Brachycephalic airway syndrome in dogs
This article is written by one of our in house veterinarians, Dr Teagan Lever.
Brachycephalic means 'short nosed' and describes breeds such as Pugs, Pekingese, Boston Terriers, Bulldogs, Boxers as well as other dogs with flat or 'pushed in' faces. Brachycephalic airway syndrome is a combination of anatomical defects which typically occur in brachycephalic breeds and combine to cause obstructed breathing. These anatomical defects are a result of years of selective breeding for the brachycephalic appearance.
What contributes brachycephalic airway syndrome?
Stenotic nares: Essentially stenotic nares is a fancy way for saying 'narrow nostrils'. Many brachycephalic breeds are born with stenotic nares, these narrowed nostrils make it much harder work to breathe air through the nose.
Elongated soft palate: Elongated soft palate occurs because the normal soft tissues of the mouth and nasal cavity have been forced to fit into a smaller space. This results in the soft palate being too long and interfering with the normal mechanics of breathing and is why brachycephalic breeds tend to snore (even when they are awake sometimes!). While it may seem harmless enough, this extra tissue again makes the act of breathing more difficult.
Hypoplastic trachea: Dogs with hypoplastic trachea have a narrowed windpipe, which again can make the act of breathing more difficult. It also makes placing a breathing tube in the windpipe during anaesthesia more challenging and risky.
Everted laryngeal saccules: These happen over time in dogs with other underlying causes of brachycephalic airway syndrome. The increased pressure generated when breathing can cause two pockets that sit next to the larynx (saccules) to turn inside out, further obstructing the airway.
So why is brachycephalic airway syndrome a big deal?
Aside from probably being pretty uncomfortable, brachycephalic airway syndrome makes affected dogs particularly susceptible to heat stress. Dogs are unable to sweat except on the footpads and nose, instead they use panting as their main means of cooling down. When the airways are compromised and dogs are unable to breathe properly panting becomes much less effective and leaves them at risk of overheating which can be fatal.
The other big issue with brachycephalic airway syndrome is that it gets worse with time, so while a young dog may be able to cope and function normally with stenotic nares or an elongated soft palate, over time the increased airway pressures and effort of breathing can cause new problems, like everted laryngeal saccules, making it more difficult for the dog to breathe and essentially stay alive. This makes affected dogs much more likely to experience respiratory distress, particularly if stressed or exercised. This is understandably upsetting for both dog and owner alike.
What can I do to help my dog with brachycephalic airway syndrome?
All brachycephalic breeds ideally should have an airway assessment performed to check for any of the anatomical defects mentioned above. This needs to be done under anaesthesia, so the time of desexing provides a great opportunity for puppies. Under anaesthesia your veterinarian can assess the soft palate for length, as well as examining the nostrils and larynx.
Stenotic nares and elongated soft palate can be corrected with surgery, and due to the progressive nature of brachycephalic airway syndrome, surgery is best done at a young age. While the surgery is relatively simple, there is a risk of swelling post operatively, so all dogs having upper airway surgery should be kept under observation for at least 24 hours after surgery.
Another contributing factor to brachycephalic airway syndrome is obesity. Being overweight can make breathing even more difficult, so it is especially important that brachycephalic breeds are kept at a lean bodyweight. Check out Pet Obesity Facts for more information about keeping your dog in shape.
All brachycephalic breeds, particularly those with brachycephalic airway syndrome should be kept out of high temperatures due to their predisposition to heat stress. They should have access to the indoors, particularly during the warmer months of the year. Avoid exercising brachycephalic breeds too strenuously or during the hotter times of the day.
Welfare consequences of brachycephalic airway syndrome
Sadly brachycephalic airway syndrome has arisen from humans selectively breeding for a physical trait which we find appealing. While there is no doubt brachycephalic breeds are adorable, have wonderful personalities and make great pets, it does pay to stop and think about the consequences of continuing to breed and pass on damaging anatomical defects. Dogs with even mild brachycephalic airway syndrome are likely to have interrupted sleep, with more severely affected dogs experiencing lethargy, weakness, fainting and distress as the condition worsens.
The RSPCA and Australian Veterinary Association are calling for a shift in the mindset of breeders and dog owners in Australia to prevent conditions such as brachycephalic airway from ocurring in the first place. For more information and to express your support head to loveisblind.org.au.