Special Senses Part 2

Question 1

describe the differences between trichiasis, distichiasis, and ectopic cilia. which is the most damaging?

Answer 1

trichiasis: hairs in normal position but are misdirected to contact the cornea, causes corneal irritation
distichiasis: abnormally positioned eyelash coming from the opening of the meibomian glands, usually no corneal damage (very mild irritation)
ectopic cilia: abnormally positioned eyelash coming FROM the palpebral conjunctiva, severe corneal damage!

Question 2

trichiasis is common in which dog breeds?

Answer 2

bracycephalic breeds like pugs and bulldogs

Question 3

describe the differences between entropion and ectopion

Answer 3

entropion: inward rolling of the eyelid causing corneal irritation (a type of trichiasis)
ectropion: outward rolling of the eyelid margin (think basset hound with droopy lower eyelids) causing chronic keratitis/conjunctivitis

Question 4

what is shown here in the top photo, and then the bottom photo?

Answer 4

top: entropion, eyelid rolling in
bottom: ectropion, eyelid rolling out

Question 5

prolapse of the 3rd eyelid has a common name of _______ and it is most common in ______

Answer 5

cherry eye, dogs

Question 6

what is the most common tumor of the canine eyelid?

Answer 6

meibomian gland tumors

Question 7

Your client brings you their new resuce dog, Andy. You examine Andy’s eye and you find this. The client is concerned. What do you tell them?

Answer 7

I would tell them that this is most likely a meibomian gland tumor and they are almost always benign so there is nothing to worry about. I would tell him we can surgically remove it or simply leave it alone and Andy will be fine.

Question 8

what is the second most common eyelid tumor in dogs? What are some of the characteristics of this tumor?

Answer 8

eyelid melanocytomas
usually benign
can look very similar to meibomian gland tumors grossly

Question 9

how do conjunctival melanomas in dogs usually behave?

Answer 9

they are malignant with frequent metastasis, usually found in the bulbar conjunctiva. these are not very common in dogs

Question 10

this is a dog eye. What kind of tumor do you suspect?

Answer 10

conjunctival melanoma

Question 11

squamous cell carcinoma of the eye is common in what animal(s)? Where does this tumor arise from

Answer 11

horses in cattle
arises from the conjunctiva

Question 12

where is squamous cell carcinoma usually found on a cow or horse? What is this type of tumor associated with?

Answer 12

on the 3rd eyelid
associated with UV light exposure

Question 13

what are 3 common gross features of squamous cell carcinomas that help with diagnosis?

Answer 13

usually it will be on non pigmented skin, will be ulcerated, and inflammed

Question 14

what is the common name of squamous cell carcinoma in a cow?

Answer 14

cancer eye

Question 15

the left is a cow, the right is a horse. what kind of tumor is this? (same for both photo)

s

Answer 15

squamous cell carcinoma

Question 16

what is the name of the glnds that produce earwax?

Answer 16

ceruminous glands

Question 17

otitis externa is most common in ____ and is the result of what 3 factors?

Answer 17

dogs
predisposing factors (conformation or breed)
primary causes (skin conditions, ectoparasites)
secondary causes (bacterial or fungal infections)

Question 18

if a dog has chronic otitis and shakes its head consistently, what can happen?

Answer 18

the dog can develop a hematoma because the shaking of the head causes trauma to the blood vessels in the pinna and causes hemorrhage into the pinna

Question 19

what kind of dogs are more prone to developing aural hematomas?

Answer 19

large breed dogs with droopy ears

Question 20

what is the fancy name for a mite infestation? Who commonly gets this?

Answer 20

otoacariasis
kittens

Question 21

a client brings you a older horse and you see depigmented plaques/warts on the concave surface of the ear. What does this horse have and what is the significane?

Answer 21

these are aural plaques caused by equine papilloma virus. these are distinct from other papilloma warts because they affect older horses. they do not regress but have no clinical significance

Question 22

this a horse ear. what are you seeing here?

Answer 22

aural plaques caused by equine papilloma virus

Question 23

what is an “ear tooth” in a horse?

