Dynamic nasopharyngeal collapse in horses

Surprising statistic: 1/4 of horses experiencing decreased performance are suffering from nasopharyngeal collapse. Difficult to diagnose, requiring dynamic endoscopy, and no known treatment, nasopharyngeal collapse often ends the career of a performance horse.
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Dynamic nasopharyngeal collapse in horses: What we know so far
Equine Vet J. 2023 Dec 12. doi: 10.1111/evj.14022. Online ahead of print.
Authors
Sharon Jeong 1 , Stephanie L Bond 1 , Albert Sole-Guitart 1
Affiliation

1 School of Veterinary Science, Faculty of Science, University of Queensland, Gatton, Queensland, Australia.

PMID: 38084762
DOI: 10.1111/evj.14022

Abstract

Dynamic nasopharyngeal collapse (NPC) is an obstructive upper airway disease that affects mainly the inspiratory phase of respiration in horses undergoing strenuous exercise. It occurs when the neuromuscular activity of the nasopharynx is overwhelmed by the intense negative pressures generated during exercise. This leads to collapse of at least one of the four components of the nasopharynx which is comprised of the two lateral walls, the dorsal roof and the ventral soft palate. As a result, the airway diameter and thus airflow become compromised. Even small changes in the airway diameter produces profound increases in negative inspiratory pressure, perpetuating the cycle of collapse. Compared to other dynamic upper respiratory tract disorders, the amount of literature on NPC as a disease entity is limited. The exact pathophysiology of NPC is unknown; however, it impacts up to one quarter of high-performance equine athletes presenting for poor performance. There is currently no definitive treatment for this severely performance-limiting condition. Thus, the prognosis for future athletic prognosis is guarded, with most horses being retired from racing or athletic use in general. Further research is warranted in this field to reduce the impact of disease and in turn, reduce the turnover rate and economic loss by enhancing the career longevity of elite equine athletes diagnosed with NPC.

Keywords: dynamic endoscopy; horse; nasopharynx; pharynx; upper respiratory disease.

© 2023 The Authors. Equine Veterinary Journal published by John Wiley & Sons Ltd on behalf of EVJ Ltd.