Pyothorax in cats and dogs

Pyothorax, or thoracic empyema, is an infection of the pleural space, characterized by the accumulation of purulent exudate. It is a life-threatening emergency in dogs as well as in cats, with a guarded prognosis. Dyspnea and/or tachypnea, anorexia and lethargy are the most typical clinical signs. Diagnosis is usually straightforward, based on the clinical symptoms combined with pleural fluid analysis, including cytology and bacterial culture. Most commonly, oropharyngeal flora is isolated in the pleural fluid. Treatment can be medical or surgical, but needs to be immediate and aggressive. In this article, an overview of the various causes of both feline and canine pyothorax with its similarities and differences is provided. Epidemiology, symptoms, diagnosis, treatment and prognosis are discussed