Conjunctiva Flashcards
the area where the palpebral conjunctiva meets the bulbar conjunctiva
conjunctival fornix
conjunctiva that lines the inner surface of the eyelid and the anterior aspect of the globe respectively
palpebral and bulbar conjunctiva
term used to describe congestion of the superficial vessels of the conjunctiva
suggest superficial disease(KCS, primary conjunctivitis, eyelid disorders causing secondary conjunctivitis, a response to superficial cornea ulceration
conjunctival hyperemia
congection of the deep conjunctival vessels, known as episcleral vessels
suggest deeper disease processes
(uveitis, glaucoma, deep/complicated corneal ulceration)
episcleral injection
Conjunctival hyperemia suggests
suggest superficial disease (KCS, primary conjunctivitis, eyelid disorders causing secondary conjunctivitis, a response to superficial cornea ulceration)
Episcleral injection suggests
deeper disease processes
(uveitis, glaucoma, deep/complicated corneal ulceration)
permanent adhesion between the conjunctiva and the cornea
Symblepharon
What is symblepharon
permanent adhesion between the conjunctiva and the cornea
What is edema of the conjuctiva called
Chemosis
What is the purpose of the conjuctiva
1) Provide smooth, lubricated surface for eyelids to contact cornea
2) Disperse tear film
3) Remove debris from ocular surface
4) Produce mucin component of tear film- goblet cells
5) Protective/ immunologic function- lymphoid follicles, IgA production
What are the protective/immunological function of the conjunctiva
1) lymphoid follicles
2) IgA production
What should you look for in the conjunctiva
petechiae, icterus, hemorrhage, palor
what lines the inner surface of the eyelids
palpebral conjunctiva
what lines the globe, starting at the limbus
bulbar conjunctiva
what completely covers the nicitans
third eye lid conjunctiva
1) palpebral surface
2) bulbar surface
how do you examine the palpebral surface of the third eyelid
retropulse the eye to examine the third eyelid
how do you examine the bulbar surface of the third eyelid
need proparacaine and lift up the third eyelid to examine the back side (bulbar surface)
How many episcleral vessels are normal
1-2 prominent episcleral vessels are normal
T/F: conjunctival pigment may be normal
True - happens with aging (conjunctival pigment on medial and lateral limbus)
produce mucinous portion of tear film
increased mucus production during inflammation
goblet cells
mucopurulent discharge of the eye is most common for
canine KCS- mucus provides growth media for bacteria and WBCs which result in mucopurulent discharge often seen with KCS, infected corneal ulcers
lymphoid follicles are normal on the
bulbar surface of third eyelid
also younger animals
small superficial vessels under the epithelium of conjunctiva
conjunctival vessels
When might you see conjunctival hyperemia
1) Conjunctivitis
2) KCS
How do you distinguish superficial conjunctiva vessels
they move when you move the conjunctiva
What is the most common eyelid mass in a dog *
meibomian gland adenoma
When might you see episcleral injection
1) Deep corneal ulcers
2) Uveitis
3) Glaucoma
in episcleral injection, the large vessels run __________
perpendicular to the limbus
How do you tell the difference between episcleral and conjunctival hyperemia
Drop phenylephrine in the eye (vasoconstriction of conjunctival vessels)
Only episcleral vessels remain following application *
What goes away when phenylephrine drops are applied to the eye
conjunctival hyperemia
side effect: may increase intraocular pressure- dilates the pupil
causes vasoconstriction of the conjunctival vessels
phenylephrine
What is a side effect of giving phenylephrine to a patient’s eye
may increase intraocular pressure- dilates the pupil
beware in glaucoma cases
congenital disease of the conjunctiva where there is a mass of normal tissue in an abnormal place (choristoma)
Dermoid
Congenital, A type of choristoma made up of keratinized epithelium and adnexal structures like hair follicles, sweat glands, and sebaceous glands.
