VM 536 Day 14 prep Laryngeal Paralysis Carey Stanley 2021 (1)
Laryngeal Paralysis in Dogs
Authors: Scout Stephan, A. Carey, Bryden J. Stanley, Michigan State University
Overview
Laryngeal paralysis is a serious medical condition in dogs that impairs the normal function of the larynx, leading to obstructed airflow. This dysfunction can significantly affect respiration and may necessitate urgent veterinary intervention to manage severe health risks.
Laryngeal Anatomy
Understanding the anatomy of the larynx is crucial for diagnosing and treating laryngeal paralysis. Key components include:
Glossopharyngeal Nerve: Responsible for sensory and motor functions in the pharynx and larynx.
Vagus Nerve: This nerve has multiple branches that innervate the laryngeal muscles and is critical for controlling voice production and respiration.
Larynx components: These include the cricoid and thyroid cartilages, arytenoid cartilages, and the associated intrinsic muscles responsible for the movement of the vocal folds.
Functions of the Larynx
The larynx serves several essential functions in dogs:
Prevents Inhalation: Acts as a barrier to prevent foreign substances from entering the trachea and lungs.
Regulates Airflow: Slight abduction at rest allows minimal airflow, while during exercise, greater abduction maximizes airflow to meet increased oxygen demands.
Voice Production: Facilitates sound creation via vibration of the vocal folds during exhalation.
Cough Reflex: Plays a critical role in effective coughing to expel debris and mucus.
Increases Abdominal Pressure: Engages during activities such as barking or straining, which is vital for certain actions like urination and defecation.
Laryngeal Paralysis
Laryngeal paralysis originates from the impairment of the recurrent laryngeal nerve, leading to denervation of the laryngeal adductors and abductors. This can manifest in various ways:
Vocal Folds & Arytenoids: Typically remain in a paramedian position, resulting in significant airflow resistance.
Paradoxical Movement: Abnormal motion patterns of the vocal folds exacerbate airflow turbulence, potentially causing mucosal swelling and increased respiratory distress.
Etiologies of Laryngeal Paralysis
Laryngeal paralysis can arise from several conditions:
Traumatic: Injury to the nerve or surrounding structures.
Iatrogenic: Complications from surgical procedures affecting the larynx.
Neoplasia: Tumor development that affects nerve function.
Myasthenia Gravis: An autoimmune disorder impacting neuromuscular transmission.
Congenital and Juvenile Laryngeal Paralysis: Seen in certain breeds and young dogs.
Geriatric Onset Laryngeal Paralysis Polyneuropathy (GOLPP): A condition affecting older dogs, especially large breed dogs such as Labradors and greyhounds, where multiple nerves are affected leading to progressive issues.
Idiopathic Laryngeal Paralysis: Common in older dogs without clear underlying causes.
Clinical Signs
Dogs with laryngeal paralysis may exhibit various clinical signs, including:
Inspiratory Stridor: A high-pitched wheezing sound during inhalation.
Reduced Exercise Tolerance: Difficulty engaging in normal physical activity due to respiratory constraints.
Gagging & Throat-Clearing: Attempting to clear the airway due to obstruction.
Weakness: Marked especially in cases diagnosed later.
Severe Symptoms: In extreme cases, cyanosis (blue mucus membranes), syncope (fainting), and tachycardia (increased heart rate) may occur.
Diagnostics
Effective diagnosis involves a combination of the following:
Physical Examination: A thorough neurological evaluation to identify signs of paralysis.
Laryngoscopy: A procedure performed under light anesthesia, allowing for direct visualization of the larynx. Key observations include arytenoid motion, evidence of hyperemia, increased vascularity of the mucosa, and flaccidity indicating denervation.
Emergency Therapy
In acute cases of laryngeal paralysis:
Environment: Create a calm, stress-free environment to reduce respiratory distress.
Oxygenation: Supplemental oxygen is critical for managing acute respiratory failure.
IV Fluids: Provide hydration and support for the system; sedation may also be administered to alleviate anxiety.
