Nonulcerative Keratopathies

Question 1

What is the general term for lesions that affect or involve the cornea that are NOT primarily ulcerative in nature. In these the overlying epithelium in intact.

Answer 1

Nonulcerative keratopathies

Question 2

When assessing a corneal foreign body what are two characteristics that may determine if you refer the patient?

Answer 2

Depth and if the foreign body is penetrating into the cornea (if not superficial refer for sx removal and repair)

Question 3

What type of foreign body has a higher risk of leading to infection?

Answer 3

Organic material (think about fungus)

Question 4

Once you remove a corneal foreign body (flush it out), how would you treat?

Answer 4

Treat as ulcerative keratitis (topical abx, mydriatic, serum or EDTA, +/- systemic anti-inflammatories for pain)

Question 5

What type of trauma is keratouveitis typically secondary to?

Answer 5

BLUNT trauma

Question 6

What clinical sign is associated with damage to the endothelium?

Answer 6

Corneal edema!

Question 7

What are treatment recommendations for post-traumatic keratouveitis?

Answer 7

Systemic NSAIDs, Topical steroids or NSAIDs (since corneal epithelium should be intact), + atropine (mydriatic).

Treatment is often in excess of 5 to 10 weeks. All edema usually dissipates at 6 to 8 weeks.

Question 8

What would be the general diagnosis of an intact cornea with signs of inflammation (CORNEA ONLY)?

Answer 8

Nonulcerative keratitis (kera- cornea; itis- inflammation).

Can further classify these by location (ex: endothelial inflammation = endotheliitis)

Question 9

What are the two traumatic or exposure etiologies for superficial keratitis?

Answer 9

KCS (uncommon), Facial nerve paralysis

Question 10

What are the two common INFECTIOUS causes for superficial keratitis?

Answer 10

Viral or fungal

Question 11

What is the viral agent(s) that is commonly associated with viral superficial keratitis in horses?

Answer 11

EHV-2 or 5

Question 12

How would you treat a keratomycosis (fungal superficial keratitis)?

Answer 12

Treat as fungal ulcer for 4 to 6 weeks minimum (these are early fungal infections of the cornea that may be fluorescein negative)

Question 13

A 8 year old QH mare presents to your clinic with a seed pod lodged in her cornea. You assess the depth of the foreign body and determine that it is superficial enough to flush off. After removal, what is this mare at high risk of developing?

Answer 13

Fungal infection (this is organic material and predisposes to infection).

Question 14

What is the typical location for an eosinophilic keratitis lesion?

Answer 14

Peripheral cornea

Question 15

A 6 year old QH gelding presents with signs of ocular discomfort (specifically blepharospasm). On your ophthalmic exam you note mucoid discharge, chemosis, conjunctival hyperemia, and white necrotic plaques that seem to originate from the peripheral cornea, and the patient is fluorescein negative, what would be your BEST differential diagnosis?

Answer 15

Eosinophilic keratitis

Question 16

A 6 year old QH gelding presents with signs of ocular discomfort (specifically blepharospasm). On your ophthalmic exam you note mucoid discharge, chemosis, conjunctival hyperemia, and white necrotic plaques that seem to originate from the peripheral cornea, and the patient is fluorescein negative. You suspect that he has eosinophilic keratitis, what additional diagnostics would you want to perform in this case? and what would you expect to see if your suspicions are correct?

Answer 16

Cytology = inflammatory cells with eosinophils!

Question 17

What is the recommended treatment for eosinophilic keratitis?

Answer 17

Topical abx + topical corticosteroids or topical immunomodulators (this is immune-mediated, so you need to modulate the immune response)!

Examples of immunomodulators = cyclosporine and tacrolimus

Can also place patient on systemic NSAIDs and mast cell stabilizing drugs (less commonly used)

Question 18

A 3 year old TB gelding that frequently competes on the track presents to your clinic with branching superficial vessels, patchy edema, and cloudy, punctate corneal lesions. He is fluorescein negative, but rose bengal positive, what is the BEST differential diagnosis for this patient?

Answer 18

Herpetic keratitis

Question 19

A 3 year old TB gelding that does not travel and lives on a small pasture presents to your clinic with prominent branching superficial vessels and patchy edema. The apposing conjunctiva also appears moderately hyperemic. He is fluorescein and rose bengal negative. The owner notes that the changes have progressed gradually over the last few weeks, what is the BEST differential diagnosis for this patient?

Answer 19

Superficial immune-mediated keratitis

Question 20

How would you treat a superficial immune-mediated keratitis?

Answer 20

Treat with topical corticosteroid and/or cyclosporine (CsA). Taper steroids after resolution and continue with cyclosporine to prevent recurrence.

If medical therapy alone doesn’t keep the horse comfortable, consider a superficial keratectomy to prevent recurrence.

Question 21

What parasite can cause a stromal keratitis?

Answer 21

Onchocerca

Question 22

How would you treat a stromal immune-mediated keratitis?

Answer 22

Treat using CsA because corticosteroid response is poor and is less responsive that superficial IMMK.