🫁 Empyema Thoracis
(AKA: Pyothorax – pus in pleural space)
🔍 Definition:
Empyema is a collection of pus in the pleural cavity, usually resulting from infection of the pleural space due to parapneumonic effusion, trauma, surgery, or rupture of pulmonary infections.
📚 Etiology:
|
Source |
Examples |
|
Parapneumonic |
Pneumonia, lung abscess |
|
Post-surgical |
Thoracic surgery, esophageal perforation |
|
Post-traumatic |
Penetrating chest injury, hemothorax |
|
Iatrogenic |
Thoracentesis, chest tube, central lines |
|
Others |
Tuberculosis, subdiaphragmatic abscess rupture |
🦠 Microbiology:
- Community-acquired:
- Streptococcus pneumoniae, Staphylococcus aureus, anaerobes, Haemophilus influenzae
- Hospital-acquired / post-op:
- Pseudomonas, Enterobacteriaceae, MRSA, VRE
- Tubercular empyema: Mycobacterium tuberculosis
🧬 Pathophysiology – 3 Stages of Empyema:
|
Stage |
Features |
|
1. Exudative |
Thin fluid, low cellularity; mostly neutrophils and proteins |
|
2. Fibrinopurulent |
Loculated fluid, ↑ LDH, ↓ glucose, ↑ neutrophils, fibrin deposits |
|
3. Organizing |
Thick pleural peel, fibroblast proliferation → trapped lung |
🧪 Clinical Features:
- Fever with chills
- Pleuritic chest pain
- Cough with or without sputum
- Dyspnea
- Decreased breath sounds and dullness to percussion
- Cachexia in chronic cases
🔬 Investigations:
1. Imaging
|
Modality |
Findings |
|
Chest X-ray |
Blunting of costophrenic angle, opacification |
|
Ultrasound (USG) |
Loculated fluid, septations (high sensitivity) |
|
CT Thorax |
Best for defining loculations, pleural thickening |
2. Thoracocentesis and Pleural Fluid Analysis
|
Parameter |
Empyema Findings |
|
Appearance |
Thick, purulent fluid |
|
pH |
< 7.2 (acidic) |
|
Glucose |
< 40 mg/dL (low) |
|
LDH |
> 1000 IU/L or >3x serum LDH |
|
Gram stain / Culture |
Positive in ~60%, always send anaerobic culture |
|
Cell count |
Neutrophil predominance |
|
ADA |
High in tubercular empyema |
🧑⚕️ Management
🧪 A. Medical Management
- Empiric antibiotics → tailored to culture
- Community-acquired: Ceftriaxone + clindamycin or metronidazole
- Hospital-acquired: Piperacillin-tazobactam or meropenem ± vancomycin
- Duration: 3–6 weeks total (IV ± oral)
- Anti-TB therapy for tubercular empyema
💉 B. Drainage
- Intercostal chest tube (pigtail or wide bore) under USG/CT guidance
- Exudative stage: simple tube drainage often sufficient
- Fibrinopurulent: may need fibrinolytics (e.g., tPA + DNase)
🛠️ C. Surgery
Indicated if:
- Loculated empyema not resolving
- Thick pleural peel with lung entrapment
- Persistent fever & sepsis despite drainage
Surgical Options:
|
Procedure |
Indication |
|
VATS |
Early loculated empyema |
|
Open decortication |
Chronic, organizing stage with trapped lung |
|
Thoracotomy |
Large collection, failed less invasive methods |
⚠️ Complications
- Bronchopleural fistula
- Trapped lung (non-expandable)
- Fibrothorax
- Sepsis and multi-organ failure
- Empyema necessitans (chest wall extension)
🧠 Key ICU Considerations
- Early diagnosis via USG-guided thoracentesis
- Monitor oxygenation and signs of respiratory compromise
- Avoid blind chest tube placement
- Use fibrinolytics in multiloculated effusions
- Daily chest tube monitoring (drainage amount, air leak, position)
📊 Empyema vs Parapneumonic Effusion (Comparison)
|
Parameter |
Parapneumonic Effusion |
Empyema |
|
Appearance |
Clear, straw-colored |
Purulent |
|
Glucose |
>60 mg/dL |
<40 mg/dL |
|
pH |
>7.2 |
<7.2 |
|
LDH |
Mildly elevated |
>1000 IU/L or >3x serum |
|
Culture |
Usually negative |
Often positive |
|
Management |
Antibiotics ± drainage |
Mandatory drainage + antibiotics |