The guttural pouches are a pair of air sacs located at the back of the skull that serve as large Eustachian tubes. They are seen in a small number of animals, including horses, and their full function is not currently known.
Guttural pouch diseases are uncommon in horses, but can have serious consequences. In some cases, guttural pouch disease can be life-threatening and require prompt veterinary attention. Horses that are bleeding profusely from their nostrils require emergency veterinary attention, as they are at risk of fatal blood loss.
The symptoms and risk levels of guttural pouch disease depend on which condition is occurring.
Guttural pouch mycosis primarily results in profuse nosebleeds, which may be fatal if enough blood is lost. Other symptoms include:
Usually, the only symptom of guttural pouch tympany is swelling around the throat in a foal. The swellings are not painful.
The guttural pouches are large dilations of the auditory tube (Eustachian tube) in horses. These structures can trap bacterial or fungal infections or air, causing significant disease.
Guttural pouch empyema refers to a bacterial infection within the guttural pouches. In most cases, this condition develops due to strangles, with pus from the infection becoming trapped in the guttural pouches. In some cases, the pus may harden and form a chondroid, a solid accumulation of pus and bacteria. Other causes of guttural pouch empyema include:
Guttural pouch mycosis is a fungal infection of the guttural pouches, usually caused by Aspergillus species. There are no known risk factors or causes of fungal infection.
Guttural pouch tympany occurs when air becomes trapped within the guttural pouches. The exact cause of the condition is unknown, but it is most common in foals.
Diagnosis of guttural pouch disease begins with a physical examination, to identify any other symptoms. Further diagnostic tests include:
Treatment depends on the condition diagnosed and can include:
Guttural pouch diseases typically do not resolve on their own, and require prompt treatment to prevent the conditions from worsening. In most cases, the prognosis is favorable to good with appropriate intervention. Some cases may recur after treatment is completed, or regress during treatment. These cases typically have a poor prognosis. Horses that develop severe nosebleeds from guttural pouch mycosis have a poor prognosis, and many affected horses die due to blood loss.
Of the three guttural pouch diseases, only guttural pouch empyema is preventable. A vaccine for strangles is available, and can help reduce symptoms in horses exposed to the bacteria. Horses diagnosed with strangles must be separated from other horses to prevent spread of infection.
Guttural pouch diseases are uncommon in horses.