If nasal discharge, a cough or heavy breathing persists, it may be necessary to use the endoscope, a flexible tube with a light and camera attached, to examine the upper airways. Endoscopy is a non-surgical, minimally invasive procedure that allows for examination of the upper respiratory tract (nostrils, nasal cavity, sinus drainage site, pharynx, larynx, guttoral pouches and trachea).
Normal procedure is to evaluate the horse with or without sedation depending on the initial complaint. After the horse is sedated, a local anesthetic is sprayed up the nasal cavity to numb the area. The endoscope is passed through the nostril and is fed up the nasal cavity along the floor of the ventral meatus. By watching the monitor, the endoscope is manoeuvred up the nasal cavity and around guttural pouches, larynx, nasopharynx and upper trachea. It can be used to detect areas of inflammation, excessive mucus production or a defect such as “roaring” (laryngeal paralysis).