Empyema

Empyema — pus within the pleural space — is most commonly a complication of pneumonia (parapneumonic effusion progressing through exudative → fibrinopurulent → organized stages). Overall mortality is approximately 20%, rising to >30% in patients over 65 and 47% in hospital-acquired cases. [1-2] Incidence is rising, and delays in drainage are associated with substantially higher mortality. [2]

1. History

• Duration and progression of respiratory symptoms: cough, fever, dyspnea, pleuritic chest pain, sputum production
• Preceding pneumonia or recent respiratory illness — parapneumonic effusions occur in 20–57% of pneumonia cases, progressing to empyema in 5–10% [1-2]
• Timing of antibiotic initiation relative to symptom onset
• Recent thoracic surgery, trauma, or procedures (risk for hospital-acquired empyema) [3-4]
• Aspiration risk factors: alcohol use, altered consciousness, dysphagia, poor dentition (anaerobic organisms)
• Important: elderly patients often present atypically — with anemia, fatigue, and failure to thrive rather than classic cough/fever/chest pain [2]

2. Alarm Features

• Sepsis or septic shock: tachycardia, hypotension, altered mental status, high lactate
• Rapidly enlarging effusion or tension physiology (mediastinal shift, tracheal deviation)
• Failure to improve on appropriate antibiotics within 48–72 hours
• Frank purulence on thoracentesis
• Hospital-acquired infection (mortality 47% vs. 17% for community-acquired) [2]
• RAPID score 5–7 (≥30% 12-week mortality) — warrants more aggressive initial therapy [2]

3. Medications

• Community-acquired empyema: [5]
  • Ceftriaxone + metronidazole, OR
  • Ampicillin/sulbactam (covers anaerobes without additional agent)
  • Clindamycin is an alternative to metronidazole for anaerobic coverage
• Hospital-acquired/post-procedural empyema: [5]
  • Vancomycin + cefepime + metronidazole, OR
  • Vancomycin + piperacillin/tazobactam
  • Meropenem + vancomycin if ESBL-producing organisms suspected
• Continue anaerobic coverage even with negative anaerobic cultures (difficult to culture) [5]
• Aminoglycosides are NOT recommended — inactivated in acidic empyema fluid and have poor pleural penetration [5-6]
• No role for intrapleural antibiotic administration [3][5]
• Do not delay antibiotics for pleural analysis unless the patient is clinically stable with an indolent infection [7]
• Intrapleural fibrinolytics: tPA 10 mg + DNase 5 mg (twice daily × 3 days = 6 doses) for loculated/complicated collections [2][6]

4. Diet

• Nutritional optimization is critical — all patients should receive adequate nutrition [2]
• Albumin <2.7 g/dL is a component of the RAPID prognostic score and predicts poor outcomes [2]
• Ensure adequate caloric and protein intake during prolonged hospitalization
• No specific dietary triggers; focus on preventing malnutrition in the setting of catabolic sepsis

5. Review of Systems

• Pulmonary: cough, dyspnea, pleuritic chest pain, hemoptysis, sputum character
• Constitutional: fever, chills, rigors, night sweats, weight loss, fatigue
• GI: dysphagia, vomiting (aspiration risk), abdominal pain (subdiaphragmatic abscess)
• Musculoskeletal: chest wall tenderness
• Hematologic: anemia symptoms (especially in elderly with atypical presentation)
• Screen for immunocompromise: HIV risk factors, steroid use, diabetes, malignancy

6. Collateral History and Family History

• Confirm antibiotic use prior to presentation (may alter pleural fluid characteristics — can convert neutrophilic to lymphocyte-predominant fluid) [6]
• Recent hospitalizations, surgeries, or invasive procedures
• Functional status and surgical candidacy (critical for treatment planning)
• Substance use: alcohol (aspiration risk), IV drug use (endocarditis → septic emboli)
• No significant hereditary predisposition, but immunodeficiency states increase risk

7. Risk Factors

• Pneumonia (most common antecedent) [2]
• Age >65 years [1-2]
• Diabetes mellitus, chronic liver disease, chronic kidney disease
• Immunosuppression (HIV, chemotherapy, chronic steroids)
• Alcohol use disorder and aspiration risk
• Poor dentition (anaerobic flora)
• Recent thoracic surgery or trauma (32.8% cumulative incidence in trauma patients) [3]
• Prolonged ICU stay (up to 62% of ICU pneumonia patients develop parapneumonic effusions) [7]
• GERD, esophageal disease

8. Differential Diagnosis

• Complicated parapneumonic effusion (CPPE) — the distinction from empyema is the presence of frank pus; management overlaps significantly [4]
• Lung abscess — may coexist; look for air-fluid level within parenchyma
• Malignant pleural effusion — lymphocyte-predominant, cytology positive in ~60%
• Tuberculous pleurisy — lymphocyte-predominant, elevated ADA (>40 U/L), consider in endemic areas [8]
• Chylothorax — milky fluid, elevated triglycerides
• Hemothorax — bloody fluid, hematocrit >50% of peripheral blood
• Subdiaphragmatic abscess with sympathetic effusion
• Esophageal rupture (Boerhaave syndrome) — low pH, high amylase, salivary origin

