Feline pyothorax - new insights into an old problem: part 1. Aetiopathogenesis and diagnostic investigation.

Feline pyothorax is a life-threatening emergency commonly encountered by the small animal clinician. Historically, thoracic wall penetration from a bite wound has been postulated to be a major route of infection. New information has challenged this dogma and indicated that aspiration of oropharyngeal flora is the usual route of infection of the pleural space in cats. A role for unusual pathogens, including gastrointestinal flora and fungal agents, has been identified in some cases, particularly in kittens. In the first of a two-part review, the clinical findings in feline pyothorax are discussed with a focus on an improved understanding of the aetiopathogenesis of the disease and subsequent implications for diagnostic investigation.