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Summary
Laryngeal paralysis is a condition in which the arytenoid cartilage on one or both sides of the larynx cannot open and close properly. Normally, the larynx (also known as the voice box) is the part of the throat that prevents food and liquid from entering the trachea and airways. When a dog or cat swallows, the arytenoid cartilage on each side of the larynx closes over the tracheal opening, allowing the food/liquid to pass into the esophagus and down the gastrointestinal (GI) tract instead of into the airways. Immediately after swallowing, the cartilage moves away from the trachea, allowing breath to move in and out of the airway as needed.
With laryngeal paralysis, the cartilage is unable to fully close and open over the tracheal opening. This is usually because the nerves (e.g. laryngeal nerve) aren’t sending signals properly. Improper opening and closing can lead to significant problems when breathing, because the airway is blocked by the immobile cartilage. Laryngeal paralysis can also cause problems when eating or drinking because the airway isn’t fully covered and food and fluid may escape down into the trachea.
Laryngeal paralysis can occur because of trauma or damage to the throat, age-related nerve disease (known as geriatric onset laryngeal paralysis and polyneuropathy), or it may be present at birth (known as a congenital condition). Laryngeal paralysis in dogs is very common, whereas laryngeal paralysis in cats is rare.
Symptoms and Identification
Common symptoms include a harsh, wheezing sound when breathing. Noisy breathing may be worse during and after exercise or when pressure is applied to the neck (e.g. using a neck leash during walks). Pets may struggle to breathe because the airway doesn’t have enough room to allow for proper air flow. Other symptoms may include coughing or gagging, especially after eating and drinking. Changes in the sound of the bark or meow may also occur, typically becoming more of a hoarse vocalization.
In severe cases, pets may struggle to breathe to the point that they collapse. This is especially common in pets that have become overheated. Coloring in the mouth may change from pale pink to dark purple. If these signs are noticed, emergency care should be sought immediately.
Diagnosing laryngeal paralysis involves heavy sedation and evaluation of the larynx and airways with either an endoscope or laryngoscope. This must be performed by a veterinarian. When looking at the larynx, the vet will be able to see that one or both of the arytenoid cartilages are not moving properly. X-rays and lab work are also needed to ensure no other diseases are occurring.
Aspiration pneumonia is common with laryngeal paralysis. This occurs when food or liquids meant for the GI tract enter the lower airways, causing an infection. Hypothyroidism, a condition in which the metabolically important thyroid gland isn’t working appropriately, can occasionally cause laryngeal paralysis. Diagnosing this disease may help improve treatment outcomes.
Affected Breeds
Laryngeal paralysis in cats is rare, so no specific breeds are affected.
Congenital laryngeal paralysis is more common in the following dog breeds:
Geriatric onset laryngeal paralysis is more common in:
Large & giant breed dogs (e.g. Great Danes)
Treatment
Laryngeal paralysis treatment varies depending on severity of symptoms. For pets who have only mild breathing and voice changes and who have no trouble with exercise, monitoring may be best. Watch for signs of trouble breathing, decreased energy levels, and increased coughing or gagging. In addition to monitoring, these pets may benefit from wearing a harness instead of a collar, decreasing exercise during hot weather, and using “slow feeders” to slow down eating (i.e. preventing accidental inhalation of food).
For pets with more severe symptoms, surgery is likely necessary. Procedures can be performed to either remove part of the arytenoid cartilage (known as a partial laryngectomy) so that the airway is less blocked, or tie back the cartilage with suture in such a way that it allows the cartilage a better range of motion (known as a laryngeal tieback procedure). Both procedures carry risks, including an increased risk for aspiration pneumonia. Neither procedure cures the problem, which is why they are only recommended in pets with moderate to severe symptoms.
Veterinary Cost
Surgery can be very technically difficult, often requiring a board-certified specialist or, at the very least, a veterinarian with many years of experience in surgery. Laryngeal paralysis surgery cost typically ranges from $2,600-$5,200, depending on how ill the pet is before surgery and how recovery goes. Cost is increased for pets who develop life-threatening breathing difficulties or severe pneumonia.
Prevention
Pets who have congenital laryngeal paralysis should not be bred because their offspring may inherit the disease.
Laryngeal paralysis itself cannot be prevented, but controlling symptoms can prevent respiratory emergencies. Avoid strenuous activity, especially in hot weather. Weight loss may also be helpful.
References
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