dermoid
What breeds commonly get dermoids
French Bulldogs, Pugs, mastiffs, great danes
How do you treat conjunctival dermoids
surgical excision or cryrotherapy and freeze bed to destroy hair follicles
if surgery need to be delayed (young dog)
-trim hairs (although sometimes shorter are sharper)
-lubrication (eyedrops)
acquired conjunctivitis
common in all species
very non-specific response
variable clinical signs
treatment varies with cause
cause of conjunctivitis varies by species
What are the clinical signs of conjunctivitis
1) Conjunctival hyperemia
2) Chemosis (swollen conjuctiva)
3) Lymphoid follicles
4) Ocular discharge (ranging from epiphora to mucopurulent discharge)
swollen conjunctiva
chemosis
T/F: you should never see any lymphoid follicles in the horse
false- sometimes its okay to see a few lymphoid follicles
What are the causes of conjunctivitis across all species
1) Bacterial:
Mycoplasma (commonly goats and cats)
Chlamydia (cats and sheep)
Relatively uncommon in other species
2) Viral:
FHV-1 + Calicivirus (cats)
Canine Distemper Virus (CDV)
3) Parasitic: Thelazia, Onchocera, Habronema, Hepatozoon, Leishmania
4) Allergic- common in young dogs
5) Neoplasia- lymphoma most common (conjunctiva is not the primary tumor)
6) Environmental / physical irritants
7) Immune mediated (eosinophilic conjunctivitis in cats and horses)
8) Other ocular disease: KCS
What are common bacterial causes of conjunctivitis
1) Mycoplasma (commonly goats and cats)
2) Chlamydia (cats and sheep)
Relatively uncommon in other species
What are common viral causes of conjunctivitis
1) FHV-1 (cats)
2) Calicivirus (cats)
3) Canine Distemper Virus (CDV)
What are common parasitic causes of conjunctivitis
Thelazia, Onchocera, Habronema, Hepatozoon, Leishmania
Allergic conjunctivitis is common in
young dogs - need to treat skin too
cytology, exam
lymphoid follicles, lymphocytes and plasma cells
What is most common neoplasia causing conjunctivitis
lymphoma most common
(conjunctiva is not the primary tumor)
immune mediated eosinophilic conjunctivitis is typically seen in
cats and horses
What is the most common cause of canine conjunctivitis
Keratoconjuncitivits sicca (KCS)
What are the major causes of conjunctival inflammation in the dog
1) KCS * (STT + clinical signs)
2) Infectious- cytology, culture, PCR (CHV, CDV)
3) Foreign body (examine fornix in front of and behind nictitans)
4) Allergic (cytology, exam- lymphoid follicles, lymphocytes and plasma cells)
5) Eyelid disease - ectropion, entropion, distichia
6) Neoplasia- older dogs with primary tumor elsewhere
What are the clinical signs of dogs with allergic conjunctivitis
+/- atopy, seasonal signs
signs tend to be bilateral
1) hyperemia
2) Chemosis
3) Lymphoid follicles
4) mucoid discharge
5) epiphora
6) Belpharospasm/blepharitis
allergic conjunctivitis tend to be unilateral or bilateral
bilateral
T/F: viral conjunctivitis in dogs has similar signalment and clinical signs
allergic conjunctivitis
What are your diagnostic techniques for conjunctivitis
1) complete ophthalmic exam and PE (other signs of allergeries and foreign body behind the third eyelid
2) Schirmer tear test - rule out KCS
3) Cytology
4) Biopsy
5) Culture and sensitivity
6) Special stains/ PCR
Conjunctival swab
a microbrush that has a softer edge to them
proparacaine
used for cytology
PCR, virus isolation +/- culture
How do you treat canine conjunctivitis
1) Treat underlying allergy / atopy (or KCS)
2) Topical anti-inflammatories are mainstay of therapy
If normal tears and quality:
*Neopolydexamethosone (3-4x/day for 2-3 weeks then taper) to treat inflammation
Diclofenac 0.1% or Ketorolac 0.5%
-NSAID 2-3x/day for 2-4 weeks then taper
Cyclosproin 0.2% (Optimmune)
-T cell inhibitor (anti-inflammatory for 2-3 times daily long term
How should you treat canine conjunctivitis if the tears are normal and normal quality of production
*Neopolydexamethosone (3-4x/day for 2-3 weeks then taper) to treat inflammation
What are the major causes of conjunctival inflammation in cats *
FHV-1 **
Chlamydia felis
Mycoplasma sp
Calicivirus
Less common: non-infectious
the most common cause of feline conjunctivitis and feline keratitis
FHV-1
what tropism does FHV-1 have
Epithelial tropism
