Investigation

The investigation of a patients with suspected empyema should include the following:

• imaging
  • chest xray - pleural effusions are usually identified as a result of clinical examination and chest radiography
    • further assessment
      • ultrasound scanning is more sensitive and specific than a plain X-ray, allows estimation of volume, localisation of effusions and assessment of loculation, and is often the initial investigation used to guide aspiration
      • contrast-enhanced CT scanning may provide additional discrimination (e.g. distinguishing empyema from parenchymal lung abscess)
• full blood count:
  • reveals a polymorphonuclear leucocytosis
    
    
• pleural fluid aspiration:
  • may be diagnostic
  • the features of a the aspirate from a classical empyema are:
    • leucocytosis
    • organisms on culture or gram staining
    • reduced glucose
    • low pH

Reference:

1. Drug and Therapeutics Bulletin 2006;44 (3): 17-20.