Brachycephalic Syndrome in Dogs
Overview of Brachycephalic Syndrome in Dogs
Brachycephalic syndrome is a group of conditions that cause resistance to airflow through the upper respiratory tract (nose, larynx) in short-nosed breeds of dogs. This syndrome is caused by anatomic abnormalities related to the shortened bones of these dogs’ compressed faces without the same proportionate shortening of the overlying soft tissues. The excess soft tissue leads to airway compromise.
Brachycephalic breeds of either sex, such as the English bulldog, Boston terrier, pug and Pekingese, are most commonly affected.
Stenotic nares (pinched nostrils), overlong soft palate and everted laryngeal saccules are the most common conditions encountered in dogs with this problem. Although the abnormalities are present at birth, clinical signs of respiratory difficulty often begin in early middle age.
Increased airway resistance from brachycephalic syndrome over a long period of time can lead to progressive respiratory difficulty. The larynx and trachea become weaker as the large negative pressure of the increased effort on inspiration continually draws them in. Eventually they may collapse causing critical airway obstruction, cyanosis (blueness to the color of the oral membranes), and possibly death.
What to Watch For
Signs of brachycephalic syndrome in dogs may include:
- Noisy breathing (especially on inspiration)
- Exercise intolerance
- Cyanosis (blue appearance of the gums due to lack of oxygen)
- Syncope (fainting)
Diagnosis of Brachycephalic Syndrome in Dogs
The diagnosis is often made based on the breed of dog and the clinical signs. Other diagnostic tests that may be performed include:
- A complete physical examination, including auscultation (listening) of the chest with a stethoscope, to help exclude other causes of respiratory difficulty
- Thoracic radiographs (x-rays) to determine if heart or lung disease is present
- Visual inspection of the nostrils to determine the presence of pinched nostrils
- Examination (under sedation) of the mouth and larynx to diagnose an overlong soft palate and/or laryngeal saccules that are turned outward
Treatment of Brachycephalic Syndrome in Dogs
Mild cases are usually managed conservatively without surgery. Although mild cases or sudden bouts of airway obstruction may be managed medically (by tranquilization, administration of oxygen, hospital use of anti-inflammatory steroids), the risk for progression of severe airway disease exists. Close monitoring of your dog for worsening of clinical signs is imperative.
- Surgical management before severe clinical signs develop is relatively easy and carries a much more favorable prognosis than attempted treatment later when the signs are more severe. Possible surgeries (depending on which abnormalities are present in your dog) include removal of a portion of the nostril to allow increased airflow, shortening the soft palate and removal of the everted laryngeal saccules.
- If medical management is pursued closely watch your dog for worsening of clinical signs.
- Prevent your dog from becoming obese as this will make it more difficult for him to breathe easily.
- Avoid excessively stressful situations, such as exercise during hot, humid weather.
- Avoid using a neck collar – use a harness instead.
- If your dog has trouble breathing, becomes cyanotic, or collapses, visit your veterinarian immediately.
- If surgical therapy is done no special care may be required once healing is complete; however, you should continue to monitor your dog for recurrence of clinical signs.
In-depth Information on Brachycephalic Syndrome in Dogs
Related diseases or disorders that mimic the signs of brachycephalic syndrome:
- Laryngeal disease. Laryngeal paralysis is a relatively common neurologic disorder of dogs that lead to inability to open (abduct) the muscles of the larynx (voice box). Laryngeal collapse is a very severe, end-stage condition of the larynx caused by chronic increased inspiratory effort and subsequent weakening of the laryngeal cartilages that would normally hold the walls of the larynx out of the airway.
- Upper respiratory cancer or mass lesions. Tumors, masses or foreign material lodged within the nasal cavity, pharynx, larynx or trachea (windpipe) can cause respiratory difficulty as the air passage is partially obstructed by the mass.
- Tracheal collapse. Usually found in small breed dogs, tracheal collapse is caused by weakness of the cartilage rings that normally hold the trachea open during breathing leading to a severe “honking” cough and dyspnea (difficult breathing).
- Bronchial obstructions. These are caused by primary bronchial collapse that compresses the left bronchus (airway).
- Heart failure. Heart failure with development of fluid accumulation in the chest or lungs can lead to breathing difficulties.
- Pulmonary (lung) disease. This is ineffective oxygenation of the blood caused by lung disease and can cause shortness of breath and difficulty breathing. Examples include bronchitis, pneumonia and lung cancer.
In-depth Information on Diagnosis
Diagnostic tests are needed in cases of upper respiratory obstruction, including:
- Complete medical history and physical examination
- The diagnosis of upper airway obstruction/brachycephalic syndrome is often simply made based on the breed of dog and the clinical signs. Although brachycephalic breeds of dog often make loud snorting noises while inhaling and are considered “normal,” clinical signs of weakness, cyanosis or fainting are indications that the dog is unable to get enough oxygen through his airways and may need treatment. Other concurrent causes for the dog’s clinical signs must be ruled-out to avoid missing the real problem.
