Brachycephalic Syndrome in Boston Terriers

BAOS is associated with variable respiratory difficulties that depend on the bone deformities present within the shortened skull. Symptoms of the condition arise as a result of the obstruction in the normal flow of air within the upper respiratory passages particularly through the nose and larynx.

Dogs suffering from BAOS usually possess pinched nostrils (stenotic nares), abnormally long soft palates, and everted laryngeal saccules. The long soft palate may droop down and create blockages in the respiratory passages specifically the larynx and trachea. In some cases the trachea is usually too small (hypoplastic trachea) to allow enough amounts of air to pass through.

A puppy may be born with the condition but fail to show any clinical manifestation early in life. Signs may start to manifest when the dog is already at the early middle age. A dog owner may first notice that there is something wrong with his Boston Terrier when it starts to snort and snore. These signs worsen during hot weather and when the dog is subject to strenuous activities such as during exercise or play. As the dog ages, the breathing difficulties generally worsen. Other common signs include poor exercise tolerance, coughing, chronic raspiness, gagging, and reverse sneezing. The dog’s mucus membranes may also have a bluish-tinged that indicates a poor oxygen supply. The dog may also suffer from moderate to severe heat intolerance, heat stroke, or collapse particularly when owners take their dogs out for a walk on a hot day.


Gastrointestinal symptoms are also common in dogs with BAOS. In their attempt to gulp in air to compensate for their breathing difficulties, they often gag, eructate, and/or vomit. One of the most common complications is aspiration pneumonia.

A short-nosed dog with breathing difficulties is more often than not diagnosed initially with BAOS. Your vet will then try to establish the specific abnormality which is causing the condition. Several important diagnostic tools include x-rays and CT-scans which can help determine the underlying cause/s. Your vet may also have to put your dog under anesthesia to allow a thorough examination and identify specific cause/s of the condition.

The mode of treatment is highly dependent on the underlying condition. Basically, treatment is aimed at addressing the obstruction by surgical removal of the offending structure. Many underlying causes including elongated soft palates, stenotic nares, and everted laryngeal saccules can be corrected with surgery. Resection of the elongated soft palates and stenotic nares help improve airflow across the air passages. Veterinarians always exercise caution during these procedures to prevent bleeding and aspiration.

In order to prevent genetic propagation, severely affected dogs or those with a family history of the defect should never be allowed to breed.