Lecture 20/21 11/7/24

Question 1

Which structures make up the larynx anatomy?

Answer 1

-palatine tonsils
-corniculate process
-cuneiform process
-vocal fold
-epiglottis

Question 2

What is the function of the caudal laryngeal nerve?

Answer 2

innervates the larynx to allow for abduction and adduction

Question 2

What does the cranial laryngeal nerve supply?

Answer 2

-taste buds
-laryngeal mucosa
-cricothyroideus muscles

Question 3

What is the normal function of the larynx?

Answer 3

-laryngeal cartilages abduct on inhalation and adduct on exhalation
-dogs that are breathing hard may keep the cartilages fully abducted

Question 4

What is laryngeal paralysis?

Answer 4

inability to abduct or adduct the arytenoids

Question 5

What are the characteristics of congenital laryngeal paralysis?

Answer 5

-associated with congenital polyneuropathies
-seen in siberian huskies, bouviers, bull terriers, dalmations, and rottweilers

Question 6

What are the characteristics of acquired laryngeal paralysis?

Answer 6

-most commonly occurs with geriatric-onset laryngeal paralysis/polyneuropathy
-can also occur with trauma and neoplasia
-seen in older golden and labrador retrievers and setters

Question 7

What are the clinical signs of acquired laryngeal paralysis?

Answer 7

-voice change
-gagging
-coughing
-dyspnea
-exercise intolerance
-pneumonia
-syncope
-cyanosis
-hind limb weakness
-dysphagia
-regurg.
-megaesophagus

Question 8

How is acquired laryngeal paralysis diagnosed?

Answer 8

-auscultation
-neurologic eval.
-thoracic rads
-contrast esophagram
-thyroid panel
-laryngoscopy

Question 9

What are the characteristics of using laryngoscopy to assess laryngeal function?

Answer 9

-pre-oxygenate dog
-want lightest anesthetic plane possible
-compare arytenoid movement to resp cycle
-want to avoid propofol, ketamine+diazepam, and alfaxalone when possible due to risk of false positive test

Question 10

What are the treatment options for laryngeal paralysis, based on severity?

Answer 10

mild:
-treat obesity
-control stress
-avoid inciting factors like heat or excitement
severe:
-unilateral arytenoid lateralization/tieback

Question 11

What are the indications for a tieback procedure?

Answer 11

-dyspnea
-exercise intolerance
-cyanosis
-poor quality of life

Question 12

What are the cons of tieback surgery?

Answer 12

-does not resolve coughing or polyneuropathy
-increases lifelong risk of aspiration pneumonia

Question 13

What are additional surgical options for laryngeal paralysis?

Answer 13

-shorten elongated soft palates
-remove everted laryngeal saccules
-permanent tracheostomy for severely affected dogs

Question 14

What is a laryngeal stent?

Answer 14

knobbed silicone tracheal stent that holds the larynx open and can be left in permanently in dogs with laryngeal paralysis

Question 15

What are the characteristics of normal tracheal anatomy?

Answer 15

-trachea is supported by series of incomplete, C-shaped cartilage rings
-ring ends are dorsally connected by trachealis muscle
-trachea bifurcates into bronchi

Question 16

What are the characteristics of tracheal collapse?

Answer 16

-progressive, irreversible tracheal weakening
-dorsal muscle and ligament become relaxed
-cartilage loses rigidity
-dynamic collapse occurs with cough or rapid breathing
-tracheal lumen eventually flattens
-inflammation decreases ciliated cells and increases mucus viscosity

Question 17

What is the presentation of collapsing trachea?

Answer 17

-middle aged toy/small breed dogs
-cough that may be stimulated with tracheal palpation
-dyspnea
-cyanosis
-syncope

Question 18

Which factors exacerbate tracheal collapse?

Answer 18

-obesity
-coughing
-exercise
-heat stress
-ET tube placement
-airway infections
-airborne irritants
-heart enlargement
-neck pressure
-elongated soft palate

Question 19

Which diagnostics are used to identify collapsing trachea?

Answer 19

-CBC/chem
-thoracic rads
-fluoroscopy
-tracheoscopy

Question 20

What are the characteristics of tracheoscopy?

Answer 20

-laryngeal exam done at induction
-evaluate trachea and bronchi
-grade collapse along entire tracheal length
-take measurements for stents
-obtain airway samples for culture and cytology as needed
-risky due to dogs not being intubated during procedure

Question 21

What are the medical management options for collapsing trachea?

Answer 21

-weight control
-cough suppressants
-sedation for excitement
-environmental modification
-steroids
-antibiotics for secondary infection
-bronchodilators for concurrent lung disease

Question 22

When should treatment of collapsing trachea go beyond medical management?

Answer 22

-cough is no longer responding to treatment
-cough disrupts dog’s ability to eat, drink, and sleep
-dog responds to medical management but has cyanosis or severe dyspnea
-quality of life is declining

Question 23

What are the characteristics of an intraluminal stent?

Answer 23

-need anesthesia to measure and place
-expensive device
-does not treat bronchial collapse
-causes irritation and coughing
-can cause dogs to develop excess mucus or granulation tissue

Question 24

What are common causes of tracheal trauma?

Answer 24

-bite wounds
-endotracheal cuff over-inflation
-intubation with metal stylet

Question 25

What are the treatment options for tracheal trauma?

Answer 25

-conservative treatment for small lacerations
-surgical repair of trachea if severe dyspnea, progressive pneumothorax, or worsening clinical signs occur