Corneal Ulceration and Perforation Flashcards
What are some causes of corneal ulcers?
-Trauma
-Corneal abrasion due to adnexal disease
-Tear film deficiency
-Exposure Keratitis
-Infection
What is the order of ulcer to corneal perforation?
Acute superficial ulcer
Mid-stromal ulcer
Deep stromal ulcer
Descemetocele
Corneal Perforation
Acute can become chronic
Acute, mid-stromal and deep can heal (Need stroma left in the eye)
Under normal circumstances how long does it take corneal ulcers to heal?
7-10 days (can be faster)
What diagnostics should you run if you think you may have a corneal ulcer?
Always - search for underlying cause and a Schirmer teat test
Specific indications: Corneal culture and corneal cytology
Usually: Fluorescein stain
What are some risk factors for corneal ulcers?
-Is tear production normal?
-Can and does the animal blink normal?
-Brachycephalic breed (exophthalmos) and pathologic exophthalmos
-Adnexal abnormalities
-Infection?
What are some signs of corneal ulcer?
-Injected Sclera
-Yellow/hypopyon in cornea
-Corneal Edema
What are some causes of delayed corneal healing?
-Corneal infection
-Unresolved source of corneal abrasion
-Keratoconjunctivitis Sicca
-Exposure Keratitis
-Neurotrophic Keratitis
-SCCED (Boxer ulcer, indolent ulcer)
What are the 2 causes of corneal infection?
Primary - Herpesvirus
Secondary - bacterial and fungal, progressive destruction cornea, stroma, increased size and depth
What is entropion?
Inward rolling of the eyelids causing hairs to abrade the cornea
-Conformational and spastic
What is distichia?
Single or multiple abnormal hairs protrude from meibomian gland opening of eyelid
- Symptoms vary and age considerations
What is an ectopic cilia?
Abnormal hairs protruding through the conjunctival surface of eyelid
-Symptomatic
-Common in young dogs
-Toy breed commonly effected
What is keratoconjunctivitis Sicca?
-Common cause corneal ulcer and delayed healing in dogs
-Mucopurulent ocular discharge, conjunctival hyperemia, vascularizing keratitis
-ID with Schirmer Tear Test
What is exposure Keratitis?
-Conformational exophthalmos
-Inability to blink due to facial paralysis
-Exophthalmos due to orbital disease
-Buphthalmos due to glaucoma
-Touch eyelid and see if they can blink over the whole thing
What is Neurotrophic Ketatitis?
-Loss of corneal sensation = spontaneous non-healing ulceration
-Opthalmic branch trigeminal nerve
-Uncommon
What is SCCED?
-Spontaneous Chronic Corneal Epithelial Defect
-Chronic non-healing superficial corneal ulcer - no underlying cause determined
-Middle-aged dogs
-Boxer ulcer, indolent ulcer, refractory ulcer, recurrent erosion
Do you treat medially or surgically for each of the listed?
Acute Superficial
Mid-Stromal
Deep Stromal
Descemetocele
Corneal Perforation
Chronic Superficial
Acute Superficial - Medical
Mid-Stromal- Medical
Deep Stromal - Medical/Surgical
Descemetocele -Surgical
Corneal Perforation -Surgical
Chronic Superficial - Surgical
What are the goals of medical therapy for corneal ulcerations?
-Prevent/control infection
-Prevent/control collagenolysis
-Increased patient comfort
-Promote corneal healing
Use antibiotics on all ulcers - don’t stop until epithelized = no stain
What bacteria commonly causes melting ulcers?
Pseudomonas
What are a majority of the ulcers encountered in practice?
Superficial (Acute)
What are the diagnostics, treatment and follow up for acute superficial ulcers?
Diagnostics: rule out underlying conditions
Treatment:
-Borad spectrum antibiotics BID/TID
-Topical atropine SID/BID
-Analgesic PRN (NSAID)
Follow up
-Recheck every 2-3 days
-Fluorescein stain to monitor
What are the diagnostics, treatment and follow up for chronic superficial ulcers?
