleural effusion and compared patients with simple effusion to those with empyema. <b>Results</b>: Seventeen children with simple pleural effusion and eighteen with empyema were enrolled. Patients with empyema had higher absolute neutrophil count, higher levels of C-reactive protein, procalcitonin, and ferritin, and lower serum albumin levels. Furthermore, they took a longer time for normalization of inflammatory markers when compared with those with pleural effusion. Invasive interventions, such as pleural drainage, and the need for intensive care were more frequent in the empyema group. <b>Conclusions</b>: Pleural effusion and empyema are two common complications of pediatric community-acquired pneumonia. Children developing pleural empyema have higher inflammatory markers and lower levels of serum albumin compared to patients with simple pleural effusion. Morbidity is significantly worse in children with empyema as they are more prone to require invasive interventions and intensive care.