When a dog inhales, through the nose or oral cavity, the air passes through a tube called the “trachea” to reach the lungs. The trachea is held open by rings of cartilage.
In the event of tracheal collapse, the cartilage rings collapse and the tube flattens, which leads to a reduction in the diameter of the tracheal lumen. There are 4 grades: grade 1 results in a slight collapse which gradually worsens until grade 4 where the trachea is completely flattened and the walls touch each other.
This pathology is generally linked to a weakening of the cartilage rings which becomes more pronounced as the animal ages. In rare cases, a congenital malformation (present from birth) can cause the same pathology in young dogs. Certain factors can contribute to aggravating this pathology: excess weight, inhalation of pollutants/smoke, excessive barking, bacterial superinfection of the trachea, repeated microlesions induced by a collar, etc.
Middle-aged and elderly small breed dogs are most frequently affected: Yorkshire Terrier, Miniature Spitz, Bichons, Chihuahua, Lhasa Apso, etc.
The main symptom is a chronic cough. Most often, owners report a very loud and characteristic cough called a “honking cough”. Cough is often exacerbated by exercise and excitement. Other symptoms that may be observed are: snoring, faster breathing and exercise intolerance.
In the most severe cases, when the diameter of the trachea is greatly reduced, dogs can develop breathing difficulties, syncope and cyanosis (the mucous membranes become gray/blue instead of pink) since the animal lacks oxygen.
The diagnosis is made following symptoms. To confirm the pathology, x-rays and/or endoscopy of the respiratory tract are carried out.
Chest x-rays can reveal collapse (collapse) of the trachea. As the collapse is often dynamic, it varies with the breathing phases and it is sometimes necessary to take several x-rays to highlight it. Endoscopy makes it possible to grade tracheal collapse and take samples.
Most of the time medical treatment is effective as a first choice. This treatment is based on cough suppressants, anti-inflammatories and bronchodilators. Medical treatment is associated with preventive measures such as weight management, wearing a harness instead of a collar, eliminating contact with substances that irritate the respiratory tract, etc. It is also necessary to avoid events or activities that stress the dog.
For severe cases, and when medical treatment is not sufficient, the installation of a tracheal stent (rigid device that keeps the trachea open) may be considered.
The response to treatment varies from one case to another but generally the prognosis is good in the medium term and reserved in the long term.
Dr Emilie Vangrinsven
Diplomate from European college of veterinary internal medicine | PhD U-Liège
Assistant at the Liege University in the university clinic for PETs | Author and co-author of numerous scientific publications