Description

Horses have a unique passageway known as a guttural pouch which is similar to the eustachian tube in humans and runs from the inside of the mouth to the inner ear.

The horse also has a group of bones inside the nostril called the turbinate bones. These structures combined play an important role in filtering and regulating the flow, temperature, and pressure of air and blood as they enter the horse's lungs and brain. Unfortunately, these passageways can become infected, injured, or invaded by tumors.

Horses that have guttural pouch tympany are born with a defect that causes the pharyngeal opening of the guttural pouch to act like a one-way valve. Air can get in, but cannot get out. Although this defect usually occurs in just one pouch, it can affect both. Most cases are noted within the first few days of a foal's life. The condition may have a genetic component and has been linked to some Arabian and Hanoverian bloodlines.

Massive swelling of the neck and throat latch because of the trapped air are characteristic of the disease. When the swollen area is tapped with a finger, it resonates like a drum, giving the condition its name. Affected horses may exhibit mild discomfort or be unable to breathe and swallow correctly.

Symptoms

• Chipmunk cheeks
• Distended nostrils
• Massive swelling of the neck and throat
• Difficulty breathing
• Inability to swallow correctly
• Snoring noises when nursing

Causes

Guttural pouch tympany is usually a defect with which a foal is born, although it may show up later as a foal matures. Recent studies show that it most likely has a genetic component, with links to some Arabian and Hanoverian bloodlines.

Prevention

Once it is established that a horse has guttural pouch tympany, breeding should be prevented to make sure the condition is not passed on to succeeding generations.

Treatment

If the guttural pouch tympany is chronic, the foal may develop aspiration pneumonia due to food going down the wrong tube. While a veterinarian may suspect guttural pouch tympany just by looking at a foal, X-rays will confirm that the guttural pouches are filled with air. The veterinarian may also perform an endoscopy of the guttural pouch under light sedation.

If only one guttural pouch is affected, it may be possible to open the affected pouch into the unaffected one, letting air escape through the side that functions normally. If both guttural pouches are affected, a veterinarian may choose to place a temporary catheter into the pouch, giving the air a pathway to escape as the opening is enlarged.

In some situations, treatment consists of surgery. If only one pouch is affected, the prognosis is very good. If both pouches are affected, surgery will be more complicated. In both cases, the veterinarian will usually treat the foal with antibiotics to prevent post-operative infections.