Idiopathic mucosal lesions of the arytenoid cartilages of 21 Thoroughbred yearlings: 1997–2001

Abstract

Summary Reasons for performing study: Mucosal ulcers and, occasionally, small granulomas on the axial surface of one or both arytenoid cartilages have been found in TB yearlings presented for post sale endoscopic examination. Objectives: To determine the incidence, endoscopic characteristics and outcome of a group of Thoroughbred yearlings affected with mucosal ulcers and granulomas of the arytenoid cartilage. Hypothesis: The incidence of mucosal ulceration of the arytenoid cartilages of yearling Thoroughbreds is relatively high compared to other upper airway abnormalities; and that the majority of mucosal ulcers heal uneventfully, although a small percentage may progress to a granuloma and, less commonly, to arytenoid chondropathy. Methods: The findings of post sale, upper airway endoscopic examinations of 3312 Thoroughbred yearlings, during a 5 year period, were reviewed, including those abnormalities listed in the conditions of sale and others not listed but considered likely to cause airway obstruction. Information obtained from the medical record of horses that had mucosal ulceration or granuloma of the arytenoid cartilage included the location and size of the lesion(s), sex of the affected horse and the presence and nature of other concurrent abnormalities of the upper portion of the respiratory tract. Additional information included treatment and results of follow‐up, endoscopic examination by the authors or attending veterinarian. Results: Mucosal lesions were seen in 0.63% of yearlings evaluated, which represented the most common, documented condition of the upper portion of the respiratory tract. The mucosal ulcers of 15 of 19 horses were considered to have healed without complication during follow‐up examination; one of the 19 horses was lost to follow‐up. Two horses affected with bilateral, arytenoid mucosal ulceration developed a granuloma at each site of ulceration. One horse developed a granuloma at a site of ulceration and, subsequently, arytenoid chondropathy. Conclusions: Arytenoid mucosal ulceration in sales yearlings was a relatively commonly encountered abnormality and a small percentage progressed to granuloma or chondropathy. Potential relevance: The mucosa of the arytenoid cartilage, particularly at the rostral margin of the vocal process, should be examined carefully during endoscopic examination of the upper portion of the respiratory tract of Thoroughbred yearlings presented for sale. Because a small percentage of mucosal ulcers may progress to granuloma or, less commonly, chondropathy, identification of mucosal ulcers of the arytenoid cartilage seen during post sale, endoscopic examination warrants notification to the purchaser and sales company. Medical therapy of affected horses should be considered and follow‐up endoscopic examination performed to determine if the lesion has healed.

Prevalence of pharyngeal and laryngeal abnormalities in Thoroughbreds racing in Australia, and their association with performance

“…Ulceration of the mucosa covering the arytenoid cartilages occurs in 0.6% of Thoroughbred weanlings examined after sale (Kelly et al 2003), but its prevalence in racehorses has not to our knowledge been reported. Mucosal ulceration had the highest prevalence (2.4%) of any abnormalities detected in the current study.…”

“…The clinical importance of mucosal ulceration is uncertain, although in the current study it was not associated with poor race performance. Lesions in 15 of 18 yearling Thoroughbreds with mucosal ulceration detected on endoscopic examination after sale and treated with antimicrobial and anti-inflammatory drugs healed within 42 days (Kelly et al 2003). However, the other 3 horses developed a granuloma at the site of ulceration with one also developing arytenoid chondritis.…”

Study of laryngopharyngeal pathology in Thoroughbred horses in southern California

“…Histology had a minor impact in the total prevalence of the lesions observed, since only one subepiglottic ulcer not evident grossly was observed on light microscopy. To our knowledge, only 2 studies describe ulcers in the larynx and/or pharynx of racehorses (Kelly et al 2003;Brown et al 2005) but there are none that describe the prevalence of lesions in the subepiglottic area and soft palate free border. In the present study, 7 (54%) of the 13 horses with laryngopharyngeal abnormalities had lesions in the subepiglottic area (subepiglottic ulcers, soft palate kissing lesions and subepiglottic scar), suggesting that an important number of abnormalities may be missed on routine upper airway endoscopy.…”

“…There are many reported abnormalities of the upper respiratory tract of Thoroughbred horses observed during endoscopy (Sweeney et al 1991;Hawkins and Tulleners 1994;Hobo et al 1995;Embertson 1998;Stick et al 2001;Kelly et al 2003); however, some anatomical structures in the laryngopharynx (i.e. the subepiglottic region and margins of the intrapharyngeal opening including the free border of the soft palate) are difficult to examine during routine endoscopy and lesions in these locations may be under reported.…”

Ultrasound features of arytenoid chondritis in Thoroughbred horses

“…The precise aetiology of arytenoid chondritis is unknown, but it is suspected to be secondary to mucosal trauma leading to a viral or bacterial infection that progresses to involve the arytenoid cartilage(s) [1,3]. Haynes et al reported on pathological findings of chondritic arytenoid cartilages following subtotal arytenoidectomy [2].…”