Parapneumonic empyema. A pitfall in diagnosis

Abstract

Two patients eventually shown to have empyema were encountered in which the initial thoracentesis revealed fluid compatible with either a simple or a complicated parapneumonic effusion. In both cases, the diagnosis of empyema was made by a second thoracentesis done at a close interval of time from a different site. Therefore, the physician should approach parapneumonic effusions systematically, and remember that in some cases, multiple thoracenteses may be required to make the correct diagnosis of an empyema.