Respiratory · Year 1 · from Respiratory

Case 1: Parapneumonic Effusion and Empyema

Clinical Image

Source: Wikimedia Commons - Pleural effusion - CC BY-SA 3.0

Patient Presentation

A 58-year-old man presents with 5 days of worsening right-sided chest pain, productive cough with purulent sputum, and fever. He was treated with oral antibiotics by his primary care physician 3 days ago for pneumonia but has not improved. The chest pain is sharp, worse with breathing, and he has noticed increasing shortness of breath. He has a history of alcohol use disorder.

Demographics

  • Age: 58 years
  • Sex: Male
  • Past Medical History: Alcohol use disorder, poor dentition
  • Medications: Amoxicillin-clavulanate (started 3 days ago)
  • Social History: Heavy alcohol use (6-8 drinks daily), homeless periods in the past

Chief Complaint

Worsening chest pain, fever, and dyspnea despite antibiotic treatment

Physical Examination

  • Temperature: 39.2°C
  • Blood pressure: 98/62 mmHg
  • Heart rate: 112 bpm
  • Respiratory rate: 28/min
  • Oxygen saturation: 90% on room air
  • General: Ill-appearing, diaphoretic
  • Respiratory:
  • Dullness to percussion right base to mid-chest
  • Decreased breath sounds right lower lung
  • Decreased tactile fremitus
  • Egophony at fluid-air interface
  • Cardiac: Tachycardic, regular

Workup

  • WBC: 22,400/μL with left shift
  • Procalcitonin: 8.5 ng/mL (markedly elevated)
  • Chest X-ray: Large right pleural effusion with loculations, right lower lobe consolidation
  • CT chest: Loculated right pleural effusion with pleural thickening and enhancement (split pleura sign), underlying consolidation
  • Thoracentesis (ultrasound-guided):
  • Appearance: Turbid, purulent
  • pH: 6.9 (very low)
  • Glucose: 20 mg/dL (very low)
  • LDH: 2,850 IU/L (very high)
  • Protein: 5.2 g/dL
  • WBC: 45,000/μL (95% neutrophils)
  • Gram stain: Gram-positive cocci in chains
  • Culture: Streptococcus anginosus

Diagnosis

Complicated Parapneumonic Effusion/Empyema

Treatment

  1. IV antibiotics: Broad-spectrum initially (ceftriaxone + metronidazole), narrow based on culture
  2. Chest tube drainage (large-bore preferred for thick pus):
  • Indicated for: pH <7.20, glucose <60, positive Gram stain/culture, or frank pus
  1. Intrapleural fibrinolytic therapy: tPA + DNase if loculated/incomplete drainage
  2. Surgical consultation: VATS debridement and decortication if medical therapy fails
  3. Nutritional support
  4. Dental evaluation for potential source
  5. Alcohol cessation counseling and resources

Physiological Principles Demonstrated

  • Parapneumonic effusion stages:
  1. Exudative (simple): Sterile, responds to antibiotics alone
  2. Fibrinopurulent (complicated): Bacterial invasion, loculations form, drainage needed
  3. Organizing (empyema): Frank pus with thick pleural peel
  • Light's criteria application: This is clearly an exudate (protein >0.5 ratio, LDH >0.6 ratio, pleural LDH >2/3 upper limit of normal serum LDH).
  • Pleural fluid pH significance: pH <7.20 indicates significant bacterial metabolism and anaerobic glycolysis in the pleural space, predicting failure of antibiotics alone.
  • Aspiration risk factors: Alcohol use, poor dentition, and aspiration increase risk of anaerobic and streptococcal infections.

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