Pleural Infections

Pleural effusion in the setting of a pneumonia

Spectrum of pleural processes from uncomplicated (sterile) parapneumonic effusion to empyema (infected)

Parapneumonic effusion are exudative, identified by the presence of any one of the following (Light's criteria):

• Pleural fluid protein/serum protein >0.5
• Pleural fluid LDH/serum LDH >0.6
• Pleural fluid LDH >2/3 upper limited of normal for serum LDH

CXR in particular lateral decubitus films showing more than 1cm of fluid

Ultrasound Chest is more accurate for quantifying volume than CXR, can also detect septations and guide pleural drainage

CT Chest should be done in all cases of suspected empyema, and non-resolving pneumonia despite adequate antibiotic therapy

Pneumonia with resolving symptoms and persistent/progressive pleural effusion

Pleural effusion is free-flowing >25mm in depth on lateral decubitus films or CT

Pleural effusion is loculated on CT

Pleural effusion is associated with thickened parietal pleura on contrast-enhanced CT

Blood cultures in all patients suspected of having a pleural infection

Serum LDH and total protein concurrently with pleural fluid sampling

Pleural fluid ALWAYS send: cell count & differential, bacterial culture, LDH, total protein, pH, glucose, cytology

• As directed by history/presentation: AFB and mycobacterial culture, fungal culture