High-speed treadmill videoendoscopic examination of the upper respiratory tract in the horse: the results of 291 clinical cases.
Authors: Tan Rachel H H, Dowling Bradley A, Dart Andrew J
Journal: Veterinary journal (London, England : 1997)
Summary
# Editorial Summary Between 1997 and 2003, Tan and colleagues reviewed high-speed treadmill videoendoscopic findings from 291 horses, identifying upper airway abnormalities in 42% of the 265 animals examined at rest, with 49% of affected horses displaying multiple concurrent disorders. Axial deviation of the aryepiglottic folds proved most prevalent (55% of the 192 horses with exercise-induced abnormalities), followed by dorsal displacement of the soft palate (39%) and idiopathic left laryngeal hemiplegia (34%), alongside less frequent conditions including arytenoid collapse, dynamic pharyngeal collapse and epiglottic entrapment. Notably, horses presenting with respiratory noise complaints were significantly more likely to demonstrate exercise-induced abnormalities than those referred for poor performance alone (82% versus 49%), and a dose-response relationship emerged between increasing severity of aryepiglottic fold deviation and the number of concurrent pathologies. For practitioners, these findings underscore that resting endoscopy alone provides incomplete diagnostic information, making dynamic exercise assessment essential when evaluating poor performance and particularly when respiratory noise is reported; the high frequency of multiple simultaneous abnormalities in a substantial proportion of cases further emphasises that high-speed treadmill videoendoscopy should be considered the gold standard where available, as it fundamentally influences treatment selection, prognostic counselling and management planning.
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Practical Takeaways
- •High-speed treadmill videoendoscopy should be routinely used for horses presenting with poor performance or respiratory noise, as nearly half develop detectable upper airway abnormalities during exercise that may not be apparent at rest
- •Plan for multiple concurrent airway abnormalities when counseling owners on diagnosis and prognosis, as half of affected horses have more than one condition
- •Horses with respiratory noise complaints have a much higher yield (82%) for finding pathology compared to poor performers (49%), helping prioritize diagnostic resources
Key Findings
- •42% of horses (112/265) undergoing resting endoscopy had recognized upper airway abnormalities
- •Axial deviation of aryepiglottic folds was the most common abnormality at 55%, followed by dorsal displacement of soft palate at 39% and left laryngeal hemiplegia at 34%
- •49% of horses had multiple abnormalities detected during high-speed treadmill videoendoscopy
- •Horses referred for respiratory noise evaluation had significantly higher detection rates (82%) compared to those referred for poor performance (49%)