High-speed treadmill videoendoscopic examination of the upper respiratory tract in the horse: the results of 291 clinical cases.

This research article examines the prevalence and types of upper respiratory tract abnormalities in horses, and the associations among them, using high-speed treadmill videoendoscopy. The two most common disorders found were axial deviation of the aryepiglottic folds and dorsal displacement of the soft palate.

Objective and Methodology of the Study

• The study aimed to identify and quantify the frequency of different upper respiratory tract disorders in horses. It also sought to identify any significant associations between the severity of axial deviation of the aryepiglottic folds and the presence of any other abnormalities.
• Using high-speed treadmill videoendoscopy, the researchers examined upper respiratory tracts of horses from November 1997 to September 2003. They reviewed the clinical records and video recordings of 291 horses, evaluating the prevalence and types of respiratory tract abnormalities during rest and exercise.

Main Findings of the Study

• A total of 265 out of 291 horses had resting endoscopy, and 42% (112/265) turned out to have a recognized abnormality.
• A significant proportion of horses exhibited more than one abnormality, with 49% of horses showing multiple disorders.
• The two most prevalent disorders were axial deviation of the aryepiglottic folds (55%), and dorsal displacement of the soft palate (39%), followed by idiopathic left laryngeal hemiplegia (34%). Less common disorders included arytenoid collapse, vocal fold collapse, dynamic pharyngeal collapse, epiglottic fold entrapment, epiglottic retroversion, rostral displacement of the palatopharyngeal arch, and right laryngeal hemiplegia.
• Horses with axial deviation of the aryepiglottic folds showed a significant correlation between increasing severity of the deviation and the increasing number of abnormalities detected, however no other associations were found.
• Horses referred for the evaluation of a respiratory noise (82%) were more likely to have an abnormality detected during exercise than those referred for poor performance (49%).

Implications and Recommendations

• High-speed treadmill videoendoscopy proved crucial for the evaluation of poor performance in horses, particularly those with a history of respiratory noise.
• Given the high occurrence of multiple abnormalities, the study suggests that high-speed treadmill videoendoscopy should be recommended where possible for accurate diagnosis, providing appropriate treatment options and offering prognosis for affected horses.