Corneal Ulcers Flashcards Preview

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Flashcards in Corneal Ulcers Deck (54)
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1
Q

Damage to which facial nerve can cause the inability to blink and corneal ulceration?

A

Facial nerve (CN 7)

2
Q

How long does an uncomplicated corneal ulcer take to heal?

A

Days (usually <5)

3
Q

How long must a corneal ulcer be present to be considered complicated?

A

> 7d

4
Q

How do you treat a complicated corneal ulcer?

A

Conjuntival flap

5
Q

How do you diagnose the cause of a melting corneal ulcer?

A

Swab for cytology and culture

6
Q

Which feline virus can manifest in ocular signs such as conjunctivitis, ulcers, and eosinophilic keratitis?

A

Feline herpesvirus (feline viral rhinotracheitis)

7
Q

What type of ulcers appear with feline herpesvirus?

A

Dendritic (linear)

8
Q

How do infected corneal ulcers appear?

A

Melting

9
Q

What does a melting ulcer indicate?

A

Deepening of ulcer into stroma

10
Q

What is the most common cause of bacterial keratitis that is also usually the cause of a melting corneal ulcer in horses?

A

Pseudomonas (gram neg rod)

11
Q

How do you treat a melting corneal ulcer in a horse?

A
TOPICAL tobramycin (aminoglycoside) for gram neg
TOPICAL cefazolin for gram pos (Staphylococcus)
12
Q

How might guttural pouch mycosis result in corneal ulceration?

A

Facial nerve paralysis

13
Q

What are underlying causes of corneal ulcers?

A

Trauma, anatomical malformation, ectopic cilia, neuro deficits, inadequate tear production

14
Q

What is ectopic cilia?

A

Cilia arising from palpebral conjunctiva

15
Q

What is distichiasis?

A

Cilia from the meibomian gland openings @ eyelid margin

16
Q

What is trichiasis?

A

Hairs from a normal location in contact w/cornea

17
Q

What is a corneal ulcer?

A

Break in the corneal epithelium

18
Q

How do you dx a corneal ulcer?

A

Fluorescein stain

19
Q

A particular type of superficial corneal ulcer that typically is non-healing/chronic, a hyaline acellular zone prevents the epithelium from adhering to the underlying stroma

A

Spontaneous chronic corneal epithelial deficits (SCCED) - aka indolent ulcer

20
Q

What is the only type of corneal ulcer that benefits from debridement?

A

Spontaneous chronic corneal epithelial deficit (SCCED) - aka indolent ulcer

21
Q

What type of uveitis does a corneal ulcer cause?

A

Reflex uveitis

22
Q

What should you never use in the eye if a corneal ulcer is present?

A

Steroids

23
Q

What are the three types of corneal ulceration that can be dx via the pattern of fluorescein stain uptake?

A

Dendritic, indolent, descemetocele

24
Q

How will fluorescein stain uptake with a dendritic ulcer?

A

Linear

25
Q

What type of dye is fluorescein stain?

A

Hydrophilic

26
Q

What layer of the eye will fluorescein stain bind to?

A

Stroma

27
Q

Loss of epithelium w/o stromal loss and heals in 7d or less is what type of corneal ulcer?

A

Simple superficial

28
Q

What causes simple superficial corneal ulcers?

A

Irritants, trauma, FHV-1

29
Q

Focal corneal edema and an ulcer margin that is very crisp indicates what type of corneal ulcer?

A

Superficial

30
Q

Complicated epithelial ulcer that does not heal properly

A

Indolent ulcer (SCCED)

31
Q

Why will an indolent (SCCED) ulcer take months to heal without treatment?

A

Lacks epithelial adherence to stroma

32
Q

Relationship at the epithelial/stromal interface is abnormal b/c hemidesmosomes don’t properly reform @ ulcer site

A

Indolent ulcer (SCCED)

33
Q

Which dog breed is predisposed to indolent ulcers?

A

Boxers >5yo

34
Q

How will fluorescein stain appear for an indolent ulcer?

A

Halo under/around ulcer margin

35
Q

Are indolent ulcers superficial or deep?

A

Superficial

36
Q

What is the most common ophthalmic condition you will see in GP that may require referral?

A

Deep corneal ulcer

37
Q

What are most deep corneal ulcers and descemetoceles caused by?

A

Infection (Staph, Strep)

38
Q

What is the most common cause of keratomalacia (melting ulcer) in dogs and cats?

A

Pseudomonas

39
Q

How might CN 5 cause a corneal ulcer?

A

CN 5 plugs into cornea and uvea so if one is irritated the other will probably be angry too

40
Q

What is the hallmark sign of a deep corneal ulcer?

A

Inappropriate level of reflex uveitis (severe miosis)

41
Q

Jello around the cornea and WBC infiltrate indicate what type of ulcer?

A

Deep corneal ulcer

42
Q

What pain medication can you use to do an exam on a deep corneal ulcer?

A

Proparacaine

43
Q

How do you treat a deep corneal ulcer?

A

Cephalosporins + aminoglycosides q1-2h for 48h

Atropine for pain management

44
Q

What medication should you add to a melting ulcer treatment regimen?

A

Anticollegenase (1% EDTA)

45
Q

When is surgery recommended for a deep corneal ulcer, perforation, or descemetocele?

A

If >50% of stromal loss or if severe infection

46
Q

How do you surgically repair a deep corneal ulcer, descemetocele, or perforation?

A

Conjunctival pedicle flap/360* conjunctival flap

47
Q

What is an important px factor for a deep corneal ulcer?

A

Indirect PLR

48
Q

A positive Seidel test indicates what?

A

Active aqueous leakage

49
Q

What type of deep corneal ulcer is most commonly seen?

A

Descemetocele

50
Q

What is a descemetocele?

A

Deep stromal ulcer

51
Q

The iris may be prolapsed and the cornea may have a wrinkled appearance with what type of ulcer?

A

Perforation

52
Q

How long does it take for corneal vascularization to occur after the corneal has ulcerated?

A

2-3d

53
Q

How quickly do corneal vessels grow toward a corneal ulcer?

A

1mm/d toward the defect

54
Q

How will fluorescein stain uptake with a descemetocele?

A

Donut/ring