Pleuropneumonia is a severe form of pneumonia most often seen in racehorses. Upper respiratory tract viral infections, as well as stressful events such as long distance transportation and racing may all contribute to development of disease. General anesthesia, immunosuppressive therapy, and poor nutritional status may also lead to compromise of the respiratory defense mechanisms. These stressful events may alter your horse's respiratory defense mechanisms. Bacterial pleuropneumonia as a result of esophageal obstruction from the aspiration of feed material is also seen in other breeds.
Clinical signs vary with the stage of the disease. Symptoms include a cough or nasal discharge, exercise intolerance, and some degree of respiratory effort as evidenced by nostril flaring or an abdominal component to expiration. Acutely, most horses are febrile, anorectic, and or lethargic. Your horse may exhibit a reluctance to move, abducted elbows or stiff forelimb gait, and may be mistaken for laminitis or exertional rhabomyolysis. Rapid weight loss may occur in chronically affected horses. The development of sternal and distal limb edema may be present in advanced cases.