Large Animal Upper Airway Conditions

Question 1

describe nasal passages exam considerations (5)

Answer 1

1. examine nasal discharge
   -any odor?
2. diminished airflow indicated by open mouthed breathing
3. deformation of face: indicates chronic
4. sneezing, snorting, head shaking
5. +/- systemic involvement

Question 2

describe sinus anatomy

Answer 2

1. review who connects!!
2. esp drainage from nasomaxillary opening

Question 3

describe endoscopic exam to determine nasal discharge source

Answer 3

1. nasomaxillary opening:
   -rostral to ethmoids
   -most caudal aspect of middle nasal meatus
   -molars are SUPER close to sinuses (tooth root infection can cause sinusitis)
2. sinusitis: discharge from nasomaxillary
   opening

Question 4

describe sinusitis

Answer 4

1. discharge from nasomaxillary opening
2. clinical signs:
   -unilateral (bilateral less common) nasal discharge
   -facial swelling if chronic and drainage prevented
   -epistaxis, head shaking weight loss, exophthalmos
3. diagnosis:
   -assume secondary until proven otherwise
   -oral exam: sedated, used speculum
   -radiographs
   -upper airway scope
4. treatment:
   -treat primary cause: extract tooth, remove mass or cyst

-flush sinus: if severe/chronic infection with lack of response to therapy
–use trephination hole: catheter directly into sinus, enables daily flushing

-antibiotics: systemic, local

-culture: sample from sinus, NOT discharge
-if secondary, presume ANAEROBES, so treat with TMS, metronidazole, chloramphenicol, penicillin

Question 5

describe rhinitis in horses

Answer 5

1. often bilateral
2. viral etiology/also can cause sinusitis
   -EHV-1 and 4
   -equine viral arteritis
   -equine influenza
   -equine rhinitis viruses
   -equine adenovirus (SCID)

Question 6

describe nasal granulomas causative agents

Answer 6

1. bacterial agents:
   -actinomyces, actinobacillus, nocardia
2. fungal:
   -rhinosporidium, aspergillus, conodiobolus, cryptococcus, coccidiodes, etc.

really need a sample to differentiate, don’t really change signs based on agent

-can for sure invade through the cribriform plate into the CNS

Question 7

what are 3 common nasal neoplasias in horses?

Answer 7

1. adenoma
2. squamous cell carcinoma
3. adenocarcinoma

Question 8

describe diagnosis of nasal masses

Answer 8

1. direct exam
2. radiography
3. rhinoscopy
4. biopsy
   -cytology, histo (necrosis common result, not super helpful), culture, PCR (bacterial and fungal, panfungal PCR helps a ton)

-sheep/goat: PCR for retrovirus
–enzoonotic nasal tumor virus (ENTV)
-sheep (ENTV-1) and goats (ENTV-2)

Question 9

describe therapy for nasal masses

Answer 9

1. surgical debulking:
   -HEMORRHAGE LIKELY
   -preemptively cross match patient, warn owner, be ready to transfuse
2. systemic treatment
3. topical/intralesional treatment: more commonly used than systemic; insert plastic tube into snoot, will lodge and can leave in
   -fungal: antifungals
   -bacterial granulomas: antibiotics
   -neoplasia: chemotherapy

Question 10

describe ethmoid hematoma in horses

Answer 10

1. clinical signs:
   -periodic epistaxis!!!
   -usually unilateral
   -usually not severe
2. slow expanding angiomatous mass of ethmoid chonchae
   -may be LOCALLY INVASIVE
   -cause unknown
3. diagnosis: endoscopy or radiographs
   -presumptive: appearance
   -definitive: biopsy and histopath (hemorrhage)
4. treatment: surgical or chemical ablation

Question 11

describe pharyngeal lymphoid hyperplasia

Answer 11

a variation of normal!!

little lymphoid populations that have had antigenic stimulation and are just doing their jobs

Question 12

describe dorsal displacement of the soft palate

Answer 12

very common in racehorses!

1. presenting complaint:
   -noise
   -poor performance
   - +/- coughing
2. clinical signs:
   -exercise intolerance
   -noise with exercise
   - +/- no signs at rest
3. caudal border of soft palate displaced dorsally to cover epiglottis, can be persistent or intermittent
   -if persistent = noise at rest
4. diagnosis:
   -presumptive: characteristic respiratory noise during exercise
   -definitive: endoscopy during work, must scope during work because sedation can exacerbate and cause false positive
5. treatment:
   -tongue tie: prevent swallowing

-modified tack: prevent mouth opening

-systemic or topical anti-inflammatory therapy!!! good response in most without needing surgical intervention

-various surgical strategies with a guarded prognosis for performance

Question 13

describe epiglottic entrapment

Answer 13

especially in racehorses!!

1. clinical signs:
   -poor performance and/or noisy breathing during exercise
   -usually nothing at rest
2. aryepiglottic folds: redundant loose ventral mucosa tissue can move up over dorsal surface of epiglottis
3. cause unknown, may be intermittent or persistent
   -often associated with epiglottitis (+/- subepiglottal cyst)
   -may be associated with chronic URT inflammation
   +/- DDSP
   -if both EE and DDSP, prognosis for athletic performance is poor
4. diagnosis:
   -endoscopy: can see outline of epiglottis but looks thickened by overlying aryepiglottic folds (DDSP = cannot see edge of epiglottis)
   -may need to eval during work
5. treatment:
   -address cyst if present, complicated surgeries to treat EE, anti-inflammatory
   -REFER

Question 14

describe laryngeal hemiplegia/roaring

Answer 14

especially in taller breeds

1. clinical signs:
   -poor performance
   -noise during exercise
   -rarely: pronounced inspiratory dyspnea at rest (if bilateral)
2. arytenoid cartilage not properly abducted during inspiration
   -L»>R
   -narrowed airway leads to increased ariway resistance
3. causes:
   -any injury to vagus nerve or recurrent layrgneal nerve
   -most causes: idiopathic dying back axonopathy
4. grading system:
   -1 = normal synchronous abduction during rest and stressed inspiration
   -4 = complete lack of movement of arytenoid on affected side
5. diagnose:
   -palpate externally: CAD atrophy
   -palpate decreased slap test response of recurrent laryngeal nerve