Corneal Pathology Flashcards
1
Q
describe corneal ulcers (5)
A
- AKA ulcerative keratitis
- epithelial loss/defect
-erosion/abrasion, ulceration/stromal exposure - green corneal opacity from fluorescein uptake
- indicates trauma, exposure, unhealthy/predisposed cornea, or herpes viral infection!!
- risk of secondary infection when present
-topical antibiotics ALWAYS indicated until healed bc are very susceptible to infection now
2
Q
describe the 3 varieties of corneal ulcers
A
- erosion/abrasion/ulceration:
-epithelium and basement membrane
-superficial and uncomplicated
-SCCED: secondary indolent - stromal loss:
-superficial, midstromal, deep stromal, descemetocele, perforation
-infiltrated, infected, melting
-edematous
-vascularized? - facet: epithelialized: fluorescein negative, stromal loss post ulceration
-there was an ulcer, it’s healed but the thickness of the cornea has not remodeled yet
3
Q
describe corneal ulceration etiologies (5)
A
- trauma
-direct
-secondary: foreign body, entropion, trichiasis, distichiasis, ectopic cilia, eyelid tumor - exposure:
-conformational/lagophthalmos
-buphthalmos
-exophthalmos - infection:
-FHV1; primary corneal pathogen, or other species specific herpesviruses; dendritic ulcers PATHOGNOMONIC although non-specific geographic ulcers may occur
-primary infectious keratitis rare except in cats; secondary bacterial and or fungal infection in face of ulceration much more common!
- tear film deficiency
-KCS/dry eye:
–lacrimal gland dysfunction of any cause
–neurogenic (lacrimal nerve)
-less commonly QTFD: qualitative tear film deficiency - neurologic deficits
-CN V (sensory): neurotopic
-CN VII (palpebral blink with exposure): paralytic
4
Q
describe evaluation considerations with corneal ulcers (3)
A
- look for/rule out underlying cause
- ulcer often guides you to problem
- uncomplicated ulcer should heal within a week
-if it has not:
–inciting cause remains: secondary trauma, infiltrated/infected
–indolent/nonhealing: primary/SCCED, or secondary (esp if inciting cause remains)
5
Q
describe reflex uveitis (3)
A
- corneal ulcers cause reflex uveitis
- a neuronal reflex from corneal nerves to anterior uveal tract with specific clinical signs
-miosis
-aqueous humor flare in the anterior chamber
–+/- hypopyon
–indicates BAB breakdown - severity of uveitis usually correlates with that of ulcer
6
Q
describe a superficial, uncomplicated, corneal ulceration (6)
A
- acute and PAINFUL
- distinct border/tight edge
- no to mild corneal edema
- no stromal loss (erosion, superficial ulceration)
- no infiltrate (uncomplicated)
- none to mild reflex uveitis
7
Q
describe treatment of a superficial, uncomplicated corneal ulceration (4)
A
- still look for underlying cause
- prevent/reduce risk of secondary infection
-broad spectrum topical antibiotics TID - address discomfort and reflex uveitis
-+/- topical atropine: alleviates clilary spasm
+/- PO NSAID (or other)
-NEVER proparicaine or topical anti-inflammatories!! (delay healing) - recheck in 1-2 weeks
8
Q
describe SCCED (4)
A
- spontaneous chronic corneal epithelial defect, also called indolent ulcer, boxer ulcer, non-healing ulcer, PED (persistent epithelial defect)
-boxers, goldens, corgis, and others overrepresented - characteristic nonadherent/loose epithelial edge
-characteristic fluorescein staining pattern - SAME as superficial uncomplicated, just doesn’t heal!!
- issue with anterior stroma impairing normal epithelial adherence (don’t stick down)
9
Q
describe SSCED treatment (7)
A
- cotton tipped applicator debridement
-topical anesthetic to remove loose epithelial edges until tight
-may even use diamond burr debridement
(like priming a wall before you paint it, easier for epi to stick down if no loose edges) - anterior stromal puncture/grid keratotomy
-stromal intervention promotes healing
-25g needle bevel up
-drag, don’t push
-generally avoided in cats - bandage contact lens/TEL flap
- still check for underlying cause
-if find one, was not SCCED but secondary indolent
-address issue and debridement only (stromal alteration not indicated) - prevent secondary infection!
-broad spectrum topical Ab TID - address discomfort and reflex uveitis
- E collar
10
Q
describe corneal stromal ulcers (3)
A
- variable depth (stromal LOSS)
-superficial, mild, or deep stromal or descemetocele; perforation (often with fibrin or iris prolapse in pugs) - variable infiltration, infection, malacia, edema, vascularization
- variable anterior uveitis:
-miosis, flare, hypopyon, fibrin in AC, hypotone
-if raging uveitis, even if ulcer doesn’t LOOK bad, it IS bad
11
Q
describe descemetocele (2)
A
- stromal loss down to descemet’s membrane
- characteristic fluor. staining pattern
12
Q
describe corneal perforation
A
if we go full thickness through the cornea, stuff comes up to plug the hole
pigment or hemorrhage in stroma suggestive of perf
13
Q
describe corneal malacia etiologies (3)
A
- endogenous proteinases/collagenases
-leukocytes
-corneal cells themselves that ramp up during injury - infection- most common!
-bacterial collagenases - topical corticosteroids (and NSAIDS??)
-potentiation of collagenase activity
-local immunosuppression
14
Q
describe assessment of stromal ulcers (5)
A
- depth
- integrity: perforation risk (depth again), malacia, anterior chamber depth
- infiltrate
- reflex uveitis status
- vascularization
15
Q
describe treatment of stromal ulcers (5)
A
- topical antimicrobials (oral too if perforation)
-broad spectrum, bug guns +/- antifungals
-indeally absed on severity, cytology, C&S
-fortified cefazolin to cover gram + cocci
-fortified tobramycin or fluroquinolones to cover gram - rods
-no ointments in eyes with current or impending perforation!
-may be needed up to hourly at first! - topical proteinase/collagenase inhibitors
-address malacia
-serum: donor commonly
–alpha-2 macroglobulin helps with melting
–keep in fridge, handle aseptically, discard after 7 days
-EDTA
-acetylcysteine - for reflex uveitis:
-topica; cycloplegia/mydriasis
–cholinergic/parasympatholytic: atropine, contraindiacted wth KCS and glaucoma, may cause drooling
-decreases pain from ciliary muscle spasm
-reduces visually significant synechiae
-may stabilize BAB reducing further uvetis - systemic anti-inflammtories
-address pain and uveitis
-MAY delay corneal healing but topical WILL delay and potentiate malacia so NO TOPICAL - other pain meds/sedation/e-collars
