Which procedure is recommended to determine the etiology of a pleural effusion?

Determining the etiology of a pleural effusion is best accomplished through thoracentesis. This procedure involves inserting a needle through the chest wall into the pleural space to extract pleural fluid for analysis. The fluid can then be examined for various parameters, including appearance, cell count, protein levels, glucose levels, pH, and the presence of bacteria or malignancy, which helps identify the underlying cause of the effusion, such as infection, malignancy, or heart failure.

In addition to its diagnostic purpose, thoracentesis can also serve a therapeutic role by relieving symptoms associated with large pleural effusions, such as dyspnea. The information gained from analyzing the fluid is critical in guiding further treatment, making thoracentesis a key procedure in the management of pleural effusions.