Chronic chondritis of the equine arytenoid cartilage.

Chronic chondritis of the arytenoid cartilage was diagnosed in 7 male Thoroughbred horses examined for obstructive upper airway disorders. The history of the cases was characterized by a 3- to 6-month progression of exercise intolerance and inspiratory dyspnea during exercise. Endoscopy revealed marked asymmetry of the rima glottidis, partial or complete inability to abduct the involved cartilage, and axial displacement of the involved arytenoid cartilage. In less severe cases, the disorder was confused with laryngeal hemiplegia. Focal elevated lesions of the involved cartilage, which were frequently seen, produced contact lesions on the contralateral cartilage. Subtotal arytenoidectomy was performed in 6 cases. Histologic examination of the removed cartilages revealed marked lamination of the cartilage with fibrous connective tissue. Granulating sinus tracts were seen in 3 cases. The surgical intervention resulted in marked improvement of exercise intolerance in 5 cases.