A condition characterized by incomplete formation or weakening of the cartilagenous rings of the trachea resulting in flattening of the trachea. It can be congenital or acquired, and extrathoracic or intrathoracic. At least initially, tracheal collapse is a dynamic condition. Collapse of the cervical trachea (in the neck) occurs during inspiration; collapse of the thoracic trachea (in the chest) occurs during expiration. Tracheal collapse is most commonly found in small dog breeds, including the Chihuahua, Pomeranian, Toy Poodle, Shih Tzu, Lhasa Apso, Maltese, Pug, and Yorkshire Terrier.
Symptoms include a cough and/or hack with gag (often called a "goose honk cough" due to its sound), especially when excited. Other symptoms include exercise intolerance, respiratory distress, and gagging while eating or drinking. Tracheal collapse is easily seen on an x-ray as a narrowing of the tracheal lumen. Treatment for mild to moderate cases include corticosteroids, bronchodilators, and antitussives. Medical treatment is successful in about 70 percent of tracheal collapse cases. Severe cases can be treated with surgical implantation of a tracheal stent (inside or outside of the trachea) or prosthetic rings. Intraluminal stenting has shown more promise for success with intrathoracic cases, especially using nitinol, a type of shape memory alloy composed of nickel and titanium.