Respiratory - Laryngeal Paralysis + Brachycephalic Airway Obstruction Flashcards
Functions of the larynx
regulate airflow
protect trachea from aspiration during swallowing
control phonation
T/F the extrinsic muscles of the larynx are responsible for laryngeal function
False, the intrinsic muscles
Innervation of the larynx
caudal laryngeal n. innervates all but 1 of the laryngeal muscles
cranial laryngeal n. innervates the cricothyroid m.
Contraction of the cricoarytenoideus dorsalis muscle results in
abduction of the arytenoid cartilages
when 1 or both of the arytenoid cartilages do not abduct ?
laryngeal paralysis –> obstructed airway
acquired laryngeal paralysis in dogs is caused by damage to or dysfunction of the
recurrent laryngeal nerve or the intrinsic laryngeal muscle
Common etiologies of acquired laryngeal paralysis
polyneuropathy polymyopathy trauma mass idiopathic
Geriatric onset laryngeal paralysis polyneuropathy is most common in
laborador retrievers
Signalment of dogs with laryngeal paralysis
> 9y large and giant dogs
Clinical signs of laryngeal paralysis
noisy inspiration, exercise intolerance, voice change, coughing or gagging (often after drinking water)
signs often exacerbated by heat, humidity, exercise
can see resp distress, cyanosis, collapse
PE findings in a dog with laryngeal paralysis
stridor
loud resp noise that occurs because airway is obstructed, in larynx or extra thoracic trachea
during inspiration
Definitive diagnosis of laryngeal paralysis requires
a laryngeal exam
Which is FALSE regarding the diagnosis of laryngeal paralysis?
A) Requires neurologic and orthopaedic exams
B) can include thyroid testing
C) rads are used to evaluate for concurrent cardiac and lower airway disease
D) none of the above
D - none of the above are false
Treatment of laryngeal paralysis
conservative - weight loss and lifestyle changes
Surgical - patients with bilateral LP, moderate or severe clinical signs
Treatment of respiratory distress due to severe laryngeal paralysis
supplemental O2 corticosteroids sedation minimize stress cool if hyperthermic intubate and mechanically ventilate dogs in severe distress
Causes of laryngeal paralysis in cats
neoplastic infiltration, trauma, iatrogenic (post-thyroidectomy), idiopathic
What is laryngeal collapse
consequence of chronic upper airway obstruction
Primary defects of brachycephalic airway obstruction syndrome?
stenotic nares
elongated soft palate
also narrowed nasal cavities, distorted turbinates, aberrant turbinates, macroglossia, thickened soft palate, redundant pharyngeal folds, tracheal hypoplasia
secondary defects of brachycephalic airway obstruction syndrome
everted laryngeal ventricles, laryngeal collapse, bronchial collapse
concurrent GI disorders common with BAOS
esophageal deviation, gastrophageal reflux, gastric stasis, pyloric hypertrophy, inflammation
Which of the following is FALSE regarding the pathophysiology of BAOS?
A) narrowed and deformed airways increase resistance and turbulent flow
B) swollen/edematous tissue contribute to airway narrowing
C) increased velocity and turbulence worsens swelling
D) positive inspiratory pressure draws respiratory tissues into airway lumen creating inflammation
D - negative inspiratory pressure draws respiratory tissues into airway lumen creating inflammation
Clinical signs of BAOS
noisy breathing snoring coughing or gagging stertor, stridor inspiratory dyspnea cyanosis, syncope, death in severely affected animals hyperthermia concurrent GI signs possible
Diagnosis of BAOS
stenotic nares via PE
cervical and thoracic rads to evaluate tracheal and bronchopulmonary abnormalities and hiatal hernia
sedated laryngeal exam
endoscopy or CT to dx nasal, pharyngeal, laryngeal, tracheal, and bronchial abnormalities
endoscopy of GIT in patients with GI signs
Treatment of BAOS
resp distress - supplemental O2, sedation, corticosteroids, minimize, stress, cool if hyperthermic, mechanically ventilate dogs in severe distress
Surgical correction - rhinoplasty, soft palate resection, laser assisted turbinectomy, ventriculectomy in some cases
T/F: surgical intervention is recommended late in the course of BAOS only after medical treatment has been attempted.
False, it is indicated early
