Ch 29 Larynx & Trachea Flashcards
Which muscle represents the cranial esophageal sphincter?
cricopharyngeus
Visibility of the trachealis membrane dorsally indicates an abnormality - True or False?
False
In __________, a visible dorsal tracheal membrane is unlikely to be responsible for clinical signs.
large-breed and asymptomatic small-breed dogs
Technique parameters for radiography of the pharyngolaryngeal region
What happens to the trachea with cervical ventroflexion?
focal dorsal displacement of the trachea (can mimic a mediastinal mass)
What is the likely position of the neck?
ventroflexion
What can extreme extension of the neck do to the appearance of the trachea on radiographs?
tracheal narrowing
Which positioning ‘‘error’’ can cause tracheal narrowing?
extreme cervical extension
The trachea curves slightly left/right of midline on DV.
right
normal or abnormal (trachea)
in cats,, what are the 2 most common pharyngolaryngeal mural neoplasias and what area do they involve?
Which canine pharyngeal neoplasia (and specific area) is most common?
What are the most common laryngeal tumors in dogs?
Ectopic thyroid carcinoma affects which laryngeal bone?
basihyoid
radiographic findings of ectopic thyroid carcinoma of basihyoid bone
Which non-BOAS dog breed has a syndrome with laryngeal narrowing and supra-arytenoid swelling (redundancy of supra-arytenoid folds)?
Norwich terriers
Is epiglottic retroversion a primary or secondary disease?
Which imaging modality is best for dg pharyngeal collapse?
which conditions are associated with pharyngeal collapse?
tracheal / bronchial collapse
Brachy syndrome
what might be the cause of pharyngeal collapse in a cat?
asthma
nasopharyngeal stenosis is more common in dogs/cats?
cats
etiology of nasopharyngeal stenosis
upper resp inflammation/infection e.g. viral rhinotracheitis
following surgery
Which etiology and signalment occurs in dogs with nasopharyngeal stenosis?
primary/congenital palato-pharyngeal dysgenesis in dachshunds
causes of pharyngitis / laryngitis
- edema in respiratory distress (brachy)
- infectious: kennel cough (infectious tracheobronchitis), FHV-1 (feline herpes / viral rhinotracheitis)
- toxic: dumb canes (dieffenbachia)
- oral cavity infection
- caustic ingestion
what (usually) causes ventral displacement of the carina?
Tracheal masses are common/uncommon and usually benign/malignant.
uncommon and benign
What are the most common canine tracheal mural masses?
Tracheal osteochondroma occurs in which signalment?
young dogs
Which feline parasite can cause tracheal granulomas and where?
aberrant tracheal Cuterebra migration
Which canine parasite can cause tracheal granulomas and where?
Malignant tracheal tumours?
Which tracheal masses tend to mineralise?
Those of cartilaginous origin e.g. osteochondroma
Wheredo aspirated foreign bodies lodge within the trachea?
at the carina
why are patients not rotated without disconnecting the tube?
can cause tracheal rupture
A pseudoairway typically occurs following which injury?
tracheal avulsion
but can occur with rupture
How does tracheal avulsion occur?
When do tracheal avulsion patients present?
often 1-3 weeks following the trauma, after which emphysema and pneumomediastinum have resolved
Where does the trachea normally avulse?
1 to 4 cm cranial to the carina
Tracheal lumen at the margins of an avulsed trachea are usually dilated/stenotic.
stenotic
cause of tracheal hypoplasia?
what percentage of BOAS dogs have tracheal hypoplasia?
approx. 39%
in what percentage of dogs is tracheal hypoplasia an incidental finding?
10%
what is the average tracheal diameter to thoracic inlet ratio of bulldogs?
13% +/- 4%
more recent paper on 32 asymptomatic EB’s - 17% rads / 26% CT
what is the smallest recorded tracheal diameter to thoracic inlet ratio in asymptomatic bulldogs?
