What is brachycephalic airway syndrome?

Brachycephalic obstructive airway syndrome (BOAS) refers to a set of airway abnormalities affecting short-nosed dogs and some breeds of cats. These abnormalities include an elongated soft palate, stenotic nares (small nostrils), a hypoplastic trachea (narrow airway to the lungs), and everted laryngeal saccules (which occurs secondarily to the other conditions).

The severe shortening of the bones of the nose and skull results in overcrowding of the soft tissues of the nose and pharynx (throat), resulting in severe airway obstruction. This condition, if not treated, can significantly impair your pet’s quality of life and can, in some cases, lead to life-threatening respiratory distress. Animals suffering from BOAS may have one or a combination of these problems.


What are the symptoms?

Brachycephalic syndrome affects breeds of dogs with short noses (brachycephalic dogs), including bulldogs, pugs, Shih-Tzus and chihuahuas. In cats, Persian and Himalayan breeds are most likely to be affected.

Common BOAS symptoms to look out for include:

  • Noisy or laboured breathing
  • Breathing difficulty
  • Wheezing
  • Snoring
  • Frequent panting
  • Struggling to exercise, especially in warm weather
  • Coughing, choking or vomiting
  • Poor sleep quality
  • Collapse

This can lead to a poor quality of life for these patients and means that you often have to make a number of lifestyle changes, for example, not taking your dog for long walks and not allowing them to over-exert themselves by playing with other dogs. These patients are also at risk of developing acute respiratory distress and heat stroke, both of which can be fatal. All brachycephalic dogs suffer from BOAS to some degree, and symptoms are often worse in warm weather, so keep an eye on them to monitor if their condition worsens.

 

The diagnosis

Diagnosing brachycephalic syndrome can usually be done by assessing your pet’s anatomy, as well as the sounds they make when breathing and a discussion of their symptoms. However, further tests, such as a throat examination, endoscopy or CT scan may be needed to assess different airway abnormalities affecting your pet.

 

How do we treat brachycephalic syndrome?

Fortunately, treatment for brachycephalic syndrome is not always necessary, so your specialist will assess whether your pet is experiencing severe symptoms and how they cope in warm weather. If they decide your pet would benefit from treatment, there are several surgical and non-surgical options, which your specialist will be able to advise you on.

Non-surgical management: Obesity can significantly worsen the signs of brachycephalic airway syndrome, so weight loss is often an important part of non-surgical treatment. Anti-inflammatory drugs and oxygen therapy may also be recommended to offer short-term relief from respiratory distress. If your dog only suffers from mild BOAS symptoms, their condition can often be managed by controlling exercise levels and keeping them cool during the summer.

Surgical management: If your pet’s airway abnormalities significantly interfere with their breathing, BOAS surgery is often the best course of action. Stenotic nares can be corrected by removing a wedge of tissue from the nostrils, and an elongated soft palate can be shortened to a more normal length. Everted laryngeal saccules can also be removed to eliminate the obstruction in the larynx.

Most dogs with BOAS will benefit from surgical correction of their primary and secondary abnormalities. During the initial consultation, we will take a thorough history from you and examine your pet in order to ascertain what your pet’s main problems are.

Once your pet is admitted to the hospital they will have a general anaesthetic and additional diagnostic imaging to further ascertain their problems and to decide on the most appropriate treatment. This will involve:

  • Laryngoscopy scan: On induction of general anaesthesia we will assess the length of the soft palate, the size of the palatine tonsils, laryngeal function and the degree of laryngeal collapse.
  • CT scan: CT allows us to assess the degree of intra-nasal obstruction, the thickness of the soft palate, the diameter of the windpipe and any secondary lung problems. We may also pick up other problems associated with brachycephalic conformation such as middle ear disease.

Corrective airway surgery is usually performed immediately after the diagnostic tests have been performed and involves some or all of the following procedures:

  • Alarplasty: this procedure results in widening of the external and internal nares.
  • Soft palate resection: this procedure removes the redundant tissue of the soft palate, permanently shortening it.
  • Tonsillectomy: this is removal of the palatine tonsils along with any redundant lateral pharyngeal tissue.
  • Laryngeal sacculectomy: This is removal of he everted laryngeal saccules (if present).

Following corrective surgery, these patients are usually discharged the following day. Typically they will be treated medically for 1-2 weeks with drugs designed to prevent gastro-oesophageal reflux and vomiting.

If you are worried your dog is showing signs of BOAS, you should discuss this with your vet, who can then arrange referral to Swift Referrals.