Chronic - haven’t healed in 7-10 days
Diagnostics - underlying reason for non-healing
Treatment - medical or surgical - ID underlying issue
What are the diagnostics, treatment and follow up for SCCED?
Chronic clinical course, lack ID cause, clinical appearance
What are clinical characteristics of SCCED?
-Chronic superficial corneal ulcer
-Epithelial Lip (fluorescein stain)
-Variable corneal pain and vascularization
-Change in size, wont heal completely with medical alone
-Rarely become infected
What is the pathogenesis of SCCED?
-Not fully understood
-Hyalinized acellular anterior corneal stroma prevent corneal epithelial adhesion
-Epithelial non-adherence usually extend well beyond obvious region of ulcer
What is the treatment for SCCED?
-Epithelial debridement (Numb and push on it with a cotton swab)
-Surgical - anterior stromal puncture (Grid keratotomy, Burr Keratotomy)
-Superficial keratectomy
-3rd eyelid flap or contact lens
-topical antibiotics until healed (solution vs ointment)
-E-collar may be required
Debridement mandatory - topical anesthetic alone, dry cotton swab, debride vigorously
-Ulcer may appear enlarged
-Debridement alone will not ensure healing
-Anterior Stromal Puncture - grid or burr keratotomy (penetrate hyalinized anterior corneal stroma, 1 collagen)
How do you perform a grid keratotomy?
-Use a 25 gauge needle
-Lightly scratch across ulcer bed
-Begin and end in normal epithelium
-Place scratches 1 mm apart
How do you perform a Burr Keratotomy?
Dremel like tool, post op infection higher
How do you manage a keratotomy postop?
-Apply topical antibiotic 3-4 times daily until healed
-90% heal in 10-14 days
-3rd eyelid flap or contact Lense
-E-collar
-Repeat procedure may be needed
What are your follow up recommendations for SCCED?
-Recheck 1x week
-Not healed 2-3 weeks surgical treatment repeated
-Don’t debride for at least 2-3 weeks following surgery (6 week for complete development of epithelial adhesion complexes)
What causes SCCED in cats?
Feline Herpesvirus
-Debridement may help or cause corneal sequestrum formation
What are the diagnostics and treatment for Mid-stromal Ulceration?
Diagnostics: Investigate underlying factors, corneal culture and sensitivity, corneal cytology
Treatment:
-Topical antibiotic, broad spectrum every 4-6 hours, solutions preferred
-Protease inhibitors (tetracycline and autogenous serum e 4-6 hours, topical atropine, analgesia)
Follow up: recheck every 24 hours then 48hrs
What are the diagnostics, treatment and follow up for deep stromal ulcers or melting ulcers?
Diagnostics: investigate risk factors, corneal culture and sensitivity, corneal cytology
Treatment:
-topical antibiotics, broad spectrum antibiotics 2-4 hours
-Protease inhibitor - tetracycline, autogenous serum 2-4 hr
Follow-up:
Hospitalize and recheck ever 24 hours
What are the diagnostics, treatment and follow up for a Descemetocele?
Surgical Case
-Medical management- deep ulcer
-Diagnostics: corneal cytology or culture, ulcer edged, Schirmer tear test
-Surgical treatment: Conjuctival flap, corneoconjuctival transposition
topical antibiotics, proteolytic inhibitors and e-collar
Follow up - recheck 1-3 weeks post op, discontinue antibiotic 3 week post op, trim flap pedicel 4-6 week post op
What are the diagnostics, treatment and follow up for corneal perforation?
Surgical condition
Diagnosis - history, culture and radiograph
Post-operative
-Topical broad spectrum antibiotic 4-6 hr
-Topical atropine 6-8hr
-Systemic broad spectrum antibiotics
-Systemic anti-inflammatory
-E-collar
