Dynamic nasopharyngeal collapse in horses: What we know so far.
Authors: Jeong Sharon, Bond Stephanie L, Sole-Guitart Albert
Journal: Equine veterinary journal
Summary
Dynamic nasopharyngeal collapse (NPC) represents a significant yet poorly understood cause of exercise-induced upper airway obstruction in horses, affecting the inspiratory phase and potentially compromising up to 25% of high-performance athletes presenting with poor performance. During intense exercise, the neuromuscular structures supporting the nasopharynx—comprising the lateral walls, dorsal roof, and ventral soft palate—can be overwhelmed by negative inspiratory pressures, leading to airway narrowing that further exacerbates the pressure gradient in a self-perpetuating cycle. Although the condition is recognised as severely performance-limiting and accounts for substantial athletic wastage and economic loss across the sport horse and racing industries, the exact pathophysiology remains poorly characterised, and currently no definitive treatment exists. This 2024 review highlights the sparse evidence base surrounding NPC compared with other dynamic upper respiratory tract disorders, emphasising that most affected horses face a guarded prognosis with retirement from athletic use being the typical outcome. The authors advocate for enhanced research efforts to clarify disease mechanisms and develop effective interventions, which could extend the competitive careers of elite equine athletes and reduce the considerable economic impact of premature retirement.
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Practical Takeaways
- •NPC should be considered in performance horses presenting with poor athletic performance or exercise intolerance, as it affects a significant proportion of high-performance athletes
- •Currently there is no effective treatment available, so focus should be on early recognition and realistic career counseling with owners regarding prognosis and likely retirement from competitive use
- •Further research is critically needed to develop therapeutic interventions that could extend athletic careers and reduce economic losses in affected horses
Key Findings
- •Dynamic nasopharyngeal collapse affects up to one quarter of high-performance equine athletes presenting for poor performance
- •NPC occurs when neuromuscular activity is overwhelmed by negative pressures during strenuous exercise, causing collapse of nasopharyngeal components (lateral walls, dorsal roof, or ventral soft palate)
- •Small changes in airway diameter produce profound increases in negative inspiratory pressure, perpetuating the collapse cycle
- •No definitive treatment currently exists; prognosis is guarded with most affected horses being retired from athletic use