Pneumonia, lung abscesses and pleuritis in adult horses: a review of 51 cases.

Case records are reviewed of 51 adult horses in which a diagnosis of pneumonia, pulmonary abscess or pleuritis had been made. Forty-five horses were afflicted with pneumonia and/or pulmonary abscesses; in 11 of these the infection was primary, whereas in 34 it was secondary to another disease process (inhalation of food or saliva, thoracic trauma, generalised infection, airway disease, neoplasia or thromboembolism). Of the 11 horses with primary pulmonary infections, 10 appeared to be associated with a previous episode of stress; this took the form of long distance travel in eight cases. There was a statistically significant association between primary pneumonia and/or lung abscesses and the use of the horses, with the highest incidence in showjumpers. Eighteen horses had pleuritis, of which 12 were secondary to pneumonia or pulmonary abscesses, two to thoracic trauma and one to generalised avian tuberculosis. Three cases of primary pleuritis were identified.