Pulmonology & Thoracic Surgery & Infectiology
Empyème pleural | Clinique Omicron Québec
Pleural empyema - also known as purulent pleurisy or pyothorax - is defined as the presence of frank pus in the pleural space, resulting from direct bacterial infection of the pleural cavity or suppurative transformation of an initially sterile parapneumonic pleural effusion. It is a serious and potentially fatal complication of bacterial pneumonia (the most frequent cause - 40 to 60 % of cases), but can also occur after thoracic surgery, penetrating thoracic trauma, pleural puncture or bronchoscopy, esophageal rupture, or by contiguity from a subphrenic or hepatic abscess (empyema with abdominal origin). The pathophysiology of parapneumonic empyema classically evolves according to three stages described by the American Thoracic Society (ATS): the exudative stage (stage I - simple parapneumonic effusion - clear or slightly cloudy, sterile fluid, low viscosity, pH >7.2, glucose >2.2 mmol/L, LDH <1,000 IU/L - drainage not mandatory if small volume) ; fibrinopurulent stage (stage II - bacterial invasion of pleural fluid → fibrin deposition → progressive partitioning - pH <7.2, glucose 1,000 IU/L, bacteria present - drainage obligatory ± intrapleural fibrinoly); and organized stage (stage III - encysted empyema - formation of a thick fibrous shell trapping the lung - surgical decortication often necessary). The incidence of pleural empyema is estimated at 3 to 4 cases per 100,000 inhabitants per year, with a hospital mortality of 10 to 20 % despite adequate treatment, reaching 30 to 40 % in immunocompromised or elderly patients.
Clinical Presentation, Microbiology, and Evaluation
- Clinical Presentation: Context of bacterial pneumonia not responding to antibiotics after 48 to 72 hours (persistent fever + clinical deterioration despite antibiotic therapy); persistent or recurrent fever + chills + general deterioration; pleuritic chest pain (lateral, increased on inspiration); progressive dyspnea (pulmonary compression by effusion); dry or productive cough; on physical examination: dullness to percussion + absence of vesicular breath sounds + decreased vocal fremitus on the affected side; underlying consolidation (if concomitant pneumonia); in the immunocompromised patient: attenuated presentation, low-grade fever, poor general condition without frank septic presentation
- Microbiology — causative agents: community-acquired empyema (post-pneumonia): Streptococcus pneumoniae (most frequent — 20-30% %— especially in children) + Streptococcus anginosus group (S. anginosus, S. intermedius, S. constellatus — strong tendency to form abscesses and empyemas — 15-20% %) + Staphylococcus aureus (MSSA and MRSA — especially post-influenza or necrotizing pneumonia) + anaerobic bacteria (Peptostreptococcus, Fusobacterium, Bacteroides — empyemas from pulmonary source by aspiration — alcoholism, dysphagia) + Gram-negative bacteria (Klebsiella pneumoniae — especially diabetics and alcoholics, Haemophilus influenzae, Pseudomonas); healthcare-associated empyema (post-surgical or post-procedure): S. aureus MRSA + multidrug-resistant Gram-negatives (Pseudomonas, Enterobacter, Klebsiella) + anaerobes; fungal empyema (Candida, Aspergillus): immunocompromised — rare but serious; Mycobacterium tuberculosis: tuberculous empyema — high prevalence countries or immunocompromised
- Risk factors: undertreated or late-diagnosed bacterial pneumonia; diabetes mellitus (risk multiplied by 3 to 4); alcoholism; immunosuppression (HIV, chemotherapy, long-term corticosteroid therapy); chronic kidney failure; swallowing disorders and gastroesophageal reflux (aspiration → anaerobes); recent thoracic or abdominal surgery; thoracic trauma; recent pleural procedures (thoracentesis, pleural biopsy)
- Initial Assessment and RAPID Classification RAPID score (Rahman 2014 Chest) — empyema prognostic score — 5 variables: Renal function (urea — 0–2 pts) + Age (0–1 pt) + Purulence (gross appearance — 0 or 1 pt) + Infection source (community-acquired vs. nosocomial — 0 or 1 pt) + Dietary factors (albumin — 0–1 pt); total score 0–7: low RAPID (0–2 — mortality 1–2 %) / moderate (3–4 — mortality 10 %) / high (5–7 — mortality 30 %— discuss immediate surgery); Light's criteria for exudate: pleural fluid LDH/serum LDH >0.6 OR pleural fluid protein/serum protein >0.5 OR pleural fluid LDH >2/3 upper limit of normal serum — all empyemas are exudates
Diagnosis and treatment
| Appearance / Treatment | Mechanism, technique and procedures | Indications, results, and precautions |
|---|---|---|
| Imaging — Thoracic CT scan and ultrasound Essential evaluation before drainage |
