Ellie J. C. Goldstein, Section Editor Diagnosis and Management of Parapneumonic Effusions

Approximately 1 million patients develop parapneumonic effusions (PPEs) annually in the United States. The outcome of these effusions is related to the interval between the onset of clinical symptoms and presentation to the physician, comor-bidities, and timely management. Early antibiotic treatment usually prevents the development of a PPE and its progression to a complicated PPE and empyema. Pleural fluid analysis provides diagnostic information and guides therapy. If the PPE is small to moderate in size, free-flowing, and nonpurulent (pH, 17.30), it is highly likely that antibiotic treatment alone will be effective. Prolonged pneumonia symptoms before evaluation, pleural fluid with a pH!7.20, and loculated pleural fluid suggest the need for pleural space drainage. The presence of pus (empyema) aspirated from the pleural space always requires drainage. Fibrinolytics are most likely to be effective during the early fibrinolytic stage and may make surgical drainage unnecessary. If pleural space drainage is ineffective, video-assisted thoracic surgery should be performed without delay. Parapneumonic effusion (PPE; i.e., pleural fluid that results from pneumonia or lung abscess) is the most common cause of an exudative pleural effusion. PPE may be the consequence of either community-acquired or nosocomial pneumonia. Be-tween 20 % and 57 % of the 1 million patients hospitalized yearl