Guttural pouch empyema can affect horses of any age, writes Dr. Lydia F. Miller in the "AAEP Forum" column in the October edition of The Horse. The condition involves pus in the guttural pouches (a mixture of white blood cells, infectious organisms, and dead cells), which usually results from upper respiratory tract infection. However, it also can develop as a complication of guttural pouch diseases, local treatment with irritating drugs, or birth defects.
Horses with this disease might show nasal discharge off and on, swollen lymph nodes or salivary glands, and have difficulty breathing or swallowing. Diagnosis of empyema is best done through endoscopic examination, to make sure the discharge is seen coming from the guttural pouches and not the lungs or sinuses. Radiographs (X-rays) of the region and culture/sensitivity testing of the discharge might provide additional information.
Treatment involves daily flushing of the guttural pouches by a veterinarian for up to four weeks to dislodge and remove dead cells, debris, infectious organisms, and other materials. Only non-irritating, physiological flushing solutions should be used to prevent further irritation, which could lead to nerve damage and additional inflammation. Other medications or treatments can be administered based on the horse's clinical signs and conditions.
Another problem, tympany, results from swelling of the guttural pouches due to air accumulation. The condition is age-related, developing in foals shortly after birth and for up to one year of age. It is also gender-related, with more fillies than colts affected. Several causes for air being trapped in the guttural pouches have been suggested, such as congenital defect or local tissue swelling from a previous respiratory infection, but none have been proven. Like other guttural pouch problems, history and clinical signs are helpful, but endoscopic examination and radiographs confirm the suspicion, rule out secondary problems, and assist in the selection of treatment. Surgery is the most satisfactory treatment.