Nasal Discharge: Where's it Coming From & What we can do about it?
by Eric J. Parente, DVM, Diplomate ACVs
Nasal discharge can represent something benign, life threatening or anything in between. Often horses are placed on antimicrobials for any nasal discharge because of limited ability to evaluate the problem and effectively treating the horse. However, with advanced diagnostic imaging and newer surgical techniques, the effectiveness of treating such patients has improved dramatically. In most cases, nasal discharge is not an emergency, but any horse with nasal hemorrhage should be evaluated immediately. While bilateral epistaxis is most commonly from exercise induced pulmonary hemorrhage and not life threatening, a severe bleed from the guttural pouch could be from one or both nares and is life threatening. Guttural pouch hemorrhage is most often the result of a mycotic infection eroding through major arteries in the pouch lining. A large volume of blood evident on endoscopic examination at the guttural pouch opening is often the only evidence needed prior to referral for surgery. Trying to endoscopically evaluate the inside of the guttural pouch close to the time of a severe bleed is usual futile since the amount of blood within the pouch will obscure visualization. Surgery is aimed at obstructing blood flow through the major vessels in the lining of the guttural pouch. Ligation at the cardiac side as a sole procedure is often ineffective because of retrograde flow, so the vessels must be obstructed or embolized on the cranial side as well. If there is not an opportunity to obstruct vessel cranial to the lesion, ligation at the cardiac side can be effective in a small percentage of horses. The surgery not only prevents further hemorrhage but also causes the mycotic lesions to resolve without any medical therapy. Any evidence of neurologic disease (laryngeal dysfunction or dysphagia) should be determined prior to surgery.