Canine Ulcerative Keratitis – The Good, the Bad and the Ugly
Louise O’Leary, ISU Ophthalmology Resident 2019
Areas Covered
• Corneal Anatomy • Definitions • Causes • Diagnosis • Management •When to refer?
Corneal Anatomy
4 layers • Epithelium • Stroma • Descemet’s
membrane • Endothelium
https://www2.vetmed.ucdavis.edu/courses/vet_eyes/eye_path/epath_overview_index.html
Definitions
• Abrasion/erosion: partial thickness epithelial loss • Ulcer: full thickness corneal epithelial loss • SCCEDS/Indolent ulcer: refractory superficial corneal ulcer w/non-adherent epithelial margins • Descemetocoele: extends to Descemet’s membrane
Classification
Simple ulcer: heals in < 7
days without stromal
involvement
Complicated ulcer:
involves stroma and/or persists
longer than 7 days
CausesInadequate corneal protection • KCS* • Macropalpebral fissure • Lagophthalmos • Qualitative tear deficiencies • Facial nerve dysfunction • Trigeminal nerve dysfunction • Ectropion
Excessive epithelial loss • Trauma* • Foreign body • Primary pathogen –
herpesvirus* • Distichiasis, ectopic cilia,
trichiasis* • Entropion • Lid tumours • Blepharitis
Clinical Signs
• Blepharospasm • Pawing/Rubbing • Epiphora • Conjunctival hyperemia • Corneal opacity • +/- Visible corneal lesion/defect •Miosis
Diagnosis – Corneal Stains
• ** Obtain STT first ** • Fluorescein – true ulcers • Rose Bengal/Lissamine Green – abrasion/erosion, qualitative tear deficiency
Diagnosis – Staining Patterns
DendriticIndolent
Stromal Descemetocoele
https://veteriankey.com/cornea/
Vin.com
http://www.theveterinaryexpert.com/eyes/corneal-ulcers-in-dogs-and-cats/
Vettimes.co.uk
Evaluation of Ulcer
• Assess depth: slit beam direct ophthalmoscope
• Assess for infection: - white/yellow infiltrate
- stromal loss - degree of uveitis
Determining Cause
Thorough ophthalmic examination with magnification: • Assess tear film health: STT (+/- Rose Bengal, +/- TFBUT) • Assess for trichiasis • Assess lid closure: palpebral reflex, +/- corneal reflex • Assess palpebrae: ectopic cilia, distichiasis, lid tumours, conformation • +/- Check behind 3rd eyelid
Management – Simple Ulcer• Prophylactic broad spectrum
topical antibiotic – neopolybac, neopolygram, terramycin, etc – QID • Atropine
• Systemic anti-inflammatories/pain meds (nsaids, steroids) • **HARD PLASTIC E-COLLAR** at all
times RECHECK - within 3-5 days
Management - Stromal/Infected Ulcer• ** Cytology and Culture** • Broad-spectrum ab coverage: 2 different abs empirically • Serum/Plasma •Min 6-8x day, up to q1-2 hours depending on severity • Atropine • E-collar • Systemic anti-inflammatories/pain medications, +-/ systemic antibioticsNevile et al 2015 Vet Ophtho
Broad Spectrum Antibiotic Choice
• Gram positive: chloramphenicol, cefazolin, neopolybac, neopolygram, ofloxacin, ciprofloxacin, terramycin,
• Gram negative: tobramycin, gentamicin, ofloxacin, ciprofloxacin, neopolybac, neopolygram, terramycin
Sampling – Culture and Cytology
• 1 drop proparacaine prior to culture – culture margin • Reapply topical anaesthetic for cytology • Cytology – cytobrush, kimura spatula, back of scalpel blade
https://www.cliniciansbrief.com/article/corneal-conjunctival-cytology
Thehorse.com
Corneal Cytology Evaluation• Examine for presence of microorganisms – rods/cocci, fungal hyphae • Examine for presence of inflammatory cells
Eclinpath.com Nevile et al 2015 Vet Ophtho
Eclinpath.com
Management – Corneal Rupture• Considerations: Seidel test, dazzle/
consensual, finance, owner goals • **Culture and Cytology** • Aggressive medical therapy • Systemic antibiosis • Atropine, anti-inflammatory, e-collar
etc • Fragile eye care • +/- Sedatives
Vettimes.co.uk
Merckveterinarymanual.com
Seidel Test• Assess for leakage of aqueous humourhttps://webeye.ophth.uiowa.edu/eyeforum/atlas/pages/corneal-
perforation-seidel-posative-.html
Management - Keratomalacia• Aggressive, frequent medical therapy
q30mins -1 hr • Anti-proteases
- Serum/plasma - Systemic doxycycline 10mg/kg PO SID - EDTA, n-acetylcysteine
• Atropine, e-collar, anti-inflammatories etc • Surgery
• Cross-linking
Vettimes.co.uk
https://www.medvetforpets.com/new-treatment-corneal-ulcers/
http://ophtalmoveterinaire.com/en/2016/02/03/ulcere-corneen-infecte/
3 Reasons Ulcers Fail to Heal
1. Instigating factor still present: e.g. distichia, ectopic cilia,
entropion
2. Infection is present
3. Indolent ulcer
Indolent Ulcers/SCCEDS• Chronic ulcers with
loose edges • > Middle aged • Boxers, any breed • Characteristic staining • Appearance: +/-
neovascularization, corneal oedema, superficial, raised/folded edges, +/- uveitis, +/- pain
Histopathology – Indolent Ulcer
https://vetcares.com/scced/
Management – Indolent Ulcer Pt.1• **E-COLLAR** • Topical abs QID • Systemic pain medications • +/- Contact lens* • +/- Atropine • +/- Serum RECHECK: 10-14 days
Management - Indolent Ulcer Pt. II• Cotton-tipped
applicator debridement • Diamond burr • Grid keratotomy/
anterior stromal puncture • Corneal glue • Thermokeratoplasty • Superficial
keratectomy
Cotton-Tipped Applicator Debridement
• Success rate – approx. 30-50% • Removes loose epithelium • Easy • Low risk • Repeatable • Be aggressive!
