Special Senses pt 4

Question 1

What is endophthalmitis?

Answer 1

Uveitis + inflammation of all 3 chambers

Question 2

Phacoclastic uveitis:
2. commonly secondary to what?
3. what is it?
4. what is the timeline?
5. can occasionally see uveitis secondary to severe or sudden onset _____ in what situations?

Answer 2

2. trauma and rupture of lens capsule
3. lens protein is recognized as foreign, leads to immune-mediated inflammation
4. severe inflammation develops ~2 wks after trauma
5. cataracts: diabetic cataracts in dogs, cataracts in rabbits associated with E. cuniculi

Question 3

This rabbit named Gorpicus was treated for lesions associated with E. cuniculi ~2wks ago (cataracts). Now he is back with this lesion. What is it?

Answer 3

Phacoclastic uveitis

Question 4

Equine recurrent uveitis: (ERU)
1. AKA?
2. most common cause of ___, ____, and ____ in horses
3. What is it?

Answer 4

1. moon blindness
2. glaucoma, cataracts, blindness
3. recurrent and progressive episodes of uveitis

Question 5

Equine recurrent uveitis (ERU): pathogenesis?

Answer 5

not really est., but we know it’s an immune-mediated response.

possible associated with Leptospira spp.

Question 6

Gorp Gorp the Horse presents to your clinic with blindness. His owner says that he has chronic eye problems and that it’s never been this bad before. He also says that Gorp Gorp was treated for Lepto a while back. What is your primary differential for what caused his blindness?

Answer 6

Equine recurrent uveitis (ERU)

Question 7

What are some sequelae of uveitis? (the first two you have to know for sure)

Answer 7

• anterior or posterior synechiae
• Phthisis bulbi
• retinal detachment
• cataracts
• corneal vascularization
• glaucoma

Question 8

What are synechiae?

Answer 8

adhesions b/t inflamed sticky iris and either the lens (posterior) or cornea (anterior)

Question 9

What is phthisis bulbi?

Answer 9

end-stage eye that is shrunken with fibrosis and disorganization

Question 10

What is the infectious cause of uveitis in bovine?

Answer 10

Malignant catarrhal fever (MCF)

Question 11

what is the infectious cause of uveitis in feline?

Answer 11

feline infectious peritonitis (FIP)

Question 12

What is the infectious cause of uveitis in rabbits?

Answer 12

encephalitozoon cuniculi

Question 13

What are the Big 4 systemic fungal diseases? - they can also cause uveitis

Answer 13

Blastomycoses, Coccidiomycosis, Histoplasmosis, Cryptococcosus

Question 14

Feline diffuse iris melanoma:
1. common or uncommon?
2. benign or malignant?
3. how does it begin?
4. recommended treatment?

Answer 14

1. common
2. malignant
3. focal/multifocal areas of hyperpigmentation of iris
4. enucleation

Question 15

Gorp the Cat has presented to your clinic for this lesion a few times (see timeline on photo). This lesion is getting worse, and you can’t find any infectious or congenital cause of it. What is your primary differential?

Answer 15

feline diffuse iris melanoma

Question 16

What is the definition of cataract? why does the lens do this?

Answer 16

opacification of the lens

pretty much the only response to injury the lens has

Question 17

Diabetic cataracts:
1. signalment?
2. Slow or rapid progression?
3. 1 eye or both eyes?

Answer 17

1. dogs w/ diabetes mellitus
2. rapid progression
3. both eyes

Question 18

what is the pathogenesis of diabetic cataracts in dogs?

Answer 18

1. high levels of glucose in the blood leads to elevated glucose in the aqueous humour
2. excess glucose absorbed by the lens is converted to sorbitol
3. sorbitol causes a hyperosmotic effect, pulling fluid into the lens
4. osmotic stress and swelling damages the lens fibres and epithelium
5. cataracts

Question 19

Nuclear sclerosis:
1. signalment?

3. how do you tell the difference b/t this and other types of cataracts?

Answer 19

1. old-age change = geriatric animals
2. shine a light, should be able to see reflection of the tapetum lucidum with NS versus not with cataract

Question 20

Gorp’s father (Grop, age 25) is presenting to your clinic with what the owner describes as “cataracts”. You shine a light in his eye and see his tapetum. What do you tell the owner?

Answer 20

Since Grop is a whopping 25 years old, he has nuclear sclerosis, a normal process that happens with age. There isn’t anything we can do to fix it (apart from taking out the eye, but either way he can’t see. and being 25 freaking years old, he isn’t a good candidate for sx)

Question 21

What is lens luxation?

