Pleural Effusion

Pleural Effusion

David Ray Velez, MD

Table of Contents

Definition
Causes
Pleural Fluid Physiology
Diagnosis
Treatment

Definition

Pleural Effusion Definition: Fluid within the Pleural Space

Types

  • Transudative Pleural Effusion: From Unbalanced Hydrostatic and Osmotic Pressures
    • Results in Smaller Proteins
  • Exudative Pleural Effusion: From Inflammation Increasing Capillary Permeability
    • Results in Larger Proteins

Causes

Transudative Pleural Effusion

  • Congestive Heart Failure (CHF) – The Most Common Transudative Cause
  • Atelectasis
  • Hepatic Hydrothorax
  • Hypoalbuminemia
  • Nephrotic Syndrome

Exudative Pleural Effusion

Pleural Fluid Physiology

Function

  • Serous Fluid
  • Acts as a Lubricant for the Parietal and Visceral Pleura
  • Prevents Adhesion During Respiration

Flow

  • Production: Parietal Circulation (Intercostal Arteries) from Bulk Flow
  • Reabsorption: Lymphatic System
    • Mostly (75%) from Lymphatics of the Parietal Pleura
    • Visceral Pleural Plays No Significant Role in Drainage

The Parietal Pleura is the Primary Determinant of Fluid Turnover

Volume

  • Normal Volume: 10-20 cc
  • Fluid Turnover Ability: 1-2 L/Day
    • Can Increase Up to 40x Normal Rates
    • Requires a Profound Increase in Production or Blockage of Lymphatics to Initiate Fluid Accumulation

Diagnosis

Generally a Radiographic Diagnosis (CXR, CT, or POCUS)

  • Minimum Volume Required to Be Seen on a Standard Upright PA CXR: 300 cc

Differential Evaluation

  • Thoracentesis and Pleural Fluid Evaluation
  • Routine Orders:
    • Cell Count/Differential
    • pH
    • Protein (Pleural and Serum)
    • LDH (Pleural and Serum)
  • Also Consider:
    • Glucose
    • Amylase
    • Cholesterol
    • Triglycerides
    • Bacterial Culture

Light’s Criteria

  • Indicates that the Effusion is Exudative
  • Criteria (Requires ≥ One):
    • Pleural:Serum Protein Ratio > 0.5
    • Pleural:Serum LDH > 0.6
    • Pleural LDH > 2/3 the Upper Limit of Normal

Three-Test Rule

  • Indicates that the Effusion is Exudative
  • Criteria (Requires ≥ One):
    • Pleural Protein > 2.9 g/dL
    • Pleural Cholesterol > 45 mg/dL
    • Pleural LDH > 0.45x the Upper Limit of Normal
  Transudate Exudate
WBC < 1,000 > 1,000
pH 7.40-7.55 7.30-7.45
Pleural:Serum Protein Ratio < 0.5 > 0.5
Pleural:Serum LDH Ratio < 0.6 > 0.6
Cholesterol < 45 mg/dL > 45 mg/dL

Specific Measures

  • Complicated Parapneumonic Effusion/Empyema: WBC > 50,000 and pH < 7.30
  • Chylothorax: Triglycerides > 110 mg/dL

Pleural Effusion 1

Treatment

Treat Any Underlying Disorder

Fluid Drainage

  • Asymptomatic: Generally No Drainage Required
  • Symptomatic: Thoracentesis vs. Thoracostomy Tube (Chest Tube)
    • *See Thoracostomy Tube (Chest Tube)
    • Thoracentesis Improves Oxygenation but No Significant Effect on A-a Gradient, LOS, or Mortality
    • Stop Immediate Drainage if Having Pain or Total Fluid > 1.0-1.5 L
      • At Risk for Re-Expansion Pulmonary Edema When Larger Volumes are Drained
    • If Fails: Thoracoscopic Talc Pleurodesis vs Long-Term Drainage

Malignant Pleural Effusion (MPE): Indications for a Tunneled Pleural Catheter

  • Recurrent Symptomatic Fluid Build-Up
  • Short Life-Expectancy (< 3 Months)
  • Poor Functional Status
  • Trapped Lung
  • Bulky Pleural Metastases
  • Failed Pleurodesis
  • Patient Preference Over Repeated Thoracentesis or Surgical Intervention

References

  1. Rosen Y. Wikimedia Commons. (License: CC BY-SA-2.0)