From the Guidelines
Thoracentesis should be performed on parapneumonic effusions in patients with pneumonia when the effusion is moderate to large or when there are signs of complications, as indicated by recent guidelines and evidence 1. When managing parapneumonic effusions, it's crucial to assess the size of the effusion and the patient's clinical response to antibiotic therapy.
- Small effusions can often be managed with antibiotic therapy alone, without the need for thoracentesis, as suggested by guidelines 1.
- However, for moderate to large effusions, or when there are signs of sepsis, failure to improve with antibiotics, or specific findings on imaging such as pleural enhancement, loculation, or increased attenuation of the extrapleural fat, thoracentesis is recommended to guide further management 1. The decision to perform thoracentesis should be based on the patient's clinical presentation, the size of the effusion, and imaging findings, with the goal of distinguishing between uncomplicated and complicated parapneumonic effusions or empyema, which require drainage. Key findings that suggest the need for drainage include a pH <7.2, glucose <60 mg/dL, LDH >1000 IU/L, positive Gram stain or culture, or grossly purulent fluid. For drainage, options include therapeutic thoracentesis, chest tube placement, or video-assisted thoracoscopic surgery, depending on the fluid characteristics and loculations, with the choice of procedure influenced by local expertise and the specific clinical scenario 1. Recent evidence emphasizes the importance of CT chest with IV contrast in the initial imaging of suspected parapneumonic effusion or empyema, highlighting findings such as pleural enhancement and pleural thickening as highly suggestive of empyema 1. Given the potential for increased morbidity, longer hospital stays, and progression to fibrothorax with untreated complicated parapneumonic effusions, a thoughtful and guided approach to thoracentesis and drainage is essential in the management of pneumonia with parapneumonic effusion.
From the Research
Indications for Thoracentesis in Parapneumonic Effusions
- Diagnostic thoracentesis is recommended for all patients with parapneumonic effusions to determine the nature of the effusion and guide management 2, 3.
- Therapeutic thoracentesis should be performed if the effusion is large or if the patient is symptomatic 4, 5.
- The decision to perform thoracentesis should be based on the size of the effusion, the presence of loculations, and the results of pleural fluid analysis, including pH, glucose, and bacterial cultures 2, 6.
Criteria for Drainage of Parapneumonic Effusions
- Effusions that meet certain criteria, such as size > 1/2 of the hemithorax, loculations, pleural fluid pH < 7.20, or positive bacterial cultures, should be drained 2, 6.
- The presence of pus or bacteria in the pleural fluid, or a pleural fluid pH < 7.00 or glucose level < 40 mg/ml, also indicates the need for drainage 3.
- Patients with complicated parapneumonic effusions or empyema should receive antibiotics and undergo drainage of the pleural space, which can be achieved through therapeutic thoracentesis, tube thoracostomy, or other methods 2, 6, 4, 5.
Management of Complicated Parapneumonic Effusions
- Complicated parapneumonic effusions require prompt intervention, including antibiotics and drainage of the pleural space 2, 6, 4, 5.
- Intrapleural fibrinolytics or thoracoscopy may be necessary for loculated effusions or those that do not respond to initial drainage 6, 4, 5.
- Open surgical intervention may be required in some cases to control pleural sepsis or restore chest mechanics 6, 5.