Lecture 16/17 10/24/24

Question 1

What are the functions of the upper airway in horses?

Answer 1

-olfaction
-phonation
-deglutition
-thermoregulation
-filtering
-conditioning inspired air
-protection of lower airway from aspiration
-conduit of airflow to and from lung

Question 2

What are the anatomical considerations regarding the upper airway of the horse?

Answer 2

-large dead space volume
-high resistance to flow
-tends to collapse in response to neg. pressure generated during inspiration

Question 3

What is the limiting factor in a horse’s exercise capacity?

Answer 3

upper airway

Question 4

What is the tidal volume and minute ventilation in a horse at rest?

Answer 4

tidal vol: 5L
minute ventilation: 75 L

Question 5

How does exercise impact a horse’s tidal volume and minute ventilation?

Answer 5

increases it 20-fold

Question 6

What is impedance?

Answer 6

-ratio of driving pressure and resulting airflow
-measure of how much airflow is opposed by the respiratory system

Question 7

What are the characteristics of impedance on inspiration and expiration?

Answer 7

-impedance is 2x as high on inspiration
-sub-atmospheric intraluminal pressures cause airway to narrow on inspiration
-positive intraluminal pressures enlarge airway diameter during exhalation

Question 8

What is the importance of the Bernoulli effect?

Answer 8

reducing the radius by 1/2 increased resistance by 16 fold

Question 9

What is a progressive ethmoidal hematoma?

Answer 9

-encapsulated, expansive, distorting, and destructive mass
-usually originates within ethmoid turbinate

Question 10

Where might a progressive ethmoidal hematoma expand into?

Answer 10

-nasal passages
-pharynx
-paranasal sinuses

Question 11

What are the clinical signs of a progressive ethmoidal hematoma?

Answer 11

-hemorrhagic or serosanguineous unilateral nasal discharge that is intermittent and not associated with exercise
-respiratory noise
-unequal airflow
-fetid breath
-facial distortion
-coughing/choking
-hematoma at external nares
-possible for horse to be affected bilaterally

Question 12

What is a cleft palate?

Answer 12

incomplete cleft that can impact the hard and soft palate

Question 13

What is the most common cleft palate presentation?

Answer 13

incomplete cleft of the soft palate that involves the caudal half to two-thirds of the structure

Question 14

In which direction do the embryonic palatal folds fuse in a cleft palate?

Answer 14

rostral to caudal

Question 15

What is aryepiglottic fold entrapment?

Answer 15

aryepiglottic folds become dorsally displaced
-fold covers tip of epiglottis and entraps it
-folds of mucous membrane tissue expand when epiglottis is elevated during deglutination

Question 16

What is dorsal displacement of the soft palate?

Answer 16

-soft palate is displaced dorsally during swallowing
-epiglottis covers the adducted arytenoid cartilages and vocal folds
-intermittent or persistent malpositioning of the caudal edge of soft palate dorsal to epiglottis

Question 17

What are the clinical signs of continuous dorsal displacement of the soft palate?

Answer 17

-continual emission of rumbling noise that is greatest on expiration
-bulging of cheeks from mouth breathing
-cough
-bilateral nasal discharge when eating
-epiglottic abnormality
-may occur after strangles or guttural pouch infection

Question 18

What are the clinical signs of intermittent dorsal displacement of the soft palate?

Answer 18

-may only occur during strenuous exercise
-intermittent noise production that is greatest during expiration
-mouth breathing
-excessive salivation
-bulging of cheeks
-coughing
-swallowing

Question 19

How is dorsal displacement of the soft palate diagnosed?

Answer 19

-history/clinical signs
-endoscopy

Question 20

What is the goal of treatment for dorsal displacement of the soft palate?

Answer 20

alleviate any primary disease of the upper respiratory tract that could cause the DDSP

Question 21

What are the treatment options for dorsal displacement of the soft palate?

Answer 21

-tying the tongue
-sclerotherapy
-surgical removal of caudal free border of soft palate
-sternothyrohyoidectomy

Question 22

What is recurrent laryngeal hemiplegia?

Answer 22

-neurogenic atrophy of intrinsic muscles of the larynx
-secondary to neuropathy of motor neurons in the recurrent laryngeal nerve

Question 23

Which side of the larynx is most commonly affected in recurrent laryngeal hemiplegia?

Answer 23

left side

Question 24

What are the characteristics of muscular innervation in the larynx?

Answer 24

-recurrent laryngeal nerve innervates all intrinsic muscles of the larynx except one
-cricothyroideus muscle is NOT innervated by recurrent laryngeal nerve

Question 25

How is recurrent laryngeal hemiplegia diagnosed?

Answer 25

-complaint of exercise intolerance -rasping roar on inspiration during exercise -physical exam to rule out other causes -palpation of larynx -long, loud grunt and sigh when threatened with a stick -inability to neigh properly/hoarseness -endoscopic examination

Question 26

What are the treatment options for recurrent laryngeal hemiplegia?

Answer 26

surgery: -ventriculectomy: adherence of vocal fold to lateral larynx wall -prosthetic laryngoplasty: mimic permanent contraction of muscle with suture -arytenoidectomy -laryngeal re-innervation

Question 27

What is chondropathy of the arytenoid cartilage?

Answer 27

chronic inflammation of the arytenoid cartilage that results in deformity, ossification, and immobility

Question 28

What are the clinical signs of chondropathy of the arytenoid cartilage?

Answer 28

-inspiratory difficulty during exercise that may progress to difficulty at rest -inspiratory noise produced during exercise and eventually at rest -equal distribution between right and left sides

Question 29

How is chondropathy of the arytenoid cartilage treated?

Answer 29

arytenoidectomy: -total: entire cartilage removed -subtotal: corniculate and muscular processes are not removed -partial: entire cartilage except muscular process is removed

Question 30

Which teeth are not associated with any sinus?

Answer 30

-premolar 2 (#6) -premolar 3 (#7)

Question 31

What are the characteristics of premolar 4/#8?

Answer 31

-rostral roots are not in a sinus -caudal roots are in the rostral maxillary sinus

Question 32

What are the characteristics of molar 1/#9?

Answer 32

-all roots are in the rostral maxillary sinus -oldest tooth in head -most commonly associated with problems

Question 33

What are the characteristics of molar 2/#10?

Answer 33

-rostral roots are in rostral maxillary sinus -caudal roots are in caudal maxillary sinus

Question 34

What are the characteristics of molar 3/#11?

Answer 34

all roots are in the caudal maxillary sinus