The use of a fibre-optic scope allows visualisation of the horse’s upper respiratory tract, including the pharynx, larynx and trachea. Endoscopic Examination also known as ‘scoping’ can be done routinely or may be indicated after coughing, nasal discharge or respiratory noise detected during exercise.
Photo: Dr Ross Alexander attaching the Dynamic Scope
On examination, the arytenoid cartilages of the larynx are evaluated for symmetry and movement. A grading system is used to assess arytenoid function during normal respiration, after swallowing and when required following nasal occlusion. Any evidence of pharyngitis, or pharyngeal lymphoid hyperplasia is noted and graded. The epiglottis is also evaluated for any ulceration or other abnormalities. The trachea is then examined for signs of infection or haemorrhage. The findings of the endoscopic examination are discussed with the trainer, enabling an appropriate treatment or management plan to be formulated.
Whilst most endoscopic examination is done in horses at rest, a dynamic endoscopic examination can be performed to assess the upper airway during exercise. Recent technological advances have enabled this examination to be carried out during morning trackwork at the racecourse. A specially designed video endoscope is fitted over the bridle, which allows the horse to work under normal training conditions and with its own tack in place. The video footage is then downloaded for frame-by-frame analysis.
Dynamic respiratory endoscopy may be recommended in horses which make an abnormal respiratory noise during work, have a history of poor performance, or to further evaluate the arytenoid movements of horses which show reduced laryngeal function at rest.
Multiple abnormalities can be detected in the upper airway during a dynamic scope, namely: collapse of the arytenoid cartilages, deviation of the aryepiglottic folds, collapse of the vocal cords, dorsal displacement of the soft palate and pharyngeal collapse. Such abnormalities can limit airflow, which leads to early fatigue and poor performance.
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