Parapneumonic effusion

File:LLL pneumonia with effusionM.jpg

A parapneumonic effusion (circled), due to a left lower lobe pneumonia.

A parapneumonic effusion is a type of pleural effusion that arises as a result of a pneumonia, lung abscess, or bronchiectasis. There are three types of parapneumonic effusions: uncomplicated effusions, complicated effusions, and empyema. Uncomplicated effusions generally respond well to appropriate antibiotic treatment. The criteria for a complicated parapneumonic effusion include the presence of pus or Gram stain–positive pleural fluid or a pleural fluid pH <7.0. Appropriate management includes chest tube drainage (tube thoracostomy). Treatment of empyemas includes antibiotics, complete pleural fluid drainage, and reexpansion of the lung.

Other treatments include the use of decortication.

Diagnostic techniques available include plain film chest x-ray, computed tomography (CT), and ultrasound. Ultrasound can be useful in differentiating between empyema and other transudative and exudative effusions due in part to relative echogenicity of different organs such as the liver (often isoechogenic with empyema).