Diseases of the Upper Respiratory Tract Flashcards by Renee DeAngelis

What are the 5 major challenges in the upper respiratory tract horses need to over come for proper respiration?

important dead space
VO2 muscles
narrow URT
obligate nasal breathers
locomotor coupling of breaths

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What are the most common causes of unilateral mucopurulent and epistaxis nasal discharge?

MUCOPURULENT - sinusitis, guttural pouch

EPISTAXIS - ethmoid hematoma, guttural pouch

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What are the most common causes of bilateral mucopurulent and epistaxis nasal discharge?

MUCOPURULENT - asthma, pneumonia

EPISTAXIS - EIPH

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How do the nostrils act in a normal horse at rest and one with respiratory disease?

flat, comma shape

nostril flares with increased respiratory effort (normal in a horse doing exercise)

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What should the airflow in horses be like?

SYMMETRICAL

reduction in airflow in one nostril indicates an obstructive lesion

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What is the false nostril? When does it commonly become prominent?

nasal diverticulum —> dead end in the dorsal nasal cavity that can be checked with one finger for abnormal conformation or masses

when the nostrils are flared

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What is an atheroma? What clinical sign is associated? How are they diagnosed?

epidermal inclusion cyst found within the false nostril

swelling

palpation and FNA to rule out neoplasia

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How are atheromas treated?

excision, burr
chemical ablation

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What meatus is targeted for nasal endoscopy? What do we try to avoid?

ventral meatus, shaped like a “U”

endoturbinates —> can cause profuse bleeding

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Where is it most common to find apical infection in the maxillary teeth? What are the 5 most common clinical signs?

1-3rd cheek teeth (106-108 and 206-208) in the rostral portion of the maxillary bone and paranasal sinuses

halitosis
nasal discharge
swelling
pain of affected tooth
decreased airflow

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How are apical infections of rostral maxillary cheek teeth diagnosed? Treated?

oral examination, endoscopy, or radiographs

extraction of affected teeth followed by sealing

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What are the most common congenital and nutritional nasal deformities?

wry nose —> lateral deviation

osteodystrophia fibrosa —> Ca:P mismatch

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Where do ethmoidal hematomas originate? Where do they end up growing?

submucosa ethmoidal labyrinth and paranasal sinus

grow into the nasal cavity and nasopharynx

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What are the 3 most common clinical signs associated with ethmoidal hematomas?

chronic, intermittent, serosanguinous discharge from the nostrils (unilateral)
decreased airflow and smell
deformity

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How are ethmoidal hematomas diagnosed? Treated?

endoscopy biopsy and radiographs

excision
ablation with 4% formaldehyde or laser for reduction

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What sinuses are able to be percussed in horses? How should it sound?

frontal and maxillary sinuses

should sound hollow bilaterally while comparing left to right and over the entire area (easier to hear with mouth open)

What is the most common cause of primary sinusitis? What is the most common clinical sign?

infection causing obstruction of normal nasomaxillary drainage

unilateral purulent nasal discharge

What is the most common cause of secondary sinusitis? What 3 clinical signs are associated?

tooth root abscess

unilateral purulent malodorous discharge
epiphora, conjunctivitis
deformation

What are the 3 ways of diagnosing sinusitis?

endoscopy
radiographs —> fluid lines
sinuscentesis/scopy

How is sinusitis treated?

antimicrobials
trephination and flush
address cause —> pull tooth

What are sinus cysts? What are the 3 most common clinical signs?

fluid-filled, space-occupying lesions found int he sinus cavities that push against the bone and make them softer

deformation
nasal discharge
reduced airflow

How are sinus cysts diagnosed? Treated?

radiographs, CT, MRI

removal

How does the pharynx look in cases of pharyngitis? In what horses is this most common? Does it usually need treatment?

follicular pharyngeal hyperplasia of the lymphoid tissue

young racehorses

it is usually self-limiting and a normal response to inhaled antigens/allergens, but it can have an effect of dynamic URT obstruction

How is pharyngitis diagnosed? What are the 2 kinds of treatment?

endoscopy

general = NSAIDs
local = spray containing glycerin, DMSO, nitrofurazone, and prednisolone

What is a cleft palate? What is the most common clinical sign?

congenital communications between the oral and nasal passages dysphagia ---> after foals nurse, there is commonly bilateral nasal discharge containing the milk

How do horses breath? How does locomotion play into their breathing?

obligate nasal breathers horses exhale on touchdown

Endoscopy at rest:

DPR = retropharyngeal recess GPO = guttural pouch opening E = epiglottis SP = soft palate

Dynamic collapse of URT:

What is dorsal displacement of the soft palate? When does it most commonly occur?

the soft palate is displaced over the epiglottis, most commonly during exercise

What are the 3 most common clinical signs associated with dorsal displacement of the soft palate?

1. horse "chokes down" towards the end of a race 2. EXPIRATORY noise during exercise caused by air expelled from the trachea pushing against the soft palate 3. decreased performance

What 3 conservative treatments are used for dorsal displacement of the soft palate?

1. nose bands or tongue ties to stop horses from swallowing 2. bit 3. Cornell collar obstructs specific head positions that are thought to induce DDSP

What is the most common surgical treatment of dorsal displacement of the soft palate? What are some other options?

tie forward to get the larynx closer to the soft palate - palatoplasty - staphylectomy - strap muscle myectomy - tracheostomy

What happens to the larynx in left laryngeal hemiplegia? What are the 2 causes?

left recurrent laryngeal neuropathy causes the left arytenoid cartilage to no longer abduct on inspiration, causing it to obstruct the trachea 1. RECURRENT - congenital in large breeds, like Warmbloods and Thoroughbreds 2. ACQUIRED - chondritis, damage to nerve, toxicity

What are the 2 most common clinical signs of left laryngeal hemiplegia?

1. INSPIRATORY noises during exercise - roaring 2. decreased performance

What test is commonly done on the larynx to confirm left laryngeal hemiplegia?

slap test - palpate over the area of the arytenoids and slap the withers on the contralateral side, resulting in slight movement/abduction - horses with LLH may have a reduced slap test due to degeneration of the nerve and a more pronounced muscular process of the arytenoid cartilage due to muscular atrophy

What is the best definitive diagnosis of left laryngeal hemiplegia?

dynamic endoscopy

What is the most common treatment for left laryngeal hemiplegia? What are some other options?

prosthetic laryngoplasty (tie back) ---> if overzealous, horse can experience dysphagia - ventricul/chord/ventriculocordectomies - pedicle nerve graft - arytenoidectomy

How do the respiratory noises associated with DDSP and LLH compare?

DDSP = expiratory noise due to air hitting and flapping the soft palate LLH = inspiratory noise (roaring)

What are the 2 most common clinical signs associated with ethmoidal hematomas?

1. unilateral discharge with possible epistaxis 2. decreased airflow