Nasopharyngeal cicatrix syndrome has been reported for horses living in central and southeastern Texas.1–3 This syndrome was first reported in 1987, and within that report1 were descriptions of horses with the syndrome as early as 1972. More recently, NCS was noted to be the most common condition in horses seen at Texas A&M University's Large Animal Teaching Hospital from 1995 to 2005 for which permanent tracheostomy was required,2 and it was the most common disorder of the upper portion of the respiratory tract seen at that hospital during that period.1–3 Clinical features of NCS include catarrhal inflammation of the nasopharynx, larynx, or both during the acute phase of the syndrome, which is replaced with web-like scarring during the chronic phase of the syndrome. Common endoscopic findings of NCS include scarring of the nasopharynx, circumferential or localized to the soft palate just rostral to the epiglottis; epiglottic deformation; bilateral arytenoid chondropathy; thickening of the vocal cords; and scarring of the salpingopharyngeal openings. Ulceration and scar formation of the mucosa of the nasal cavities and proximal aspect of the trachea are also observed in some cases. Severity of the syndrome ranges from abnormalities that are detected as incidental findings at the time of endoscopic examination of the upper portion of the respiratory tract to obstruction of the upper respiratory tract so severe that the horse requires permanent tracheostomy for survival.2 A recent study4 on a subset of the population of horses evaluated in the study reported here identified nasal discharge, exercise intolerance, respiratory stridor, and respiratory distress as clinical signs associated with endoscopic findings of NCS.
Despite long-standing awareness of this condition and its anecdotally high morbidity rate in some geographic regions, risk factors for the condition have received little investigation. The purpose of the study reported here was to determine risk factors associated with the development of NCS in horses.
Markov chain Monte Carlo
Nasopharyngeal cicatrix syndrome
WinBUGS, version 3.1.1, MRC Biostatistics Unit, Camridge, England.
2. Chesen AB, Rakestraw PC. Indications for and short- and long-term outcome of permanent tracheostomy performed in standing horses: 82 cases (1995–2005). J Am Vet Med Assoc 2008; 232: 1352–1356.
3. Dean PW, Cohen ND. Arytenoidectomy for advanced unilateral chrondropathy with accompanying lesions. Vet Surg 1990; 19: 364–370.
4. Norman TE, Chaffin MK, Bisset WT, et al. Association of clinical signs with endoscopic findings in horses with nasopharyngeal cicatrix syndrome: 118 cases (2003–2008). J Am Vet Med Assoc 2012; 240: 734–739.
5. Lunn D, Spiegelhalter D, Thomas A, et al. The BUGS project: evolution, critique and future directions. Stat Med 2009; 28: 3049–3067.
6. Gildea S, Arkins S, Cullinane A. Management and environmental factors involved in equine influenza outbreaks in Ireland 2007–2010. Equine Vet J 2011; 43: 608–617.