[Pleural effusion in pneumonia]

Parapneumonic effusions are frequent (40%) but normally no clinical problem. If a parapneumonic effusion is seen on chest X-ray or by ultrasonic investigation, a thoracocentesis should be done whenever possible without risk. Investigations of the pleural fluid should include: aspect, pH-value, protein, glucose, microbiology (gram stain and culture, and cytology. Based on the extent of the effusion, the finding of free floating or loculated effusion and the results of pleura fluid investigation patients could be categorized in four risk groups. Very low and low risk for poor outcome is normally characterized by a small or moderately free floating effusion, clear pleural fluid and a pH > 7.2. In these risk groups no further intervention seems to be necessary. For patients with moderate or high risk (pus, large effusion (> 1/2 hemithorax), loculated effusion, pH < 7.2 a drainage therapy is recommended. For larger parapneumonic effusions and for complicated parapneumonic free floating effusion tube drainage therapy seems to be sufficient. However, for empyema or large lobulated effusions video-assisted thoracoscopy surgery followed by local fibrinolytic treatment might produce the best results.