9%
what is the average tracheal diameter to thoracic inlet ratio of (non-bulldog) brachycephalics? e.g. pugs
16% +/- 3%
what is the average tracheal diameter to thoracic inlet ratio of non-brachy dogs?
20% +/- 3%
The ratio between tracheal diameter and cricoid cartilage height is smaller / larger for brachycephalic breeds.
smaller
Tracheal diameter to thoracic inlet ratio in cats?
18% in DSH, 20% in Persians
Tracheal hypoplasia has been reported in a kitten with
mucopolysaccharidosis VII
Which tracheal change has been reported in a kitten with MPS VII?
Tracheal hypoplasia
Signalment for tracheal collapse
middle age - old
small & toy breed dogs
In which respiratory phase does dynamic intrathoracic tracheal collapse occur?
expiratory
is tracheal collapse always dynamic?
no, can be static
In which respiratory phase does dynamic cervical (including thoracic inlet) tracheal collapse occur?
inspiratory
What effect does coughing have on intrathoracic tracheal collapse?
exacerbates it, due to the increase in intrathoracic pressure
How does a chronic cough worsen tracheal collapse?
the inflammation causes further chondromalacia
What is a possible sequel to cervical tracheal collapse?
laryngeal collapse and upper respiratory edema
Which modality has greatest agreement with bronchoscopy for tracheal collapse?
fluoroscopy
What are the phases of fluoro study of tracheal collapse?
Which bronchi are most commonly collapsed on bronchoscopy with this condition?
R middle
L cranial
When is bronchial collapse easiest to see / diagnose?
Fluoro with an induced cough
which techniques can help improve detection of bronchial collapse?
- performing fluoro in RL and LL
- sternal recumbency
Which technique might help in diagnosing bronchial collapse in very small patients?
dynamic digital radiography
- increases patient those, though
What is the normal variation of tracheal diameter during the respiratory cycle?
up to 25% of the diameter
In CT, what is the normal variation in tracheal CROSS SECTIONAL AREA and HEIGHT, during the resp cycle (not tracheal collapse disease)?
24% CT cross sectional area and 19% variation in height
In tracheal / bronchial chondromalacia and collapse, collapse of the principal bronchi would occur during which phase of the respiratory cycle?
expiration
In which respiratory phase would you see dynamic herniation of the lung lobe?
expiration
Why would lungs herniate during expiration and not inspiration?
Air that enters the lungs during inspiration, cannot be expelled due to collapse of the bronchi, and so when the thoracic cavity becomes smaller during expiration, and the lungs are the same volume instead of smaller, they herniate for the lack of space.
In what percentage of dogs does the thoracic trachea have dorsal kinking due to complete air way obstruction during expiration or cough?
39%
What is examined during follow-up radiographs after tracheal stent placement?
- fracture or migration of the stent
- excessive granulation at stent edges
- subsequent collapse at unstented locations
Etiology of tracheal collapse in cats
Radiographic signs of upper airway obstruction (9 + 2 possible complications)
In which 2 neoplasias does hyoid bone lysis occur?
ectopic thyroid carcinoma (basihyoid)
tonsillar SCC
What is the most common location of pharyngeal neoplasia (and which neoplasia)?
tonsillar fossa of the oropharynx, SCC
*can be bilateral
Which findings of the pharynx may occur in feline acromegaly?
mucosal proliferation
D
A
C; Laryngeal collapse occurs in LL direction so not visible on LL rads unless severe
A
B
B
C
D
A, then C, also MCT, melanoma, plasma cell tumour, oncocytoma
D
C, and cats
A
A (caudal displacement is correct)
B
C
A
B
B
C
What is the difference in measurement of the trachea on radiographs vs. CT?
What can US of the larynx tell us regarding laryngeal paralysis?
What are underlying causes of lar par?
Which breeds are overrepresented for LarPar?
hereditary - bouvier des flandres
otherwise - retrievers (lab, golden, flat coated)
