Special Senses pt 1 Flashcards
What is the palpebral conjunctiva? How about the bulbar conjunctiva?
palpebral: back of eyelids
bulbar: covers the surface of the globe up to the cornea/limbus
What is trichiasis? common signalment? why does it matter?
hairs in a normal position are misdirected to contact the cornea
brachycephalic dogs with nasal folds
corneal contact causes irritation
abnormalities of the cilia are more common in ___ than in other species.
dogs
Your patient, Nosewise the Pug, came in for a regular check up. You notice this lesion. What is it? Is it concerning?
Trichiasis
not super concerning as brachycephalic are predisposed to it, but corneal contact causes irritation
What is distichiasis? why does it matter?
abnormally positioned eyelash coming from the opening of the Meibomian glands at the eyelid margin
minimal corneal damage. doesn’t really matter
You patient Blankette presents with this lesion. What is it? (hint: the eyelash doesn’t seem to be coming from the palpebral conjunctiva, nor are they in normal positioning….)
distichiasis
Label this picture
A: districhiasis
B: ectopic cilia
C: trichiasis
You patient Terry presents with this lesion. What is it?
Ectopic cilia
What is entropion? what does it cause? signalment?
inward rolling of the eyelid margin because of inadequate length
causes corneal irritation
certain breeds of dog and sheep
entropion is a form of _____. Surgical correction works ____.
Trichiasis
well
Lumpe the dog comes into your clinic presenting with this lesion. You notice that his cornea is irritated. What is your diagnosis and what do you do to correct it?
Entropion
surgery
What is ectropion? which eyelid is usually affected? what can it cause?
outward rolling of the eyelid margin due to excessively long lax eyelid
lower eyelid
can cause chronic keratitis, conjunctivitis
This is Plodder the dog. What lesion does he have?
Ectropion
Prolapse of the gland of the third eyelid:
1. AKA?
2. why does it happen?
3. common in what species?
4. how do you treat?
- cherry eye
- result of laxity of the connective tissue anchoring the third eyelid
- dogs
- surgery
Blodeman the dog comes to your clinic with this lesion. What is it? How do you treat it?
Prolapse of the gland of the third eyelid / cherry eye
surgery to fix
What is the most common tumor of the canine eyelid? malignant or benign?
Meibomian gland tumors
predominately benign
meibomian gland tumors:
1. gross appearance
2. treatment
- grey, pink or tan exophytic alopecia Masses coming from the eyelid margin
- surgical excision
Garlik the dog is brought into your clinic with this lesion. What is it? What is the Garlik’s prognosis?
Meibomian gland tumor
prognosis is good with surgical excision
eyelid melanocytoma:
1. malignant or benign?
2. how to diagnose?
- usually benign
- biopsy because they can look similar to Meibomian gland tumors
Gorp presents to your clinic with this lesion. What are your 2 differential diagnoses? How do you figure it out?
Eyelid melanocytoma & meibomian adenoma
biopsy
You see this eyeball on necropsy. What do you think is going on?
Conjunctival melanoma
Conjunctival melanoma:
1. malignant or benign?
2. where is usual location?
- malignant and aggressive with frequent metastasis
- bulbar conjunctiva
conjunctival melanomas can be _____, which means without pigment.
amelanotic
Squamous cell carcinomas of the eye arise from the _____. They are most common in what species?
conjunctiva
cattle + horses > cats
what is the common name for squamous cell carcinoma of the conjunctiva in cattle? why is this super significant?
cancer eye
cattle are condemned at slaughter if they have a tumor, even if it has nothing to do with the actual meat that is going to be sold
name 3 common gross features of squamous cell carcinoma that can help in diagnosis?
non-pigmented skin
ulcerated
inflamed
What is the most common ocular tumor of horses? where is it often located?
squamous cell carcinoma of the conjunctiva
3rd eye lid
SCCs of the conjunctiva are associated with ____.
UV light exposure
what are ceruminous glands?
glands that produce ear wax
What is otitis externa?
inflammation of the external ear
otitis externa is most common in ____. it is the result of interaction of the following 3 factors: _____, _____, _____.
Dogs
predisposing factors
primary causes
secondary causes
What are the predisposing factors for otitis externa?
conformation of the ear (droopy ears), breed, external ear moisture
what are the primary causes of otitis externa?
ectoparasites, foreign bodies, generalized skin conditions (allergies, etc)
What are the secondary causes of otitis externa?
bacterial infections, fungal infections
Gorp comes back to your clinic with this lesion. What is going on?
Otitis externa
You are doing a necropsy on a dog’s ear. What is the lesion?
otitis externa
What is the pathogenesis of aural hematomas?
- chronic otitis (externa or media)
- head shaking
- trauma to blood vessels in pinna (centrifugal shearing forces)
- hemorrhage into tissues of pinna
- aural hematoma
Aural hematomas can be seen in these species: ___, ____, _____. They are most common in _____-____ _____ with _____ ____. They are resolved by _____.
dogs, cats, pigs
large-breed dogs with droopy ears (labs and Goldens)
fibrosis
You are doing a necropsy of a pig’s ear. What is the lesion?
Aural hematoma
Gorp is back at your clinic AGAIN!!! What is the lesion? What do you think happened?
aural hematoma
Gorp had chronic otitis that lead to head shaking, which traumatized the blood vessels in the pinna, which caused hemorrhage into the tissues of the pinna
What is otocariasis?
mite/tick infestation in the ear
otocariasis is a common problem in what age/species?
kittens
Aural plaques of horse:
1. AKA?
2. gross appearance?
- aural papillomatosis
- pale raised hyperkeratotic, depigmented plaques/warts on concave surface of ear
aural plaques of horses are caused by? how are they significant?
equine papillomavirus
not significant (cosmetic)
Your horse Gorpius has these lesions on his ears. What are they? What do you do now?
Aural plaques or aural papillomatosis
do nothing - not clinically significant
What are equine dentigerous cysts? What is the cause?
rare congenital cyst that occurs at the base of the ear, often with a fistula leading to the surface
result of malpositioned tooth stem cells during development (can contain teeth!)
common name = ear tooth
You horse (named Gorp) presents with this lesion. What is it? Is it a problem? What is the treatment?
dentigerous cyst
no (primarily cosmetic problem)
sx excision
Gorp the dog is back again! This time, this is his lesion. What is going on? What does it imply?
ear tip necrosis
implies vascular origin to the insult
Ear tip necrosis: how can you tell it’s that?
sharp line of demarcation from surrounding normal tissue (infarct!)
What are some common causes of ear tip necrosis?
- frost bite
- bacterial septicemia (salmonella in pigs and cattle)
- toxins (ergot)
- viral (FIP in cats, although rare!)
- hypersensitivity reaction
tumors of the external ear can arise secondary to _____ _____ of the ear
chronic inflammation
what external acoustic meatus tumor do we have to know? species? benign or malignant? common or rare?
tumors of the ceruminous glands
cats & dogs
malignant (ceruminous adenocarcinomas)
rare
