What is Guttural Pouch Empyema?
This infection affects the air chambers on the sides of the horse’s neck, causing them to thicken and fill with pus. This condition is notoriously difficult to treat due to the difficulty in removing all bacteria from the area. However, recent research has shown that in adult animals who receive prompt care, recovery may be expected.
Guttural pouch empyema is an infection that can occur in horses due to bacterial infection. This infection is often secondary to equine distemper, a contagious upper respiratory disease that is caused by Streptoccocus equi.
Symptoms of Guttural Pouch Empyema in Horses
- Thick, purulent nasal discharge
- Difficulty breathing
- Difficulty swallowing
- Bleeding from the nose
- Facial nerve paralysis
- Swelling of the neck
- Decreased performance or exercise tolerance
Causes of Guttural Pouch Empyema in Horses
The guttural pouches are structures that are unique to few species of animals. These structures are large air filled sacs, positioned on either side of the neck, below the ear of the horse. They are lined with a thin membrane, which separates them from nerves and the jugular artery. Due to their placement, trauma to these structures can cause severe consequences, affecting swallowing, respiration, facial control and head position.
Guttural pouch empyema is the infection of these structures caused by bacterial invasion. This is often secondary to equine distemper, a contagious upper respiratory disease caused by Streptoccocus equi, a gram positive bacterium. This infection causes the membranes of the pouch to become thickened and fill with pus. The exudate will often spread to the eustachian tubes and into the throat and nasal passages.
Diagnosis of Guttural Pouch Empyema in Horses
Your veterinarian will perform a full head to tail examination on your horse, and discuss their clinical history, symptoms and recent behavior with you.
As equine distemper is a common precursor to this condition the same diagnostic examinations may be performed to confirm the presence of S.equi.
Your veterinarian may choose to take a nasopharyngeal swab of the back of your horse’s throat. They may also perform a guttural pouch wash, this is performed by inserting a catheter through the nose into the guttural pouch. Your veterinarian will flush the pouch with sterile saline and then aspirate the saline and sample of exudate back into a sterile syringe. These samples will both be sent to a laboratory for testing. Confirmation of the presence of the bacteria will enable a diagnosis to be made.
Treatment of Guttural Pouch Empyema in Horses
Your veterinarian will discuss the best treatment plan for your horse with you. The most common treatment is daily lavage for 5-10 days, this may require hospitalisation or daily visits from your veterinarian to perform treatment.
Antimicrobials may also be recommended for your horse to encourage bacteria elimination, protect the airways from contaminated drainage and reduce the risk of infection from aspiration pneumonia. The most commonly used antibiotic is penicillin, which may be given via intravenous or intramuscular injection. A topical penicillin gel may also be used that can be applied to the guttural pouch lining to enhance bacterial clearance. If your horse is suffering from pain, anti-inflammatories or other analgesic medication will be offered.
In 20% of cases the horses will not respond to conservative treatment and surgical intervention may be necessary. In these cases, abscesses may form, however, your veterinarian may be able to lance these to encourage draining and flush the pouch to remove as much exudate as possible. If this is not successful, your veterinarian will discuss the numerous approaches that may be indicated for your horse; scalpel incision or laser surgery may be recommended.
Recovery of Guttural Pouch Empyema in Horses
The prognosis for horses suffering from this disease is good if treatment is commenced early. 80% of horses will make a full recovery when treated with daily irrigation. If your horse is showing signs of improvement after 10 days of treatment, continued irrigation may be recommended. For young foals, the prognosis may be very guarded due to the risk of anatomical defects.
In horses who require surgery it is expected that only a short period of hospitalisation is needed. Following infection, your horse should have three repeat cultures performed and isolation protocols followed until negative results have returned.
If your horse suffers from recurrent empyema your veterinarian may recommend a fistula is created to manage this. Disease control is an important consideration if your horse is infected with this disease due to the highly contagious nature. The following measures should be taken:
- Isolate your horse and any other horses who have had contact with the unwell animal
- Regularly disinfect your horse’s stables, water trough, feed bowls, or other equipment that comes into contact with your horse