Pleuropneumonia

Definition: infection of the lungs as well as the pleural lining between the lungs and the chest wall Signs: fever, depression, lethargy, loss of appetite and evidence of pain in the chest area, which may include shallow respiration, guarding and flinching when the area is touched, short strides, reluctance to move or lie down, and an anxious expression. Nasal discharge may be present. Causes: Pleuropneumonia is a bacterial infection that can develop when a horse inhales any of a number of different species, including Streptococcus equi zooepidemicus, Esch- erichia coli and Staphylococcus aureus. The disease can be a secondary infection that sets in after a viral respiratory disease; pleuropneumonia can also develop after other factors inhibit the lung’s defenses, such as strenuous exercise, general anesthesia or long-distance trailering while the horse is unable to lower his head. Diagnosis: In addition to observation of signs, a veterinarian will use a stethoscope to listen for unusual sounds in the lungs; the heartbeat may also be muffled. Ultrasound examination will identify accumulated fluid in the chest cavity. Blood tests will be con- sistent with bacterial infections. Treatment: Tubes may be inserted into the horse’s chest to drain accumulated fluids. Ultrasound examinations may be repeated as needed to identify and drain new pockets of fluid as they develop. In addition, the horse will need intensive treatment with antibiotics as well as supportive care including nonsteroidal0 antiinflammatory drugs (NSAIDs) and other analgesic0 drugs. Complications: Some cases of pleuropneumonia may persist for weeks or months despite intensive treatment. Potential complications of the disease include scarred or necrotic lung tissue, systemic bacterial infections (septicemia), inflammation of the veins within the lungs (thrombophlebitis) and laminitis. Prognosis: A horse’s chances of survival are reasonably good when treatment is started within 48 hours of the start of the disease. Different studies have cited survival rates from about 50 percent to 98 percent, and the chances of returning to athletic work ranged from 61 percent to 89 percent. Factors that lead to poorer outcomes include delay in the start of treatment and the development of complications such as laminitis.