Exam 2 - Equine Surgical Diseases of the Upper Airway Flashcards
what is another name for epidermal inclusion cysts?
atheromas
what is the treatment for atheromas?
medical - injection of alcohol or formalin
surgical - extirpation
good prognosis - cosmesis may be an issue
what is the pathogenesis of redundant alar folds?
tissue that creates the false nostril creates an inhalatory obstruction & stertor
how is redundant alar folds diagnosed?
lifting with a finger to see if that solves the problem or suturing percutaneously while exercising
what is the treatment for redundant alar folds?
surgical resection required
what are some causes of unilateral epistaxis?
trauma, sinus disease, & progressive ethmoid hematoma
what are some causes of bilateral epistaxis?
GP mycosis
exercise induced pulmonary hemorrhage
where do you expect the lesion to be in the nasal passages for unilateral nasal discharge? what about bilateral nasal discharge?
unilateral - rostral to the nasal septum
bilateral - caudal to nasal septum
what is the most common cause of bilateral epistaxis?
exercise induced pulmonary hemorrhage
what is the treatment for ethmoid hematomas?
transendoscopic injection of 4-10% formalin - multiple treatments
surgical extirpation - big deal, severe hemorrhage, can originate in the sinus
what are some common causes of unilateral purulent discharge?
sinusitis
guttural pouch empyema
fungal rhinitis
what are some common causes of bilateral purulent discharge?
guttural pouch empyema
nasopharyngeal or tracheal disease
thoracic disease
what is probably the most common upper airway problem seen in equine practice?
paranasal sinusitis
what is the big difference between primary & secondary sinusitis?
primary - diagnosis of exclusion
what would you expect to see on culture in primary sinusitis?
1 bug!!!
what is the treatment of primary sinusitis?
empirical - 30 days of antibiotics, commonly use trimethoprim-sulfa
what should you rule out in secondary sinusitis?
trauma, neoplasia, nasal passage/oral disease, apical dental disease
what is the most common neoplasia seen in equine upper airways?
squamous cell carcinoma
why does the presence of anaerobic bacteria on an oral exam in a horse with suspected secondary sinusitis help your physical exam?
what sinus does the blue dot indicate? what is the landmark?
frontal sinus - most versatile
60% of the distance from mid-line to the medial canthus
0.5cm caudal to the line joining the medial canthus
what sinus does the black dot indicate? what is the landmark?
caudal maxillary sinus
2cm rostral & 2cm lateral to the medial canthus
what sinus does the red dot indicate? what is the landmark?
rostral maxillary sinus
40% of the distance from the rostral end of the facial crest to the level of the medial canthus
1cm ventral to a line joining the infraorbital foramen to the medial canthus
what are the most common signs of paranasal cysts?
facial deformation, nasal discharge, respiratory noise, & unilateral decreased airflow
what is the treatment for paranasal cysts?
surgical extirpation - usually done sinuscopically
what is a major differential for a paranasal cyst? prognosis?
squamous cell carcinoma - very bad prognosis
both lesions are expansile & space occupying
what animals are typically affected by paranasal cysts?
horses of any age but most commonly young adults
what surgical approach is shown here? what are the landmarks?
maxillary flap
dorsal to the facial crest
rostral to the medial canthus
ventral to the nasolacrimal duct
caudal to the rostral aspect of the facial crest
what surgical approach is shown here? what are the landmarks?
frontonasal flap
midline
just caudal to the medial canthus
dorsal to the nasolacrimal duct
caudal to the rostral aspect of the facial crest
what are the advantages & disadvantages of using a bone flap as a surgical approach?
pros: greater surgical exposure, can be done standing or under general, & doesn’t require special equipment or techniques
cons: higher complications rate, making the flap can be hard, & requires a separate trephination site to allow for repeat lavage
what sinuses are indicated by the blue, red, & black dots?
blue - frontal sinus
red - rostral maxillary sinus
black - caudal maxillary sinus
what are the advantages of using sinuscopy?
minimally invasive, excellent access, can be done standing so less hemorrhage, & allows repeated, high volume lavage
how is a sinus lavage performed?
trephine a hole using a 14 G needle & drill
use tap water with dilute betadine and salt or sterile saline
use a sterile stomach pump & tube with an electronic fluid pump or gravity/drip set
what is the I-IV grading system used for pharyngeal collapse?
I - 1 wall collapses
II - 2 walls collapse
III - 3 walls collapse
IV - 4 walls collapse
what is the mild-severe grading system used for pharyngeal collapse?
mild - obstruction is equivalent to the closure of the pharynx to the rima glottis
low moderate - obstructs 30% of the glottis
high moderate - obstructs 50% of the glottis
severe - complete closure of the pharynx with opposing pharyngeal walls touching each other
what is the treatment for pharyngeal collapse?
not a lot - rule out lower airway disease & manage if present & rule out neurologic disease & treat if present
fenestrate guttural pouch
treat inflammation
what are some major diseases that affect the guttural pouch?
empyema, chondroids, guttural pouch mycosis, guttural pouch tympany, & temporohyoid osteoarthropathy (THO)
if guttural pouch mycosis is found incidentally or the horse isn’t actively hemorrhaging, what can be done?
fenestration has been shown to resolve the mycotic plaque without systemic or topical treatment
if guttural pouch mycosis is found and the horse is actively hemorrhaging, what can be done?
occlude the vessels involved!!!
what are the pros & cons for using a transarterial coil/plug embolization in a horse with guttural pouch mycosis?
