Brachycephalic Syndrome Part I: Breathing and Oral Health

Posted 04.18.23 by Drew McWatters, DVM

Most people are not familiar with the term brachycephalic, but all are familiar with the dog breeds it refers to. Pugs, Boston Terriers, Pekingeses, Boxers, Bulldogs, Shih Tzus, or any one of the other breeds with pushed in or short faces are all “brachycephalic” breeds. The term refers to the length of their upper jaw, coming from the Greek roots brachy, meaning short, and cephalic, meaning head.

Brachycephalic dogs have been bred so as to possess a normal lower jaw that is in proportion to their body size, but a compressed upper jaw. By doing this we have created a cute, almost human-like appearance but have compromised these animals in many important ways. Owners of these breeds or people considering owning one of these breeds need to be aware of their unique medical conditions. While there are unique medical conditions that affect the whole bodies of brachycephalic dogs, we will focus on the problems that specifically arise in the head and neck from the abnormal jaw anatomy.

The Respiratory System and Brachycephalic Airway Obstruction Syndrome

The first area to be aware of if the airway/breathing problems these dogs can have. Brachycephalic breeds make a lot of snorting respiratory sounds simply because of the way their throats and faces are shaped. Very similar to a human who snores dramatically, there is simply not enough space for air to move freely so it makes the snorting sound as it rushes over the surrounding tissues. While these sounds can be “normal” it is important to note that, without intervention, these problems can dramatically worsen over time leading to emergent and, sometimes, life-threatening issues. There are 5 anatomical defects that can inhibit air movement in brachycephalic breeds.

Stenotic Nares

This is a fancy name for narrowed nostrils. The brachycephalic dog’s respiratory passage begins with very small, often slit-like, nasal openings for breathing. This leads to increased pressure in the airway because they are breathing through such small holes. Increased pressure increases the risk of other anatomical defects (everted laryngeal saccules and laryngeal collapse) and can exacerbate other defects (elongated soft palate). Even if puppies are not showing respiratory problems, studies have shown that increasing the size of the nares as a puppy leads to a more favorable prognosis as an adult. In selecting a puppy, it is a good idea to look at the nostril sizes on each member of the litter and look for the widest opening. Stenotic nares can be surgically corrected after age five months and is often done in conjunction with spaying or neutering.

Enlarged Tongue (Macroglossa)

The brachycephalic dog’s tongue is thicker and wider than other breeds. This means there is less room for air in the mouth and back of the throat. Because of this, most brachycephalic dogs need to open their mouths to breath even though they are breathing through their noses. The French and English bulldogs seem particularly predisposed to this issue.

Elongated Soft Palate

The soft palate is the soft tissue in the back of the throat just behind the hard palate (“roof of the mouth”) and separates the nasal passages from the back of the mouth. It functionally keeps air in the nose and food in the mouth. In brachycephalic dogs, the palate is often longer and thicker than usual. Like the enlarged tongue, this takes up additional space in the air way and decreases space for air to move. If it gets too long, it will actually get drawn into the wind pipe (trachea) when the dog breathes in, partially obstructing the flow of air into the lungs. Over time, this problem only worsens because the increased pressure in the airway from the other anatomical defects leads to swelling (edema) and inflammation of the palate which makes it even larger and longer. Early surgical correction by shortening the elongated palate is indicated in many of these dogs, especially English Bulldogs.

Everted Laryngeal Saccules

The normal larynx (also known as the “voicebox”) has two small pockets called saccules. Because brachycephalic dogs have an increased effort to breathe, over time these little pockets will actually turn inside out or evert. When this occurs, it partially obstructs the throat, making it harder for air to pass into the trachea and lungs. The condition can be corrected surgically if needed.

Tracheal Stenosis/Hypoplastic Trachea

The trachea is also known as the windpipe. The brachycephalic dog’s windpipe is always smaller than a similar sized dog of a different breed. This means that even after breathed-in air fights through all the previously notes anatomical problems, it is then moving into a smaller than normal tube in order to reach the lungs. Like a funnel that is too small, this makes air movement less efficient which makes the brachycephalic dog at risk of hypoxia (low oxygen levels). This is the only anatomical defect that cannot be surgically corrected so it is very important to correct the other problems so the air is moving as freely as possible before it gets to the trachea.

Risk factors for a Respiratory Emergency

In dogs, airway movement is not only important for breathing but also the primary way dogs dissipate heat and cool themselves. A dog with a more conventional face and throat is able to pass air quickly over the tongue through panting. This causes saliva to evaporate from the tongue as air is passed across it and the blood circulating through the tongue is efficiently cooled and circulated back to the rest of the body. In the brachycephalic dog, so much extra work is required to move the same amount of air that the airways become inflamed and swollen. This leads to a more severe obstruction, distress, and further over-heating. If severe enough, this can lead to heat stroke, which is a life-threatening condition. Because of this, anything that causes overheating or heavy breathing can lead to an acute respiratory emergency. Owners of brachycephalic breeds must help their pet avoid any situation where overheating and heavy breathing can occur.

Oral Health

They have 42 teeth like all other breeds, but they have much less room to put all the teeth. This leads to many dental conditions including tooth crowding, abnormal bite pattern, excessive tartar build-up, and periodontal disease. At-home dental care starting as a puppy is paramount and following the dental care recommendations of your vet is key to a happy mouth.

So What do You Do?

While this all sounds very discouraging, the good news is that they are conditions that can be surgically corrected and problems that can be mitigated. The most important thing is to talk to your vet about what problems your dog has and how they can be treated and managed. I meet many owners who just see their dog’s problems as “normal” and don’t speak up to advocate for them. Just because it’s “normal” for a breed doesn’t mean it’s not something that needs to be addressed. Early intervention often means the difference between a long healthy life for your dog and a lifetime of problems.

Brachycephalic breeds can be wonderful dogs with fun, unique personalities but, as you can see, brachycephalic ownership is not for the faint of heart. But by talking to your vet about your dog’s specific problems, together you can formulate a plan to make sure you brachycephalic dog has a long, healthy, happy life.