Consider how pneumonia appears in the horse, and you might picture a foal in intensive care, but in reality the condition can affect horses of all ages. While some pneumonia cases are very challenging to treat, veterinarians can rehabilitate many of these patients successfully with the proper approaches.

During a presentation at the 2011 American Association of Equine Practitioners convention, held Nov. 18-22 in San Antonio, Texas, Harold McKenzie III, DVM, MS, Dipl. ACVIM, gave attendees an in-depth look at the most effective techniques for diagnosing and managing equine bacterial pneumonia.

"Bacterial lower respiratory infections have greater clinical impact than viral infections because of the substantial risk of complications ranging from focal abscessation to pleuropneumonia," said McKenzie, an associate professor in equine medicine at the Marion duPont Scott Equine Medical Center in Leesburg, Va.

Disease Development

McKenzie explained that pneumonia arises in the airway lumen (cavity) and ranges in severity based on how much of the horse’s body is involved (more on that in a moment). The disease is typically initiated by “major exposure” overwhelming and impairing the horse’s defense mechanisms.

Simple cases of bacterial pneumonia involve the primary airway and rarely affect the lungs, with no abscesses or little to no consolidation (fluid-filling resulting in solidification into firm, dense masses) evident. Veterinarians consider c complicated when substantial consolidation occurs, abscesses form, or pleuropneumonia secondary to bacterial bronchopneumonia develops, character