From the Guidelines
The primary cause of empyema is bacterial pneumonia, with Streptococcus pneumoniae, Staphylococcus aureus, and anaerobic bacteria being the most common culprits, leading to pus accumulation in the pleural space.
Etiology of Empyema
The etiology of empyema is multifactorial, but bacterial pneumonia is the most common cause, responsible for approximately 60-70% of empyema cases 1. Other causes include lung abscess, chest trauma, chest surgery, esophageal rupture, and rarely, hematogenous spread from distant infections.
Common Pathogens
The most common pathogens involved in empyema are:
- Streptococcus pneumoniae
- Staphylococcus aureus
- Anaerobic bacteria These pathogens can lead to the development of empyema, which typically follows a three-stage process: the exudative phase with thin fluid, the fibrinopurulent phase with loculations and thicker fluid, and the organizing phase with thick peel formation 1.
Treatment and Management
Treatment depends on the stage of empyema, but generally involves antibiotics (often broad-spectrum initially, such as a combination of a beta-lactam and metronidazole or clindamycin) and drainage procedures 1. Early empyema may require only antibiotics and thoracentesis, while more advanced cases need chest tube drainage or surgical intervention like video-assisted thoracoscopic surgery (VATS) or thoracotomy with decortication. Prompt diagnosis and treatment are essential to prevent complications such as lung restriction, chronic infection, and respiratory compromise.
Key Considerations
Key considerations in the management of empyema include:
- Prompt antibiotic treatment to cover the most likely organisms
- Drainage procedures to remove pus and fluid from the pleural space
- Surgical intervention for advanced cases or those that do not respond to medical treatment
- Prevention of complications such as lung restriction, chronic infection, and respiratory compromise 1.
From the Research
Etiology of Empyema
The primary cause of empyema is a bacterial infection of the pleural space. The most common microorganisms responsible for empyema include:
- Streptococcus pneumoniae, particularly in children 2
- Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA) 2, 3
- Haemophilus influenzae type b 4
- Streptococcus milleri group 2
- Anaerobic bacteria, such as pigmented Prevotella and Porphyromonas species, Bacteroides fragilis group, and Fusobacterium species, often associated with aspiration pneumonia and lung abscesses 5
Risk Factors and Epidemiology
The incidence of empyema has been increasing worldwide, affecting both children and adults, particularly healthy young adults and older patients 2. The use of the pneumococcal conjugate vaccine has led to a replacement phenomenon, with the emergence of new pneumococcal serotypes and an increase in MRSA cases 2, 3.
Clinical Presentation and Management
Empyema can be treated with antibiotics and chest tube drainage, but early drainage with or without intrapleural fibrinolytics is often required 6. In some cases, surgical decortication or video-assisted thoracic surgery (VATS) may be necessary 6, 3. The clinical course and management of empyema depend on various factors, including the causative microorganism, patient age, and underlying health conditions.