41
edits
Changes
Jump to navigation
Jump to search
Corneal Ulceration - Dogs and Cats (view source)
Revision as of 16:02, 14 February 2014
, 16:02, 14 February 2014Created page with "A '''corneal ulcer''' is a loss of epithelium on the surface of the cornea. It is also known as an '''ulcerative keratitis''' as there is always a degree of inflammation accom..."
A '''corneal ulcer''' is a loss of epithelium on the surface of the cornea. It is also known as an '''ulcerative keratitis''' as there is always a degree of inflammation accompanying the loss of epithelium.
==Signalment==
More common in dogs than cats, as cats are less likely to suffer trauma to their corneas. Animals with large, open palpebral fissures (eg '''Brachycephalics''') are at higher risk of corneal trauma.
==Clinical Signs==
Clinical signs can include signs of ocular pain, such as blepharospasm and miosis. There is often ocular discharge and an aversion to light.
==Diagnosis==
The ulcer may be visible on examination of the eye. Applying '''fluorescein''' dye to the eye will stain exposed layers of epithelium. If the center of a deep ulcer does not stain, this indicates the '''Descemet's Membrane''' is exposed.
Corneal ulcers often have '''underlying causes''', which if not treated will cause the ulcer to recur. It is important to assess the eyelids fully for any '''entropian''', '''ectropian''', '''ectopic cilia''' or '''foreign bodies''' which may be present. Palpebral reflex and lid closure should also be checked. Consideration should also be given to testing '''tear production''' and '''bacterial''' and '''viral''' culture if appropiate.
==Treatment==
Ulcers can be classified into '''simple''' or '''complex''' ulcers which can help determine which treatment is needed. Simple ulcers are '''shallow''' so heal without ''stromal'' involvement and heal within '''seven days'''. Complex ulcers are '''deeper''' so heal with stromal involvement, '''and/or''' take more than seven days to heal.
Complex ulcers can be further classified into one of three categories to assist in resolving the ulcer:
* '''Underlying cause not identified/resolved'''
* '''Infected'''
* '''Indolent''', seen only in dogs
===Medical Treatment===
Regardless of cause, all ulcers should be treated with a range of medications.
====Antibiotics====
Broad spectrum topical [[antibiotics]] should be applied. Even if the ulcer does not appear infected, disruption of the corneal epithelium predisposes to infection.
'''Systemic''' antibiotics are unlikely to reach the cornea unless it is well vascularised or after '''conjunctival graft''' surgery.
====Mydriatics====
Exposure and stimulation of corneal nerves can result in a ''reflex'' anterior '''uveitis'''. Topical '''atropine''' is used to control this, with the dose tapered once adequate pupil dilation is achieved. Atropine should not be used in cases of '''keratoconjunctivitis sicca''' as it can disrupt tear production.
====Analgesia====
Systemic [[NSAIDs|Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)]] should be administered whilst the eye is painful. Topical [[steroids]] or NSAIDs should '''not''' be applied as they may disrupt healing of the ulcer.
====Preventing Self-Trauma====
It is important animals do not rub at their eyes, making the corneal ulceration worse. Devices to prevent self–trauma, such as elizabethen collars can be used if necessary.
===Deep Ulcers===
Deep ulcers require additional therapy to resolve.
====Melting Ulcers====
'''Collagenases''' are enzymes produced by some '''bacteria''', as well as degranulating [[neutrophils]] and disrupted epithelial cells and stromal cells. The enzymes can liquefy the corneal stroma, resulting in a rapidly progressive, "melting" ulcer. Bacteria commonly involved include ''Psuedomonas Aeruginosa'', ''coagulase–positive Staphylococci'', ''beta–haemolytic Streptococci'' and other gram–negative bacteria.
Samples for culture should be taken, and frequent topical antibiotic therapy should be applied.
'''Anti—collagenase''' therapy may be applied. This is done by harvesting '''serum''' from the patient then applying topically to the eye.
These animals can require intensive therapy so consideration should be given to '''hospitalisation'''.