9. Past Medical History

• Prior pneumonia episodes or pleural infections
• Previous thoracic surgery or chest tube placement
• History of lung resection (risk for bronchopleural fistula and post-pneumonectomy empyema) [6]
• Chronic lung disease (COPD, bronchiectasis)
• Malignancy (especially lung, breast, lymphoma)
• Immunosuppressive conditions or medications

10. Physical Exam

• Vitals: fever, tachycardia, tachypnea, hypoxia; hypotension suggests sepsis
• Inspection: splinting, decreased chest wall movement on affected side
• Percussion: stony dullness over the effusion
• Auscultation: decreased or absent breath sounds; bronchial breathing at the upper border of the effusion; decreased tactile fremitus
• Palpation: tracheal deviation away from the affected side (large effusion)
• Signs of sepsis: altered mental status, mottled skin, delayed capillary refill
• Assess for subcutaneous emphysema (bronchopleural fistula)
• Examine dentition (source of anaerobic organisms)

11. Lab Studies

• Pleural fluid analysis (cornerstone of diagnosis): [5-6]
  • pH <7.2 → most important predictor of need for drainage
  • Glucose <40 mg/dL
  • LDH >1000 IU/L
  • Gram stain and culture (inoculate aerobic AND anaerobic blood culture bottles at bedside — increases yield) [5]
  • Cell count with differential (neutrophil predominant)
  • Protein, LDH for Light's criteria (exudate confirmation)
  • Frank pus = empyema by definition — no need to check pH [7]
• Serum labs: CBC, BMP (renal function for RAPID score), lactate, blood cultures, albumin (<2.7 g/dL = poor prognosis), CRP, procalcitonin
• Serum CRP >200 mg/L combined with pleural glucose <60 mg/dL has 98% specificity for complicated effusion [6]
• Culture sensitivity is only ~56%; bedside inoculation of blood culture bottles improves yield [7]

12. Imaging

• Point-of-care ultrasound (POCUS) — first-line and superior to CT for detecting septations and loculations [6-7]
  • Echogenic swirling fluid suggests pus
  • Septations/loculations indicate complicated effusion
  • Anechoic fluid does NOT rule out culture-positive effusion [7]
  • Positive likelihood ratio of 6.92 for CPPE (vs. 2.20 for CT) [6]
• Chest X-ray: costophrenic angle blunting; lateral decubitus film to assess free-flowing vs. loculated fluid
• Contrast-enhanced CT (venous/pleural phase): indicated when sepsis persists >48 hours after drainage [6]
  • "Split pleura" sign — enhancement of both visceral and parietal pleura
  • Thickened parietal pleura, increased extrapleural fat attenuation
  • Gas bubbles within the effusion (anaerobic organisms)
  • Evaluates for malpositioned chest tubes, lung abscess, subdiaphragmatic abscess, bronchopleural fistula
• MRI: no established role in adults; may be considered in pediatrics as radiation-free alternative [6]

13. Special Tests

• RAPID Score (Renal function, Age, Purulence, Infection source, Dietary/albumin) — scores 0–7; score 5–7 = high risk (≥30% 12-week mortality) [2]
• Light's Criteria — confirms exudative effusion (pleural/serum protein >0.5, pleural/serum LDH >0.6, or pleural LDH > two-thirds upper limit of normal) [7]
• Bedside thoracentesis — diagnostic and therapeutic; use ultrasound guidance
• Adenosine deaminase (ADA) — if TB is suspected (sensitivity ≥79%, specificity ≥83%) [8]
• Pleural fluid CRP >100 mg/L has comparable discriminative value to pH and glucose for CPPE [6]

The following figure from the NEJM illustrates a practical management algorithm for parapneumonic effusions and empyema:

14. ECG

• Not a primary diagnostic tool for empyema
• Obtain to evaluate for tachycardia, atrial fibrillation (common in sepsis), or signs of right heart strain
• Rule out pericarditis if chest pain is diffuse or positional (diffuse ST elevation, PR depression)
• Large left-sided effusions may cause low voltage or electrical alternans

15. Assessment

Empyema progresses through three stages: [4]

• Stage I (Exudative): free-flowing sterile exudate; may resolve with antibiotics alone
• Stage II (Fibrinopurulent): bacterial invasion, fibrin deposition, septations/loculations, pH <7.2 — requires drainage
• Stage III (Organized): fibroblast proliferation, pleural peel ("rind") formation — often requires surgical decortication

