Epiglottic Entrapment

Monique Matherne
Dr. Marilyn Rumbaugh

Attention all thoroughbred and standardbred race horse owners!!! Is your horse performing to its potential? Does the jockey notice your horse breathing loudly during exercise? Granted, there are several processes that can cause these problems, but I would like to discuss one of them with you … epiglottic entrapment.

The epiglottis is a triangular, lid-like piece of cartilage located at the base of the tongue. It covers the entrance of the trachea when your horse swallows, preventing food and water from entering the airways. The epiglottis is covered by mucous membranes which are thin layers of epithelium (cells). When these membranes are loosely attached, they can flip over the top of the epiglottis, trapping it in its resting position.

Epiglottic entrapment causes a variety of signs that suggest upper airway involvement. The severity and type of signs are dependent on the amount of tissue trapping the epiglottis, the amount of irritation in that area, and the other abnormalities that might be present. The most common complaints made by owners are poor performance and/or noisy breathing; the noise is heard louder on expiration. Your horse may also have a nasal discharge or a cough that is present while exercising or eating. However, there are a small percentage of horses that show no signs at all when affected by this condition.

If you are concerned about your horse’s performance and it is making noise while breathing, you should call your veterinarian for an appointment. Conditions that cause these signs are generally not life threatening, but they can affect how well your horse races and therefore affect its earning potential, i.e. your pocket book. When your veterinarian arrives, he will perform a thorough physical exam on your horse to be sure the problem is in the upper airway. The best way to diagnose this condition is with an endoscope, a fiber optic tube that allows visualization of the epiglottis and surrounding structures. Your veterinarian will be able to see that it is still in its correct position and he will see the general shape of the epiglottis. However, it will no longer have its normal notched border and the blood vessels on the top of it cannot be seen. Some horses only experience this condition periodically, in which case a normal endoscopic exam will not be sufficient. A high-speed treadmill may be help to better evaluate these situations. The treadmill will simulate the stress your horse is under while exercising and could provoke an episode of epiglottic entrapment.

Once your horse has been diagnosed with this disorder, you will need to decide which surgical option is best for him. The ultimate goal of therapy is to free the epiglottis and to prevent re-entrapment. The two most common methods performed are trans-nasal laser surgery and trans-oral surgery with a curved bistoury (an instrument shaped like a hook with a cutting edge). The laser surgery is performed using the endoscope to guide the laser toward the epiglottis in order to remove the extra membrane. This procedure can be performed in a standing horse under sedation. The oral surgery is performed through the mouth with a bistoury. This instrument is used to split the membrane down the middle, releasing the epiglottis. Your horse will have to go under general anesthesia for this procedure, so it may involve more risk.

Once your veterinarian is finished with the procedure, your horse will be placed on anti-inflammatory drugs such as bute and Banamineâ. The amount of these drugs will be decreased slowly over the next week. He may also have a nasal catheter to administer medication directly to the surgical area. During his recovery period, your horse should only be allowed out of his stall for light hand-walking exercise. After this time, he will be scoped again. Providing that there are no complications, he can slowly resume training. If there are any complications when he is re-evaluated, your horse will require more rest and additional therapy, depending on the problem.

Surgical correction of epiglottic entrapment offers quite a good outcome. Most horses recover with no complications and return to competition with more vigor, breathing easier and performing better. Although there is some risk involved with surgery, the benefit to your horse’s health, and possibly to his overall winnings, justifies this procedure.


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