[Practical management of pleural effusion].

There are many different diseases that can be associated with pleural effusions. When a pleural effusion is discovered, two questions need to be answered: 1) is the effusion a transudate or is it an exudate?, and 2) if the effusion is an exudate, what is the disease responsible for its production?. Answers to these questions can be obtained in more than two-thirds of patients testing the pleural fluid by diagnostic thoracentesis. The remainder may require watchful waiting until resolution or further diagnostic procedures, either non-invasive (radiologic imaging) or invasive (bronchoscopy, pleural biopsy, thoracoscopy).