Page 678 - The Veterinary Care of the Horse

• Unnecessary stress should be avoided.

VetBooks.ir GUTTURAL POUCH DISEASE

The guttural pouches are a pair of air-filled sacs which lie between the roof of the
nasopharynx and the base of the brain. They are outpouchings of the Eustachian tubes

connecting the middle ear with the nasopharynx. They are lined with mucous membrane and
drain into the nasopharynx via ostia (openings) which are covered by flaps of cartilage.

These only open when the horse swallows. A number of important nerves and blood vessels
run through and around the guttural pouches.

There are three main diseases of the guttural pouch:
• tympany

• empyema

• mycosis.

Guttural pouch tympany

This is a quite rare congenital condition whereby an anatomical or functional defect allows
one (or occasionally both) pouches to fill with air but not to empty. Young foals are the most

likely to be affected. The pouch becomes distended and a swelling is visible in the parotid
region behind the mandible. This is not painful but affected foals may have difficulty

breathing and eating as a result of the swelling. Milk may return down the nostrils after
attempts to swallow. The normal drainage of mucus may be obstructed leading to secondary

bacterial infection and a mucopurulent nasal discharge.
The condition is diagnosed on the clinical signs and can be confirmed by radiography and

endoscopy. Treatment involves creating a window in the thin septum between the two
pouches so the air from both can drain from the normal pouch into the nasopharynx. The

outcome is usually good. Complications include inhalation pneumonia and guttural pouch
empyema. Repeat surgery is sometimes necessary.

Guttural pouch empyema

This is when the guttural pouch(es) fill up with pus. It can occur as a sequel to strangles or
other upper respiratory infections. The retropharyngeal lymph nodes can form abscesses

which burst and drain into the guttural pouches. The disease usually affects one guttural
pouch but is occasionally bilateral. The main symptom is a unilateral purulent nasal