Thoracic X-ray (PSA): unilateral pleural effusion ± concomitant parenchymal opacity (pneumonia) ± hydroaeroid level (bronchopleural fistula or gas-producing germ); chest CT scan with injection (reference examination): characterizes effusion (free or partitioned - spontaneous hyperdensity of purulent fluid - density >20 HU suggestive), thickens parietal and visceral pleura (split pleura sign - enhancement of both pleural sheets after injection - very specific for empyema, sensitivity 68 %, specificity 92 %), detects fibrinous partitions (cloisonnement), identifies underlying compressed but viable lung parenchyma, guides choice of drainage site, detects a bronchopleural fistula (hydro-aeric level in the empyema); pleural ultrasound (in patient's bed): detects effusion + assesses echogenicity (free anechogenic vs. partitioned hyperechogenic fluid) + guides diagnostic and therapeutic thoracentesis in real time (reduced risk of iatrogenic pneumothorax - British Thoracic Society 2022) | Thoracic CT is essential before any decision for surgical drainage or fibrinolysis — it allows mapping the empyema, identifying septations, assessing predictable lung expansion, and planning the surgical approach (VATS); pleural ultrasound at the patient's bedside is systematically recommended before any thoracentesis (BTS 2022) — it guides the puncture site + reduces complications (iatrogenic pneumothorax from 2-4 % to <1 % with ultrasound guidance); the «split pleura sign» on CT is the most specific radiological sign to differentiate empyema from a peripheral lung abscess (in an abscess, the wall is thick and the lung does not open upon drainage). |
| Pleural fluid analysis — diagnostic thoracentesis Key diagnostic step before antibiotic therapy |
Ultrasound-guided diagnostic thoracentesis: collection of 20 to 50 mL of pleural fluid for complete analysis — macroscopic (appearance: frank pus — thick yellow or greenish → definite empyema; cloudy → infected exudate) + biochemistry (pH — measured on heparinized tube in blood gas analyzer — glucose — LDH — proteins — amylase if pancreatitis suspected) + cytology (cell count — neutrophils >80 % → bacterial infection) + bacteriology (aerobic + anaerobic culture + Gram stain + mycobacteriology if tuberculosis suspected + fungi if immunocompromised) — collection in blood culture bottles (aerobic + anaerobic) → increases bacteriological yield by 20 to 30 %; criteria for complicated pleural effusion requiring drainage: macroscopic pus OR pH <7.2 OR glucose <2.2 mmol/L OR positive culture/Gram stain OR significant ultrasonographic loculation (BTS 2010 and 2022) | Pleural fluid pH (<7.2) is the most important biochemical criterion for deciding on drainage — never measure on an EDTA tube (false results) — use a heparinized tube and analyze immediately on a blood gas analyzer; pleural fluid pH <7.0 is associated with a high risk of progression to organized empyema and predicts a poor prognosis without early drainage; the macroscopic appearance of frank pus is sufficient on its own to diagnose empyema and decide on drainage without waiting for bacteriological results; pleural cultures are negative in 30 to 40 % of empyemas (prior antibiotic therapy, inadequate collection technique, anaerobes difficult to culture) → the diagnosis remains clinical and biochemical if culture is negative |
| Empirical and targeted antibiotic therapy Start before culture results |
Empirical IV antibiotic therapy to be started as soon as diagnosis is made (after microbiological sampling): community-acquired empyema (stage I-II): amoxicillin-clavulanate 2.2 g IV x 3/day (covers Gram-positive + anaerobes + H. influenzae) OR ceftriaxone 2 g IV x 1/day + metronidazole 500 mg IV x 3/day if penicillin allergy; severe community-acquired empyema or suspected MRSA (necrotizing pneumonia, post-influenza): vancomycin 25-30 mg/kg/day IV by continuous infusion (target area under the curve AUC/MIC 400-600) + piperacillin-tazobactam 4.5 g IV x 4/day (or meropenem 1 g x 3/day if Pseudomonas suspected); nosocomial empyema (post-surgical): vancomycin + meropenem (broad coverage for Gram-negative + MRSA); adjustment to antibiogram as soon as results are available; total duration: 4 to 6 weeks minimum (often 3 to 4 weeks IV then oral switch if good drainage) - duration guided by clinical and biological response | Antibiotics alone (without drainage) are insufficient to treat stage II–III empyema—antibiotic penetration into thick pus is poor, and the acidic environment (pH <7) inactivates aminoglycosides and reduces the efficacy of many beta-lactams; fluoroquinolones (ciprofloxacin, levofloxacin) have good pleural penetration but their spectrum is insufficient against anaerobes and streptococci—do not use as monotherapy; oral switch is possible after 5 to 7 days IV if fever resolves + oral tolerance + good drainage—amoxicillin-clavulanate 875/125 mg × 3/day PO for community-acquired empyemas due to pneumococcus or streptococcus; oral linezolid (600 mg × 2/day): good pleural penetration—option for oral switch if MRSA or enterococcus |
| Pleural drainage and intrapleural fibrinolysis MIST2 — tPA + DNase — Stage II standard treatment |
