Soft Tissue Veterinary Surgeon Hannah Prestwood explains why certain dog breeds have breathing difficulties and what can be done to help them.
Brachycephalic dog breeds such as French bulldogs, Pugs, Shih Tzu are becoming increasingly popular breeds in the UK. However, these dogs commonly suffer from a disease called Brachycephalic Obstructive Airway Syndrome, more commonly known as BOAS.
These dogs are bred with a shorter muzzle, but their soft tissue structures within the upper airways are not shorter. They therefore have a long soft palate and larger tongue, resulting in obstruction of the larynx and pharynx. There is also commonly constriction of the nasal passage resulting in reduced airflow through the nose, made more severe with stenotic (narrowed) nares or ‘nostrils’. Consequently, brachycephalic breeds are unable to control their body temperature due to this excess soft tissue restricting their pant mechanism, making them more prone to heat stroke and collapse. Obstruction of the airways also results in the animal having to increase its respiratory effort in order to breathe, which gives them the characteristic snoring noise when breathing.
Over time this continued negative pressure causes the soft tissue of the airways to become hyperplastic (inflamed) and the laryngeal cartilages collapse making the obstruction worse. Once the laryngeal cartilages have collapsed for an extended period of time it is very difficult to reverse the damage. It is therefore important that dogs are checked at an early age so surgery can be carried out before further damage is caused, this is usually at 1-2 years of age.
Surgeons at Eastcott Veterinary Referrals commonly operate on BOAS patients. Firstly, inspection of the pharynx is carried out to assess the level of damage or collapsed. Detailed imaging of the upper respiratory tract can be performed using our CT scanner, in order to check for any other obstructive pathology which may not be obvious to the naked eye.
Surgery involves removing the end of the soft palate making it shorter (picture 1a+b), this allows air to pass through the pharynx more freely. If the animal is in a more advanced stage of the syndrome the laryngeal saccules are also removed to stop them collapsing into the larynx.
Picture 1a: Brachycephalic dog with long soft palate before surgery
Picture 1b: Brachycephalic dog after the soft palate has been surgically resected
During the final stage of surgery the nares of the dog are widened (picture 2a+b), as opening up the front of the nose can help to increase airflow through the nasal cavity.
Picture 2a: Brachycephalic dog with stenotic nares before surgery
Picture 2b: Brachycephalic dog after surgery to widen the nares
The patient is carefully monitored during recovery to check that there is no severe swelling after the operation, but normally patients are back home the next day, with a full recovery and reduction of symptoms after 2 weeks if treated early in the disease process.
After surgery animals are more energetic on walks, can control their temperature more effectively, and are less likely to experience respiratory collapse when older. It is therefore very important to check brachycephalic breeds even if they are not yet showing clear clinical signs respiratory distress and respiratory noise, as the earlier the syndrome is treated the better the outcome for the patient.