ABSTRACT
I. Introduction Diagnostic thoracocentesis (or pleurocentesis) is performed since more than 150 years and remains the first step to be taken in the evaluation of a pleural effusion of unknown origin (1). Thoracocentesis can be combined with closed needle pleural biopsy, a procedure first described in 1955 and refined thereafter (2). The analysis of pleural fluid offers the opportunity of diagnosing the underlying disease directly, or provides valuable information for narrowing the spectrum of possible causes. Moreover, pleural fluid findings may precipitate immediate therapeutic steps in parapneumonic effusion or empyema. Closed needle biopsy, although less often practiced nowadays, is of importance in TB pleurisy and pleural malignancy. Diagnostic thoracocentesis as well as closed needle biopsy are simple and straightforward procedures, and severe complications are rare. This chapter will discuss the technique, indications and contraindications, yield, complications, and limitations of each method. Slight overlap with other chapters may occur where diagnostic yields are dealt with, and the reader is kindly asked to consult the relevant chapters for in-depth information about specific diseases.
