The larynx is essentially your dog's voice box that allows them to bark and make other noises. Some breeds are particularly prone to the larynx developing problems and becoming paralyzed, which can cause changes in their voice and potentially affect their ability to breathe. Most cases will require surgery to correct the issue, but the long-term prognosis is good.
The larynx is positioned at the very back of the dog's throat, at the entrance to their trachea (windpipe). It contains the vocal cords, of which there are two sets on either side of the pipe. These move in unison to change how the air flows in and out and make sounds. They also protect the lungs from anything solid going down them.
The nerves that supply the larynx arise in the brain, travel down the neck, through the chest cavity and back up again. Paralysis of the larynx occurs when these nerves are damaged or stop functioning.
Causes of Laryngeal Paralysis
Causes of this are variable. In some breeds such as Bouvier des Flandres, Dalmatians, Siberian Huskies, and Bulldogs, Laryngeal Paralysis is a congenital condition (present at birth), but it is far more common for dogs to acquire the disease. Cancer, trauma to the neck region, degenerative nerve conditions, and some hormonal diseases can all cause damage to the nerves, but in the majority of patients, no obvious abnormalities are found and it is simply an age-related decline in nerve function. Large breed dogs such as the Labrador Retriever, Golden Retriever, Newfoundland, and Saint Bernard are particularly susceptible to this.
Symptoms of Laryngeal Paralysis
The symptoms of a paralyzed larynx include panting, noisy breathing, change in the bark sound, intermittent coughing, and a reduced exercise tolerance. In many cases, the condition develops slowly over time and can often be put down to just 'old age' before pet parents realize that there is an actual problem. Some dogs cope fine when they are resting and only display signs when they begin to exercise. However, if they start panting excessively (for example, in hot weather), this can overpower their coping mechanisms and they can become distressed, collapse and require emergency treatment.
Diagnosing Laryngeal Paralysis
The condition is diagnosed based on the appropriate symptoms, especially if they occur in a commonly affected breed. Your vet may also want to view the larynx directly, which is generally done under an anesthetic. They will be able to see the cords moving, sometimes directly and sometimes using an endoscope, and usually it is obvious that it is not functioning properly. The vet will also take blood tests, looking particularly for hormonal disorders, as well as X-ray your dog's chest to ensure the damaged larynx hasn't allowed any fluid to run into the lungs.
Treatment for Laryngeal Paralysis
The treatment will depend on the underlying cause but as this isn't found in most cases, vets will generally advise surgery to fix permanently one, or both, sides of the larynx in an open position. This means your dog will be able to breathe freely and the vast majority do very well after their operation.