194 Macquarie Road, Warners Bay New South Wales 2282 49567719
Obstructive Airway disease
Brachycephalic obstructive airway syndrome (BOAS)
Brachycephalic is a term meaning "short-headed" and includes flat-faced breeds such as English and French bulldogs, pugs, Boston terriers, boxers, bull mastiffs, pekingese and shih tzus. They have a compacted skeleton, but the soft tissues in the head do not shrink in proportion, resulting in a short and narrowed airway and excessive soft tissues protruding into it.
It is not normal for dogs to make noise when they breathe. Sadly, selective breeding has gone to extremes to create these flat faced dogs for their cuteness, but at the expense of normal breathing. It is often perceived as "normal" for these breeds to be noisy breathers, but it means they are working hard to breathe in enough oxygen.
Clinical signs of brachycephalic obstructive airway syndrome (BOAS) can include noisy breathing, exercise intolerance, retching, gagging, snoring, coughing, heat intolerance, reverse sneezing, interrupted sleep and sometimes collapse. Some dogs with an long soft palate sleep upside down so the soft palate does not fall into the airway. Depending on the abnormalities present in each dog, surgery may address a combination of anatomic deformities detailed below.
Stenotic nares
This refers to narrowed nostrils. Try gently pinching your own nose either side with your fingers and after just a few breaths you will realise how unpleasant breathing becomes. Narrowed nasal passages often leads to open mouth breathing and panting, as it is too much effort to breathe through the nose. Even small improvements in the nostril diameter can make a big difference to ease of breathing. Stenotic nares surgery involves removing excessive nasal tissue to open up this part of the airway.
Elongated soft palate The soft palate separates the nasal passage from the mouth. When it is too long it flaps down into the throat, creating snoring sounds and impeding airflow into the lungs. We cannot assess whether the soft palate is elongated until your pet is anaesthetised, but in ~85% of brachycephalic dogs the soft palate is abnormally long. Surgery involves making the palate shorter.
Everted laryngeal saccules ( see image below) In a normal dog these are a little pocket within the throat that allow vibration of the vocal cords. Excessive negative pressures within the airways can cause these pockets to turn inside out, which causes partial obstruction of the airway. This cannot be evaluated until your pet is anaesthetised. If these are found to be significantly everted, they will need to be removed.
Everted tonsils
Significantly enlarged tonsils can impede airflow within the mouth. Mildly everted tonsils should revert to normal after other parts of the airway are surgically addressed. This is assessed when your pet is anaesthetised and the tonsils are removed if indicated.
Secondary changes
The extra work required to breathe and turbulent airflow results in airways becoming inflamed and swollen, which worsens airway obstruction and adds to the work required to breathe. This becomes a progressive cycle of worsening inflammation and obstruction. These dogs are more prone to heat stroke and complete airway obstruction which are life-threatening conditions. Airway surgery has better outcomes when it is performed before many of these secondary changes develop. The prognosis is good in most young animals after surgical intervention.
The nasal cavities behind the nose are compacted and torturous, leading to high airflow resistance. Some dogs have a hypoplastic trachea (narrow windpipe) which cannot be fixed surgically. Chronic cases can develop laryngeal collapse of the windpipe which can make things even worse
Although we do our best by surgically addressing the above problems, not all brachycephalic malformations have a surgical fix available. The tongue is oversized compared to the rest of the head which contributes to obstruction of the mouth. Unfortunately no surgery can transform these dogs into a "normal" dog. Most dogs will still have some degree of airway noise after surgery, but overall 85-90% dogs are improved with surgery. It is important to keep these dogs a lean weight throughout life so there is less pressure on the airways.
Gastrointestinal diseaseA lot of owners do not realise that BOAS problems often also lead to digestive problems. Dogs must suck air in harder when breathing, which creates negative pressure within the airways, which sucks up digestive juices from the stomach. This results in regurgitation or vomiting. Many dogs will show improvement in these signs after airway surgery, but some may need to remain on medications ongoing for management.
Dogs with significant airway issues should not be bred. If you are getting another brachycephalic puppy in future, we recommend choosing breeders that are trying to improve the breed standard with longer noses and less medical problems.
Age at which surgery is recommended (unless significant clinical signs earlier):· French bulldogs, pugs, boston terriers- 8-12 months old.· English or British bulldogs- 10-14 months old.Keep in mind a small proportion of dogs may require a follow up surgery later due to progressive changes.
Drs Alice Read and Cathy O'Neill perform BOAS surgery here at Vetz