Introduction: Horses have two unique pouches that are an extended part of the eustachian tubes. These guttural pouches are air-filled sacs that lie just above and behind the pharynx area (throat-latch region). Each pouch has many of the cranial nerves and even part of the carotid artery passing through the lining of the pouch. Problems such as empyema, mycosis, and tympany can occur with these structures.
Guttural Pouch Empyema: Guttural pouch empyema is an infection in the guttural pouch or pouches that is usually caused by bacteria. These bacterial infections are often a result of some sort of previous respiratory infection or even strangles. The bacterial infection causes purulent material (infectious discharge) and fluid to form inside the guttural pouch. These horses will often have an ongoing nasal discharge with difficulty eating and breathing. Chondroids or hard balls of the purulent material can form with time.
Diagnosis: This problem is often identified with radiographs and/or endoscopic exam. With radiographs, chondroids are sometimes identified. During an endoscopic exam, the endoscope is taken directly into the guttural pouch and evidence of infection can be directly identified.
Treatment: The real challenge with this problem is getting the pus/infection to drain out of the pouch. Systemic antibiotics are often used to help reduce and hopefully clear the infection; however, the antibiotics alone are often not enough to clear the infection. This is where flushing of the pouch is also required. Different solutions (saline with antibiotic) can be used for the flushing, and the flushing is often performed daily. If a sample of the discharge can be collected, it should have a culture and sensitivity performed on it. The culture will identify what organism is causing the infection, and the sensitivity will identify what antibiotics will work against that organism. If the horse does not respond to the flushing and injectable antibiotics, surgical drainage is often required. If the treatment is performed early and properly, many of these cases recover completely.
Guttural Pouch Mycosis: This is a fungal infection of the guttural pouch. The signs associated with this infection depend on what nerves or vessels are compromised by the fungal infection in the pouch. For example, if the infection has damaged some of the blood vessels, epistaxis (bleeding from the nose) will occur. A small trickle or simply just drops of blood can come out of one or both nostrils. In severe cases, where invasion of a major blood vessel has occurred, the horse may actually bleed to death over a short period of time. If the nerves of the head are compromised, difficulty eating (dysphagia) may result. Epistaxis followed by dysphagia are the two most commonly seen signs.
Diagnosis: This problem is often identified based on clinical signs and an endoscopic exam. During an endoscopic exam, the endoscope is taken directly into the guttural pouch where evidence of the fungal infection can be directly identified. Fungal lesions that are brown, yellow, black or white may be seen inside the pouch.
Treatment: Treatment for this problem can be challenging and sometimes unsuccessful. Currently, the most successful method of treatment involves surgery. During surgery, the carotid artery that is commonly involved with these infections is blocked. This prevents any blood from flowing through the artery and prevents a fatal hemorrhagic event. The lack of blood flow also causes the wall of the pouch to heal and the fugus to die off with time.
Other less successful treatments include topical anti-fungal treatments and anti-fungal medications administered systemically to the horse. If these treatments work, the fungus takes longer to regress and the potential for fatal hemorrhaging increases.
Guttural Pouch Tympany: Guttural pouch tympany is a problem usually found in animals that are less than 1.5 years old. It is a condition where one or both guttural pouches becomes over-filled with air. This problem has been associated with a birth defect where the air is let into the pouch but not out. Infections in the guttural pouch are also thought to cause swelling and prevent air from escaping.
Clinical Signs: The foals that suffer from this problem will often have a slight to moderate swelling in the throat latch area. This site is often not painful when touched and very soft. As the air inside the pouch increases, the horse may experience difficulty eating (dysphagia) and breathing (dyspnea).
Diagnosis: Most cases of guttural tympany can be diagnosed based on identifying the soft swelling in the throat latch area, along with signs of difficulty breathing and eating. Endoscopic exams and radiographs can also be used to help identify the problem.
Treatment: Cases of guttural tympany can be relieved temporarily by removing the air trapped inside the pouch through the neck region or through the opening into the pouch itself. These techniques usually only solve the problem for a short time because the pouch gradually fills back up with air. To prevent the problem from recurring, surgical treatments are usually required. With these surgical procedures, permanent changes are made to the pouch that allow the air to escape. Most horses recover fully after the surgery has been performed.