Laryngeal Paralysis in Dogs #
Laryngeal paralysis is a condition affecting the function of the larynx in dogs. It is characterized by the failure of the arytenoid cartilages and vocal folds to abduct properly, leading to airway obstruction. This disease is commonly observed in older, large-breed dogs and can significantly impact their quality of life.
Signalment #
Laryngeal paralysis is most commonly diagnosed in middle-aged to older dogs, typically over 8 years of age. Large and giant breeds are predisposed, with Labrador Retrievers, Golden Retrievers, and Saint Bernards being among the most commonly affected. Males are more frequently diagnosed than females. Studies indicate a higher prevalence in these breeds, although definitive epidemiological data is still limited.
Clinical Signs #
Dogs with laryngeal paralysis exhibit clinical signs due to upper airway obstruction and reduced airflow. Common clinical signs include:
- Increased respiratory noise, often described as a high-pitched inspiratory stridor
- Exercise intolerance
- Coughing or gagging, particularly after eating or drinking
- Heat intolerance
- Cyanosis (in severe cases)
- Episodes of respiratory distress, which can be life-threatening
As the disease progresses, dogs may experience acute respiratory crises, particularly in hot or humid weather.
Diagnostic Tests #
Diagnosis of laryngeal paralysis involves a combination of clinical history, physical examination, and specialized diagnostic tests. The following methods are commonly employed:
Laryngeal Examination Under Light Sedation #
The definitive diagnosis is made via direct visualization of the larynx using laryngoscopy. This is performed under light sedation (e.g., propofol) to allow assessment of arytenoid movement during inspiration. In affected dogs, the arytenoid cartilages remain static or paradoxically collapse inward instead of abducting. Studies suggest that laryngoscopy has high diagnostic specificity but variable sensitivity depending on sedation depth.
Thoracic and Cervical Radiography #
Radiographs are taken to rule out concurrent conditions such as aspiration pneumonia, megaesophagus, or thoracic masses that may contribute to respiratory signs.
Bloodwork and Thyroid Testing #
Hypothyroidism has been associated with laryngeal paralysis. A complete blood count, serum biochemistry, and thyroid function tests (T4 and free T4) are often recommended to assess for underlying metabolic conditions.
Electromyography and Nerve Conduction Studies #
Although not commonly performed in routine practice, electromyography can help identify neuromuscular disease in cases where generalized polyneuropathy is suspected.
Surgical Criteria #
Surgical intervention is indicated for dogs experiencing moderate to severe respiratory distress or frequent episodes of airway obstruction. Criteria for surgery include:
- Severe inspiratory stridor and dyspnea
- Cyanosis or syncope
- Exercise intolerance significantly affecting quality of life
- Recurrent respiratory crises or pneumonia despite medical management
Surgical Management #
The most commonly performed surgical procedure for laryngeal paralysis is unilateral arytenoid lateralization (tie-back surgery). This procedure involves suturing one arytenoid cartilage in an abducted position to permanently increase airway patency while minimizing the risk of aspiration pneumonia.
Other surgical techniques, such as partial laryngectomy, castellated laryngofissure, and laryngeal reinnervation, have been described but are less commonly utilized due to complications and limited efficacy. Unilateral arytenoid lateralization remains the preferred method due to its balance between efficacy and minimized complications.
Adverse Events Associated with Surgery and Anesthesia #
While surgery can significantly improve respiratory function, complications may occur. The most notable postoperative complications include:
Aspiration Pneumonia #
Aspiration pneumonia is the most common and serious complication of laryngeal tie-back surgery, occurring in approximately 20-30% of cases. This results from impaired laryngeal closure, allowing food or liquid to enter the trachea. Symptoms include:
- Coughing after eating or drinking
- Fever
- Lethargy
- Acutely increased respiratory effort
Studies have shown that dogs that develop aspiration pneumonia postoperatively often require long-term management and have a guarded prognosis. Prevention strategies include feeding dogs a slow-controlled diet, using elevated food bowls, and avoiding large meals.
Seroma and Infection #
Postoperative seromas may develop at the surgical site, particularly in large dogs. Most cases resolve with conservative management, but in rare cases, infection may necessitate antibiotic therapy or surgical drainage.
Suture Failure or Breakage #
Sutures placed during arytenoid lateralization may loosen or break, leading to recurrence of clinical signs. Revision surgery may be required in such cases.
Persistent Respiratory Noise #
Some degree of inspiratory stridor often persists after surgery. However, it typically does not affect the dog’s overall respiratory function.
Anesthetic Risks #
Older dogs undergoing anesthesia for laryngeal paralysis surgery are at increased risk due to comorbidities such as neoplastic disease, aspiration pneumonia, or neurological disorders. Careful anesthetic planning with preoperative stabilization, oxygen supplementation, and cautious induction is essential.
Conclusion #
Laryngeal paralysis is a significant airway disorder in older, large-breed dogs, often requiring surgical intervention for long-term management. While unilateral arytenoid lateralization is the preferred treatment, it is associated with risks such as aspiration pneumonia and suture failure. Comparisons with conservative management suggest that while surgery improves respiratory function, mild cases may benefit from medical management alone. Proper patient selection, perioperative care, and owner education are crucial in achieving favorable outcomes.
References #
- Monnet E. (2017). Surgical Treatment of Laryngeal Paralysis in Dogs: An Overview. Veterinary Surgery, 46(1), 24-30.
- White R.A.S., & Stanley B.J. (2008). Laryngeal Paralysis in Dogs: Pathophysiology and Management. Journal of Small Animal Practice, 49(1), 3-9.
- Broome C., Walsh V., & Monnet E. (2019). Postoperative Complications of Unilateral Arytenoid Lateralization in Dogs. Journal of Veterinary Internal Medicine, 33(2), 764-772.
- Fossum T.W. (2020). Small Animal Surgery. 5th Edition, Elsevier.
