What is Laryngeal Paralysis?
Laryngeal paralysis is a common condition of mid-to-older dogs that involves the loss of normal function of the larynx. The larynx, commonly known as the voice box, is a collection of cartilage flaps or laryngeal folds that sit in the back of the throat over the entrance to the trachea (wind pipe). Muscles attach to the larynx allowing it to open when breathing and close when dogs are eating and drinking to protect their airways. When the larynx becomes paralyzed, the folds stay in the closed position even when the dog is trying to breathe, causing breathing to be much more difficult.
There are many possible causes of laryngeal paralysis, but the most common cause is what is known in medicine as idiopathic. This means there is not an identifiable cause. Most often, the condition occurs in older dogs, particularly Labrador Retrievers and Golden Retrievers. St. Bernards, Newfoundlands, and English Setters can also be affected. Most of the time, laryngeal paralysis does not advance to other parts of the body. However, some dogs have developed neurologic or nervous system signs within a year of diagnosis, suggesting that laryngeal paralysis is part of a more generalized problem (degenerative polyneuropathy, which affects multiple nerves).
How to tell if your dog has Laryngeal Paralysis:
Signs of laryngeal paralysis are usually a result of failing laryngeal muscles. Dogs with laryngeal paralysis are noisy when breathing in, particularly when panting. In early stages of the disease, owners may miss these abnormal sounds. As the disease worsens, dogs may:
- Get tired more easily
- Develop a change in the sound of their bark
- Cough/gag when eating and/or drinking
Signs may continue for months-to-years before becoming an issue for the dog. Severe upper airway blockage can occur during demanding exercise or in heat and humidity, which results in respiratory distress and collapse. The issues can get worse as increased breathing rates and panting cause the laryngeal folds to become swollen and inflamed and aggravate the airway obstruction. Dogs that have more generalized signs (degenerative polyneuropathy) may have difficulty swallowing, regurgitation, and weakness in their hind limbs.
Laryngeal paralysis is often suspected based on physical examination and neurological examination findings. Increased sounds when the animal breathes in can usually be heard during the physical exam. A neurological exam will demonstrate evidence of generalized signs in dogs with polyneuropathies. A laryngeal exam with a laryngoscope, endoscope, ultrasound or CT – typically performed under sedation – may show failure of the larynx to open when attempting to breathe in. Thoracic radiographs (showing the part of the body between the neck and stomach) can be performed to look for expansion of the esophagus (food pipe). General blood work (complete blood count or CBC and serum biochemistry profile) can demonstrate evidence of metabolic diseases, myopathies (disease of muscle tissue), endocrine/hormonal diseases or infections. Since some cases of laryngeal paralysis have been linked to hypothyroidism (underactive thyroid gland), thyroid function testing may be performed.
There are different treatment options available, dependent upon the severity of the condition and quality of life. Dogs that are not seriously affected may be medically managed in a careful manner. Such management involves moderation in exercise, weight loss, and possibly anti-inflammatory medications to reduce swelling in the larynx.
Dogs that have severe difficulty breathing may be candidates for surgery. Multiple surgical techniques are available, however “laryngeal tie back” surgery is the most popular procedure. This operation, also known as arytenoid lateralization, involves stitching one or both sides of the larynx into a permanently open position to relieve upper airway blockage. Tie back surgical procedures carry the risk of leaving the airway unprotected and increase the risk for aspiration pneumonia (a lung infection that develops after food or liquid is inhaled). As a last resort, a tracheostomy – or incision in the windpipe – can be performed.
What to expect after treatment:
The projection for improvement of signs and quality of life is generally good-to-excellent for idiopathic laryngeal paralysis. Unilateral (one sided) laryngeal tie back surgery usually results in less respiratory upset, less respiratory noise, and improved exercise tolerance, but leaves dogs at risk for developing aspiration pneumonia (see above).
Dogs with more generalized signs (degenerative polyneuropathy) tend to develop additional neurological signs within one year following the diagnosis. While it can be difficult to predict which dogs will develop more generalized signs, dogs that don’t progress can continue to live a good quality of life following successful treatment of laryngeal paralysis.
If you have concerns about your dog or cat, and you need to locate a board-certified internal medicine veterinarian with a neurology specialty or veterinary surgeon, use the VetSpecialists.com search tool on the website’s homepage. The tool allows you to search for a veterinary specialist, then select the type of animal along with your location by zip code or city name. Contact the hospital of your choice to discuss your pet’s signs and to review whether there is a need for a referral from your primary care veterinarian.