Laryngeal Paralysis - LarPar
The larynx is the medical term for the voice box, and is the front door of the trachea (windpipe). The muscles of the larynx are responsible for opening and closing the windpipe during normal breathing, as well as vocalization. Laryngeal paralysis occurs when the muscles or nerves of the larynx no longer function normally to open the airway during breathing. When the larynx fails to open, this forces dogs to breathe through a more narrow opening which makes a hoarse or wheezing sound that worsens with excitement or activity. Dogs with laryngeal paralysis also may have a change in their bark sound and sound more raspy.
How is Lar Par dianosed?
Physical exam - exam findings are typically enough to make a tentative diagnosis of laryngeal paralysis.
Sedated airway exam - Sedation is required in order to evaluate the back of the throat and airway to confirm the diagnosis of laryngeal paralysis before surgery.
Chest X-rays - because laryngeal paralysis patients are at a higher risk for developing aspiration pneumonia, chest x-rays are recommended to rule this out before pursuing anesthesia. This test also screens for megaesophagus (enlarged and dysfunctional esophagus) which may be a component of GOLPP.
Blood work - this information is used to develop the safest anesthesia and pain management plan for the patient
Thyroid testing - Dogs with laryngeal paralysis and hypothyroidism (low thyroid hormone) may improve with treatment of hypothyroidism and may not require surgery.
How exactly is Lar Par treated?
There is an emergent, medical and surgical treatment protocol for Lar Par, depending on the immediate need of the pet.
Dogs presenting in an urgent respiratory crisis (collapse, blue gums, extreme wheeze, stress) need to be stabilized prior to surgery. Nearly all dogs in respiratory crises are able to return to their previous, albeit abnormal, state of breathing but ultimately will require surgery to improve breathing and reduce the risk of sudden death from respiratory failure.
The following therapies are indicated in dogs presenting in a respiratory crisis:
Anti-inflammatory steroid medication (only if not already on NSAIDS)
+/- endotracheal intubation (breathing tube placement)
Once recovered from the respiratory crisis, dogs are often managed with a tapering course of steroid medication and sedatives to prevent another episode before surgery can be scheduled.
Laryngeal paralysis is typically a slowly progressing disease that commonly affects older large breed dogs like Labrador Retrievers. Dogs typically show mild clinical signs initially such as change in voice, exercise intolerance and excessive noisy panting that progress weeks to months. Often, the condition worsens in heat or after exercise. As dogs pant or breathe harder to oxygenate, the airway tissues become inflamed, leading to further obstruction of the airway, which may lead to episodes of severe respiratory distress. Laryngeal paralysis patients are at a higher risk for dangerous overheating because they cannot effectively control their temperature with panting. When severely affected, dogs are at risk of collapse and death from inability to oxygenate.
Laryngeal paralysis is often one component of a larger progressive neurologic syndrome in older dogs called Geriatric Onset Laryngeal Paralysis Polyneuropathy or GOLPP for short. The most common abnormalities with GOLPP are laryngeal paralysis, regurgitation, and stumbling or wobbling in the hindlimbs. This is because the nerves that control the muscles of the larynx, esophagus, and the hind legs are most affected by this progressive disease. There is no treatment for GOLPP itself, so therapy is aimed at improving breathing as this has the greatest impact on quality of life.
Younger dogs are very rarely affected by laryngeal paralysis, however there is a genetic predisposition in Siberian Huskies, Bouvier des Flandres, Dalmations, Great Pyrenees, and Bull Terriers. In these younger dogs, the disease is not slowly progressive and is severe at a young age, requiring surgery.
Signs of laryngeal paralysis:
High-pitched wheezing or raspy breathing
Exercise intolerance, collapse
Change in bark sound
Gagging and regurgitation
If severe, respiratory failure, blue gums, death
How would Lar Par be medically managed?
