Subepiglottic cysts are an uncommon cause of respiratory noise in young horses. They are likely present from birth but remain undetected until the horse begins exercise training. These cysts are suspected to arise from remnants of the thyroglossal duct. Clinical signs include respiratory noise and exercise intolerance. Large cysts may produce coughing, dysphagia, and aspiration in foals. Diagnosis is determined by endoscopic examination of the upper respiratory tract. The cyst appears as a smooth-walled, fluctuant mass that contains thick, yellow, mucoid material. Occasionally, the mass is not visible in the nasopharynx, and oral examination under general anesthesia may be required to identify it. Histologically, subepiglottic cysts are lined with a combination of stratified squamous and pseudostratified columnar epithelium. Treatment involves complete removal of the secretory lining of the cyst. Rupture of the cyst results in immediate decompression, but recurrence is common. The most common approach is ventral laryngotomy, although transendoscopic Nd:YAG laser surgery has been used for complete excision.
OTHER TOPICS IN THIS CHAPTER
Respiratory Diseases of Horses
Overview of Respiratory Diseases of Horses
Equine Herpesvirus Infection
Equine Influenza
Equine Viral Arteritis
Hendra Virus Infection in Horses
Pleuropneumonia in Horses
Rhodococcus equi Pneumonia in Foals
Acute Bronchointerstitial Pneumonia in Foals
Strangles in Horses
Recurrent Airway Obstruction in Horses
Inflammatory Airway Disease in Horses
Exercise-induced Pulmonary Hemorrhage in Horses
Laryngeal Hemiplegia in Horses
Pharyngeal Lymphoid Hyperplasia in Horses
Dorsal Displacement of the Soft Palate in Horses
Epiglottic Entrapment in Horses
Subepiglottic Cyst in Horses
Fourth Branchial Arch Defect in Horses
Diseases of the Nasal Passages in Horses
Diseases of the Paranasal Sinuses in Horses
Guttural Pouch Disease in Horses