Empyema

Infected pleural space — complicated parapneumonic effusion requiring drainage; three stages: exudative → fibrinopurulent → organizing

Symptoms / Associated Sx

  • Fever (persistent or new fever during pneumonia treatment)

  • Pleuritic chest pain (worsening)

  • Dyspnea

  • Night sweats, weight loss (subacute/chronic empyema)

  • Dullness to percussion; decreased breath sounds at base

  • Signs of sepsis (tachycardia, hypotension) — ongoing bacteremia from infected pleural fluid

Denies

  • Prior antibiotic treatment resolving fever (treated parapneumonic may not need drainage if resolving)

  • Prior thoracentesis with benign fluid characteristics (reduces empyema likelihood)

  • Improving clinical course on antibiotics (raises question of alternate diagnosis)

Social History (SHx)

Prior pneumonia or thoracic surgery (post-operative empyema), esophageal rupture, dental procedure, aspiration risk factors (stroke, alcohol, seizures), immunosuppression, diabetes (increased infection risk), prior thoracentesis, prior pleural procedures.

Main Etiology

  • Parapneumonic (most common — bacterial pneumonia → reactive effusion → bacterial seeding → empyema)

  • Most common organisms: Streptococcus milleri group (most virulent parapneumonic), Streptococcus pneumoniae, S. aureus/MRSA, gram-negative rods, anaerobes (aspiration)

  • Post-surgical: thoracotomy, thoracoscopy, cardiac surgery, esophageal surgery

  • Esophageal rupture (Boerhaave) — left-sided empyema; food particles in fluid; surgical emergency

  • Hematogenous seeding (bacteremia → pleural infection)

Most Common DDx

  • Simple parapneumonic effusion (reactive; pH >7.2; glucose >60; negative culture; responds to antibiotics alone — no tube needed)

  • Malignant pleural effusion (exudate; lymphocytic; cytology positive; no fever; weight loss; cancer history)

  • Hepatic hydrothorax (cirrhosis + ascites; transudative; SAAG <1.1; no fever; responds to diuretics)

  • Tuberculous pleuritis (lymphocytic exudate; ADA >40; subacute course; endemic area or exposure; AFB culture)

  • Chylothorax (milky; triglycerides >110 mg/dL; lymphatic disruption from thoracic duct injury or lymphoma)

  • Pleural effusion from PE (small unilateral exudate; pleuritic pain; no fever initially; CTPA confirms)

DATA

  • CBC (leukocytosis with left shift)

  • BMP, LFTs (baseline; hepatic disease contribution)

  • Blood cultures × 2 (bacteremia common)

  • CXR (effusion; loculation; air-fluid level in empyema)

  • Chest ultrasound (echogenic fluid = fibrinopurulent; loculations; guide drainage)

  • CT chest with contrast (best characterization of loculations, pleural thickening, lung abscess, trapped lung)

  • Thoracentesis — pleural fluid analysis (diagnostic and treatment planning):

    • pH <7.2 → complicated/empyema → chest tube required

    • Glucose <60 mg/dL → complicated parapneumonic

    • LDH >1000 IU/L → exudative/complicated

    • Frank pus → empyema → chest tube regardless of other values

    • Gram stain + aerobic/anaerobic culture (in blood culture bottles)

Home Meds

  • Anticoagulants (hold before thoracostomy; INR <1.5)

  • Prior antibiotics (document — guides organism prediction and resistance)

Plan

  • Drainage (mandatory for empyema or complicated parapneumonic — pH <7.2, positive Gram stain/culture, or frank pus):

    • Chest tube thoracostomy: 14–20 Fr pigtail catheter (image-guided) for simple empyema; 28–32 Fr large-bore for thick loculated empyema

    • All empyema requires drainage — antibiotics alone are insufficient

  • Intrapleural fibrinolytic therapy (for loculated fibrinopurulent empyema not draining adequately):

    • tPA (alteplase) 10 mg + DNase 5 mg in 30 mL NS instilled into chest tube BD × 3 days (MIST-2 trial — improves drainage, reduces surgery rate)

    • Clamp tube × 1h after each instillation → release and drain

  • Antibiotics:

    • Community-acquired empyema: Ceftriaxone 2 g IV daily + Metronidazole 500 mg IV q8h (anaerobic coverage)

    • Healthcare-associated / post-surgical: Piperacillin-tazobactam 3.375 g IV q6h

    • MRSA risk: Add Vancomycin 15–20 mg/kg IV q8–12h

    • Duration: 2–4 weeks IV → step-down to PO (Amoxicillin-clavulanate 875 mg PO BID) for total 4–6 weeks

  • VATS (video-assisted thoracoscopic surgery):

    • Indication: failed chest tube drainage + intrapleural fibrinolytics (organizing stage III); trapped lung; thick peel preventing re-expansion

    • Thoracic surgery consult if not improving after 3–5 days of drainage + fibrinolytics

  • Serial CXR (daily — assess drainage, re-expansion)

  • Chest ultrasound (bedside — assess residual fluid, loculations)

  • Chest tube output monitoring and patency checks (flush with 20 mL NS q8h to maintain patency)

  • Daily CBC, BMP, CRP; trend fever curve; follow blood + pleural fluid cultures; narrow antibiotics at 48–72h

  • Pulmonology + thoracic surgery consult; interventional pulmonology for complex cases

  • PT/OT — breathing exercises; ambulation

  • Discharge: Completion of IV → PO antibiotic course (4–6 weeks total); chest tube removal when output <50 mL/day, pH normalizing, afebrile + clinically improving; outpatient CXR follow-up; thoracic surgery follow-up for organizing empyema or trapped lung; pulmonology 2–4 weeks

Red Flags

  • Persistent fever >72h on appropriate antibiotics + empyema → inadequate drainage; chest tube malpositioned or loculated → CT chest + tPA/DNase or VATS

  • Esophageal rupture suspected (left-sided empyema + food particles in fluid + history of retching) → surgical emergency; CT esophagram; thoracic surgery immediately

  • Septic shock from empyema → ICU; broad-spectrum antibiotics; urgent chest tube drainage (source control)

  • Trapped lung (lung fails to re-expand after drainage) → decortication or VATS; thoracic surgery consult

  • Contralateral mediastinal shift + massive empyema → tension hydropneumothorax; urgent large-bore drainage

Senior IM Resident Pearls

  • pH <7.2 mandates chest tube — this is the key decision point for empyema/complicated parapneumonic; do not manage with antibiotics alone; pH >7.2 with free-flowing fluid = antibiotics alone acceptable with close monitoring

  • MIST-2 trial: tPA 10 mg + DNase 5 mg twice daily × 3 days reduced surgical intervention rate from 34% to 4% in loculated empyema; tPA alone or DNase alone is inferior — the combination is required

  • Streptococcus milleri group (S. anginosus, S. constellatus, S. intermedius) is the most virulent parapneumonic organism — commonly forms abscesses and progresses rapidly to empyema; always treat aggressively

  • Small-bore pigtail (14–16 Fr) is equivalent to large-bore for simple free-flowing empyema (MIST-1 trial equivalent); large-bore only needed for thick pus or failed small-bore drainage

  • Common mistake: Giving antibiotics without thoracentesis in a patient with pneumonia + effusion — you cannot determine if drainage is needed without pH and Gram stain; every parapneumonic effusion >1 cm requires thoracentesis