Early in the disease, laryngeal paralysis can be effectively managed medically as dogs typically only have louder breathing and exercise intolerance. The goal of medical management is to make environmental and lifestyle changes to avoid respiratory distress episodes and overheating. Because surgery comes with an elevated risk of aspiration pneumonia, medical management is recommended until laryngeal paralysis is significantly impacting your pet’s quality of life (severe exercise intolerance, constant loud panting, collapse). Some dogs benefit from anti-inflammatory steroid administration to reduce the inflammation in the airway. If your pet is already on NSAIDS (eg. carprofen, meloxicam, previcox) for arthritis or any other reason, they cannot be treated with steroid medication as the combination can cause dangerous side effects.
Dogs with laryngeal paralysis do not tolerate additional weight on the body well. These dogs in particular should be kept as thin as possible to prevent overheating. The top of the spine and ribs should be easily felt when petting those areas, if not, there is the presence of excess in these locations. Low fat diet and controlled exercise is the main way to encourage a healthy weight for your dog. Laryngeal paralysis dogs that are kept at a thin body condition are much less likely to have life-threatening respiratory distress episodes.
Use a harness instead of a neck collar when walking your pet, this will prevent additional pressure on the throat and airway when on leash.
Avoid Excess Heat
Dogs cannot sweat to cool down like people can. Their main way to control body temperature is through panting/breathing. Because dogs with laryngeal paralysis have difficulty breathing, they also have difficulty regulating their body temperature and are prone to extreme overheating. Dogs with laryngeal paralysis should avoid exercise and play outside during the hottest times of day. Monitor your pet closely when active for difficulty breathing and give them frequent breaks in a cool environment.
Stressful situations cause dogs to pant excessively and overheat. This can lead to episodes of difficult breathing in dogs with laryngeal paralysis. If you know your dog gets stressed or over excited with visitors or storms, a light sedative can be given to help keep them calm during the excitement and prevent breathing issues. A sedative medication can be prescribed by your veterinarian if needed.
Avoid Respiratory Irritants
Anything with a strong smell can be irritating to the airway of dogs and can cause coughing and worsen breathing. This includes smoke, candles, incense, perfumes, and sprays. Keep in mind that dogs are much more sensitive to smells than humans are. Try to minimize your dog’s exposure to anything with a strong scent or which may be irritating to the airway.
When would surgical intervention be
recommended for Lar Par?
In dogs with moderate to severe laryngeal paralysis, or whose quality of life is otherwise greatly impacted by their disease, surgical therapy is recommended. Because laryngeal paralysis prevents the airway from opening normally, the goal of surgery is to permanently open the airway at the larynx. Several surgical procedures have been described to treat laryngeal paralysis with varying success. The most consistent positive results have been reported with a procedure called Unilateral Cricoarytenoid Lateralization, also known as the “tie-back” procedure. This surgery involves making a small surgical incision in the side of the neck in order to place a strong, non-absorbable suture which permanently holds the airway open at the level of the larynx. After surgery, dogs have immediate relief of clinical signs and are able to breathe more normally with improved activity levels. Many owners report amazement in how much more energy their dog regains after surgery. However, because the airway is permanently open, dogs are unable to close their airway when swallowing food and water, and so are at a much higher risk for aspiration of food and water into the windpipe and development of pneumonia. Additionally, dogs can no longer go swimming after this surgery has been performed to avoid the risk of drowning. To minimize the risk of aspiration pneumonia, the airway is not opened to its maximum size, but is only enlarged enough to improve breathing. However, the risk remains present in all dogs after surgery, as aspiration pneumonia is reported in 20-30% of tie-back patients. Some episodes of pneumonia are controlled with antibiotics, while others may be severe and fatal. Dogs with chronic regurgitation and evidence of esophageal dysfunction before surgery are at a higher risk for developing this complication. Because of the life-long risk for aspiration pneumonia after surgery, medical management of laryngeal paralysis is recommended until it is no longer effective.
At your pet’s surgical evaluation, our doctors will evaluate your pet, learn more about their lifestyle and discuss your goals to determine if and when to pursue surgical treatment.