Final Exam - Conjunctiva & Lacrimal System Flashcards
what are the 3 main red eye conditions?
keratoconjunctivitis, uveitis, & glaucoma
what is chemosis?
edema of the conjunctiva
what is conjunctival hyperemia?
term used to describe congestion of the superficial vessels of the conjunctiva
a predominant finding of conjunctival hyperemia suggests what?
superficial disease, such as: tear film disorders (KCS), primary conjunctivitis, eyelid disorders causing secondary conjunctivitis, & a response to superficial corneal ulceration
what are conjunctival lymphoid follicles?
response to non-specific antigenic stimulation
presence of cinjunctival lymphoid follicles anywhere but the bulbar surface of the 3rd eyelid is consistent with a diagnosis of what?
conjunctivitis
what is the conjunctival fornix?
area where the palpebral conjunctiva meets the bulbar conjunctiva
what is conjunctivitis?
inflammation exclusive to the conjunctiva
what type of conjunctivitis is most common in dogs? what about cats?
dogs - allergic conjunctivitis cats - infectious conjunctivitis
what is episcleral injection?
congestion of deep conjunctival vessels known as episcleral vessels
the presence of episcleral injection suggests what?
presence of deeper diseases such as: uveitis, glaucoma, & deep/complicated corneal ulcers
what is epiphora? what is it a common response to?
abnormal overproduction of tears, normal response to ocular irritation
what are ghost vessels? what do they mean?
non-perfused corneal blood vessels - provide evidence of previous keratitis
what are goblet cells? what pathology do they contribute to?
cells present within conjunctival epithelium & produce the inner most mucous layer of the 3 layers of the tear film - in conjunctivitis, will overproduce mucus causing mucoid discharge
what is keratitis?
inflammation of the cornea
what is the most common clinical sign of keratitis? what other signs are seen?
neovascularization is the most common - others include corneal pigmentation, corneal fibrosis, corneal ulceration, & white blood cell infiltration
why is mucopurulent discharge most commonly found in patients with KCS?
due to the loss of the aqueous portion of the tear film which then causes mucus overproduction, bacterial overgrowth, & subsequent white blood cell recruitment
what is symblepharon?
permanent adhesion between the conjunctiva & the cornea
what are the 5 landmarks of the conjunctiva you should be able to recognize?
- palpebral conjunctiva
- conjunctival fornix
- palpebral surface (3rd eyelid conjunctiva)
- bulbar surface (3rd eyelid conjunctiva)
- bulbar conjunctiva
T/F: isolated, prominent, j-shaped episcleral vessels are most often normal variants seen on the conjunctiva
TRUE
what makes conjunctival pigment normal? what makes it abnormal?
normal - is it is an isolated finding abnormal - scleral pigment often
abnormal that is associated with pigment proliferation (ocular melanosis & neoplasias) or scleral thinning
T/F: conjunctival biopsy can be performed with topical anesthetic alone
TRUE
what cells may be seen on epithelial cytology from a dog with conjunctivitis from allergies? what about an infectious/inflammatory cause?
allergic - eosinophils
infectious/inflammatory - neutrophils
T/F: the presence of epiphora is always abnormal, but it is not specific for any one disease & just indicates ocular irritation/pain
TRUE
if you see mucoid/mucopurulent ocular discharge, what is producing it? what conditions should you put on your differential list?
goblet cells! they will overproduce mucus when they are inflamed - need to think about KCS & doing a schirmer tear test
follicles in the conjunctiva are only a normal finding if they are located where?
only normal if found on the bulbar surface - abnormal if seen anywhere else
what can you do to elevate the 3rd eyelid during an ophthalmic exam?
retropulse the globe to elevate the 3rd eyelid
if a dog presents with the presence of follicles all over the conjunctiva, what condition should you think of?
primary conjunctivitis & non-specific antigenic stimulation
where are superficial vessels of the cornea located? what about the deep vessels?
superficial - just under the epithelium & deep - located in the episclera
if you see conjunctival hyperemia, what disease category should you be thinking of?
superficial disease causing superficial irritation & superficial vessels are angry
T/F: episcleral injection means these are vessels that can be seen with the naked eye
TRUE
what are some ocular conditions that feature episcleral injection?
episcleritis, canine glaucoma/lens subluxation, uveitis, & deep ulcers
what signalment of dogs are affected by allergic conjunctivitis?
young dogs and/or atopic dogs
what clinical signs are seen with allergic conjunctivitis in dogs?
lymphoid follicles are a specific sign!!!!! blepharospasm, epiphora, mucoid discharge, & hyperemia
what does the presence of lymphoid follicles without evidence of keratitis indicate?
satisifes a diagnosis of primary allergic conjunctivitis (aka - follicular conjunctivitis)
how is a diagnosis of allergic conjunctivitis in a dog made?
patient meets the compatible signalment, patient has compatible clinical signs, & the minimum database of STT/fluorescein dye/tonometry are within normal limits
how is allergic conjunctivitis in dogs treated?
treat underlying atopy if present & treat the eye - mainstay of therapy are topical anti-inflammatories
what are your 3 choices of topical anti-inflammatories for canine allergic conjunctivitis?
steroid - NeoPolyDex ointment (small bead 2-3X/day for 3 weeks then recheck)
NSAID - diclofenac 0.1% solution (1 drop 2X/day for 3 weeks then recheck)
t-cell inhibitor - optimmune ointment (cyclosporine 0.2%, small bead 2-3X/day for 6 weeks then recheck)
what are the 3 layers of the tear film?
