Pleural effusion...

Yesterday we reviewed a patient with a giant pleural effusion (after bouncing back from a short admission for pneumonia)

For a reminder of Light's criteria see the previous post HERE

notice the shifted trachea AWAY from the whiteout

For the guidelines of see this article

But some of the main points:

Exudative effusion can be divided  into:


Category 1:  Minimal, free-flowing effusion (< 10 mm on lateral decub CXR) and unknown culture/gram stain and unknown pH --> SIMPLE
Category 2: Small to moderate free-flowing effusion (> 10 mm and < 1/2 hemithorax) and negative culture and Gram stain and pH > 7.20 (i.e., an uncomplicated) 
Category 3: Large free-flowing effusion ( > 1/2 hemithorax) or Loculated or thickened parietal pleura or positive culture/Gram stain or pH < 7.20 (i.e., a complicated) 
Category 4: Frank pus  (Empyema)


• Categories 1 and 2 have good outcomes and do not usually require drainage. 

• Categories 3 and 4 have poor outcomes and generally require drainage. The panel reviewed the literature on the management of these effusions. 

Some  fun facts of pH: 
Can be low in infection and malignancy. 

<7.20 in parapneumonic infection is indication for drainage 

<7.20 in malignancy predicts a poor response to pleurodesis ( and a poor prognosis eg. a median survival of only 30 days)