Laryngeal Paralysis In Dogs
Written by Shula Berg BVSc CertAVP(GSAS) GPAdvCert(SASTS) MRCVS
Clinically reviewed by Elizabeth McLennan-Green BVM&S CertAVP(SAM) MRCVS
Table of Contents
- Overview
- Symptoms
- Diagnosis
- Treatment
- Outlook
The larynx is the connection between the upper airways (nose and mouth) and the trachea (windpipe). It is a semi-rigid structure made up of five cartilages and muscle, which acts as a valve and contains the vocal cords. The larynx plays an important role in breathing, swallowing, and creation of sound - in people, the larynx is often referred to as the “voice box”. Branches of the laryngeal nerves control the movement of the different parts of the larynx, allowing it to open and close as needed.
Laryngeal Paralysis occurs when the nerves and muscles are not moving the larynx normally, specifically affecting the arytenoid cartilage and the vocal folds. Normally, these structures are abducted (pulled outwards) out of the airway during inspiration to allow air into the trachea. In Laryngeal Paralysis, they do not move and therefore cause partial obstruction of the airway.
Laryngeal Paralysis is most commonly seen in medium to large breed dogs over 10 years of age, with males affected more frequently than females. Labradors, Golden Retrievers, Setters and Pointers seem to be predisposed. Most cases of Laryngeal Paralysis are known as idiopathic, meaning no underlying cause is identified. Uncommonly, paralysis can be caused by trauma to the neck (such as dog bites), tumours of the thyroid or chest cavity, or generalised nerve disorders, though these are usually accompanied by other symptoms. A congenital (genetic) form is very rarely seen in young dogs. Laryngeal Paralysis can occur in cats, but this is very rare and usually as a result of trauma or tumours.
What are the symptoms of Laryngeal Paralysis?
Laryngeal Paralysis often develops slowly, and symptoms may appear gradually. One or both sides of the larynx can be affected, but symptoms are often more obvious when both sides are paralysed. Common symptoms include:
- Noisy breathing, especially during inhalation (breathing in) – this is known as stridor
- Exercise intolerance, or unwillingness to exercise
- Change in bark (dysphonia) affects roughly 50% of dogs
- Discolouration of the gums to a blue-purple colour, especially after exertion
- Fainting, especially after exertion, in severe cases
- Coughing while eating or drinking
Symptoms will usually become more pronounced when the dog is required to breathe faster or more deeply – this often occurs during warm weather, during or after exercise, or when the dog is excited and/or stressed (such as car journeys or house visitors). Occasionally, dogs can suffer severe breathing difficulties or collapse due to inability to inhale enough oxygen. This is an emergency and requires urgent treatment.
Which tests are used to diagnose Laryngeal Paralysis?
The age and breed of the dog and description of symptoms will often lead to a high suspicion for Laryngeal Paralysis. It is important, however, to rule out other conditions, especially as most cases are older patients. A full clinical examination will be performed, and your vet may recommend a general blood test to provide an overview of organ health and asses suitability for some medications.
The only way to definitively diagnose Laryngeal Paralysis is to observe the movement of the arytenoid cartilages during breathing. This is performed under a very light dose of anaesthesia; the patient must be sleepy enough to allow examination but not so sleepy that the anaesthetic stops the cartilages moving normally. Often, chest x-rays are performed under the same anaesthetic to rule out underlying causes or other conditions that could affect treatment.
How is Laryngeal Paralysis treated?
Laryngeal Paralysis is progressive, and symptoms will gradually worsen. The only definitive treatment is surgical, using a procedure known as unilateral arytenoid lateralisation (often referred to as a “laryngeal tie-back”). This works by permanently abducting one of the arytenoid cartilages to open the airway. Even if both sides are paralysed, only one side needs surgery to achieve a successful outcome. The surgery has good success rates, however, it is a complex procedure due to the anatomy of the neck. Complications can occur, so referral is often advised to a specialist surgeon, or a vet with a particular interest in surgery and relevant experience. Following recovery, there remains an increased risk of aspiration pneumonia due to the inability of the airway to close when eating or drinking.
Less commonly, a permanent tracheostomy can be performed as a salvage procedure. This creates a permanent opening into the trachea, bypassing the larynx. Although it is less technically demanding to perform than a unilateral arytenoid lateralisation, there is a much higher risk of complications, so it is usually reserved for cases where initial surgery has failed, or there are other complicating factors.
Due to the age of most affected dogs, and the costs involved, some people feel surgery is not the right decision for their pet. Medical management can be attempted, however, this will only slow down progression and is best suited to patients with mild symptoms. Lifestyle changes are the most important consideration, including avoiding strenuous exercise, stress and excitement, keeping patients cool, and weight loss if needed. For some patients, light sedatives may be helpful.
What is the outlook for dogs with Laryngeal Paralysis?
The prognosis for dogs with Laryngeal Paralysis is variable depending on the severity of symptoms, presence of other conditions, and treatment chosen. Dogs who successfully undergo arytenoid lateralisation can do very well, with a significant improvement in quality of life and excellent long term prognosis. Dogs who are managed medically have a more guarded prognosis. Although management can reduce symptoms, sometimes for a long time, the condition is progressive and eventually most patients will need putting to sleep. All dogs with Laryngeal Paralysis are at risk of a sudden respiratory event requiring emergency treatment.
Disclaimer
Please note that the content made available on this webpage is for general information purposes only. Whilst we try to ensure that at the time of writing all material is up to date and reflects industry standards, we make no representation, warranties or guarantees that the information made available is up to date, accurate or complete. Any reliance placed by yourselves is done so at your own risk.
Page last reviewed: 23rd April 2024
Next review due: 23rd April 2026