Epiglottic entrapment is a less common cause of respiratory noise and exercise intolerance. In this condition, the aryepiglottic fold completely envelops the apex and lateral margins of the epiglottis. The general shape of the epiglottis is visible, and the soft palate is located normally, ventral to the epiglottis. However, the distinct serrated margins of the epiglottis and the dorsal epiglottic vascular pattern are obscured by a fold of aryepiglottic mucosa. The exact cause for entrapment remains unknown but epiglottic hypoplasia has been reported in some affected horses. Chronic entrapment may result in ulceration and thickening of the aryepiglottic tissue or the epiglottic mucosa.
Clinical Signs of Epiglottic Entrapment in Horses
The most common signs include inspiratory and expiratory noise during exercise and poor performance. Less common signs include cough, nasal discharge, and headshaking. In mature non-racehorses, cough is the most consistent clinical sign.
Diagnosis of Epiglottic Entrapment in Horses
Diagnosis is determined by endoscopic examination; over-ground endoscopy may be required to detect intermittent entrapment during exercise.
Treatment of Epiglottic Entrapment in Horses
Persistent entrapment is treated surgically. Surgical correction of epiglottic entrapment through transendoscopic axial division of the aryepiglottic fold using an Nd:YAG or diode laser is the preferred approach to free the epiglottis, with a relapse rate of ~5%. Other approaches include transnasal or transoral transection via curved bistoury (~0%–15% relapse), transendoscopic axial division with electrocautery (40% relapse)(1), transoral wire‐snare resection, or direct excision through a laryngotomy or pharyngotomy. Some intermittently affected horses can be managed successfully with exercise restriction and anti-inflammatory treatment.
References
Gutierrez-Nibeyro SD. Epiglottic Entrapment. In: Diseases of the Respiratory System. Large Animal Internal Medicine 6th Edition, Smith BP, Van Metre D, Pusterla N, Eds. Elsevier Inc, Philadelphia. 2020:629–630.
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