zita makra dvm sziu vet faculty equine department and clinic...

Zita Makra DVMSZIU Vet Faculty

Equine Department and Clinicmakra.zita@aotk.szie.hu

Corneal ulceration

Nonulcerative keratitisCorneal stromal abscessEquine recurrent uveitisEyelid lacerations

Corneal ulcerationVery commonSight-threatening, corneal perforation!Etiology

opportunistic bacteria fungiStreptoc. Aspergillus,Staphyloc. spp. Fusarium spp.Pseudomonas aerug.

PathogenesisPathogenesis

1. Corneal epithel damage2. Bact./fungi → corneal epithel, corneal stromal fibroblast, tear

PMN→ inflammatory cytokines3. Corneal epithel cells, PTF neutrophil leukocytes→ proteinases,

elastase, collagenase4. Stromal destruction → melting ulcer

ClinicalClinical signssigns

♦pain (photophobia, blepharospasm, epiphora)♦anterior uveitis (miosis, cyclospasm, hypopion)♦corneal oedema

DiagnosisDiagnosis::-slit lamp biomicroscope-microbiological sampling → AB test-cytologic sampling→fungal hypha- Pas/Grocott stain-fluorescein dye

Descemetocele: fungi>bact., special fluorescein dyedanger of perforation → prompt surgical intervention

TherapyTherapy::

SPL:- AB (chloramphenicol, tobramycin, gentamycin, ciprofloxacin)

q2-6 h- antimycotic (natamycin, fluconazol, voriconazol): q4-6 h- antiproteinase: autolog serum + 0,1% EDTA/10%

acetylcistein q1-2 h- atropin 2% q4-6 h, decreasing dose- flunixin or phenylbutazone iv/po 5-7 days- (syst. Antibiotic)

Contraindicated: corticosteroids and local anesthetics

SurgicalSurgical interventionintervention::- superfitial, indolent: punctated/grid keratotomy- deep: debridement keratectomy / pedicle conj.flap +

amniotic membrane graft

Nonulcerative keratitis

1. Nonulcerative keratouveitis- sport horses- paralimbal stromal infiltration- uveitis- immune-mediated- corticosteroid and atropin subconjunctivally

- parenteral NSAID 2. Nonulcerative interstitial keratitis

- pigmentation3. Eosinophilic keratoconjunctivitis

- proliferation

Corneal stromal abscessEtiology:Epithelial cells cover (healed ulcer) encapsulated infectiousagents/foreign body in the stroma (Fluorsc.-)

Prominent yellowish opacity in the cornea + vascularisation + uveitis.

Therapy: see deep ulcer

Surgery:lamellar keratoplastypenetrating keratoplasty cornea transplantation

Equine recurrent uveitis (ERU)

Classic:- active phase+calm periods

Subclinical uveitis:- no observed bout of imflamm.(insidious) - chronic ERU (cataract, phthisis)

- Appaloosa, draft

Primarly posterior uveitis (Europian horses)

Equine recurrent uveitis (ERU)

Causes:1. Ocular insult- Trauma- Infectious (Leptospira, Strepto.)- Corneal disease

1.Episode acute uveitis Immune response-multiple recurrentepisodes-ERU

Uveitis results in the influx of inflamm. cells into the eye (Tly) persistent ly → hypersensitivity of uvea.

80 % unilateral, at 4-8 years of age 1. Uveitis

Complex pathophysiology:-non-specific multifocal origin

-individual genetic predisposition (MHC I. ELA-A9)

-immun-mediated recurrent/persistent panuveitis

-blood-aquous humor, blood-retina barriers break down

PathophysiologyPathophysiology::

Ag →blood-eye barrier ↓ → 1. Neutrophyls, 2. Ly-s in iris stroma, +serumproteines, fibrocytes, clotting factors in the aqueoushumor, vitreous, retina⇒serous-fibrinous inflammation + cellularinfiltration ∼ (Ly follicles)Type IV. late hypersensitivity reaction: TH1

Infectious agents/Ag get into the eye → 1. uveitisAg is permanently present in the eye →recurrent attacks

Ag-antibody complexImmunologically sensitized TH can become reactive due to

similar Ag/ autoantigen stimulus (S-Ag)

AcuteAcute clinicalclinical signssigns((activeactive phasephase):):

- photophobia, miosis- corneal edema- aq. flare, hypopyon- hypotony- chorioretinitis

ChronicChronic phasephase ((remnantsremnants--prepre--purchpurch. . examexam!):!):

- corneal edema- synechia posterior (iris bombae, pupillar occlusion)- pigment on the lens capsule, cataract, lens sublux. / lux.

(glaucoma)- peripapillary depigmentation

TreatmentTreatment::

- local corticosteroids (dexam. 3 mg / predn. 40 mg, triamcinolon 2mg subconj.)

- atropine (1 mg subconj., later 2% eyedrop/ointment)- corneal injury →cyclosporin / diclofenac- systemic NSAID

For 14 days, then must taper off dose +10 days

Important rule!Every painful, red (injected) eye needs to be stained withfluorescein to diagnose or ruleout corneal ulcers!

TreatmentTreatment::

Surgical: pars plana vitrectomy in the calm period:- to eliminate the recurrent inflammation- to save the eye bulb- to improve the vision

Surgical TreatmentTreatment::

bioerodible, sustained release of CsA-immunosuppressant, deep scleral lamellar cyclosporineimplant, against cell-mediated immunity

Eyelid lacerations:

Emergency Correct anatomical reposition!

References

D.E. Brooks: Ophthalmology for Equine Practitioners2nd ed., Tenton Newmedia, Jackson, WY

K.N. Gelatt: Essentials of Veterinary Ophthalmology1st ed., Lippincott W&W, Philadelphia, 2000.

B. Gilger: Equine Ophthalmology2nd ed., Elsevier Saunders, Missouri, 2011.

K.N. Gelatt: Veterinary Ophthalmology3rd ed., Lippincott W&W, Philadelphia, 1999.

Equine Ophthalmology Supplement 2.EVJ, Nov., 1983.

Equine Ophthalmology Supplement 10.EVJ, Sept., 1990.

J.D. Lavach: Large Animal Ophthalmology, CV Mosby, St Louis, 1990.