What is collapsing trachea?
Weak cartilaginous rings are unable to maintain their conformation during the normal respiratory cycle. There is a tendency that during inspiration (breathing in) the trachea will flatten narrowing the airway. In unaffected dogs, the trachea is able to resist the negative pressures caused by inspiration and maintain its shape.
How can I tell if my dog has collapsing trachea?
Dogs may express a number of symptoms including:
- Unusual noise when breathing
- Persistent coughing
- Exercise intolerance
- Acute respiratory arrest
Patients suffering from collapsing trachea may present with respiratory noises such as honking and wheezing. Coughing can be more severe in some patients who will present with a sudden increase or recurring hacking cough. It is important to note however that some patients will not exhibit any clinical symptoms of the disease.
Two cases showing the characteristic ‘honk’ associated with tracheal collapse
What is the cause of collapsing trachea?
The precise cause of tracheal collapse is unknown, however due to the consistent occurrence within certain breeds it is suggested there is a genetic basis to the disease. It is particularly common in toy poodles, Yorkshire Terriers, Maltese and Chihuahuas. It is also documented that in affected patients the tracheal cartilages become hypocellular (have an abnormally large number of cells) and there is degeneration within the cells alluding to this being the cause of the disease but this is unconfirmed.
How is collapsing trachea diagnosed?
Often a presumptive diagnosis will be given based on the clinical history and symptoms of the patient with more intensive investigations delayed to reduce the stress caused by physical examination on the respiratory system. The most reliable method of diagnosis is tracheoscopy which allows for the extent and severity of the collapse to be determined. This method of diagnosis does require general anaesthesia which makes some patients ineligible for such diagnostics. Plain radiography may also be used but this has a lower efficiency in detecting abnormalities, a CT scan is often the better method for identification of pulmonary changes. It is important to note that during investigations into diagnosis, clinicians will also try to establish any contributing factors to the severity of the patient’s symptoms.
How is collapsing trachea treated?
This is recommended in all patients with tracheal collapse. It is often directed at any of the contributing factors/causes found during diagnosis and/or management of symptoms such as the cough. Corticosteroids may be used to relieve inflammation and aerosol products delivered via an inhaler may be suggested for prolonged use. Anti-secretory agents are often used to reduce the volume of mucus secreted into the airway. Other changes to the surroundings, such as removal of airway irritants, and changes to the diet can have a profound impact on disease expression.
Surgical management is often used for patients with severe structural abnormalities or where medical management has proven unsuccessful. Surgery often involves the placement of 5-8 plastic rings which provide structural support to the tracheal cartilages and muscle. This is the most conventional surgery with clinical improvement noted in 75-85% of patients.
Intra-luminal stents are self-expanding or balloon-expandable stents which can be inserted into the lumen of the trachea to provide support for patients affected by tracheal collapse. It is recommended that, due to the progressive nature of this disease, the entire length of a patient’s trachea is stented. It is important that stent size is measured accurately to limit complications such as stent migration or fracture. Placement of stents generally result in significant improvement in clinical signs immediately after placement however they do require ongoing medical management and frequent monitoring.
Flexible, metallic stents are placed into the trachea to help maintain the structure of the trachea, and can help relieve many of the symptoms of tracheal collapse.
What is the prognosis of collapsing trachea in dogs?
Prognosis for dogs with collapsing trachea is variable and often depends on the changes implemented into aspects of the patients lifestyle. Selection of treatment is very individual so the long-term prognosis of patients is therefore dependent on the choice elected. Many patients can be successfully managed with medical treatment alone whereas some require surgical stabilisation of the trachea.