Should paracentesis be performed for parapneumonic effusion?

Management of Parapneumonic Effusions

Thoracocentesis should be performed for parapneumonic effusions that are moderate to large in size, or when there are signs of infection or respiratory compromise. 1

Diagnostic Approach

• Ultrasound must be used to confirm the presence of pleural fluid collection in suspected parapneumonic effusion 1
• Blood cultures should be performed in all patients with parapneumonic effusion 1
• When available, sputum should be sent for bacterial culture 1

Pleural Fluid Analysis

• Pleural fluid must be sent for microbiological analysis including Gram stain and bacterial culture 1
• Aspirated pleural fluid should be sent for differential cell count 1
• Tuberculosis and malignancy must be excluded in the presence of pleural lymphocytosis 1
• If there is any indication the effusion is not secondary to infection, consider an initial small volume diagnostic tap for cytological analysis 1

Decision Algorithm for Management

Step 1: Assess Size and Characteristics of Effusion

• Small effusions (<10 mm rim of fluid on lateral decubitus or less than one-fourth of the hemithorax opacified):

  • Usually resolve with antibiotic therapy alone 1
  • No drainage typically required 1, 2

• Moderate to large effusions (>one-fourth of hemithorax opacified):

  • More likely to cause respiratory compromise 1
  • Often benefit from drainage 1, 3

Step 2: Evaluate Pleural Fluid Characteristics

• Indications for drainage:
  • Purulent fluid (empyema) 2
  • pH < 7.20 2, 3
  • Glucose < 60 mg/dL 3
  • LDH > 3 times upper normal limit for serum 3
  • Positive Gram stain or culture 3
  • Loculated effusion 2
  • Effusion occupying more than 50% of hemithorax 3

Step 3: Management Based on Assessment

• For uncomplicated, small effusions:

  • Antibiotics alone are usually sufficient 1, 4
  • Monitor for clinical improvement 5

• For moderate risk effusions:

  • Perform therapeutic thoracentesis 3, 5
  • If fluid reaccumulates but patient is clinically improving and fluid parameters are favorable (pH > 7.2, glucose > 60 mg/dL), observation may be appropriate 5

• For complicated effusions/empyema:

  • If a child has significant pleural infection, a drain should be inserted at the outset 1
  • Repeated taps are not recommended for significant pleural infections in children 1
  • In adults with complicated parapneumonic effusions, repeated therapeutic thoracentesis (RTT) may be considered as a first-line approach with success rates of up to 81% 6

Antibiotic Management

• All cases should be treated with intravenous antibiotics 1
• Coverage must include Streptococcus pneumoniae 1
• Broader spectrum coverage is required for hospital-acquired infections, as well as those secondary to surgery, trauma, and aspiration 1
• Where possible, antibiotic choice should be guided by microbiology results 1

Important Considerations and Pitfalls

• Timing is critical: Effusions which are enlarging and/or compromising respiratory function should not be managed by antibiotics alone 1
• Avoid delayed intervention: Early active treatment should be considered as conservative treatment can result in prolonged duration of illness and hospital stay 1
• Ultrasound guidance: Always use ultrasound to guide thoracentesis or drain placement to reduce complications 1
• Chest CT limitations: Chest CT scans should not be performed routinely for parapneumonic effusions 1
• Procedure safety: Chest drains should be inserted by adequately trained personnel to reduce the risk of complications 1
• Monitoring for failure: If a patient remains pyrexial or unwell 48 hours after admission for pneumonia, parapneumonic effusion/empyema must be excluded 1