Brachycephalic obstructive airway syndrome

Brachycephalic obstructive airway syndrome (BOAS), also known as brachycephalic airway obstructive syndrome (BAOS), brachycephalic airway syndrome (BAS), and brachycephalic syndrome (BS), is a pathological condition affecting short nosed dogs and cats which can lead to severe respiratory distress. There are four different anatomical abnormalities that contribute to the disease, all of which occur more commonly in brachycephalic breeds: an elongated soft palate, stenotic nares, a hypoplastic trachea, and everted laryngeal saccules. Because all of these components make it more difficult to breathe in situations of exercise, stress, or heat, an animal with these abnormalities may be unable to take deep or fast enough breaths to blow off carbon dioxide. This leads to distress and further increases respiratory rate and heart rate, creating a vicious cycle that can quickly lead to a life-threatening situation.

Causes and risk factors

The primary anatomic components of BOAS are stenotic nares (pinched or narrowed nostrils) and soft palate hyperplasia. In addition to this mucosal hyperplasia and collapse of the airway can aggravate the condition. ==Breed prevalence==

Breed prevalence

The breeds most commonly affected are the Bulldog, French Bulldog, Pug, and Boston Terrier. Other brachycephalic breeds include: the Pekingese, Shih Tzu, Lhasa Apso, Cavalier King Charles Spaniel, Boxer, Dogue de Bordeaux, Brussels Griffon, and Bullmastiff. == Signs and symptoms ==

Signs and symptoms

, have less compromised thermoregulation and thus are more tolerant of vigorous exercise and heat. Symptoms of brachycephaly include: snoring, dyspnoea, emesis, stridor, insomnia, cyanosis, syncope, and dysphagia. After waking from surgery, most dogs that are intubated will try to claw out their tracheal tube. In contrast, brachycephalic dogs often seem quite happy to leave it in place as it opens the airway, making it easier to breathe. Secondary conditions Other conditions may be observed concurrently. These include swollen/everted laryngeal saccules, which further reduce the airway, collapsed larynx, and chronic obstructive pulmonary disease caused by the increased lung workload. == Treatment ==

Treatment

Treatment consists of surgery for widening the nostrils, removing the excess tissue of an elongated soft palate, or removing everted laryngeal saccules. Early treatment prevents secondary conditions from developing. Potential complications include hemorrhages, pain, and inflammation during and after surgery. Some veterinarians are hesitant to perform soft palate correction surgery. With CO2 surgical lasers, these complications are greatly diminished. == Prevention ==

Prevention

Avoiding stress, high temperatures, and overfeeding can reduce the risk. Using harnesses instead of collars can avoid pressure on the trachea. The risk of brachycephalic syndrome increases as the muzzle becomes shorter. Removing all affected animals from the breeding pool may cause some breeds to be unsustainable and outcrossing to non-brachycephalic breeds might be necessary. ==Other health problems==