Laryngeal Paralysis in Dogs

What is Laryngeal Paralysis in Dogs?

The larynx is a tubular structure at the top of the windpipe (trachea). It is also known as “voice box” because it produces sound as air moves past it. In addition to sound, the larynx works with the epiglottis (a flap of cartilage covering the airway during swallowing) to prevent food from entering the trachea.

Laryngeal paralysis occurs when the muscles contract to open the airway stop functioning properly. This can prevent the larynx from opening and closing normally.

There are several types of diseases that can affect the larynx, such as:

• Laryngitis: inflammation of the cartilage or soft tissue of the larynx.
   
• Laryngeal edema: swelling caused by the accumulation of fluid in tissues.
   
• Laryngeal tumors: growths or masses on the larynx or surrounding structures.
   
• Laryngeal chrondropathy: infectious condition of the cartilage, which most often occurs from injury caused by sticks (or other foreign material). These injuries can cause an abscess or bacterial infection.
   
• Laryngeal paralysis: (most common) A disease in which the muscles that open the larynx/voice box become weak due to a degenerative disease of the nerves and muscles that allow the larynx to open and close normally.

Certain diseases like laryngitis or edema are more likely to occur in younger dogs, while other conditions such as a laryngeal tumor or laryngeal paralysis are more common in older pets.

Diseases that affect the airway can be life threatening. A dog should be taken to a veterinarian immediately if they have:

• Difficulty breathing

• Bluish or purple tongue/gums

• Facial swelling

Symptoms of Laryngeal Paralysis in Dogs

A significant increase in panting or loud breathing is often the first symptom noted in dogs with laryngeal paralysis. The symptoms of this disease tend to be gradual, but the pet parent might also notice:

• An increase in panting during stress or on hot/humid days

• Noisy panting

• Exercise intolerance/lethargy

• Voice change

• Anxiety

• Coughing or gagging when eating or drinking

• Respiratory distress

• Heat stroke

• Dark red, purple or blue gums

• Collapse

Symptoms usually start mildly but will grow progressively worse. A dog will generally start with increased panting behaviors. Dogs with laryngeal paralysis are more prone to overexertion and overheating in warmer and humid environments, as they are not able to effectively cool themselves through panting. This can lead to heat stroke, respiratory distress or even collapse and death.

The condition can develop at any age due to a congenital defect, but it more commonly develops in older giant- and large-breed dogs, especially Labrador and Golden Retrievers, St. Bernards, Irish Setters, and Newfoundlands.

Laryngeal paralysis of both hereditary and acquired forms usually worsen slowly. The partial obstruction in the airway interferes with the amount of oxygen a dog can take in, eventually leading to shortness of breath.

Over time, a dog will become anxious, causing it to breathe faster (but not more efficiently). This can lead to respiratory distress and even death.

If you notice symptoms of heavy breathing, respiratory distress, excessive panting even in cool environments, a swollen face or gums have changed to blue or purple in color, take your dog to a veterinarian immediately.

Causes of Laryngeal Paralysis in Dogs

Laryngeal paralysis is a condition in which the muscles that open the larynx/voice box do not function properly. Generally, this is due to a degenerative disease of the nerves and muscles.

Laryngeal paralysis can be an inherited disorder, but it is more commonly seen as an acquired condition. It is also thought to be a symptom of a larger neurologic condition called Geriatric Onset Laryngeal Paralysis Polyneuropathy (GOLPP).

In time, dogs with GOLPP may have other symptoms of other neurologic weaknesses such as rear leg weakness, and their esophagus may become distended (megaesophagus), which causes difficulty swallowing and sending food down the esophagus to the stomach.

Dogs with this condition are typically 10 years of age or older. Less commonly, laryngeal paralysis can be caused by nerve damage that impacts the larynx. This can be from trauma, like a dog bite, a deep wound or from a cancerous lesion in the area.

How Veterinarians Diagnose Laryngeal Paralysis in Dogs

To diagnose laryngeal paralysis, your veterinarian may sedate the dog to visualize its larynx and the functionality of the cartilage/muscles when they open and close.

In a normal larynx, both sides of the larynx will open and close widely on one breath. In a dog with laryngeal paralysis, the larynx will sit unmoving in a semi-open position.

Your veterinarian is likely to recommend thorough diagnostic testing that includes a complete blood panel, thyroid testing and neck and chest X-rays/radiographs. Radiographs are important to diagnose other potential causes of coughs and to determine if there are any side effects of laryngeal paralysis such as aspiration pneumonia — an infection that occurs in the lungs after food or stomach contents are accidentally breathed into the lungs.

Additional diagnostics or a referral to a specialty hospital may be needed for advanced treatment.

Treatment of Laryngeal Paralysis in Dogs

Laryngeal paralysis is typically treated by surgery in which two permanent sutures are used to hold one half of the larynx open to allow for easier passage of air. This is called a laryngeal tie-back surgery or Unilateral Arytenoid Lateralization (UAL).

An incision is made on the side of your dog’s neck to access the larynx for the placement of sutures. The success rate of laryngeal tie-back surgery is very high.

Less common surgical options may be available as well, and should be discussed with your veterinarian.

Until surgery can be performed, there are a few things you can do to help your dog feel better:

• Avoid collars around the neck. A harness will help avoid any external pressure on the larynx

• Avoid heat and make sure your dog is in a cool well-ventilated environment

• Limit activity

• Reduce anxiety

If your dog is experiencing respiratory distress, your veterinarian may intubate your pet by placing a tube down its throat to ensure sufficient oxygen is getting to the lungs. Intravenous (IV) fluids may also be needed to decrease your dog’s temperature.

Recovery and Management of Laryngeal Paralysis in Dogs

Recovery after laryngeal tie-back surgery is similar to other anesthetic procedures. For example, exercise will be restricted for several weeks. In addition, dogs that have had the procedure should not be allowed to swim for the rest of their lives to avoid the risk of breathing in water.

Coughing or gagging is initially normal while eating or drinking, but tends to resolve over time. The pet parent should be aware of the symptoms of food/water aspiration, which is the most common complication of this surgery. Approximately 25 percent of dogs will have aspiration pneumonia at some point after surgery.

Complications from degenerative nerve/muscle conditions such as GOLPP are possible. Please monitor your dog closely for vomiting, gagging or regurgitation, as these can be a symptom of megaesophagus. Your dog should also be monitored for hind leg weakness, and if noticed, notify your vet immediately.