Case File

Relieving the symptoms of Brachycephalic Airway Obstruction Syndrome (BOAS) starring ‘Doug the Pug’

No one can resist smiling at a happy little pug passing you in the street or deny that a friend’s new French bulldog puppy is indeed very sweet, but sadly that cuteness comes at a huge cost to these breeds’ ability to breathe normally.

The term ‘brachycephalic’ refers to the shortened skulls that typify breeds such as the Pug, French and English Bulldogs and Boston Terriers (see the difference in skull shape and length below). While the bones of the skull are of normal width, their length is severely reduced (see photo below). This leads to a mis-match between the soft tissues of the skull, which are of normal length, and the nasal cavity and throat, which are shortened. This can mean overlong soft palates being sucked into wind pipes and over full nasal chambers.  The overall result is at best, some snoring and noisy breathing, and at worst – respiratory distress that can lead to collapse and death. The signs typically worsen with age and weight gain due to the increased pressures needed to obtain the same amount of air, with time, leading to thickening of tissues and airway collapse.

While we can’t alter all of the features that can come with brachycephalic breeds, thankfully help is at hand in surgically correcting some of the problems!

Nostrils

One of the common features of BOAS is narrow nostrils.

If we go back to our school day physics, a small increase in a pipe’s diameter, reduces resistance a lot – for example a 2 fold increase in a pipe’s radius, reduces resistance 16 fold, try sucking/blowing air through different size straws to test it! Similarly, if we increase the radius of a nostril, resistance to airflow decreases dramatically. So, this is one way we can help improve airflow to our brachy patients! How we increase the radius of the nostril is by removing a wedge of tissue from the nostril wall and stitching the edges together.

Soft Palate

As mentioned previously, the other issue brachycephalic dogs struggle with is the length of their soft palate. Over 85% of dogs displaying BOAS have overlong soft palates. This simplified schematic demonstrates the effect this has on airflow.

Resecting the overlong portion of the soft palate improves the amount of air reaching the windpipe.

Now let’s meet the star of this article: Doug the Pug!

Doug the Pug presented for routine neutering and it was noticed he had the classic, small nostrils that can impede airflow through the nose and the ‘rasping’ breathing that can indicate an overlong soft palate. He was a very happy boy and in fantastic lean condition so these issues weren’t yet hindering him from enjoying his life but the sooner we addressed these issues, the more we can do to prevent the secondary changes from occurring.  Doug also had redundant facial skin that not only hinder airflow through the nostrils but also rub against the eye surface. The ‘folds’ can also harbour bacteria leading to skin infections due to lack of air circulation. Doug was booked in for a work-up and surgery at our Portishead branch to see how much we could help him.

As part of our work-up Doug had radiographs taken of his chest and skull, and a camera put down his windpipe and up behind his nose to screen for concurrent issues like pneumonia, airway collapse and excessive nasal tissue - all of which can be seen with BOAS. The lateral chest radiograph did show a congenital abnormality of the sternum, and whilst this decreases the overall chest capacity, it is unlikely to compromise Doug’s breathing much more. Happily, other than a slightly smaller windpipe diameter, Doug was clear of complicating factors so we could proceed with treatment.

LATERAL SKULL AND NECK

LATERAL CHEST – NOTE THE NARROW WINDPIPE AND ‘PUSHED UP’ BREASTBONE (STERNUM)

First of all, the overlong soft palate was trimmed back so that he didn’t have this sitting in the top part of his windpipe any more. Then he had the extra facial folds resected and lastly, he had his nostrils widened. Doing this leads to an improvement in clinical signs in almost 90% of cases and importantly, reduces the risk of progression of clinical disease.

Here are some intra-operative before and after photos:

PRE-NOSTRIL WIDENING AND FOLD RESECTION

PRE-NOSTRIL WIDENING AND FOLD RESECTION

Doug the Pug went on to have a straight forward recovery, and while it is expected to have some sneezing/gagging and bloody nasal discharge for a period post-op, we were fortunate that these were minimal in Doug’s case.

Here is a photo of Doug a mere 10 days after treatment – note his much wider nostrils and less skin blocking his nostrils.

His owner felt he was immediately clearer in his breathing, and quieter around the house as well! While the change in appearance can take time to get used to, I think we can all agree that Dog the Pug is as handsome as ever, with the benefit of now being able to breathe a little bit easier.

It is of course important that Doug stays in shape and avoids undue stress on his respiratory system – avoiding the heat of mid-day etc for the long term but the changes made should hopefully go towards reducing the impact of his shortened skull on his day-to-day life.