Telediagnostics are here for pets! Brachycephalic airway syndrome / Zomedica / VetGuardian / dvm360

Brachycephalic (obstructive) airway syndrome is a general term that groups together a number of primary and secondary respiratory conditions that are commonly observed in the juvenile brachycephalic canine breeds. These are most often seen in conjunction, rather than individually, resulting in a congenital upper airway obstruction.
Primary conditions include: elongated soft palate, hypoplastic trachea, nasopharyngeal stenosis (nasal turbinate abnormalities), and stenotic nares. Secondary conditions include everted laryngeal saccules, everted tonsils (amygdalitis), and laryngeal collapse.
The incidences of the conditions involved with this syndrome are as follows: elongated soft palate 62 to 100%, hypoplastic trachea 11 to 46%, stenotic nares 17 to 94%, everted laryngeal saccules 39.4 to 87%, everted tonsils 5 to 56%, abnormal nasopharyngeal turbinates 20 to 100%, and laryngeal collapse 8 to 53%.
The most common combination of conditions are those abnormalities present at birth, which are the elongated soft palate and stenotic nares. However, an elongated soft palate can occur independent of stenotic nares. The combination of elongated soft palate, stenotic nares, everted saccules, and everted tonsils is seen in 32% of cases. Of those with stenotic nares, 72% also have everted laryngeal saccules. Of those with everted laryngeal saccules, 66% have everted tonsils.
Stenotic nares are considered congenital in the English Bulldog, French Bulldog, and Pug breeds. It is also seen commonly in the Boston Terrier, Boxer, Cavalier King Charles Spaniel, Lhasa Apso, Pekingese, and Shih Tzu breeds. Laryngeal collapse is seen in 28.3% of Pug dogs. Hypoplastic trachea is most commonly noted in the English Bulldog breed. The Chinese Shar Pei can be seen with stenotic nares, an elongated soft palate, and laryngeal paralysis. The incidence of canine stenotic nares exceeds that of feline (incidence of 2.6%).
This condition is uncommonly found in feline breeds. Affected brachycephalic feline breeds include the Persian and Himalayan.
Affected canine breeds and their incidences include the English Bulldog (61% incidence), Pug (21%), Boston Terrier (9%), Boxer, French Bulldog, Pekingese, and Shih Tzu (less than 10%). Brachycephalic dog breeds have an odds ratio of 38 for the risk of developing this syndrome when compared to other canine dog breed types. Mesocephalic dog breeds that have been reported include Chow Chow, Pomeranian, and Rottweiler.
Dogs can be affected as early as several months of age with a mean of 4 to 5 years of age. The mean weight of affected dogs is 21.5 kg. The canine male to female ratio has been reported to be 2:1 while the female to male ratio has been reported to be 1.6:1.
These primary and secondary airway diseases may lead the way for secondary gastrointestinal conditions. However, because the brachycephalic breeds are also predisposed to primary gastrointestinal conditions, it may not be possible to discern all possible etiologies in a single affected patient.
It is thought that approximately 89 to 100% of dogs show significant improvement post-operatively. Classically, preoperative mortality rates were reported to be 15%. More recent mortality rates are reported to be 4%.
Ideally, surgery is performed at 3 to 4 months of age. The success incidence in those dogs that are treated at 4.5 to 6 months of age is 76.4% with a permanent tracheostomy tube being needed if no response is seen. Overall outcome by 6 months postoperatively is excellent in 65% and good in 25% while overall outcome seen by 1 year postoperatively is excellent in 50% of cases, moderate in 48% of cases, and poor in 2% of cases. The success rate in those dogs with laryngeal edema is 54%.
Post-operative improvement is seen 85 to 100% of dogs after elongated soft palate resection.
Postoperative gastrointestinal clinical signs are less frequent than preoperatively, with 66.7 to 91% resolution occurring postoperatively. A good to excellent outcome, as per owner evaluation, is seen in 68% of cases when only the respiratory clinical signs are treated. This success rate increases to 89%, based on owner evaluation, if the gastrointestinal clinical signs are treated and resolve. Improvement seen with surgery and eventual discontinuation of gastrointestinal medications after management is 80%, with resolution of gastrointestinal changes occurring by 6 months post-operatively as determined by endoscopic evaluation.