Chest tube (tube thoracostomy): small caliber 10–14 Fr drain (ultrasound-guided Seldinger catheter) sufficient for non-loculated, free-flowing fluid empyemas — large caliber 20–28 Fr drain if thick pus or bronchopleural fistula — gravity drainage or gentle suction (−10 to −20 cmH₂O); Intrapleural fibrinolysis (MIST2 — Rahman 2011 NEJM): indication if loculated empyema or inadequate drainage after 24–72h (thick fluid, pH <7.0, loculations seen on ultrasound); MIST2 protocol: alteplase (tPA) 10 mg + DNase (dornase alpha — Pulmozyme) 5 mg in separated intrapleural instillations × 2/d × 3 days (6 doses of each) — tPA lyses fibrin (destroys loculations) + DNase degrades neutrophil DNA (reduces pus viscosity) → liquefaction of loculated pus → easier drainage; MIST2 results: reduced drainage duration from 5 to 3 days + reduced rescue surgeries from 34% to 16% at 3 months vs placebo % | Availability in Quebec: alteplase (Activase) reimbursed by RAMQ for empyema since MIST2 data — DNase (Pulmozyme) reimbursed for cystic fibrosis, off-label use for empyema (compassionate prescription — usually accepted in hospitals); monitoring with drainage + fibrinolysis: daily drained volume + fluid appearance + fever + follow-up CT scan on days 3-5 to assess response; drainage success criteria: >200 mL/day of drained fluid + clinical improvement (resolving fever, improved dyspnea) + lung expansion on radiological imaging; drainage failure criteria → surgery: insufficient drainage after 5–7 days of fibrinolysis + thick pleural peel visible on CT scan + trapped lung not re-expanded |
| Thoracic Surgery — VATS and Decortication Stage III empyema or failure of medical drainage |
VATS (video-assisted thoracoscopic surgery): gold-standard surgical treatment - resection of fibrinous septa + evacuation of pus + cleaning of pleural cavity under direct vision + placement of drains in optimal position; indications: stage II empyema resistant to intrapleural fibrinolysis (dense, unlysed septa) + early stage III empyema (soft shell still resectable by VATS) + post-surgical empyema + empyema of complex onset (high RAPID score); open thoracic decortication (thoracotomy): resection of the thick fibrous shell trapping the lung (established stage III) - heavier procedure - reserved for chronic organized empyema where VATS is impossible - significant morbidity (bleeding, bronchopleural fistula, insufficient re-expansion); open drainage (Eloesser thoracostomy - window thoracostomy): reserved for patients too fragile for formal surgery + chronic empyema with associated bronchopleural fistula. | Early VATS (within 7 to 14 days of diagnosis) yields better results than late decortication—the fibrous tissue is still soft and resectable; VATS mortality for empyema is 2 to 5 % in experienced centers vs 10 to 15 % for open decortication thoracotomy (Wurnig 2006 EJCTS); hospital stay after VATS: 7 to 14 days on average vs 14 to 21 days after thoracotomy; discharge criteria after surgery: drain removed (flow <100 mL/day + absence of air leak) + fever resolved + radiologically confirmed lung reexpansion + oral antibiotic step-down; postoperative respiratory rehabilitation recommended (respiratory physiotherapy + incentive spirometry) |
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Bronchopleural fistula — a dreaded complication: Bronchopleural fistula (BPF) is an abnormal communication between the bronchial tree and the pleural space, which can complicate empyema (erosion of the bronchial wall by pus) or result from pulmonary resection surgery (defect on the bronchial stump). It manifests as the appearance of a hydro-aeric level in the empyema on CT scan, worsening dyspnea, increased purulent productive cough, and persistent air leak in the drain. Diagnosis is confirmed by bronchoscopy. Management is surgical (fistula closure ± muscle flap plasty) combined with prolonged surgical drainage. The mortality rate for post-pneumonectomy BPF is 30 to 50%. In any patient with a pleural drain presenting with a persistent air leak, BPF should be suspected and a bronchoscopy performed.
Emergency - Tension Sepsis and Empyema
Dial 911 you should seek emergency care immediately if a patient with pneumonia develops: persistent fever >48–72h under antibiotics worsening dyspnea + unilateral dullness → parapneumonic empyema to exclude urgently (CT scan + thoracentesis). .
Signs of severe sepsis on empyema (qSOFA criteria: respiratory rate >22/min + disturbance of consciousness + SBP (<100 mmHg) → IV fluid resuscitation + broad-spectrum antibiotics + emergency drainage — high mortality without rapid intervention.
Tension empyema (hydro-aeric level + mediastinal deviation + acute respiratory distress) → immediate emergency drainage.
Consult at Clinique Omicron
Clinique Omicron physicians provide post-hospitalization follow-up for patients treated for pleural empyema, including clinical and radiological monitoring, oral antibiotic adjustment, surveillance for lung re-expansion, and referral to thoracic surgery or pneumology if the condition worsens. Patients with pneumonia who do not improve with treatment are referred to the emergency department for complication assessment. Consultations are available at our service points in Quebec and via telemedicine. To make an appointment, visit cliniqueomicron.ca.
The content of this page is for informational purposes only and does not replace the advice of a qualified healthcare professional. Pleural empyema is a medical and surgical emergency requiring prompt hospitalization, drainage, and appropriate antibiotic therapy.
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