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.