DDX of complications of bacterial pneumonia

Approach to complications of bacterial pneumonia:

  • 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