Brachycephalic Obstructive Syndrome BOS

Brachycephalic breeds are the 'short nosed' breeds such as Pugs, Boxers, Bulldogs and Boston Terriers. Unfortunately along with their very cute looks these breeds may suffer from Brachycephalic Obstructive Syndrome (BOS). This syndrome occurs as a result of a combination of:

kvc newsletter winter-1stenotic nares (narrow nostrils)
enlongated soft palate (the floppy part at the back of the throat)
hypoplastic trachea (narrow windpipe)
everted laryngeal saccules (structures at the back of the throat)



Not all dogs will have all these problems and some will have all. The first three are abnormalities that are present in puppies. These structural abnormalities occur as a result of the short, wide skull bones and result in increased airway pressure. The best way to imagine this is to imagine trying to breath through a drinking straw! Everted laryngeal saccules occur as a result of the increased pressure in the airway, this may also further lengthen the soft palate. These factors then further restrict airflow and increase airway pressure, exacerbating the problem.kvc newsletter winter-2

Affected dogs will have noisy breathing, which often gets worse when excited or exercising. They may snore, cough and pant a lot and tire quickly when exercising. Severely affected dogs may collapse. These symptoms are often worse during warm or humid weather. Difficulty eating and swallowing may also be seen. Diagnosis can often be suspected on the basis of the breed, history and exam but examination under anaesthetic is required to confirm to diagnosis.

Because the syndrome gets worse with time it is important that treatment is performed as early as possible. Stenotic nares and elongated soft palate are best treated surgically. In affected puppies this may often be combined with desexing. Everted laryngeal saccules are also treated surgically. Hypoplastic tracheas cannot be surgically corrected but treatment of other abnormalities that are present will help. In certain breeds or if the abnormalities are severe we may recommend treatment by a specialist surgeon.

If you are concerned about your pet's breathing please come in for an assessment and to chat with one of our vets.