https://www.ndsr.co.uk/en-GB/specialist-referral-service/pet-health-information/ophthalmology/recurrent-corneal-erosions
Diamond Burr Debridement • Prep well – sterile surface • Remove lose edges w/CTA
first • Gentle pressure over ulcer
bed approx. 60-90 seconds • Easy, repeatable, minimal
scarring • Risk of seating infection
deeper https://www.alloymedical.com/algerbrush-ii-diamond-instrument-for-smoothing-corneal-scleral-edges-brpt-rm-medium-round-unit-with-35mm-pterygium-diamond-burr-chi-678
Grid Keratotomy/Anterior Stromal Puncture•Local +/- sedation, +/- GA
•Prep well – sterile surface
•25 g needle •100-150 lines extending 1-2mm past periphery
•Greater risk
•Contraindicated in cats!
https://pdfs.semanticscholar.org/6634/0a4dcc8538f9da1b82fa8b016f701efdec5c.pdf
When to ReferRoutine appt: •Non-healing indolent ulcers – DBD, grid, superficial keratectomy • Recurrent corneal ulcers with endothelial dysfunction – Gundersen flap, corneal cross-linking, thermokeratoplasty
EMERGENT REFERRALS: • Deep corneal ulcers - > 50% corneal thickness lost – surgery recommended • Keratomalacia- surgery, corneal cross-linking
References• Ledbetter EC, Gilger BC. Diseases and surgery of the canine cornea and sclera. In: Gelatt KN, Gilger BC, Kern TJ, editors. Veterinary
Ophthalmology. Ames, IA: Wiley-Blackwell; 2013. pp. 976–1049.
• Ellison Bentley , DVM, DACVO Christopher J. Murphy , DVM, PhD, DACVO. (2004) Thermal cautery of the cornea for treatment of spontaneous chronic corneal epithelial defects in dogs and horses. Journal of the American Veterinary Medical Association 224:2, 250-253.
• Miller T, Gilger B, Maggio F, Davidson M. Use of thermokeratoplasty for treatment of ulcerative keratitis and bullous keratopathy secondary to corneal endothelial disease in dogs: 13 cases (1994–2001). Journal of the American Veterinary Medical Association. March 1, 2003, Vol. 222, No. 5, Pages 607-612
• Chandler H, Metzler A, Bras D et al. In vivo effects of adjunctive tetracycline treatment on refractory corneal ulcers in dogs. Journal of the American Veterinary Medical Association. August 15, 2010, Vol. 237, No. 4, Pages 378-386
• Dees, D. D., Fritz, K. J., Wagner, L. , Paglia, D. , Knollinger, A. M. and Madsen, R. (2017), Effect of bandage contact lens wear and postoperative medical therapies on corneal healing rate after diamond burr debridement in dogs. Vet Ophthalmol, 20: 382-389.
• Spiess, BM, Pot, SA, Florin, M et al. Corneal collagen cross-linking (CXL) for the treatment of melting keratitis in cats and dogs: a pilot study. Veterinary Ophthalmology 2013.
• 16 Pot, SA, Gallhofer, NS, Matheis, FL et al. Corneal collagen cross-linking as treatment for infectious and noninfectious corneal melting in cats and dogs: results of a prospective, nonrandomized, controlled trial. Veterinary Ophthalmology 2013
• Pot, S. A., Gallhöfer, N. S., Walser-Reinhardt, L. , Hafezi, F. and Spiess, B. M. (2015), Treatment of bullous keratopathy with corneal collagen cross-linking in two dogs. Vet Ophthalmol, 18: 168-173.
• Horikawa T, Thomasy SM, Stanley AA, et al. Superficial Keratectomy and Conjunctival Advancement Hood Flap (SKCAHF) for the Management of Bullous Keratopathy: Validation in Dogs With Spontaneous Disease. Cornea. 2016;35(10):1295-304.
QUESTIONS??