Monitoring: Close observation for any signs of respiratory distress is essential; intubation readiness may be necessary.
Thermal Management: Use ice packs or fans to cool the patient if overheating occurs due to stress or respiratory effort.
Surgical Interventions
Surgical options include:
Arytenoid Mobilization: Can be performed using unilateral or bilateral approaches, depending on the severity of the paralysis.
Techniques include:
Cricoid-Arytenoid Laryngoplasty (CAL): A procedure to improve the position and movement of the arytenoid cartilages.
Thyroid-Arytenoid Lateralization (TAL): This technique helps open the airway by repositioning laryngeal structures.
Both techniques aim to improve the size of the airway lumen, though risks such as aspiration pneumonia remain (10-20%). Successful surgical outcomes often yield immediate symptom alleviation and a marked improvement in the dog's quality of life.
Post-surgical Care
After surgery, monitoring for complications such as aspiration pneumonia is critical due to the inherent risks. Regular follow-ups are necessary for optimal recovery and adjustment of care practices. High owner satisfaction has been reported with successful surgical procedures.
Current Management Approaches
Feeding Adjustments: Inclined feeding stations are recommended to reduce the risk of aspiration in pets with concurrent esophageal dysfunction.
Neurological Care: Regular assessments to manage swallowing difficulties and monitor for aspiration pneumonia.
Veterinary Follow-ups: Recommended every 3-6 months to ensure ongoing health and management of any emerging issues related to the condition.
Role of Physical Therapy
Physical therapy plays an important role in managing laryngeal paralysis and its effects. Therapies may include:
Balance and strengthening exercises to address neuropathy.
Use of specialized equipment, such as exercise balls, coordination ladders, and water treadmill activities for comprehensive rehabilitation.
Conclusion
Laryngeal paralysis in dogs is a multifaceted condition that necessitates careful and timely diagnosis and management to optimize health outcomes. Tailoring management approaches to the individual needs of each dog is crucial for providing the best possible care.
VM 536 Day 14 prep Laryngeal Paralysis Carey Stanley 2021 (1)
Laryngeal Paralysis in Dogs
Authors: Scout Stephan, A. Carey, Bryden J. Stanley, Michigan State University
Overview
Laryngeal paralysis is a serious medical condition in dogs that impairs the normal function of the larynx, leading to obstructed airflow. This dysfunction can significantly affect respiration and may necessitate urgent veterinary intervention to manage severe health risks.
Laryngeal Anatomy
Understanding the anatomy of the larynx is crucial for diagnosing and treating laryngeal paralysis. Key components include:
Glossopharyngeal Nerve: Responsible for sensory and motor functions in the pharynx and larynx.
Vagus Nerve: This nerve has multiple branches that innervate the laryngeal muscles and is critical for controlling voice production and respiration.
Larynx components: These include the cricoid and thyroid cartilages, arytenoid cartilages, and the associated intrinsic muscles responsible for the movement of the vocal folds.
Functions of the Larynx
The larynx serves several essential functions in dogs:
Prevents Inhalation: Acts as a barrier to prevent foreign substances from entering the trachea and lungs.
Regulates Airflow: Slight abduction at rest allows minimal airflow, while during exercise, greater abduction maximizes airflow to meet increased oxygen demands.
Voice Production: Facilitates sound creation via vibration of the vocal folds during exhalation.
Cough Reflex: Plays a critical role in effective coughing to expel debris and mucus.
Increases Abdominal Pressure: Engages during activities such as barking or straining, which is vital for certain actions like urination and defecation.
Laryngeal Paralysis
Laryngeal paralysis originates from the impairment of the recurrent laryngeal nerve, leading to denervation of the laryngeal adductors and abductors. This can manifest in various ways:
Vocal Folds & Arytenoids: Typically remain in a paramedian position, resulting in significant airflow resistance.
Paradoxical Movement: Abnormal motion patterns of the vocal folds exacerbate airflow turbulence, potentially causing mucosal swelling and increased respiratory distress.
