CRP and empyema: NP: necrotizing pneumonia; PPE: parapneumonic effusion; EMP: empyema; IQR: interquartile range; CRP: C-reactive protein; WBC: white blood cells; CT: computed tomography; VATS: video-assisted thoracoscopic surgery; PICU: Pediatric Intensive Care Unit; IV antibiotics: intravenous antibiotics; CCAP: complicated community-acquired pneumonia