Conjunctiva Flashcards
What cells make up the conjunctiva?
Epithelium
Goblet cells
Lymphoid tissue
Vasculature
How can you get a sample of conjunctiva for cytology?
Cotton swab, kimura spatula, back of scalpel blade
What do you see in the typical cytology of a dog with conjunctivitis ?
Epithelial cells and neutrophils
The mucous part of the tear film is produced by??
Globlet cells of the conjunctiva
Mucous provides a good media for bacterial growth and recruitment of white blood cells creating a ___________ discharge?
Mucopurulent
Mucopurulent discharge is most commonly found with what ocular disease?
Keratoconjunctivitis sicca
Where are conjunctival lymphoid follicles usually found?
Bulbar surface of the third eyelid
Enlarged lymphoid follicles on the injunctive indicates?
Non-specific antigenic stimulation
Likely a primary conjunctivitis
What are the two types of vessels in the conjunctiva ?
Conjunctival vessels — superficial small vessels
Episceral vessels — larger deeper vessels
Conjunctival hyperemia is secondary to?
Superficial irritation (eg conjunctivitis, superficial corneal ulcer, keratoconjunctivitis)
Episceral injection is usually secondary to?
Deeper inflammation or congestion
— large identifiable vessels that course perpendicular to the limbus
What are disorders of the canine conjunctiva?
KCS
Allergic conjunctivitis
Infectious conjunctivitis (adenovirus, herpesvirus, distemper)
Clinical signs of allergic conjunctivitis?
Blepharospasm Epiphora Mucoid discharge Hyperemia Lymphoid follicles
Signalment associated with allergic conjunctivitis ?
Young atopic dogs
What are causes of viral conjunctivitis?
Adenovirus
Herpesvirus
Distemper
How can you make a diagnosis of primary conjunctivitis?
Compatible signalment (young dog with allergies)
Clinical signs (conjunctival pathology without keratitis or episceral/intraocular pathology)
Minimum data base in normal limits
How do you treat a primary conjunctivitis?
Often self limiting
Irrigation with eyewash
Symptomatic used of topical anti-inflammatories
Treat underlying cause of atopy
- avoid offending allergen/hyposensitization
- symptomatic use of topical anti-inflammatories
What topical anti-inflammatories are the mainstay for primary conjunctivitis?
Neomycin - polymixin- dexamethasone - steroid
Diclofenac -NSAID
Optimmune (cyclosporine) - Tcell inhibitor
What are the most common causes of feline conjunctivitis?
Feline herpesvirus keratoconjunctivitis
Chlamydia conjunctivitis
Mycoplasma conjunctivitis
Calicivirus
What are the 3 forms of FHV1 ?
Primary (young cats) - acute lysis
Latency
Recrudescence - lysis and disease
What is the pathophysiology of herpesvirus?
Mucosal eatery followed by viral replication and systemic viremia
Incorporation into host DNA
Epithelial tropism — epithelial cytolysis
—> blepharospasm, epiphora, and mucoid discharge (concurrent URI)
Latency —> FHV invades sensory nerve endings of trigeminal nerve and travels to ganglion
Recuredescent —> reactivation of virus, usually be stress , Replication in sensory axon and migration back to epithelial tissues
Clinical signs associated with FHV?
Blepharospasm, epiphora, mucoid discharge
Hyperemia
Conjunctival and possible corneal ulceration
Symblepharon (adhesion between conjuntiva and cornea)
What stain can you use to determine conjunctival ulceration
Rose bengal stain
What stain can you use to determine corneal ulceration?
Fluorescein stain
What pattern of corneal ulceration if pathognomic for FHV infection?
Dendritic
What occurs if two ulcerated surfaces (conjunctival and corneal) heal together?
Symblepharon
What are possible tests to diagnose FHV?
Cytology — intranuclear inclusion bodies
Fluorescent antibody testing
PCR
Virus isolation
Treatment of FHV?
Antiviral therapy
- topical cidofovir
- oral famciclovir
- lysine ( substitutes for arginine and inhibits viral replication)
Supportive care
-erythromycin (topical)
What is a common autoimmune sequela from FHV1 infection?
Feline eosinophilic keratoconjunctivitis
Clinical signs of feline eosinophilic keratoconjunctivitis ?
Blepharospasm, epiphora, mucoid, or mucopurulent discharge, +/- corneal ulceration
Raised white or yellow corneal or conjunctival infiltrates
T/F: finding a single eosinophil on cytology of the conjunctiva is diagnostic for feline eosinophilic keratoconjunctivitis
True
Treatment for feline eosinophilic keratoconjunctivitis ?
Immunomodulation - topical cyclosporine
Anti-inflammatory —NSAIDS or steroids
Antiviral — cidofovir or famcyclovir
What is a specific clinical sign for chlamydial conjunctivitis ?
Chemosis (conjunctival edema)
T/F: chlamydial conjunctivitis causes corneal or conjunctival ulceration
False
How can you confirm diagnosis of chlamydial conjunctivitis ?
Cytology — intracytoplasmic inclusion bodies
PCR, history, compatible clinical signs
Treatment of chlamydial or mycoplasma conjunctivitis?
Topical
- oxytetracycline (tetracyclines)
- erythromycin (macrolides)
Oral
-doxycyline
You do a cytology in a cat with blepharospasm, epiphora and mucoid discharge.
It shows numberous coccidia membrane associated bacterial illusions. What is this?
Mycoplasma associated conjunctivitis
How is calicivirus differentated from herpesvirus?
Oral ulceration are pathognomic for calicivirus
Treatment for calicivirus?
Erythromycin - topical
