Lecture 24 5/1/25 Flashcards
(30 cards)
What is immune-mediated keratitis (IMMK)?
-idiopathic lymphoplasmacytic corneal inflammation with no uveitis
What are the clinical signs and history of IMMK?
-minimal to no pain
-often pruritic
-corneal cloudiness
-vessels
-minimal infiltrate or pigment
What are the classifications of IMMK?
-epithelial/superficial: superficial vessels +/- intermittent corneal ulcers
-mid to deep stromal: deeper vessels
-endothelial: usually no vessels, but focal area of corneal edema that keeps worsening and keratic precipitates
What is the etiology of IMMK?
-unknown
-theories include viral, environmental, and allergies
How is IMMK diagnosed?
-appropriate clinical signs
-diagnosis of exclusion; rule out primary ulcers, uveitis, and stromal abscess
What is the treatment for IMMK?
trial and error
-topical NSAIDs
-topical steroids (caution)
-cyclosporine/tacrolimus (superficial dz)
-systemic antihistamines
-systemic antivirals
-systemic NSAIDs
-episcleral cyclosporine implants
-allergy management
-surgery; lamellar keratectomy or stem cell therapy
What is infectious bovine keratoconjunctivitis/pink eye/IBK?
-inflammation of cornea and conjunctiva of cows due to bacterial infection
-keratitis and conjunctivitis
What are the clinical signs of IBK?
-corneal lesions that are centrally located
-white infiltrate with accompanying keratitis
-ulceration that may progress to keratomalacia and perforation
What is the etiology of IBK?
-main causative agent is Moraxella bovis
-often complex dz with multiple pathogens
-spread by face flies
-UV radiation aggravates condition
How is IBK diagnosed?
-clinical signs
-herd history
-cytology
-culture
-PCR
What is the treatment for IBK?
-topical antibiotics or gentacin pink eye spray
-topical and/or subconjunctival steroids
-antiseptic labelled for IBK (vetericyn)
-NM flap
-temporary tarsorrhaphy
-eye patch
-systemic analgesics and anti-inflammatories
-intramuscular tetracycline or subcutaneous tulathromycin
-vaccination possible but not efficacious
How is IBK prevented?
-insecticides/fly management
-maintain pastures
-quarantine new animals
What is the prognosis for IBK?
-most will heal even without therapy
-should recommend treatment of valuable animals that need good vision and painful animals
-tremendous losses from decreased weight gain; must manage at herd level
What are the characteristics of infectious keratoconjunctivitis in small ruminants?
-very similar to cattle dz
-infectious causes include Chlamydia, Mycoplasma, and Branhamella
What are the characteristics of equine recurrent uveitis?
-inflammation of iris, ciliary body, choroid, and/or retina that recurs periodically (2+ episodes)
-“classic” form mostly affects anterior
-panuveitis/posterior uveitis form affects posterior
-insidious form has chronic low-grade inflammation with no obvious flares or pain
-most common cause of blindness in horses
What are the breed predispositions for ERU?
-appaloosas
-warmbloods
What are the clinical signs of ERU?
-red, watery eye
-signs of anterior uveitis; flare, miosis
-butterfly lesions/bullet hole lesions/retinal detachment (posterior)
-secondary cataracts
-secondary glaucoma
-corpora nigra atrophy
-hyperpigmentation of iris
-phthisis bulbi (end stage)
What is the etiology of ERU?
-immune-mediated
-infectious agents involved via immune mechanism
-may have chronic active infection sequestered in eye
-most common organism candidate is Leptospira
What is the pathogenesis of ERU?
initial infection leads to inflammation and recruitment of lymphocytes to uveal tissue, resulting in molecular mimicry
How is ERU diagnosed?
-clinical signs and history
-lepto. testing of C values; compare ocular fluid titers to serum titers
What is the treatment for ERU?
-topical steroids, NSAIDs, and atropine
-systemic NSAIDs
-suprachoroidal delayed-release cyclosporine implant (long term)
-low dose gentamicin intravitreal injection
What is the prognosis for ERU?
-individual flare ups are not hard to control, but each one causes more and more permanent damage
-more than 70% of appaloosas go blind; 87% develop bilateral dz
-50% of all horses across all breeds go blind in one or both eyes
What is SCC?
tumor of ocular epithelia seen in horses and cows
What are the clinical signs of ocular SCC?
-pink, proliferative lesion
-may be ulcerative, esp. at eyelid margins
-seen on lids, 3rd eyelids, conjunctiva, and cornea
