ISSN 2398-2969      

Chronic superficial keratitis

icanis

Synonym(s): Pannus, Überreiter's syndrome


Introduction

  • Cause: immune-mediated corneal and conjunctival condition affecting primarily the middle-aged German Shepherd dog German Shepherd Dog, but several other breeds can be affected. Ultra-violet light is a predisposing factor.
  • Signs: bilateral lesions first seen at ventro-lateral limbus.
  • Progressive, potentially blinding, but no discomfort or irritation.
  • Same as keratitis Keratitis.
  • Diagnosis: history, clinical signs, ophthalmic examination.
  • Treatment: chemotherapy. Topical steroid, cyclosporine or a combination.
  • Prognosis: will recur without regular treatment.

Pathogenesis

Etiology

  • Immune-mediated.
  • Breed predisposition for German Shepherds shows heritable nature but more likely as a polygenic inheritance than a single gene defect.

Specific

  • Ultraviolet/solar radiation involved in pathogenesis.
  • Altitude-more difficult to control at high altitudes. Latitude and longitude are less important, only being relevant with regard to sunlight exposure.

Pathophysiology

  • Inflammation of the cornea that does not retain fluorescein (non-ulcerative). Alteration of corneal clarity may be due to neovascularization, edema, cellular infiltration, pigmentation, lipid or calcium deposition and scarring (fibrosis).
  • Immune-mediated (cell-mediated immunity to corneal/conjunctival antigens) - ultraviolet radiation may alter immunogenicity of antigens), vascular lesion appears at temporal limbus and invades cornea - pigmentation follows vascularization. May also affect nictitating membrane. Epithelium remains intact.
  •  Pigmentary keratitis Pigmentary keratitis - usually associated with chronic keratitis, pigment produced in epithelium, anterior stroma and migrates from perilimbal melanocytes, secondary to corneal vascularization. Impairs vision when becomes central. Note differential diagnoses.
  • Stages:
    • Lymphocyte and plasma cell infiltration.
    • Vascularization.
    • Pigmentation.
    • Fibrovascular plaque formation.
  • A composite of these stages is seen: varying pigmentation, vascularization and fibrovascular plaque formation depending on severity and chronicity. May be concurrent, chronic conjunctivitis and plasma cell thickening of the membrana nictitans.

Timecourse

  • Life-long disease.

Diagnosis

This article is available in full to registered subscribers

Sign up now to obtain ten tokens to view any ten Vetlexicon articles, images, sounds or videos, or Login

Treatment

This article is available in full to registered subscribers

Sign up now to obtain ten tokens to view any ten Vetlexicon articles, images, sounds or videos, or Login

Outcomes

This article is available in full to registered subscribers

Sign up now to obtain ten tokens to view any ten Vetlexicon articles, images, sounds or videos, or Login

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Azoulay T (2014) Adjunctive cryotherapy for pigmentary keratitis in dogs: a study of 16 corneas. Vet Ophthalmol 17, 241-249 PubMed.
  • Williams D L, Hoey A J & Smithermann P (1995) Comparison of topical cyclosporin and dexamethasone for the treatment of chronic superficial keratitis in dogs. Vet Rec 137 (25), 635-639 PubMed.
  • Chavkin M J, Roberts S M et al (1994) Risk factors for development of chronic superficial keratitis in dogs. JAVMA 204 (10), 1630-1634 PubMed.
  • Petrick S W & van Rensburg I B K (1989) Corneal anatomical differences in the etiology of chronic superficial keratitis. JSAP 30 (8), 449-453 PubMed.

Other sources of information

  • Gelatt K N (ed) (1999) Veterinary Ophthalmology. 3rd Edn. Lippincott: Williams & Wilkins. ISBN 0683300768.

Can’t find what you’re looking for?

We have an ever growing content library on Vetlexicon so if you ever find we haven't covered something that you need please fill in the form below and let us know!

 
 
 
 

To show you are not a Bot please can you enter the number showing adjacent to this field

 Security code