Answer 21

dislocation of the lens
can be anterior or posterior
can be partial (subluxation) or complete

Question 22

What is the difference between anterior and posterior lens luxation?

Answer 22

anterior: painful and increases risk of glaucoma
posterior: less likely to be problematic

Question 23

Lens luxation:
1. what usually happens when you get a luxated lens?
2. what is primary luxation?
3. what is secondary luxation?

Answer 23

1. cataract development
2. no known associated ocular disease, can be congenital
3. trauma, glaucoma

Question 24

why is anterior lens luxation more likely to cause glaucoma?

Answer 24

obstructs the iridocorneal angle

Question 25

Feline Posttraumatic Ocular Sarcoma: 1. common or uncommon? 2. initiated by what? 3. arise from where? 4. infiltrative?

Answer 25

1.. second most common primary ocular tumor in cats 2. ocular trauma or severe ocular disease (delay of years) 3. lens epithelium 4. yes. highly

Question 26

what is the most common primary ocular neoplasm of cats? Second most common?

Answer 26

1. diffuse iris melanoma 2. feline posttraumatic ocular sarcoma

Question 27

Feline posttraumatic ocular sarcomas resemble what other neoplastic entity of cats?

Answer 27

vaccine associated sarcoma: both trauma associated, delayed onset, sarcomas, invasive/aggressive

Question 28

Retinal detachment is a common sequelae to what?

Answer 28

uveitis and endophthalmitis

Question 29

What are the 2 main mechanisms by which retinal detachment occurs?

Answer 29

1. exudative detachment: increase permeability of choroid vessels leads to fluid accumulation behind retina 2. tractional detachment: replacement of fibrin/exudates within the vitreous by fibrosis causing traction on the retina

Question 30

what does retinal detachment lead to?

Answer 30

ischemic degeneration

Question 31

Where is the potential space where fluids/inflammation can accumulate, causing retinal detachment?

Answer 31

between the outer nuclear layer and the retinal pigmented epithelium (RPE)

Question 32

Glaucoma: 1. species? 2. leading cause of ____ in SA? 3. clinical ____ with a variety of causes leading to ____ ____ ____ leading to ____ _____ _____ _____

Answer 32

1. dog > cat > horse 2. enucleation 3. syndrome, reduced aqueous outflow, sustained elevated intraocular pressure

Question 33

Glaucoma can be primary or secondary: 1. What is primary glaucoma? 2. what is secondary glaucoma?

Answer 33

1. occurs w/o significant acquired disease 2. blockage of the iridocorneal angle by exudates and cells

Question 34

Is glaucoma common in horses? Why or why not?

Answer 34

no horses rely more heavily on the unconventional pathways of aqueous humour flow, so even if the iridocorneal angle is obstructed, they don't usually develop glaucoma

Question 35

What are the 2 types of primary glaucoma?

Answer 35

Goniodysgenesis open-angle glaucoma

Question 36

Goniodysgenesis: 1. what is it? 2. signalment? 3. how does it relate to glaucoma?

Answer 36

1. maldevelopment of the trabecular meshwork where the aqueous drains, failure of normal remodelling during development 2. dogs (purebreds) 3. risk factor for glaucoma. If animal develops glaucoma after having this, it has primary glaucoma

Question 37

What is open-angle glaucoma? signalment? common or rare?

Answer 37

dysfunction of the angle w/ no histologic evidence of malformation beagles (inherited form) rare in vet med

Question 38

We have discussed multiple melanocytic tumors in the special senses lectures. Compare and contrast them. - eyelid melanocytoma - conjunctival melanoma - feline diffuse iris melanoma - canine melanocytic tumor/diffuse iris melanoma - limbal melanoma in dogs - Limbal melanocytic neoplasia

Answer 38

- eyelid melanocytoma: benign, 2nd most common eyelid tumor of dogs - conjunctival melanoma: malignant & aggressive with frequent metastasis, usually bulbar conjunctiva, can be amelanotic - feline diffuse iris melanoma: common, malignant. Begins as focal or multifocal areas of hyperpigmentation of iris, fast or slow progression, often develops glaucoma, enucleation recommended - canine melanocytic tumor/diffuse iris melanoma: originate form iris, ciliary body > choroid, usually benign melanocytomas - limbal melanoma in dogs: usually benign - limbal melanocytic neoplasia: benign melanocytomas, dogs > cats, darkly pigmented, expansile, extend into adjacent cornea and sclera, derived from melanocytes of the limbus