Lecture 16/17 10/24/24 Flashcards
What are the functions of the upper airway in horses?
-olfaction
-phonation
-deglutition
-thermoregulation
-filtering
-conditioning inspired air
-protection of lower airway from aspiration
-conduit of airflow to and from lung
What are the anatomical considerations regarding the upper airway of the horse?
-large dead space volume
-high resistance to flow
-tends to collapse in response to neg. pressure generated during inspiration
What is the limiting factor in a horse’s exercise capacity?
upper airway
What is the tidal volume and minute ventilation in a horse at rest?
tidal vol: 5L
minute ventilation: 75 L
How does exercise impact a horse’s tidal volume and minute ventilation?
increases it 20-fold
What is impedance?
-ratio of driving pressure and resulting airflow
-measure of how much airflow is opposed by the respiratory system
What are the characteristics of impedance on inspiration and expiration?
-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
What is the importance of the Bernoulli effect?
reducing the radius by 1/2 increased resistance by 16 fold
What is a progressive ethmoidal hematoma?
-encapsulated, expansive, distorting, and destructive mass
-usually originates within ethmoid turbinate
Where might a progressive ethmoidal hematoma expand into?
-nasal passages
-pharynx
-paranasal sinuses
What are the clinical signs of a progressive ethmoidal hematoma?
-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
What is a cleft palate?
incomplete cleft that can impact the hard and soft palate
What is the most common cleft palate presentation?
incomplete cleft of the soft palate that involves the caudal half to two-thirds of the structure
In which direction do the embryonic palatal folds fuse in a cleft palate?
rostral to caudal
What is aryepiglottic fold entrapment?
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
What is dorsal displacement of the soft palate?
-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
What are the clinical signs of continuous dorsal displacement of the soft palate?
-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
What are the clinical signs of intermittent dorsal displacement of the soft palate?
-may only occur during strenuous exercise
-intermittent noise production that is greatest during expiration
-mouth breathing
-excessive salivation
-bulging of cheeks
-coughing
-swallowing
How is dorsal displacement of the soft palate diagnosed?
-history/clinical signs
-endoscopy
What is the goal of treatment for dorsal displacement of the soft palate?
alleviate any primary disease of the upper respiratory tract that could cause the DDSP
What are the treatment options for dorsal displacement of the soft palate?
-tying the tongue
-sclerotherapy
-surgical removal of caudal free border of soft palate
-sternothyrohyoidectomy
What is recurrent laryngeal hemiplegia?
-neurogenic atrophy of intrinsic muscles of the larynx
-secondary to neuropathy of motor neurons in the recurrent laryngeal nerve
Which side of the larynx is most commonly affected in recurrent laryngeal hemiplegia?
left side
What are the characteristics of muscular innervation in the larynx?
-recurrent laryngeal nerve innervates all intrinsic muscles of the larynx except one
-cricothyroideus muscle is NOT innervated by recurrent laryngeal nerve
How is recurrent laryngeal hemiplegia diagnosed?
-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
What are the treatment options for recurrent laryngeal hemiplegia?
surgery:
-ventriculectomy: adherence of vocal fold to lateral larynx wall
-prosthetic laryngoplasty: mimic permanent contraction of muscle with suture
-arytenoidectomy
-laryngeal re-innervation
What is chondropathy of the arytenoid cartilage?
chronic inflammation of the arytenoid cartilage that results in deformity, ossification, and immobility
What are the clinical signs of chondropathy of the arytenoid cartilage?
-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
How is chondropathy of the arytenoid cartilage treated?
arytenoidectomy:
-total: entire cartilage removed
-subtotal: corniculate and muscular processes are not removed
-partial: entire cartilage except muscular process is removed
Which teeth are not associated with any sinus?
-premolar 2 (#6)
-premolar 3 (#7)
What are the characteristics of premolar 4/#8?
-rostral roots are not in a sinus
-caudal roots are in the rostral maxillary sinus
What are the characteristics of molar 1/#9?
-all roots are in the rostral maxillary sinus
-oldest tooth in head
-most commonly associated with problems
What are the characteristics of molar 2/#10?
-rostral roots are in rostral maxillary sinus
-caudal roots are in caudal maxillary sinus
What are the characteristics of molar 3/#11?
all roots are in the caudal maxillary sinus