What are the two forms of FHV-1
1) Primary disease (young cats)
2) Recrudescence with stress (lysis)
Where does FHV-1 remain latent
trigeminal ganglion
What is the prevalence of FHV-1
100% seropositive (exposed)
80% persistently infected (establish latency in trigeminal ganglion)
50% shed virus spontaneously or during periods of stress
70% shed virus after exposure to corticosteroids (chronic steroid use)
70% of cats with FHV-1 will shed virus after
exposure to corticosteroids (chronic steroid use)
-includes topical steroids
What are the clinical signs of FHV-1 in the exposure (typically kittens and adolescents)
1) Upper respiratory tract infection (URTI)
2) Ocular signs (belpharospasm, epiphora, and mucoid discharge)
when does the primary infection of FHV-1 in naive cats/kittens typically resolve
within 2-4 weeks (often tend to not treat young cats)
During primary infection FHV-1 virions invade
sensory nerve endings of the trigeminal nerve
1) travel to the trigeminal ganglion +/- within the cornea
2) Viral DNA incorporated into the host
3) Sick cats recover to healthy cats
When might latent FHV-1 become reactivated
-Spontaneous
-Environmental stress
-Corticosteroids
-Co-infection
What happens when FHV-1 becomes reactivated
Viral replication and migration down sensory axons to epithelial tissues
-Subclinical shedding
-Immunopathological disease: Conjunctivitis, keratitis, dermatitis, symbleparon, URTI,
clinical signs may be unilateral or bilateral but not symmetric
What are the clinical signs of FHV-1
1) URT signs
2) Chemosis
3) Geographic corneal ulcer
4) Dendiritic ulcer
5) Conjunctivitis and mucoid discharge
6) Symblepharon (in-utero)
7) Keratitis
8) Plaques- eosinophilic keratoconjunctivitis
where the conjunctiva forms a permanent adhesion to the cornea
from in-utero
symblepharon
In a cat, if conjunctivitis is present with a history of keratitis and/or URT assume
FHV-1
there is no definitive test for FHV-1: look at the history signalment, clinical signs
How do you treat FHV-1
1) Reduce stress
2) Supportive care: topical antibiotic if ulcers present (erythromycin)
*No neomycin-polymyxin in cats (REACTIONS)
3) L-lysine 500mg PO BID (adult) q24h (kitten)
may not help or wont hurt, treat all cats in household
4) Cidofofovir 0.5% solution BID (topical anti-viral) if only ocular signs present
AND/OR
5) Famciclovir 40mg/kg PO TID - oral anti-viral to treat ocular and URT signs, wide dose range
What ulcer is pathognomic for FHV-1
dendritic ulcer: ulcers stain along the corneal nerves (abrasions along nerve)
ulcers stain along the corneal nerves (abrasions along nerve)
dendritic ulcer
What embryonic defect are seen in kittnes infected with FHV-1
Symblepharon: conjunctiva formed a permanent adhesion to cornea
Intra-ocular changes
T/F: there is no definitive test for FHV-1
true -look at history, signalment, clinical signs
T/F: neomycin-polymyxin is used to treat ulcers in cats *
FALSE- absolutely not they have reaction locally anaphylaxis
For FHV-1, what topical antibiotic should you use if there are ulcers present
Erythromycin ointment
*Never neomycin-polymyxin or formulations with it (cats have reactions)
For cats with FHV-1, what can you add to their diet
L-lysine 500mg PO BID (adult) q24h (kitten)
topical anti-viral used for FHV-1 cases if only ocular signs are present
Cidofofovir 0.5% solution BID
oral anti-viral to treat FHV-1 ocular AND URT signs
Famciclovir 40mg/kg PO TID
Cidofovir is administered _________ for ______ while Famciclovir is administered ________ for _________
Cidofovir: Topical antiviral only for ocular signs
Famciclovir: Oral antiviral for ocular and URT
obligate intracellular bacteria that is the second most common cause of conjunctivitis behind FHV-1
typically in young and/or stressed cats *
Chlamydia felis
What is not seen in Chlamydophia and Mycoplasma conjunctiva infections *
ulcerations of conjunctiva or cornea
What are the clinical signs of Chlamydia felis *
1) Belpharospasm
2) Epiphora
3) Mucoid or mucopurulent discharge
4) Hyperemia
5) Chemosis
What is a very specific clinical sign that makes you think the cat has Chlamydophilia
Chemosis
T/F: Mycoplasma causes chemosis
false- not likely
likely Chlamydophilia
How do you treat Chlamydia felis infections?
