Guttural Pouch

Guttural Pouch/Graphic Western Horse Magazine

What is a guttural pouch? It is not really that easy to define a horse's guttural pouch. It is understood where it is located and how the anatomy presents; however, much of what a guttural pouch does remains somewhat of a mystery. The horses's guttural pouch is an "air-filled out-pouching of the auditory or Eustachian tube. While all mammals have auditory tubes, not all have these pouches. Horses, mules and donkeys have the largest, with one pouch lying on each side of the back of the throat." The Mysterious Guttural Pouch The pouches contain arteries, some cranial nerves: facial, glossopharyngeal, vagus, accessory, and hypoglossal.

Disease of the Guttural Pouch

• Guttural pouch tympany/a birth defect.
• Pus collection in pouches (empyema)
• Fungal infection (mycosis/Aspergillosis most common fungi.)
• Inflammation of the middle and inner ear

Theories About Other Uses of Horse's Guttural Pouch

It was once thought that perhaps the guttural pouch functioned as a regulator for pressure changes. However, now it is thought that the guttural pouch acts as a cooling device for the horse's brain..."Researchers now believe that heat is removed from the exercising horse's brain via transfer from the blood to the air in the guttural pouch and then out through the pharynx. This mechanism also provides a clue as to why diseases occur in this anatomical area and why those diseases can be deadly..." The Mysterious Guttural Pouch

Diagnosis of Guttural Pouch Disease:
Clinical Signs:

• Nasty, nasal discharge
• Painful swelling in the parotid area (side of the face)
• Stiff head carriage and harsh breathing
• Fever
• Depression
• Anorexia
• Epistaxis (nose bleed)
• Dysphagia (difficulty in swallowing)
• Rhinititis/nasal discharge/dyspnea (shortness of breath)
• Acute enteritis (inflammation of the small intestine)
• Bleeding in horses with mycosis
• Colitis caused from invading aspergillus in intestinal mucosa
• Locomotal disturbances/from spread of infection to brain
• Visual disturbances/from spread of infection to optic nerve
• Diagnosis is determined by endoscopic examination of the guttural pouch
• Radiographs of the pharynx will demonstrate a fluid line in the guttural pouch and may allow the clinician to identify an associated retropharyngeal mass

Treatments:

• Lavage-Rupturing the abscess
• Surgical drainage
• Tracheotomy
• Endoscopic removal depending on severity
• Systemic and topical antimicrobial therapy accompanies treatments
• Embolization of the internal carotid artery

Guttural Pouch disease is a really nasty problem. It is imperative that your vet be called immediately before many complications may arise as the disease progresses.

For More Information:

Western Horseman Magazine/January 2001. An excellent reference article.