Brachycephalic – it's fancy for 'short faced'
If you own a Bulldog (French, Aussie or English), Pug, Boston, Boxer, Pekingese or Shih Tzu, this is a word you need to know. These breeds are all brachycephalic – they have been bred to have a normal sized lower jaw and a short (compressed) upper jaw.
Now, we're not breed bashing here (I have a Frenchie), but it's really important to know about the special needs of your pet so that you can keep him or her healthy.
The respiratory system of short-faced dogs
Have you ever wondered why your gorgeous squishy-faced dog makes more snorting/snuffling sounds than other longer-snouted dogs? Perhaps you've just considered it normal?
Well, respiratory noise is 'normal' for brachycephalic breeds but it's not normal for dogs. The noise is because selective breeding has led to deformity of the shape of both the snout and the throat. The degree of deformity varies with breed and between individuals within breeds.
On a day-to-day basis, most brachycephalics are not bothered by these deformities. But these breeds do have limitations that you need to recognise.
Let's have a look at the specific deformities in detail.
The respiratory system starts at the nose. Brachycephalic dogs often have very narrow, slit-like nostrils that can't flare open to let more air in. These are called stenotic nares.
Because they can't always get enough air in through their nose, brachycephalics tend to do a lot of open-mouth breathing. Even minimal exercise usually brings about panting. They also swallow air, which can contribute to wicked flatulence.
It's possible to surgically widen stenotic nares. If you have a pup with narrow nostrils, we can add on a 'nose job' at castration or spay.
It's not just that the tongue looks big in a short snout, some brachycephalics do have large/thick tongues. The tongue takes up more space in the mouth and entrance to the throat (the pharynx), further obstructing airflow.
Bulldogs (all types) are the most commonly affected.
There's not much we can do about this – we don't surgically reduce tongue size.
Long soft palate
The soft palate is a flap of tissue that extends from the hard palate (roof of the mouth) back into the pharynx. It separates the oral cavity from the nasal passages.
Although the bones of the upper jaw have become shortened with selective breeding, the soft tissues remain about the same size. This means that the soft tissues don't fit and the soft palate ends up flapping down into the throat.
Virtually all brachycephalics have a long soft palate. It's the main thing that creates the noises squishy faces make when breathing (and snoring).
Again, because it takes up space in the throat, it obstructs airflow. If it becomes swollen from excess panting, barking or kennel cough, it can cause acute breathing difficulty.
A long soft palate also increases the chance of your dog having episodes of reverse sneezing (video). Note that your dog is not choking during reverse sneezing. It sounds much worse than it is – and definitely doesn't warrant a dash to an emergency centre.
The soft palate can be surgically trimmed.
This is another fancy term. It means a narrow windpipe. Apart from just reducing the amount of air that can be breathed in and out, having a narrow trachea can be an anaesthetic risk.
Some brachycephalics have such a tiny windpipe that we find it difficult to place a tube that supplies anaesthetic gas and oxygen. Even small tubes designed for little cats can be too big. This means we can't 'secure an airway'.
Dogs with hypoplastic tracheas also tend to develop things like pneumonia.
There is no cure for a hypoplastic trachea.
There are two small pockets in the larynx (voice box), that can 'evert' or turn inside out when a dog is breathing heavily. When they evert, they cause an obstruction to airflow (further increasing breathing effort).
Pugs seem to be the most affected by this. The saccules can be surgically removed, but often if we fix other things like the nares and the soft palate, the saccules stop everting.
Brachycephalic airway obstruction syndrome
Your dog might have all these deformities and still be perfectly happy and active. But what you need to know is that your squishy face will not pant as effectively as a longer snouted dog.
What we mean by effective panting is regulating body temperature by moving air over the tongue. A key way that dogs keep cool is by breathing air rapidly over the tongue, causing saliva to evaporate taking heat with it (ie evaporative cooling). The blood in the tongue is cooled and then circulated around the body.
Brachycephalic dogs simply move less air per breath than others. They need to work much harder to move enough air to create evaporative cooling. The problem is that breathing harder can lead to swelling of the airways – which further obstructs breathing and leads to overheating and respiratory distress. This is brachycephalic airway obstruction syndrome (BAOS or just brachycephalic syndrome). Make no mistake, it can be fatal.
Brachycephalic dogs overheat more easily than other dogs
What's a nice day for you might be too hot for your dog.
It's important to recognise the limitations of your dog – brachycephalics can have problems keeping cool in warmer weather and when exercising. Also, things change over time and what your dog used to be able to do as a pup might cause respiratory distress in middle age.
For most brachycephalics, simply keeping cool in warm conditions (and avoiding obesity) is enough to keep BOAS at bay. But for others, surgery to widen the airway and increase airflow is necessary.
BOAS surgery includes:
enlarging the narrow nostril openings
trimming the long soft palate
removing the saccules (not always necessary)
If your dog suffers severe acute BOAS, we may need to perform a tracheostomy to bypass the obstructed airway. Some dogs might even need a permanent tracheostomy.