1. Parapneumonic Effusions and Empyema
Journal Club
Preethi Yeturu and Navneesh Sharma
February 18, 2009

2. Pleural Effusions
Abnormal accumulation of fluid in the pleural space due to a disruption of the equilibrium across pleural membranes
Normal pleural fluid
clear ultrafiltrate of plasma pH
Protein content <2%, WBC <1000
LDH <50% of plasma LDH
Two types
Transudate
Exudate

3. Transudate
Increased capillary hydrostatic pressure or decreased colloid oncotic pressure
Pleural membranes intact
Permiability of capillary membranes normal
Fluid is an ultrafiltrate of plasma
Causes
CHF
Cirrhosis
Nephritic syndrome

4. Exudate
Altered permeability of pleural membranes and capillaries or obstruction of lymphatic drainage of pleural space
Light’s criteria: one or more of following must be present
Pleural fluid/serum protein >0.5
Pleural fluid/serum LDH>0.6
Pleural fluid specific gravity >1.018
Causes
Parapneumonic TB
Malignancy PE

5. Parapneumonic Effusions
Any pleural effusion associated with bacterial pneumonia, lung abscess or bronchiectasis
Most common cause of exudative pleural effusions in US
40-60% of bacterial pneumonias result in pleural effusions
Three types
Uncomplicated parapneumonic effusion
Complicated parapneumonic effusion
Empyema

6. Uncomplicated Effusions
Parenchymal infection leads to increased interstitial fluid that causes accumulation of sterile pleural effusion
Pleural fluid is often small (<10mm)
sterile w/ small amount of PMNs
glucose and pH wnl
Resolve with resolution of pneumonia and treatment w/ antibiotics

7. Complicated Effusions
Persistent bacterial infection of previously sterile pleural fluid
Pleural fluid
Many PMNs, bacteria and cell debris
Acidosis - pH and glucose decrease
LDH increases
Possible deposition of fibrin on pleura - formation of multiple locules

8. Empyema
Characterized by bacteria seen on gram stain or aspiration of pus
60% from complicated parapneumonic effusions
20% after thoracic surgery
Pleural fluid
Possible formation of pleural peel that can encase the lung and hinder reexpansion

9. Clinical Manifestations
History
Acute febrile episode
Dyspnea
Cough - w/ purulent sputum
Pleuritic chest pain
Weight loss
Physical exam
Dullness to percussion
Diminished breath sounds in affected hemithorax
Decreased tactile fremitus
Egophony
Pleuritic friction rub

10. Diagnosis - Imaging CXR
blunting of costrophrenic angle on upright films
Lateral decubitus films - better view of subpulmonic effusions, show if effusion is freely-flowing, thickness of effusion

11. Diagnosis - Imaging CT - w/ IV contrast is optimal
Allow for differentiation betwn parenchymal and pleural disease
Contrast enhances pleural surface

12. Diagnosis Thoracentesis Sample if any of following are present
Free flowing but >10mm in lateral decubitus film
Loculated
Associated w/ thickened parietal pleura on CT - suggests empyema
Complications - pain, bleeding, pneumothorax, puncture of liver or spleen

13. Analysis of Pleural Fluid
Gross examination for color, turbidity and odor
Microbiology - gram stain and cultures
pH or glucose, LDH, protein
CBC w/ differential

14. Analysis of Pleural Fluid
Characteristics of Pleural Fluid
Simple parapneumonic effusion
Complicated parapneumonic effusion
Empyema
Appearance
May be slightly turbid
Cloudy
Pus
Biochemical markers
pH >7.30
pH <7.20
n/a
LDH maybe slightly elevated
LDH >1000 IU/L
Glucose >60 mg/dL or pleural/serum ratio >0.5
Glucose <35 mg/dL
Nucleated cell count
Neutrophils usually <10,000 cells/μL
Neutrophils + + (usually >10,000 cells/μL)
Microbiology: Gram stain
Negative
May be positive
Microbiology: culture

15. Categories risk for poor outcomes
Pleural Space Anatomy
Pleural Fluid Bacteriology
Pleural Fluid Chemistry
Category
Risk of Poor Outcome
Drainage
A0: Minimal, free-flowing effusion (<10 mm on lateral decubitus)
and
Bx: Culture and Gram stain results unknown
Cx: pH, glucose unknown 1
Very low No
A1: Small to moderate free-flowing effusion (>10 mm and <½ hemithorax)
B0: Negative culture and Gram stain
C0: pH ≥ 7.20, glucose > 60 mg/dL 2
Low
A2: Large, free-flowing effusion (≥½ hemithorax), loculated effusion, or effusion with thickened parietal pleura or
B1: Positive culture and Gram stain
C1: pH < 7.20, glucose < 60 mg/dL 3
Moderate
Yes
B2: Pus 4
High

16. Treatment Depends on type and category of effusion
Uncomplicated - category 1 or 2
Resolves w/ antibiotic treatment alone
Does not need drainage
Complicated - category 3
Variable response to antibiotics alone - thus often treated like empyema
Empyema - category 4
Requires complete drainage
Goal of therapy:
Sterilization of cavity - antibiotics for 4-6 weeks
Complete drainage as evidenced by minimal chest tube output and CT documentation that no residual loculations persist
Obliteration of empyema cavity w/ adequate lung expansion

17. Drainage of Effusion Theurapeutic thoracentesis Tube thoracotomy
Often left until rate of drainage <50mL/day and cavity is closed
W/ fibrinolytics - intrapleural administration was suggested for loculated effusions
Reported data does not demonstrate benefit in most pts
Thoracoscopy
Alternative treatment for multiloculated empyema
Open thoracostomy
Open drainage at inferior border of empyema cavity w/ chest tube
Preferred in pts who cannot tolerate thoracotomy

18. Drainage of Effusion Thoracotomy w/ decortication
For pts who require additional drainage after trial of tube thoracostomy and thoracoscopy
Or pt who have fibrin deposition that hinders ability of lung to expand

19. Thank you!!