Written By: Jacqueline Nobles, DVM, DACVECC

A common reason pets visit the ER is difficulty breathing. This can be a symptom of several different diseases including brachycephalic obstructive airway syndrome (BOAS).

BOAS is a condition caused by anatomic anomalies, predominantly in short-nosed or brachycephalic (flat and wide-shaped skull) breeds of both dogs and cats. The syndrome is characterized by several indicators, including narrowing or stenosis of the nares (nostrils), elongation of the soft palate, a small or hypoplastic trachea, and eversion of tissues into the lumen of the larynx. The resistance to breathing through small and convoluted airways results in functional changes to the tissues of the larynx, ultimately leading to complete obstruction of the airway.

Breeds Predisposed

• Brachycephalics are generally those with cute smushed faces, which can cause health problems like BOAS. Dogs that are considered Brachycephalics include:
• Pugs
• Boston terriers
• English bulldogs
• French bulldogs
• Pekingese
• Shih Tzus
• Boxers

Symptoms

There are various signs and symptoms of BOAS to watch for including:

•  Inspiratory stridor (loud, open-mouthed breathing during inspiration)
• Cyanosis (blue gum color)
• Exercise intolerance
• Rapid breathing
• Snoring
• Acute collapse
• Retching
• Vomiting
• Diarrhea

Diagnosis

To obtain an accurate diagnosis, your veterinarian will perform a physical exam, and if he or she suspects BOAS then more diagnostics may be conducted. This could include an upper airway exam, x-rays and/or other advanced imaging.

In addition to breathing difficulty, a canine diagnosis with BOAS could also result in:

• Stenotic nares
• Elongated soft palate
• Everted laryngeal saccules
• Hypoplastic trachea
• Laryngeal collapse

Treatment

All brachycephalic dogs are at risk for BOAS and most will experience the symptoms or ailments that are listed above. Fortunately, for minimally affected pups, pet parents can establish a regular exercise routine, a healthy diet, and avoid overheating to help with breathing and ease other symptoms.

Additionally, it has been suggested that early surgical intervention of stenotic nares in affected dogs reduces the risk of secondary changes occurring that can lead to severe cases of BOAS.

In severe cases of BOAS, patients must be intubated (have a tube placed in the airway to bypass the obstruction) in order to prevent respiratory arrest. Due to the advanced stage of disease in many patients, which can ultimately result in laryngeal collapse, we are often forced to perform surgery to alleviate the obstruction. Options for surgery include trimming the soft palate, removing the saccules, and opening up the nares by removing wedges of tissue. Since most brachycephalics are born with BOAS, surgical interventions should be performed as early as possible in order to improve breathing. In the later stages of BOAS, patients develop complete collapse of the larynx, and even with the aforementioned surgical procedures, they may struggle to breathe. Thus, the best option may be to permanently bypass the upper airway by creating a permanent opening in the trachea (tracheostomy).

The COVE: BOAS Patient Success Story

Molly, a 10-year-old female Boston terrier, was transferred to The COVE for severe respiratory distress and suspected cardiac disease. Upon arrival, Molly was sedated and placed on oxygen. Even with supplemental oxygen, she continued to struggle, and this warranted placement of an endotracheal tube in order to facilitate breathing. As soon as her intubation was complete, Molly’s condition improved.

To check for cardiac disease, an ultrasound of the heart (echocardiogram) was performed, and it was concluded that Maggie’s heart was functioning normally. Additionally, chest X-rays, an ultrasound of the lungs, and an upper airway exam were performed. Most of the diagnostics failed to show evidence of cardiac disease, but the upper airway exam showed a severely elongated soft palate, swelling of the laryngeal tissues, and collapse of the larynx consistent with severe end-stage BOAS. The chest X-rays also showed changes consistent with chronic lower airway disease.

Due to the severity of her condition, it was in Molly’s best interest to completely bypass her upper airway by performing a permanent tracheostomy. Following surgery, Molly did have complications, including pneumonia (which we suspected on presentation), vomiting, and diarrhea. However, she continued to fight for six days until she was finally discharged. Molly is happily at home with her family and is breathing better than ever.

Brachycephalic Pups: The Last Word

Brachycephalic pups, with their little smushed faces, are indeed quite cute, but unfortunately, the abnormality that makes them famous can be dangerous. It is important to continually monitor your pet and contact your primary care veterinarian or nearest veterinary emergency hospital immediately if you notice any of the symptoms listed above. Ideally, addressing these issues early on will increase your furry family member’s quality of life and long-term well-being.