Brachycephalic Obstructive Airway Syndrome (BOAS) is a condition that affects certain dog breeds with short, “flattened” faces, commonly referred to as brachycephalic dogs. These dogs, known for their unique and adorable facial features, can suffer from significant breathing difficulties due to the anatomical structure of their skull and upper respiratory systems. If you have a brachycephalic breed or are considering bringing one into your home, understanding BOAS and how it impacts your dog’s health is important to understand so your dog may live a comfortable and healthy life.

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What is a Brachycephalic Dog?

The term brachycephalic refers to dogs with short, flat faces and compressed skulls. These dogs have a distinctive “pushed-in” look with shortened muzzles, a genetic trait bred into certain dog breeds. While these breeds often have an adorable appearance, their unique skull structure can lead to breathing issues due to the altered anatomy of their upper airways.

Some of the most well-known brachycephalic dog breeds include:

• English Bulldogs
• Pugs
• French Bulldogs
• Boston Terriers
• Boxers
• Shih Tzus
• Lhasa Apsos
• Pekingese
• Chinese Sharpei

While these dogs are beloved for their cute looks, their flattened faces come with significant health challenges, particularly their ability to breathe comfortably.

What is Brachycephalic Obstructive Airway Syndrome (BOAS)?

BOAS is a condition characterized by the upper airway obstruction caused by the anatomical features of brachycephalic dogs. Their skulls and airways are compressed, resulting in several anatomical issues that restrict airflow, causing difficulty breathing. The severity of the symptoms can range from mild to severe and may worsen over time, leading to potentially life-threatening complications.

What Are the Symptoms of BOAS?

The symptoms of BOAS can vary depending on the degree of airway obstruction, but common signs include:

• Noisy breathing: Dogs may snore, wheeze, or make snorting sounds due to restricted airflow.
• Gagging when eating or drinking: Difficulty swallowing food or water, often accompanied by gagging.
• Labored breathing: Dogs may struggle to breathe, especially during exercise or in hot, humid weather.
• Open-mouth breathing: Dogs may breathe with their mouths open as they attempt to get enough air.
• Bluish gums: Reduced oxygen levels can cause the gums to appear blue instead of the usual pink.
• Collapse: In severe cases, the dog may collapse due to lack of oxygen or respiratory distress.

What Causes BOAS?

BOAS is caused by several anatomical variations in the respiratory system of brachycephalic dogs. These variations interfere with the flow of air into the lungs, making it harder for the dog to breathe.

Common contributing factors to BOAS include:

• Stenotic nares: Small, narrow nostrils that can collapse when the dog inhales, restricting airflow.
• Elongated soft palate: The soft palate can extend too far back into the throat, blocking the airway.
• Everted laryngeal saccules: Tissue near the vocal cords that gets sucked inward during inhalation, obstructing airflow.
• Hypoplastic trachea: A windpipe that is abnormally narrow, further limiting airflow.

In addition to these factors, other potential contributors to BOAS may include:

• Laryngeal collapse
• Enlarged tonsils
• Overly large tongues
• Nasopharyngeal turbinates

As the condition progresses, it becomes more difficult for dogs to breathe, leading to inflammation and swelling of the airway tissues, further exacerbating the problem.

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How Is BOAS Diagnosed?

Diagnosis typically occurs between the ages of 1 and 4 years, though the severity can vary. Diagnosis is based on a combination of breed, clinical symptoms, and physical examination. Some of the diagnostic tools include:

• Visual inspection: Observing stenotic nares (narrow nostrils) during a routine exam.
• Anesthesia: Light anesthesia may be required to fully assess the soft palate and laryngeal saccules.
• X-rays: X-rays of the neck and chest can reveal the diameter of the trachea.
• Advanced imaging: Techniques like endoscopy or CT scans may be used to get a more detailed view of the upper airway.

How Is BOAS Treated?

Treatment for BOAS depends on the severity of the condition. In mild cases, conservative management can help reduce symptoms and improve the dog’s quality of life:

• Maintain a healthy weight: Overweight dogs may experience more difficulty breathing, so keeping them at a healthy weight is essential.
• Avoid overheating: Brachycephalic dogs are particularly sensitive to heat and humidity. Make sure they have a cool environment and avoid vigorous exercise in hot weather.
• Controlled activity: Limit intense exercise to avoid putting too much strain on their respiratory system.
• Use a harness: Instead of a collar, which can put pressure on the airway, use a harness to walk your dog.

For dogs with more severe cases of BOAS, surgery may be required to correct the structural problems causing airway obstruction:

• Stenotic nares surgery: Removing a small wedge of tissue to enlarge the nostrils and improve airflow.
• Soft palate surgery: Shortening an elongated soft palate to prevent it from obstructing the airway.
• Everted saccules surgery: Removing tissue that is blocking airflow near the vocal cords.

However, it’s important to note that hypoplastic trachea (a narrow windpipe) cannot be surgically corrected.

Potential Complications and Emergency Situations

BOAS can lead to serious complications if not addressed. In severe cases, a laryngeal collapse (failure of the airway structures to maintain their shape) may occur, which can worsen breathing problems. Additionally, dogs with BOAS are at an increased risk for conditions such as:

• Bronchial collapse
• Gastrointestinal disorders (e.g., hiatal hernia, gastroesophageal reflux)
• Aspiration pneumonia

If your dog is experiencing a respiratory crisis (e.g., severe labored breathing, collapse), it is essential to seek immediate veterinary attention. Emergency care may include oxygen therapy, sedation, and in some cases, a temporary tracheostomy to bypass the upper airway obstruction.

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Prevention and Outlook

Since BOAS is a genetic condition, prevention primarily involves responsible breeding practices. Dogs with severe breathing difficulties or structural airway issues should not be bred to reduce the risk of passing on the condition to future generations.

For dogs with milder cases of BOAS, they can lead a normal life with proper management. Early surgical intervention in younger dogs (under 2 years old) often leads to better outcomes. However, dogs with laryngeal collapse or severe airway obstruction may have a poorer prognosis.

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