Guttural pouch tympany (GPT) is a rare condition of foals that usually occurs within a few days of birth. It is thought to result from a congenital malfunction of the pharyngeal opening of the pouch, as opposed to a physical obstruction. GPT most commonly affects fillies more than colts, with Arabian breeds being most susceptible. The disorder usually occurs unilaterally.
The guttural pouch, or diverticulum of the auditory tube, extends downward from the base of the skull and the atlas and opens within the nasopharynx of the horse.
It is lined with a thin mucous membrane and divided by the stylohyoid bone into medial and lateral components.
GPT can be fatal without surgical treatment. Even with surgical treatment, the horse can potentially develop postoperative pharyngeal neuromuscular dysfunction.