Choose antibiotic that has intracellular penetration, BID-TID
Topical:
Erythromycin ointment (Macrolide)
Why might you not want to use oxytetracycline (terramycin) to treat bacterial feline conjunctivitis
Polymyxin is in terramycin and cats have reactions to neomycin-polymyxin
What topical antibiotic should you use for Chlamydia felis
Erythromycin ointment BID-TID
What topical antibioitc should you use for mycoplasmal conjunctivitis in cats
Erythromycin ointment BID-TID
RNA virus that causes conjunctivitis in cats
far less common than FHV-1 -seen in shelter environments/cattereis
oral ulceration is pathognomonic for disease
Calicivirus
Calicivirus causes
Conjunctival and oral ulcerations
How do you treat feline conjunctivitis calicivirus
Supportive care
Topical antibiotic to treat conjunctival ulcers
What is the most common cause of bovine conjunctivitis
Moraxella bovis
What systemic diseases in cattle cause conjunctivitis
Infectious bovine rhinotracheitis
Malignant catarrhal fever
What causes infectious bovine keratoconjunctivitis in cattle
Moraxella bovis
What are the clinical signs of infectious bovine keratoconjunctivitis
1) Conjunctivitis
2) Keratitis- central corneal ulceration /edema that ay become abscessed
How do you treat infectious bovine keratoconjunctivitis
1) Various antibiotics - topical terramycin (oxytet.) or subconjunctival procaine penicillin
2) Eyepatch, tarsorrhaphy
3) Limit Predisposing factors: UV light, environment, hereford, hereford crosses, face flies
4) Prevention: control flies and UV light exposure, breeding programs, vaccinate, isolated affected/ contagious animals
a surgical procedure that partially or completely closes the eyelids by sewing them together
can be used to treat infectious bovine keratoconjunctivitis
tarsorrhaphy
What antibiotics can you use for infectious bovine keratoconjunctivitis
Various antibiotics - topical terramycin (oxytet.) or subconjunctival procaine penicillin
What breeds are predisposed to infectious bovine keratoconjunctivitis
Herefords
What are the three most common parasites causing conjunctivitis in horses
1) Onchocerca
2) Habronema
3) Thelazia
What are the clinical signs of equine parasitic conjunctivitis
1) Parasite on medial canthal nodules (sulfur granules)
2) Conjunctival hyperemia
3) Mucoid discharge
4) Chemosis
5) Depigment of medial canthus
How do you treat equine parasitic conjunctivitis caused by onchocerca, habronema, thelazia
two dose ivermectin 2 weeks apart
control fly population
inflammation with neo-poly-dex
Conjunctival neoplasia is typically benign or malignant?
Malignant
How do you diagnose conjunctival neoplasia
fine needle aspirate
How do you treat conjunctival neoplasia
local excision + adjunctive therapy (cryoablation, chemotherapy, hyperthermia)
enucleation may be required
What are the different kinds of conjunctival neoplasia
1) Canine Papiloma
2) Medial Conjunctival Melanoma
3) Hemangioma
4) Equine Conjunctival SCC
most common ocular tumor in horses
squamous cell carcinoma
Wha are the predisposing factors of ocular SCC in horses
-Non-pigmented adnexa
-High altitude
-Sun exposure
-Breeds: Haflingers, Belgians, QH, Paints
What horse breeds are predisposed to SCC
Haflingers, Belgians, QH, Paints
How do you treat equine SCC
Excisions
Cryotherapy, beta-radiation, chemotherapy, immunotherapy
*No perfect treatment for SCC
Is FHV-1 mostly unilateral or bilateral
unilateral
Dogs with conjunctival hemangiosarcoma
Benign behavior
-excise, cryotherapy, beta-radiation
Compare and contrast conjunctival hemangiosarcoma in dogs and horses
Dogs: typically benign- excise, cryotherpay, b-rad
Horses: May be aggressive/metastatic - enucleation/exenteration is often necessary
Is chlamydia typically unilateral or bilateral
bilateral
Horses with conjunctival hemangiosarcoma
May be aggressive/metastatic - enucleation/exenteration is often necessary
