Management of Parapneumonic Effusions

Annotation for Point A

The standard method to estimate the amount of pleural fluid has been the lateral decubitus chest roentgenogram. Recent comparative studies indicate that ultrasound is a more reliable method to quantitate a pleural effusion.^21-25 This is a grade A recommendation. As previously mentioned, an effusion measured up to 4 mm is considered normal.¹² Furthermore, an effusion is expected to accompany severe pneumonia.^7-9 Clinical studies by Light et al.²⁶ indicated that infections involving an effusion of less than 10 mm will resolve with antibiotics alone, and this has been supported by subsequent series.^27,28 This is a level I prognostic evidence. Consequently, ultrasonography-guided thoracentesis is recommended for effusions greater than 10 mm. This is a grade B recommendation.