Empyema

• • Pyothorax: Pus within pleural cavity, usually thick, creamy, malodorous

  • Etiology includes:

  • -In setting of pneumonia, lung abscess, bronchiectasis, it is referred to as parapneumonic (60%)

    -Postsurgical (20%)

    -Post-traumatic (10%)

    -Less common causes include esophageal rupture and other chest wall or mediastinal infections

  • 3 temporal phases:

  • 1. Acute exudative

    -Sterile low viscosity pleural fluid

    -Low WBC count and lactic dehydrogenase (LDH)

    -Normal glucose

    -Normal pH

    2. Transitional (fibrinopurulent)

    -Increase in turbidity, WBC, and LDH

    -Low glucose and pH

    -Fibrin deposited thereby fixing the lung

    3. Chronic organizing

    -Occurs 7-28 days after disease onset

    -Exudates thickens, causing further fixation of lung

    -pH < 7.0

    -Glucose < 40 mg/dL

Epidemiology

• • Most organisms are anaerobic bacteria: bacteroides, fusobacterium, peptococcus

  • Staphylococcus is cause in > 90% of children under 2 years; common cause in adults also

  • E coli, Pseudomonas cause 66% of aerobic, gram-negative empyemas

  • Rarely fungi and Entamoeba histolytica can cause empyemas

  • Average number of bacterial species isolated: 3.2 per patient

  • Incidence of complications with Staph pneumonias in adults:

  • -Abscess (25%)

    -Empyema (15%)

    -Effusion (30%)

  • Incidence of complications with Staph pneumonias in kids:

  • -Abscess (50%)

    -Empyema (15%)

    -Pneumatocele (35%)

    -Effusion (55%)

Symptoms and Signs

• • Rarely asymptomatic

  • Fever, pleuritic chest pain, dyspnea, hemoptysis, cough

  • Tachycardia, anemia, tachypnea, diminished breath sounds, clubbing

Imaging Findings

• • Chest film and chest CT:

  • -Pneumonia

    -Lung abscess

    -Pleural effusion

    -Mediastinal shift away if large empyema

• • Thoracentesis is diagnostic

  • -In early empyema, pleural fluid may not be purulent

    -pH < 7.0

    -Glucose < 40 mg/dL

    -LDH > 1000 U/L

    -Suggests evolving empyema despite negative Gram stain and culture

    -Frank pus usually develops later in empyema development

• • Chest CT: May be necessary if loculated

  • Bronchoscopy: Performed to exclude presence of endobronchial obstruction

  • Thoracentesis: Diagnostic

• • Goals:

  • -Control infection

    -Remove purulent material with lung reexpansion

    -Eliminate underlying disease process

  • Options:

  • -Repeated thoracentesis

    -Chest tube drainage

    -Rib resection with open drainage

    -Decortication and empyemectomy

    -Thoracoplasty

    -Muscle flap closure

Treatment Algorithm: Empyema

• • Clear thoracentesis

  • -Check Gram stain and culture

    -If positive, thoracentesis/chest tube

    -If negative, check pH, glucose, LDH; chest tube if indicated

  • Pus on thoracentesis

  • -Place chest tube

    -Convert to open drainage

    -Perform sinogram: No cavity, then withdraw tube; small cavity, evaluate how well drained—if well drained, then slowly advance tube—if not well drained, then consider rib resection, thoracoscopy, or new chest tube; large cavity, if well drained, slowly advance tube—if no reexpansion, consider decortication—if not well drained, consider early decortication, rib resection, or Eloesser procedure

  • Residual spaces, continued sepsis: Consider open drainage procedures 10-14 days after chest tube (allows time for pleural fusion

  • Rib resection: Of short segments of 1-3 ribs in dependent portion

  • Eloesser procedure: Simple rib resection and open flap drainage

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