====Surgical Treatment====
Corneal ulcers deeper than half the depth of the cornea take longer to heal due to the cornea's limited ability to regenerate, so can benefit from surgical techniques to aid healing. Techniques recommended include '''conjunctival grafts''', '''temporary tarsorrhaphies''' and '''third eyelid flaps'''
==References==
Maggs, D et al (2007) '''Slatter's Fundamentals Of Veterinary Ophthalmology''' (Fourth Edition) ''Saunders''
Peiffer, Robert J, and Petersen-Jones, Simon M (2008) '''Small Animal Ophthalmology''' (Fourth Edition) ''Saunders''
[[Category:Corneal Diseases - Cat]]
[[Category:Corneal Diseases - Dog]]
==Signalment==
More common in dogs than cats, as cats are less likely to suffer trauma to their corneas. Animals with large, open palpebral fissures (eg '''Brachycephalics''') are at higher risk of corneal trauma.
==Clinical Signs==
Clinical signs can include signs of ocular pain, such as blepharospasm and miosis. There is often ocular discharge and an aversion to light.
==Diagnosis==
The ulcer may be visible on examination of the eye. Applying '''fluorescein''' dye to the eye will stain exposed layers of epithelium. If the center of a deep ulcer does not stain, this indicates the '''Descemet's Membrane''' is exposed.
Corneal ulcers often have '''underlying causes''', which if not treated will cause the ulcer to recur. It is important to assess the eyelids fully for any '''entropian''', '''ectropian''', '''ectopic cilia''' or '''foreign bodies''' which may be present. Palpebral reflex and lid closure should also be checked. Consideration should also be given to testing '''tear production''' and '''bacterial''' and '''viral''' culture if appropiate.
==Treatment==
Ulcers can be classified into '''simple''' or '''complex''' ulcers which can help determine which treatment is needed. Simple ulcers are '''shallow''' so heal without ''stromal'' involvement and heal within '''seven days'''. Complex ulcers are '''deeper''' so heal with stromal involvement, '''and/or''' take more than seven days to heal.
Complex ulcers can be further classified into one of three categories to assist in resolving the ulcer:
* '''Underlying cause not identified/resolved'''
* '''Infected'''
* '''Indolent''', seen only in dogs
===Medical Treatment===
Regardless of cause, all ulcers should be treated with a range of medications.
====Antibiotics====
Broad spectrum topical [[antibiotics]] should be applied. Even if the ulcer does not appear infected, disruption of the corneal epithelium predisposes to infection.
'''Systemic''' antibiotics are unlikely to reach the cornea unless it is well vascularised or after '''conjunctival graft''' surgery.
====Mydriatics====
Exposure and stimulation of corneal nerves can result in a ''reflex'' anterior '''uveitis'''. Topical '''atropine''' is used to control this, with the dose tapered once adequate pupil dilation is achieved. Atropine should not be used in cases of '''keratoconjunctivitis sicca''' as it can disrupt tear production.
====Analgesia====
Systemic [[NSAIDs|Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)]] should be administered whilst the eye is painful. Topical [[steroids]] or NSAIDs should '''not''' be applied as they may disrupt healing of the ulcer.
====Preventing Self-Trauma====
It is important animals do not rub at their eyes, making the corneal ulceration worse. Devices to prevent self–trauma, such as elizabethen collars can be used if necessary.
===Deep Ulcers===
Deep ulcers require additional therapy to resolve.
====Melting Ulcers====
'''Collagenases''' are enzymes produced by some '''bacteria''', as well as degranulating [[neutrophils]] and disrupted epithelial cells and stromal cells. The enzymes can liquefy the corneal stroma, resulting in a rapidly progressive, "melting" ulcer. Bacteria commonly involved include ''Psuedomonas Aeruginosa'', ''coagulase–positive Staphylococci'', ''beta–haemolytic Streptococci'' and other gram–negative bacteria.
Samples for culture should be taken, and frequent topical antibiotic therapy should be applied.
'''Anti—collagenase''' therapy may be applied. This is done by harvesting '''serum''' from the patient then applying topically to the eye.
These animals can require intensive therapy so consideration should be given to '''hospitalisation'''.
====Surgical Treatment====
Corneal ulcers deeper than half the depth of the cornea take longer to heal due to the cornea's limited ability to regenerate, so can benefit from surgical techniques to aid healing. Techniques recommended include '''conjunctival grafts''', '''temporary tarsorrhaphies''' and '''third eyelid flaps'''
==References==
Maggs, D et al (2007) '''Slatter's Fundamentals Of Veterinary Ophthalmology''' (Fourth Edition) ''Saunders''
Peiffer, Robert J, and Petersen-Jones, Simon M (2008) '''Small Animal Ophthalmology''' (Fourth Edition) ''Saunders''
[[Category:Corneal Diseases - Cat]]
[[Category:Corneal Diseases - Dog]]