Trouble Breathing

With selective and successful (or unsuccessful depending on how you view it) breeding in dogs, veterinarians see a lot of congenital problems in pets.  One of the more common problems we see is in short nosed breed dogs (Boston Terriers, Bulldogs, etc) called brachycephalic airway syndrome.  This isn't just one problem, but a combination of problems that can lead to difficulty breathing.

If you talk to the owner of one of these dogs, you likely will hear them describe noisy breathing, snoring, and sometimes gagging; but problems can also become more serious with faining episodes, turning blue, or even death in severe cases.  So what causes these problems?  It all stems from the selective breeding of the shorter or no-nose at all trait.  This has lead to collateral problems; in particular an elongated soft palate, stenotic nares (narrow nasal passage), and hypoplastic trachea (narrow windpipe).  Over time this can lead to negative pressure in the back of the throat, which can cause further damage including everted laryngeal saccules (these interfere with the opening of the airway) and in worst case scenarios laryngeal collapse (complete blockage of the airway).

 

So why is it such a big deal to have these traits?  If the traits are mild, then it may not be a huge deal; however, with extreme cases the traits can interfere with breathing.  As you can see from the above image, the larynx is the area in the back of the throat where two functions connect (breathing and eating).  There is a small structure called the epiglottis that covers the opening of the airway (windpipe) when a pet is eating and drinking to prevent food or water from entering the windpipe.  This should only cover the windpipe during swallowing and otherwise the larynx and windpipe should be open and free to allow air to pass into the lungs.  Dogs with long soft palates have problems because the back of the soft palpate can interfere with the windpipe opening and prevent air from passing into the windpipe and lungs.  The noisy breathing or snoring is from the air being blocked by the soft palate.  The narrow nasal passages also interfere with the movement of air.  Like I said before, in mild cases this is not terrible, but as dogs age or in extreme cases the soft palate can get worse (swollen) and completely obstruct the airway.  This can become life threatening if the pet cannot get this unblocked as they essential suffocate from lack of oxygen.

If the soft palate dose not completely block the airway, over time the back of the throat (larynx) can get worse as the negative pressure placed on the larynx from the narrowed passageway can cause it to weaken and essentially collapse leading to blockage of the airway as well.  In these cases, the only real way we can help is to perform a permanent tracheostomy (make a hole in the neck of the dog that connects to the windpipe) for them to breath through.

Obviously, making a hole in the neck of a pet is not the most ideal.  Fortunately, there are some things we can do prior to this point to help out dogs with serious breathing problems.  We essentially correct the problems surgically.  This typically involves widening the openings of the nostrils to allow more air to move through the nasal passage along with shortening the soft palate to a more normal length.  These procedures are most effective when performed on younger dogs as it prevents pressures from working on the larynx and weakening it.  Many times these can be performed during a spay or neuter procedure, so a second anesthetic event is not needed.

Soft palate after resection. Courtesy of Vet Specialists of South Florida

Although the procedures may not completely rid a pet of noisy breathing, in most cases dogs show considerable improvement in breathing, as well as exercise tolerance.  For more information on this condition, you can visit this link.