Pet Health Library

Background

The larynx (voice box) is the collection of cartilages responsible for your voice and control of airflow during respiration. Normal laryngeal function protects the airway by closing off the lumen (the passageway for air) when swallowing to prevent aspiration of food or water. When open, breathing – and barking – occurs.

Laryngeal paralysis – often called “lar par” – is a common respiratory disorder that results when the arytenoid cartilages do not open, blocking air flow into the windpipe and lungs. Dysfunction of the arytenoid cartilage leads to breathing difficulties, changes in vocalization, reduced exercise and heat tolerance, as well as an increased risk of aspiration pneumonia due to food and water getting into the lungs.

The cause of most cases of laryngeal paralysis is unknown but is attributed to Geriatric Onset Laryngeal Paralysis and Polyneuropathy (GOLPP) where multiple nerves controlling the larynx and other muscles degenerate.  Hypothyroidism, neck injuries or tumors are less common causes.

Risk Factors

• Age: laryngeal paralysis primarily affects older dogs
• Breed: large dog breeds more commonly develop laryngeal paralysis
  • A congenital form (present at or shortly after birth) occurs in some breeds such as Bouvier des Flandres, Bull Terriers, white-coated German Shepherds, and Siberian Huskies.

Signs

Affected dogs may present:

• A high-pitched whistling sound when breathing (stridor)
• Changes in vocalization
• Difficulty breathing
• Excessive panting
• Coughing
• Gagging
• Regurgitation
• Gums or tongue turning blue (cyanosis)
• Collapse

In some cases where the laryngeal paralysis is part of a more generalized condition, the dog can show:

• Difficulty placing the paws on the ground normally.
• Tripping, stumbling or dragging paws
• Slowly worsening hind limb weakness
• Loss of limb muscle mass

Diagnosis

To diagnose laryngeal paralysis and develop a treatment plan, a veterinarian will perform a sedated laryngeal exam where they watch the movement (or decreased movement) of the arytenoid cartilages.  GOLPP has been associated with genetic mutations in some dogs.  Identification of the mutation via genetic testing does not help treatment but can guide breeding programs.

Treatment

There is no cure for laryngeal paralysis.

For some dogs, using a harness for walks, weight loss, a cool environment, sedation and limited exercise during hot weather are enough to mitigate the clinical signs of laryngeal paralysis.

For dogs with severe cases, veterinary surgeons will surgically suture the larynx open. This surgery improves respiration, but the risk of aspiration pneumonia will remain as this does not restore full function to the larynx. Aspiration pneumonia itself can be resolved in some cases, but in others it can remain a constant challenge. Aspiration pneumonia is treated with antibiotics and supportive care through oxygen therapy.

In respiratory emergency events caused by laryngeal paralysis, the dog will receive oxygen therapy, intravenous (IV) fluids, and calming medication. If the dog is overheating, veterinarians will work to cool them down.

Use of a ventilator to provide temporary breathing assistance may be necessary in cases of aspiration pneumonia or respiratory emergencies caused by laryngeal paralysis.

Prevention

Unfortunately, laryngeal paralysis cannot always be prevented as it is often associated with genetics or other underlying medical issues. However, you can lower the probability of your pet developing laryngeal paralysis by maintaining a healthy body weight and avoiding collars. Choose a well-fitting harness when going out for walks and limit rough play that can pull at the neck, like tug-of-war.