Special Senses pt 4 Flashcards
What is endophthalmitis?
Uveitis + inflammation of all 3 chambers
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?
- trauma and rupture of lens capsule
- lens protein is recognized as foreign, leads to immune-mediated inflammation
- severe inflammation develops ~2 wks after trauma
- cataracts: diabetic cataracts in dogs, cataracts in rabbits associated with E. cuniculi
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?
Phacoclastic uveitis
Equine recurrent uveitis: (ERU)
1. AKA?
2. most common cause of ___, ____, and ____ in horses
3. What is it?
- moon blindness
- glaucoma, cataracts, blindness
- recurrent and progressive episodes of uveitis
Equine recurrent uveitis (ERU): pathogenesis?
not really est., but we know it’s an immune-mediated response.
possible associated with Leptospira spp.
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?
Equine recurrent uveitis (ERU)
What are some sequelae of uveitis? (the first two you have to know for sure)
- anterior or posterior synechiae
- Phthisis bulbi
- retinal detachment
- cataracts
- corneal vascularization
- glaucoma
What are synechiae?
adhesions b/t inflamed sticky iris and either the lens (posterior) or cornea (anterior)
What is phthisis bulbi?
end-stage eye that is shrunken with fibrosis and disorganization
What is the infectious cause of uveitis in bovine?
Malignant catarrhal fever (MCF)
what is the infectious cause of uveitis in feline?
feline infectious peritonitis (FIP)
What is the infectious cause of uveitis in rabbits?
encephalitozoon cuniculi
What are the Big 4 systemic fungal diseases? - they can also cause uveitis
Blastomycoses, Coccidiomycosis, Histoplasmosis, Cryptococcosus
Feline diffuse iris melanoma:
1. common or uncommon?
2. benign or malignant?
3. how does it begin?
4. recommended treatment?
- common
- malignant
- focal/multifocal areas of hyperpigmentation of iris
- enucleation
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?
feline diffuse iris melanoma
What is the definition of cataract? why does the lens do this?
opacification of the lens
pretty much the only response to injury the lens has
Diabetic cataracts:
1. signalment?
2. Slow or rapid progression?
3. 1 eye or both eyes?
- dogs w/ diabetes mellitus
- rapid progression
- both eyes
what is the pathogenesis of diabetic cataracts in dogs?
- high levels of glucose in the blood leads to elevated glucose in the aqueous humour
- excess glucose absorbed by the lens is converted to sorbitol
- sorbitol causes a hyperosmotic effect, pulling fluid into the lens
- osmotic stress and swelling damages the lens fibres and epithelium
- cataracts
Nuclear sclerosis:
1. signalment?
- how do you tell the difference b/t this and other types of cataracts?
- old-age change = geriatric animals
- shine a light, should be able to see reflection of the tapetum lucidum with NS versus not with cataract
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?
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)
What is lens luxation?
dislocation of the lens
can be anterior or posterior
can be partial (subluxation) or complete
What is the difference between anterior and posterior lens luxation?
anterior: painful and increases risk of glaucoma
posterior: less likely to be problematic
Lens luxation:
1. what usually happens when you get a luxated lens?
2. what is primary luxation?
3. what is secondary luxation?
- cataract development
- no known associated ocular disease, can be congenital
- trauma, glaucoma
why is anterior lens luxation more likely to cause glaucoma?
obstructs the iridocorneal angle
Feline Posttraumatic Ocular Sarcoma:
1. common or uncommon?
2. initiated by what?
3. arise from where?
4. infiltrative?
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
what is the most common primary ocular neoplasm of cats? Second most common?
- diffuse iris melanoma
- feline posttraumatic ocular sarcoma
Feline posttraumatic ocular sarcomas resemble what other neoplastic entity of cats?
vaccine associated sarcoma: both trauma associated, delayed onset, sarcomas, invasive/aggressive
Retinal detachment is a common sequelae to what?
uveitis and endophthalmitis
What are the 2 main mechanisms by which retinal detachment occurs?
- exudative detachment: increase permeability of choroid vessels leads to fluid accumulation behind retina
- tractional detachment: replacement of fibrin/exudates within the vitreous by fibrosis causing traction on the retina
what does retinal detachment lead to?
ischemic degeneration
Where is the potential space where fluids/inflammation can accumulate, causing retinal detachment?
between the outer nuclear layer and the retinal pigmented epithelium (RPE)
Glaucoma:
1. species?
2. leading cause of ____ in SA?
3. clinical ____ with a variety of causes leading to ____ ____ ____ leading to ____ _____ _____ _____
- dog > cat > horse
- enucleation
- syndrome, reduced aqueous outflow, sustained elevated intraocular pressure
Glaucoma can be primary or secondary:
1. What is primary glaucoma?
2. what is secondary glaucoma?
- occurs w/o significant acquired disease
- blockage of the iridocorneal angle by exudates and cells
Is glaucoma common in horses? Why or why not?
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
What are the 2 types of primary glaucoma?
Goniodysgenesis
open-angle glaucoma
Goniodysgenesis:
1. what is it?
2. signalment?
3. how does it relate to glaucoma?
- maldevelopment of the trabecular meshwork where the aqueous drains, failure of normal remodelling during development
- dogs (purebreds)
- risk factor for glaucoma. If animal develops glaucoma after having this, it has primary glaucoma
What is open-angle glaucoma? signalment? common or rare?
dysfunction of the angle w/ no histologic evidence of malformation
beagles (inherited form)
rare in vet med
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
- 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