Key prognostic factors: hospital-acquired source, advanced age, renal impairment, hypoalbuminemia, and delayed drainage all predict worse outcomes. [2] Mortality approaches 20% overall and is substantially higher with treatment delays. [2]

16. Treatment Plan

All patients: [2]

• Appropriate IV antibiotics (do not delay)
• DVT prophylaxis
• Adequate nutrition
• Peripheral blood cultures

Drainage strategy (stepwise escalation): [2][6][9]

• Small-bore chest tube (14-French pigtail catheter preferred; avoid <12-French due to higher failure rate) [2]
• Intrapleural tPA + DNase if inadequate drainage: tPA 10 mg + DNase 5 mg, administered sequentially or concurrently, twice daily × 3 days (6 doses total) [2][6][9]
  • Associated with 60% reduction in pleural fluid on imaging
  • Does NOT reduce mortality but reduces surgical referral and hospital stay [2]
• VATS decortication — if medical management fails or patient is a good surgical candidate [6]
  • Success rates 82–92%; hospital stay 5–7 days
  • Early VATS (within 10 days of presentation) associated with better outcomes [6]
  • Surgical referral should be considered at day 3 post-chest tube if ongoing sepsis, radiological persistence, or clinical deterioration [6]
• Open thoracotomy — reserved for VATS failure or late-stage disease; higher morbidity and mortality (3.7% vs. 2.8% for VATS) [6]

Antibiotic duration: typically 2–4 weeks; guided by clinical response, inflammatory markers, and imaging

17. Disposition

• All confirmed empyema cases require hospital admission — this is not an outpatient diagnosis [2]
• ICU admission: sepsis/septic shock, hemodynamic instability, respiratory failure requiring mechanical ventilation
• Surgical consultation triggers: [6]
  • Failure to improve after 48–72 hours of antibiotics + drainage
  • Persistent sepsis at day 3 post-chest tube
  • Organized/loculated collection not amenable to tube drainage
  • Failed tPA/DNase therapy
• Discharge criteria: afebrile, improving inflammatory markers, chest tube removed (output minimal), tolerating oral antibiotics, adequate nutrition
• Mean hospital stay: ~12 days with tPA/DNase; ~5–7 days with early VATS [2]

18. Follow Up / Return Precautions

• Follow-up imaging (chest X-ray or ultrasound) at 4–6 weeks post-discharge to assess for residual collection, trapped lung, or pleural thickening [3]
• Pulmonary function monitoring after discharge, especially post-surgical patients [3]
• Transition to oral antibiotics guided by culture sensitivities; complete full antibiotic course
• Return precautions: recurrent fever, worsening dyspnea, chest pain, purulent sputum, hemoptysis
• Consider repeat imaging sooner if symptoms recur
• Nutritional rehabilitation — ensure albumin recovery
• Patients with RAPID score 5–7 warrant closer follow-up given ≥30% 12-week mortality risk [2]
• Long-term: most patients recover well with early treatment; residual pleural thickening is common but usually does not impair function significantly

References

1. Intra-Pleural Fibrinolytic Therapy Versus Placebo, or a Different Fibrinolytic Agent, in the Treatment of Adult Parapneumonic Effusions and Empyema. — Altmann ES, Crossingham I, Wilson S, Davies HR. The Cochrane Database of Systematic Reviews. 2019.

2. Pleural Disease. — Feller-Kopman D, Light R. The New England Journal of Medicine. 2018.

3. Thoracic Trauma WSES-AAST Guidelines. — Coccolini F, Cremonini C, Moore EE, et al. World Journal of Emergency Surgery : WJES. 2025.

4. Surgical Versus Non-Surgical Management for Pleural Empyema. — Redden MD, Chin TY, van Driel ML. The Cochrane Database of Systematic Reviews. 2017.

5. The American Association for Thoracic Surgery Consensus Guidelines for the Management of Empyema. — Shen KR, Bribriesco A, Crabtree T, et al. The Journal of Thoracic and Cardiovascular Surgery. 2017.

6. ERS/­ESTS Statement on the Management of Pleural Infection in Adults. — Bedawi EO, Ricciardi S, Hassan M, et al. The European Respiratory Journal. 2023.

7. Pleural Effusion: Diagnostic Approach in Adults. — Shen-Wagner J, Gamble C, MacGilvray P. American Family Physician. 2023.

8. Guide to Utilization of the Microbiology Laboratory for Diagnosis of Infectious Diseases: 2024 Update by the Infectious Diseases Society of America (IDSA) and the American Society for Microbiology (ASM). — Miller JM, Binnicker MJ, Campbell S, et al. Clinical Infectious Diseases : An Official Publication of the Infectious Diseases Society of America. 2024.

9. Comprehensive Review of Chest Tube Management: A Review. — Anderson D, Chen SA, Godoy LA, Brown LM, Cooke DT. JAMA Surgery. 2022.