Pleural Empyema in Six Horses: A Retrospective Case Series.
Authors: Battistin Lorena, Cerri Fabrício Moreira, Watanabe Marcos Jun, Takahira Regina Kiomi, Ribeiro Márcio Garcia, Rocha Noeme Sousa, de Oliveira-Filho José Paes, Borges Alexandre Secorun, Amorim Rogério Martins
Journal: Journal of equine veterinary science
Summary
# Pleural Empyema in Horses: A Clinical and Pathological Overview Pleural empyema represents a severe, often fatal condition in horses characterised by bacterial or fungal infection within the pleural space; this retrospective case series of six horses provides valuable insights into its clinical presentation, diagnostic findings, and treatment challenges. All affected horses displayed dyspnea (inspiratory or mixed type) and tachypnea, whilst four showed coarse crackles on thoracic auscultation and four presented with fever—though clinical signs were non-specific, with only two horses exhibiting pleural friction or effusion sounds on examination. Laboratory work consistently revealed marked inflammatory changes including leukocytosis (mean 16.22 × 10³/µL with severe neutrophilia at 12.32 × 10³/µL), hyperfibrinogenemia (633 mg/dL), and elevated globulins and urea suggesting systemic inflammation and possible renal compromise; pleural fluid analysis confirmed exudative effusion in five of six cases. The microbial population was notably diverse, encompassing fungal (Aspergillus fumigatus) and multiple bacterial species including Streptococcus equi subspecies zooepidemicus, Pseudomonas aeruginosa, and Enterobacter cloacae, with in vitro sensitivity testing favouring ceftiofur and penicillin, yet the 83% mortality rate underscores the disease's aggressive nature and resistance to conventional antibiotic therapy. For practitioners, pleural empyema should be considered in horses with refractory respiratory distress and systemic inflammation; early thoracic ultrasonography and aggressive pleural sampling remain essential for diagnosis, though the characteristically poor prognosis warrants candid client discussions and consideration of advanced
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Practical Takeaways
- •Pleural empyema carries an extremely high mortality rate (83%) despite antimicrobial therapy; early recognition of respiratory distress, fever, and pleural effusion is critical for intervention attempts
- •Multiple bacterial and fungal pathogens can be involved; culture and sensitivity testing of pleural fluid and transtracheal wash samples should guide antimicrobial selection, with ceftiofur showing highest efficacy in this series
- •Severe cases develop fibrin deposits and pleural adhesions that may compromise treatment outcomes; this condition should be considered refractory and managed with aggressive multimodal therapy from initial diagnosis
Key Findings
- •All 6 horses presented with tachypnea and inspiratory/mixed dyspnea; 4 of 6 had hyperthermia and coarse crackling on auscultation
- •Pleural fluid analysis showed exudate in 5 of 6 cases with leukocytosis (16.22 × 10³/μL) and neutrophilia (12.32 × 10³/μL)
- •Multiple pathogens isolated including Aspergillus fumigatus, Streptococcus species, Pseudomonas aeruginosa, and others; ceftiofur and penicillin showed best in vitro sensitivity
- •Fatality rate was 83% (5 of 6 horses) with fibrin deposition and pleural adhesions noted at post-mortem, indicating refractory disease