pros - excellent prognosis if caught in time
cons - requires specialized equipment & expertise
how is catheter embolization used for guttural pouch mycosis in a horse that is actively hemorrhaging?
catheterize internal carotid, external carotid, & major palatine artery to occlude the maxillary artery
remove catheters later
what is protective for nasopharyngeal cicatrix?
stalling & moving them out of texas
what are some presentations seen in nasopharyngeal cicatrix?
severity of obstruction
environmental concerns - most likely will see more in summer
active inflammation vs. chronic scarring
what disease process is shown?
nasopharyngeal cicatrix
what is the treatment for mild nasopharyngeal cicatrix?
no obstruction - coughing & nasal discharge
medical management with throat spray, potentially antibiotics, & change environment
what are some signs of severe nasopharyngeal cicatrix?
maybe minimal
nostril flaring, extended head/neck, distressed, & very loud breathing
what are the 5 major disease processes that affect the larynx in horses?
- dorsal displacement of the soft palate
- recurrent laryngeal neuropathy
- subepiglottic cyst
- epiglottic entrapment
- axial deviation of the aryepiglottic folds (racehorses - must use dynamic exam)
what disease process is shown here on this dynamic exam?
axial deviation of the aryepiglottic folds
what clinical signs are seen with persistent dorsal displacement of the soft palate?
coughing, aspiration pneumonia, & weight loss
what clinical signs are seen with dorsal displacement of the soft palate?
intermittent or permanent
exercise intolerance - may be severe enough to cause dyspnea, cyanosis, or collapse
noise during exercise - primarily expiratory
what is the pathophysiology of dorsal displacement of the soft palate?
caudal free margin becomes malpositioned dorsal to the epiglottis
cross-sectional area of the pharynx is reduced
airflow resistance increased which causes abnormal respiratory noise & exercise intolerance (exhalatory obstruction)
what are some suggested etiologies of dorsal displacement of the soft palate?
secondary to generalized pharyngeal inflammation
hypoplastic/malformed epiglottis
neuromuscular dysfunction - palate
secondary to RLN - increased respiratory pressure
excessive laryngeal retraction - laryngohyoid malposition
how is dorsal displacement of the soft palate diagnoses?
upper airway endoscopy - resting has a strong PPV but dynamic is better
rest - 60% of horses had laryngeal asymmetry & 10% had DDSP
exercising - 15% had laryngeal asymmetry & 50% had DDSP
what is a laryngeal tie-forward?
reposition the laryngohyoid apparatus - advances the larynx rostrally using the basihyoid bone as an anchor & decreases the distance between the larynx & hyoid
combine with tenectomy of sternothyroideus
what is a laryngeal tie-forward used to treat surgically?
dorsal displacement of the soft palate
what is the pathogenesis of recurrent laryngeal neuropathy?
loss of myelinated nerve fibers in the recurrent laryngeal nerve (left more common) & progressive atrophy of the cricoarytenoideus dorsalis muscle
what are the proposed mechanisms of RLN?
mechanical stress, ischemic nerve damage, pressure/trauma, infectious, vitamin deficiencies, & toxic insults
what are the clinical signs of RLN?
inspiratory noise, exercise intolerance
what is this lesion?
paralysis of the left recurrent laryngeal nerve
how is RLN diagnosed?
endoscopy - resting & dynamic
ultrasound - echogenicity of the cricoarytenoideus dorsalis muscle
what are grades I-IV of RLN at rest?
I - normal abduction & symmetry of both arytenoids
II - asynchronous movement, full abduction achieved (sub grades I-III)
III - asynchronous movement, full abduction not achieved (sub grades I-III)
IV - complete paralysis
what are the dynamic grades A-C of RLN ?
A - symmetric full abduction
B - arytenoid/vocal fold incomplete abduction
C - severe dynamic laryngeal collapse with exercise
what does treatment of RLN depend on?
severity, discipline of the horse, presenting complaint - noise only, & results of diagnostic exams
when is a tie-back indicated for RLN?
exercise intolerance
unacceptable noise in competition
arytenoid collapse on dynamic scope
progressive disease
what treatment options are available for RLN?
nothing
tie-back procedure
ventriculocordectomy (noise)
combination
why is a tie-back important?
cost, complications - coughing, dysphagia, pneumonia, infection/seroma
what is the success rate of tie-back surgery?
50-90%
what is the primary surgical intervention for RLN?
prosthetic laryngoplasty - almost always done standing
what are the treatment options for a subepiglottic cyst? what is the prognosis?
gigli wire snare or laser
excellent
what are the treatment options for epiglottic entrapment? what about using a hooked bistoury?
laser - greater than 90% success, don’t laser the cartilage
hooked bistoury - big complications
what may be seen on tracheal evaluation that is supportive of inflammatory airway disease in horses?
increased mucus in the trachea
where should a temporary tracheostomy be placed?
middle to caudal 1/3 of the neck where the sternocephalicus muscles converge - way easier to do them standing but let the horse collapse if they’re gonna
tracheal rings 2-6
should you use sedation when placing a temporary tracheostomy?
no - avoid if at all possible
what is more common primary or secondary sinusitis?
secondary
what causes secondary sinusitis in horses?
basically a sequelae of other issues - trauma, neoplasia, nasal passage/oral disease, apical dental disease
how do you treat secondary sinusitis?
treat the primary cause
what teeth communicate with the caudomaxillary sinus in the horse?
10 & 11 cheek teeth
what teeth communicate with the rostromaxillary sinus in the horse?
8 & 9
