TRACHEAL STENOSIS AND COLLAPSE IN HORSES

Conditions that result in decreased tracheal diameter occur infrequent ly in horses. Tracheal stenosis and collapse can, however, produce dra matic clinical signs, including respiratory strider, dyspnea, and cyan osis. Typically, tracheal stenosis results from trauma to the tracheal rings, trauma and abscessation of regional lymph nodes, peritracheal hematomas, or neoplasia. Tracheal collapse might be related to abnorma l tracheal cartilage matrix and is most often diagnosed in ponies and miniature horses. The diagnosis of tracheal stenosis and collapse is b ased on signalment, history, clinical signs; and endoscopic radiograph ic findings. Primary or secondary tracheal stenosis can occur in horse s of any breed, age, or sex. The main goals in treating equine patient s with tracheal stenosis and collapse are to restore the normal round to oval shape of the lumen and to normalize airflow to the lungs. The method of treatment depends on the cause of the stenosis as well as th e length and location of the involved tracheal segment. In all cases, it is necessary :to treat the underlying condition. If the lesion can be treated successfully, the prognosis for patients with extraluminal tracheal collapse lapse is generally favorable. If tracheal lumen size does not return to normal, surgical reconstruction of the trachea may be required; especially if the patient is intended for athletic use. In horses with tracheal collapse secondary to pneumonia; a successful outcome may be achieved by appropriate medical therapy. This article d iscusses the clinically relevant anatomic features of the trachea that predispose it to stenosis and collapse. Also considered are the patho genesis, clinical signs, diagnosis, treatment, and prognosis of each o f these conditions in horses.