NOISY BREATHING: SIGNS OF BRACHYCEPHALIC AIRWAY SYNDROME

In August of each year the signs are right to take a road trip to Louisville and the Kentucky State Fair. While there I consume my two corn dogs with mustard, watch the sheep being sheared for competition, observe the show cow stalls, and attend the horse show each night.

These are familiar signs of the end of summer. Especially noteworthy is the “fancy costume turnout” Harry Potter themed miniature horse class. 

Speaking of signs, I think it is perceived as acceptable that dogs with smashed faces (English Bulldogs, Pugs, Boston Terriers, Lhasa Apsos, Shih Tzu’s) normally snort to breathe. From the dog's perspective, there is often a fight to breathe through two very small holes similar to a chip bag clip on your own nose.

WHAT ARE “STENOTIC NARES” AND THE RELATIONSHIP TO BRACHYCEPHALIC AIRWAY SYNDROME?

 Stenotic nares are a genetic malformation of the cartilage in the nasal openings that worsen with age. They are a one part of a larger issue called brachycephalic airway syndrome. The other components are an elongated soft palate (too long roof of the mouth) and hypoplastic trachea (too small diameter windpipe).  In some dogs the damage is so severe it causes eversion of the lining of the voice box (laryngeal saccules) so that swollen tissue is blocking the airways.  There are varying degrees of obstruction between dogs.

The left photo is a dog with stenotic nares. The photo below is normal nasal opening.

WHAT HAPPENS?Over time the “pinched nostrils” can lead to an increased effort to breathe during inspiration (breathing inward). This can lead to collapse of the voice box (larynx) leading to significant respiratory distress. 

ARE THERE SIGNS THAT CAN ALERT OWNERS TO POTENTIAL RESPIRATORY DISTRESS? 

Dogs with mild disease will have noisy breathing with exercise or excitement. Others simply snore when relaxed or asleep. Severely affected animals have more pronounced nasal sounds, appear to tire easily with exercise, and may faint after exercise. Other symptoms may include coughing, gagging, retching and vomiting. Symptoms are often worse in hot or humid weather.

WHY DO GI SIGNS DEVELOP CONCURRENTLY WITH THE AIRWAY DISEASE?

The negative pressure created with restricted breathing suctions stomach acid into the esophagus (reflux/heartburn). This leads to coughing, gagging, vomiting, and aspiration pneumonia is some cases.

HOW IS IT DIAGNOSED?Diagnosis is BASED externally on the diameter of the nasal passage opening. Other testing will require sedation with radiographs, and measurement of the length of the roof of the mouth (soft palate), and visual of the larynx (voice box).


 WHAT IS THE TREATMENT?

 SURGERY as early as 6to 9 months of age to correct the stenotic nares (to dilate opening) and possibly shortening the roof of the mouth (soft palate) are key components of treatment. Keeping pets in a healthy weight range, avoiding  high heat and humidity, use of a harness to keep pressure off the trachea are key. In emergency situations, steroids, oxygen therapy, and even temporary tracheostomies may be needed.

WHAT IS THE PROGNOSIS?
Dogs under two years of age at the time of surgical correction have better post-operative results than dogs that are older. Dogs that only require surgical correction for stenotic nares and/or an elongated soft palate have a better prognosis that those with multiple issues.  Concurrent complications  such as allergic bronchitis or heart disease have a poorer prognosis. 

WHAT ABOUT BREEDING THESE AFFECTED DOGS?

They should not be bred to lower propagation of the anatomical defects. For examples of how breeds have changed over the last 100 years that have increased the risk of these and other issues, review the websites below.


https://dogbehaviorscience.wordpress.com/2012/09/29/100-years-of-breed-improvement/

http://www.dailymail.co.uk/news/article-2519314/How-century-breeding-improvement-turned-healthy-dogs-deformed-animals.htmlhttp://www.dogster.com/the-scoop/dog-breeds-breeding-photos-dogs-of-all-nations

Betsy Sigmon, DVM, Diplomate American Board of Veterinary Practitioners Canine & Feline

Hospital Director, Creature Comforts Animal Hospital 

Cary, NC