Etiologies of Laryngeal Paralysis
Laryngeal paralysis can arise from several conditions:
Traumatic: Injury to the nerve or surrounding structures.
Iatrogenic: Complications from surgical procedures affecting the larynx.
Neoplasia: Tumor development that affects nerve function.
Myasthenia Gravis: An autoimmune disorder impacting neuromuscular transmission.
Congenital and Juvenile Laryngeal Paralysis: Seen in certain breeds and young dogs.
Geriatric Onset Laryngeal Paralysis Polyneuropathy (GOLPP): A condition affecting older dogs, especially large breed dogs such as Labradors and greyhounds, where multiple nerves are affected leading to progressive issues.
Idiopathic Laryngeal Paralysis: Common in older dogs without clear underlying causes.
Clinical Signs
Dogs with laryngeal paralysis may exhibit various clinical signs, including:
Inspiratory Stridor: A high-pitched wheezing sound during inhalation.
Reduced Exercise Tolerance: Difficulty engaging in normal physical activity due to respiratory constraints.
Gagging & Throat-Clearing: Attempting to clear the airway due to obstruction.
Weakness: Marked especially in cases diagnosed later.
Severe Symptoms: In extreme cases, cyanosis (blue mucus membranes), syncope (fainting), and tachycardia (increased heart rate) may occur.
Diagnostics
Effective diagnosis involves a combination of the following:
Physical Examination: A thorough neurological evaluation to identify signs of paralysis.
Laryngoscopy: A procedure performed under light anesthesia, allowing for direct visualization of the larynx. Key observations include arytenoid motion, evidence of hyperemia, increased vascularity of the mucosa, and flaccidity indicating denervation.
Emergency Therapy
In acute cases of laryngeal paralysis:
Environment: Create a calm, stress-free environment to reduce respiratory distress.
Oxygenation: Supplemental oxygen is critical for managing acute respiratory failure.
IV Fluids: Provide hydration and support for the system; sedation may also be administered to alleviate anxiety.
Monitoring: Close observation for any signs of respiratory distress is essential; intubation readiness may be necessary.
Thermal Management: Use ice packs or fans to cool the patient if overheating occurs due to stress or respiratory effort.
Surgical Interventions
Surgical options include:
Arytenoid Mobilization: Can be performed using unilateral or bilateral approaches, depending on the severity of the paralysis.
Techniques include:
Cricoid-Arytenoid Laryngoplasty (CAL): A procedure to improve the position and movement of the arytenoid cartilages.
Thyroid-Arytenoid Lateralization (TAL): This technique helps open the airway by repositioning laryngeal structures.
Both techniques aim to improve the size of the airway lumen, though risks such as aspiration pneumonia remain (10-20%). Successful surgical outcomes often yield immediate symptom alleviation and a marked improvement in the dog's quality of life.
Post-surgical Care
After surgery, monitoring for complications such as aspiration pneumonia is critical due to the inherent risks. Regular follow-ups are necessary for optimal recovery and adjustment of care practices. High owner satisfaction has been reported with successful surgical procedures.
Current Management Approaches
Feeding Adjustments: Inclined feeding stations are recommended to reduce the risk of aspiration in pets with concurrent esophageal dysfunction.
Neurological Care: Regular assessments to manage swallowing difficulties and monitor for aspiration pneumonia.
Veterinary Follow-ups: Recommended every 3-6 months to ensure ongoing health and management of any emerging issues related to the condition.
Role of Physical Therapy
Physical therapy plays an important role in managing laryngeal paralysis and its effects. Therapies may include:
Balance and strengthening exercises to address neuropathy.
Use of specialized equipment, such as exercise balls, coordination ladders, and water treadmill activities for comprehensive rehabilitation.
Conclusion
Laryngeal paralysis in dogs is a multifaceted condition that necessitates careful and timely diagnosis and management to optimize health outcomes. Tailoring management approaches to the individual needs of each dog is crucial for providing the best possible care.
