Pleural effusion

Background

• Exudative
  • Active fluid secretion or leakage w/ high protein content
• Transudative
  • Imbalance between hydrostatic (e.g. CHF) and oncotic (e.g. nephrotic syndrome)
  • Fluid has low protein content

Diagnosis

Detection of exudative pleural effusion

• 99% Sn, 65-85% Sp
  • Pleural fluid/serum protein ratio >0.5 OR
  • Pleural fluid/serum LDH ratio >0.6 OR
  • Pleural fluid LDH > two thirds of upper limit for serum LDH

Exudative Effusion Tests

• Gram stain and culture
• Cell count
  • Neutrophil predominance: parapneumonic, pulmonary embolism, pancreatitis
  • Lymphocytic predominance: cancer, tuberculosis, postcardiac surgery
• Glucose
  • Low glucose seen in parapneumonic, malignant, TB, and RA
• ABG (pH)
  • Normal pleural fluid pH = 7.64;
  • In parapneumonic effusions, <7.10 predicts development of empyema or persistence and indicates need for thoracostomy tube drainage
• Amylase: Elevated in pleural effusions due to pancreatitis or esophageal rupture
• TB
• India ink
• Cytology

Work-Up

Thoracentesis

DDx

Common

1. Transudative
   1. CHF
2. Exudative
   1. Cancer
   2. PNA w/ parapneumonic effusion
   3. PE

Less Common

1. Transudative
   1. Nephrotic syndrome
   2. Cirrhosis
      1. Both via hypoalbuminemia and transdiaphragmatic leakage of ascites
2. Exudative
   1. Viral, fungal, or parasitic infection
   2. SLE, RA
   3. Uremia
   4. Pancreatitis
   5. Amiodarone

Treatment

• Dyspnea at rest
  • Therapeutic thoracentesis w/ max drainage 1-1.5L to avoid reexpansion pulmonary edema
• Empyema
  • Drain w/ large-bore thoracostomy tube
• Parapneumonic Effusion
  • Consider thoracostomy tube drainage if:
  • Comorbid disease
  • Failure to respond to abx tx
  • Anaerobic organisms
  • Pleural fluid pH <7.10
  • Effusion involving >50% of thorax or air-fluid level on CXR
• CHF
  • Diuretic therapy resolves >75% of effusions w/in 2-3d

See Also

Thoracentesis

Source

Tintinalli