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An Urban Experience
C. Clercx1
1University of Liège, Department of Clinical Sciences of Companion Animals and Equine, LIEGE-SART TILMAN, Belgium
The term Brachycephalic Syndrome (BS), also previously named Brachycephalic Airway Obstructive Syndrome(BAOS), refers to a disorder resulting from multiple anatomic abnormalities commonly found in brachycephalic breeds of dogs, mainly the English and French Bulldog and the Pug. It is also recognized in Persian cats. This syndrome causes respiratory and digestive symptoms, and is a frequent cause of respiratory distress in brachycephalic dogs (1).
Conformational anomalies in brachycephalic dogs are related to breeding selection of ‘hypertypes’, which leads to progressive shortening of the face and nose, with subsequent shortening of the bony structures of the skull without concurrent reduction in surrounding soft tissues (2).
Primary inherited abnormalities include stenotic nares, elongated/thickened soft palate, hypoplastic trachea, and, sometimes, protrusion of nasal turbinates into
the nasopharynx, namely caudal aberrhant turbinates (3). In some dogs the soft palate can be too long in addition to being exceptionally thick; macroglossia can also occur. Secondary lesions develop as a probable consequence of increased pressures on the pharyngeal, laryngeal, and intrathoracic structures during breathing. These lesions include everted laryngeal saccules, progressive laryngeal collapse, and probably bronchial collapse (mainly collapse of the left main bronchus). Besides, subepiglotic cysts, severe edema of the
dorsal aspect of the laryngopharynx and laryngeal granulomas (‘kissing lesions’) all further narrow the
air passage at the laryngeal inlet (4). The severity and
the combination of these abnormalities will vary. To complicate matters even further, these dogs can have various accompanying gastrointestinal abnormalities involving the distal esophagus, stomach, and duodenum including inflammatory disease with coexisting functional or anatomic anomalies (cardial atony, gastroesophageal reflux, gastric retention, pyloric mucosal hyperplasia, and pyloric stenosis) (5)(1).
Clinical presentation
The abnormalities associated with the BS impair air
flow through the upper airways and cause clinical
signs of upper airway obstruction including noisy respiration, stridor, stertor, exercise and heat intolerance, respiratory distress, cyanosis, syncope, gagging and retching, and sometimes sleep apnea. The clinical signs are exacerbated by exercise, excitement, and high environmental temperatures. As a result, some dogs can be presented with life-threatening clinical signs of airway obstruction. Digestive signs such as regurgitation and vomiting are common. Secondary aspiration pneumonia is also a common associated finding and must be addressed.
A tentative diagnosis can be based on the breed and clinical signs. Laryngoscopy and thoracic radiography are essential diagnostics. Thoracic radiographs are preferably performed before anesthesia, in order to detect possible associated aspiration pneumonia, tracheal and cardiac sizes, presence of vertebral anomalies, and iatal hernia. Bronchoscopy and gastroscopy are necessary in order to assess the full scope of the existing abnormalities
and are helpful in providing an accurate prognosis and the best treatment recommendation. However, selection of the diagnostic procedures should be based on each animal condition. It is important to recognize and treat accordingly those dogs which are susceptible to quickly develop life-threatening airway obstruction and collapse, possibly before the end of the examination. Indeed,
in some dogs with strongly impaired oxygenation, manipulation is dangerous, and sedation if not anesthesia is required before starting diagnostic tests. Recovery from anesthesia should be closely monitored.
Animals presented with life-threatening upper airway obstruction should be cooled, oxygenated, sedated,
and in severe cases anesthesia and intubation are immediately required. A tracheotomy might be indicated in the case of severe upper airway occlusion. In somewhat less critical cases, sedation, cooling and oxygen are hence needed before starting complementary tests. In other less severe cases medical therapy consisting of anti-inflammatory doses of short-acting glucocorticoids (prednisone, 0.5 mg/kg q12h) will
suffice, and allows the owners to take an appointment for surgical treatment in better conditions. One should remember that apparently stable patients are susceptible to worsen suddenly, especially if the temperature is elevated, if the dog is stressed or excited. Some owners appear surprisingly abnormally confident (while you are not!), just because their pet has never been breathing

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