Answer 23

an equine dentigerous cyst, they are congential cysts at the base of the ear often with a fistula connecting to the surface. they are from tooth stem cells being placed in an abnormal location. They cause no pain or problems to the horse

Question 24

this is a horse ear. what are you seeing here?

Answer 24

a dentigerous cyst

Question 25

what causes ear tip necrosis?

Answer 25

it is from ischemic injury specifically infarcts. Examples: frost bite, vasculitis, immune mediated, viral, toxicities, etc

Question 26

this is from a calf. what is this?

Answer 26

ear tip necrosis (you can see sharp lines of demarcation)

Question 27

the most common external aucostic meatus tumors in dogs and cats are _______. How do these tumors behave?

Answer 27

tumors of the ceruminous glands
these are usualy malignant esp in cats

Question 28

this is the ear of a cat. Given this mass is locally invasive, what is this tumor most likely?

Answer 28

a creuminous adenocarcinoma, a malignant tumor

Question 29

otitis media is common in what animal(s)? what are clinical signs?

Answer 29

ruminants and pigs
signs: droopy ears, head tilt, frequently occurs in conjunction with respiratory disease

Question 30

what classic pathogen is associated with otitis in cattle and what pathogen for pigs?

Answer 30

cattle: mycoplasma bovis
pigs: pasturella multocida

Question 31

this is the tympanic bullae. what is this?

Answer 31

suppurative otitis media

Question 32

if an animal has penumonia, where should you also look for disease?

Answer 32

look in the ears, specifically the tympanic bullae

Question 33

what is this disease? the photo on the left is normal and the one on the right is diseased

Answer 33

otitis media

Question 34

What is Horner’s syndrome? What are some clinical signs?

Answer 34

result of loss of innervation to the eye which can be secondary to otitis media
clinical signs: constricted pupil, eye pulled back, head tilt, prolapsed 3rd eyelid, anisocoria, dilation of blood vessels on the affected side

Question 35

what disease is this?

Answer 35

horner’s syndrome ( right side of the cat is affected, left side of this photo)

Question 36

nasopharyngeal polyps occur in what animal? how do they relate to the ear?

Answer 36

young cats
can also have/cause otitis externa or media with one of these

Question 37

guttural pouch disease involes which two common etiologies?

Answer 37

streptococcus equi equi (strangles)
aspergillus sp

Question 38

these are in the guttural pouch of a horse. what is the name for these?

Answer 38

chondroids (pus stones from a chronic strep infection)

Question 39

what is temporohyoid osteoarthropathy of horses? what are clinical signs

Answer 39

the joint between the proximal hyoid bone and the temporal one can become degernative and undergo bony proliferation and fusion of the joint
clinical signs: abnormal behavior like ear rubbing and problems chewing, severe acute vestibular signs or facial nerve damage if the joint fractures

Question 40

what are the two types of vestibular disease?

Answer 40

peripheral vestibular disease (involving internal ear sensory receptors)
primary vestibular disease (involving the brainstem and cerebellum)

Question 41

what causes peripheral vestibular disease in geriatric dogs?

Answer 41

it is often idiopathic, is acute onset, and starts to show improvement 2-3 days without treatment

Question 42

what are 3 differentials for a rabbit with a head tilt?

Answer 42

otitis media
trauma
encephalitozoon caniculi

Question 43

rabbits can get this strange gram positive fungi which targets the brain, kidney, and eyes. What is it called?

Answer 43

encephalitozoon caniculi

Question 44

what are the 3 body systems that encephalitozoon caniculi infects in rabbits?

Answer 44

eye, kidney, and brain

Question 45

What would you see on histology of a a kidney from a rabbit with a E. caniculi infection?

Answer 45

granulomatous inflammation

Question 46

what gross lesions will you see with a rabbit with E caniculi?

Answer 46

pitting of the renal cortex and cataracts in the eyes

Question 47

this is a rabbit kidney. what are you suspicious of?

Answer 47

encephalitozoon caniculi