- The veterinarian should obtain a complete medical history and perform a thorough physical examination. It is especially important that auscultation (examination with a stethoscope) of the chest is performed to listen for abnormalities in the lungs or irregularities in the heartbeat.
- Thoracic radiographs (chest X-rays) also may be taken, particularly if auscultation of the chest was questionable or abnormal, in order to confirm or refute heart or lung causes of the respiratory difficulty.
- Visual inspection of the nostrils confirms the diagnosis of stenotic nares. Stenotic nares have reduced openings compared with those of a normal dog’s nose.
- In order to confirm the presence of overlong soft palate and/or everted laryngeal saccules, the dog must be sedated or lightly anesthetized and the veterinarian must examine the back part of the oral cavity and larynx.
- An abnormally long soft palate will reach the base of the covering of the larynx and the epiglottis, and in severe cases it may be sucked into the laryngeal opening as the dog inhales. Normally the palate barely reaches the tip of this structure.
- Everted laryngeal saccules are seen arising from normally hidden crypts in the walls of the larynx adjacent to the vocal folds. They are not visible in a normal dog, but can be sucked out of their crypts with excessive negative pressure during inspiration (when air is drawn into the lungs). The presence of everted laryngeal saccules indicates a more severe form of brachycephalic syndrome and is thought to represent an early stage of laryngeal collapse.
In-Depth Information on Treatment
Treatment for upper respiratory obstruction may include one or more of the following:
- Many brachycephalic breeds of dogs have stenotic nares and overlong soft palates that cause stridulous breathing but never cause more serious clinical signs. These mild cases (“normal” for their breed) are usually managed conservatively without surgery. Conservative management is directed at preventing excessive respiratory effort requiring the dog to move air faster than the airways will allow.
- Obesity makes it more difficult for the dog to move air in and out of the lungs due to compression on the diaphragm and chest wall. Excess fat in the tissues around the airways impedes airflow through the airways. Obese dogs also have trouble eliminating excess heat and are forced to pant more than usual. These all cause the dog to have an increased respiratory effort and exacerbate the problem.
- Excessively stressful situations increase the tissues’ oxygen demands and will cause the dog to increase his respiratory effort. Hot, humid weather is very difficult for these dogs to deal with and they should be kept quiet in an air-conditioned environment whenever possible.
- A very important management technique, to prevent breathing becoming more difficult than it already is, is for these dogs to avoid the use of a neck collar. When the dog pulls of the collar it compresses part of the trachea, further exacerbating the airway obstruction. An over the shoulders-type harness should be used instead.
- Although mild cases are often managed conservatively, the risk for progression of severe airway disease exists. Months and years of increased inspiratory effort can lead to severe problems with the larynx. Close monitoring of the dog for worsening of clinical signs is imperative.
- The surgical corrections for stenotic nares and overlong soft palate are relatively easy and carry excellent prognoses when performed early in the course of the disease. Surgical management later in the course of the disorder is less successful and may not be possible if the larynx has become weakened.
Surgical corrections include:
- Stenotic nares resection is widening of the size of the opening through the nostrils by removal of a small piece of the wall of each nostril. It can be performed with a scalpel or a surgical laser.
- Resection of overlong soft palate is removal of the excess length of the soft palate that is hanging into the airway. It is carefully trimmed with a scalpel and scissors and then sutured closed, or a surgical laser can be used to minimize hemorrhage and requires no sutures.
- Resection of everted laryngeal saccules is removal of the swollen tissues protruding from the walls of the larynx at their bases. Occasionally, a tracheotomy tube is needed to allow an unobstructed view of the larynx to allow this procedure.
- Your veterinarian’s recommendations for medical management should be followed very closely to avoid respiratory crisis situations. Progression of clinical signs may indicate the need for surgical intervention.
- If the dog becomes dyspneic (has trouble breathing), cyanotic or collapses, visit your veterinarian immediately. Severe respiratory distress leads to periods of low oxygen and can cause irreversible injury to the body.
- After surgery, the dog may be completely cured and may never have another breathing problem. The dog should be monitored for recurrence of clinical signs.
- Brachycephalic syndrome is a congenital anatomic disorder. Decades of “unnatural” selection in shaping these breeds of dogs to look the way that they do has created the problem. These dogs’ genetic codes direct their development and cannot be altered or prevented from creating the problem. The only thing a conscientious owner can do, if they own one of these breeds of dogs, is close monitoring for characteristic signs related to the disorder and treat the dog early to prevent future problems.