Differential diagnosis of complications of pediatric bacterial pneumonia

• Pleural effusion
• Pleural empyema
• Necrotizing pneumonia
• Lung abscess
• Bronchopleural fistula
• Pneumatocele
• Bronchiectasis

Approach to the differential diagnosis of complications of bacterial pneumonia:

• Less than 10% of bacterial pneumonias become complicated
• Effusion vs. empyema:
  • Effusion – pleura does not enhance on chest CT + pleural fluid is non-septated and free-flowing
  • Empyema – pleura does enhance on chest CT, pleural fluid is septated (best seen on US) and loculated
• Pneumatocele vs. abscess:
  • Abscess appears earlier in infection + has thick irregular walls + lasts long time
  • Pneumatocoele occurs later in infection + has thin wall + usually no air fluid level
• Abscess vs. empyema:
  • Abscess is spherical in shape + destroys lung
  • Empyema is nonspherical in shape + displaces lung + has split pleura sign + has obtuse angles to chest wall + has thickened pleura
• Necrotizing pneumonia is infected lung that does not enhance
• Bronchopleural fistula can be diagnosed when air collections in the lung and pleural space are adjacent to each other