Respiratory - Laryngeal Paralysis + Brachycephalic Airway Obstruction

Question 1

Functions of the larynx

Answer 1

regulate airflow
protect trachea from aspiration during swallowing
control phonation

Question 2

T/F the extrinsic muscles of the larynx are responsible for laryngeal function

Answer 2

False, the intrinsic muscles

Question 3

Innervation of the larynx

Answer 3

caudal laryngeal n. innervates all but 1 of the laryngeal muscles
cranial laryngeal n. innervates the cricothyroid m.

Question 4

Contraction of the cricoarytenoideus dorsalis muscle results in

Answer 4

abduction of the arytenoid cartilages

Question 5

when 1 or both of the arytenoid cartilages do not abduct ?

Answer 5

laryngeal paralysis –> obstructed airway

Question 6

acquired laryngeal paralysis in dogs is caused by damage to or dysfunction of the

Answer 6

recurrent laryngeal nerve or the intrinsic laryngeal muscle

Question 7

Common etiologies of acquired laryngeal paralysis

Answer 7

polyneuropathy
polymyopathy
trauma
mass
idiopathic

Question 8

Geriatric onset laryngeal paralysis polyneuropathy is most common in

Answer 8

laborador retrievers

Question 9

Signalment of dogs with laryngeal paralysis

Answer 9

> 9y large and giant dogs

Question 10

Clinical signs of laryngeal paralysis

Answer 10

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

Question 11

PE findings in a dog with laryngeal paralysis

Answer 11

stridor
loud resp noise that occurs because airway is obstructed, in larynx or extra thoracic trachea
during inspiration

Question 12

Definitive diagnosis of laryngeal paralysis requires

Answer 12

a laryngeal exam

Question 13

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

Answer 13

D - none of the above are false

Question 14

Treatment of laryngeal paralysis

Answer 14

conservative - weight loss and lifestyle changes

Surgical - patients with bilateral LP, moderate or severe clinical signs

Question 15

Treatment of respiratory distress due to severe laryngeal paralysis

Answer 15

supplemental O2
corticosteroids
sedation
minimize stress
cool if hyperthermic 
intubate and mechanically ventilate dogs in severe distress

Question 16

Causes of laryngeal paralysis in cats

Answer 16

neoplastic infiltration, trauma, iatrogenic (post-thyroidectomy), idiopathic

Question 17

What is laryngeal collapse

Answer 17

consequence of chronic upper airway obstruction

Question 18

Primary defects of brachycephalic airway obstruction syndrome?

Answer 18

stenotic nares
elongated soft palate

also narrowed nasal cavities, distorted turbinates, aberrant turbinates, macroglossia, thickened soft palate, redundant pharyngeal folds, tracheal hypoplasia

Question 19

secondary defects of brachycephalic airway obstruction syndrome

Answer 19

everted laryngeal ventricles, laryngeal collapse, bronchial collapse

Question 20

concurrent GI disorders common with BAOS

Answer 20

esophageal deviation, gastrophageal reflux, gastric stasis, pyloric hypertrophy, inflammation

Question 21

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

Answer 21

D - negative inspiratory pressure draws respiratory tissues into airway lumen creating inflammation

Question 22

Clinical signs of BAOS

Answer 22

noisy breathing
snoring
coughing or gagging
stertor, stridor
inspiratory dyspnea
cyanosis, syncope, death in severely affected animals
hyperthermia
concurrent GI signs possible

Question 23

Diagnosis of BAOS

Answer 23

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

Question 24

Treatment of BAOS

Answer 24

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

Question 25

T/F: surgical intervention is recommended late in the course of BAOS only after medical treatment has been attempted.

Answer 25

False, it is indicated early