- oil/lipid - outermost, contains meibomian glands
- aqueous - middle, 65% lacrimal glands & 35% gland of 3rd eyelid
- mucinous - innermost, conjunctival goblet cells
what are the 3 functions of the tear film?
nourish, cleanse, & protect the ocular surface
what are the 2 categories of KCS?
quantitative & qualitative
what is the most common cause of KCS in dogs?
immune-mediated destruction
what drugs are associated with causing KCS?
sulfonamides & atrophine
what is neurogenic KCS?
loss of parasympathetic innervation to the lacrimal gland that causes unilateral dry eye & xeromycteria (dry nose)
what is an example of an iatrogenic cause of KCS?
surgical excision of the gland of the 3rd eyelid
what is quantitative KCS?
aqueous deficiency that is diagnosed by the schirmer tear test < 15 mm/min + clinical signs
T/F: KCS is the only common cause of bacterial conjunctivitis in dogs
TRUE
what is the common clinical history seen in patients with KCS?
patient presented with mucupurulent discharge & they were prescribed a topical antibiotic which cleared up the discharge but once stopped, the discharge returned - STT never performed
what is qualitative KCS?
lipid or mucin deficiency that is diagnosed by the schirmer tear test >/= 15 mm/min + clinical signs
what signalment of dogs are predisposed to KCS?
toy breeds, brachycephalics, & cocker spaniels
T/F: in dogs with KCS, the disease is often bilateral
TRUE
what clinical signs of KCS are associated with keratitis?
superficial corneal neovascularization (most consistent clinical sign) that starts at the dorsal limbus of the cornea, corneal fibrosis, superficial corneal pigmentation, corneal ulceration, & white blood cell infiltration
what clinical signs are seen in dogs with KCS that are associated with conjunctivitis?
mucopurulent discharge is the easiest way to recognize this disease macroscopically
why is superficial neovascularization of the cornea with dorsal distribution common in dogs with KCS?
the remaining tear film of the eye provides health to the ventral cornea!!! not seeing these vessels on the ventral aspect!
what is the effect of topical cyclosporine in dogs with KCS?
it suppresses further destruction of the lacrimal tissue, directly stimulates tear production, & anti-inflammatory effects such as reducing vessels, clears fibrosis, & clears pigments
what are the 4 objectives in treating KCS?
- replace the tears (lubricate with artificial tears 2-6 times daily)
- stimulate more tears (topical cyclosporine)
- anti-inflammatory therapy (cyclosporine)
- temporary antibiotic therapy (to clear the initial bacterial infection while the tear film recovers)
after doing routine KCS treatment on a dog for 4-6 weeks, and at recheck, improvement is seen, how is your therapeutic protocol changed?
decrease lubricant to 2X/day & continue optimmune 2X/day
at the 3-4 month recheck for a patient that is responding well to routine therapy for KCS, what are your continued therapy plans?
lubricate as needed for redness, continue optimmune 2X/day, & recheck annually for optimmune refills!
what are some potential causes of neurogenic KCS?
trauma, severe otitis interna, neoplasia, & idiopathic cause
what surgical therapy is used for KCS?
parotid duct transposition for cases where medical therapy fails to recover tear production & clinical signs persist
in cats, you should consider utilizing what diagnostic test for diagnosing separate causes of feline conjunctivitis?
conjunctival cytology
what are the most common causes of feline conjunctivitis in order of prevalence?
- feline herpesvirus keratoconjunctivitis
- chlamydial conjunctivitis
- mycoplasma conjunctivitis
- calicivirus conjunctivitis
what are the 3 clinical forms of feline herpes that are clinically recognized?
primary disease - young cats with acute lysis of epithelium latency - period of silence recrudescence - lysis & disease (periods of stress)
what percentage of cats shed herpes during periods of stress?
50%
what is the most common cause of feline conjunctivitis & feline keratitis
feline herpesvirus
what clinical signs are seen in cats with an URI from herpes causing ocular surface infections?
primary infection of FHV-1 in naïve cats/kittens with a high occurrence of outbreaks in shelter environments that naturally resolves in 2-4 weeks - blepharospasm, epiphora, & mucoid discharge alongside URI signs
what is neonatal ophtalmia?
**
what are the non-specific signs related to FHV-1?
blepharospasm, epiphora, & mucoid discharge
what are the more specific & very specific signs related to FHV-1?
more specific - URTI (more common with primary infection) & hyperemia is for herpes!!! very specific - conjunctival & possible corneal epitheial ulceration (dendritic ulcers are pathognomonic), & symblepharon
what are dendritic ulcers pathognomonic for in cats? what do they represent?
FHV-1 infection, represents one form of a continuum of epithelial lysis (punctate, linear, dendritic, & geographic)
what is symblepharon?
permanent adhesion between the conjunctiva & the cornea
what is historic keratitis?
inactive & non-perfused superficial neovascularization (ghost vessels)
if you observe conjunctivitis & evidence of active or historic keratitis in a cat, you should consider what as the cause of the conjunctivitis?
FHV-1 over any other cause
which are you more likely to see clinically, dendritic or geographic ulcers in a cat with FHV-1 infection causing conjunctivitis?
geographic - FHV-1 still most likely culprit
what occurs when two ulcerated epithelial surfaces heal to each other?
symblepharon - adhesion of the conjunctiva to the cornea
T/F: symblepharon in cats occurs most often with FHV-1 infections
TRUE
what do you need to build a case for FHV-1 associated conjunctivitis?
history, clinical signs, response to therapy, & maybe other tests (cytology looking for intranuclear inclusion bodies, fluorescent antibody testing, PCR, & virus isolation)
what are you looking for on cytology that would support a diagnosis of FHV-1 associated conjunctivitis?
intranuclear inclusion bodies
what questions should you consider in your clinical assessment of a cat that you suspect has FHV-1 associated conjunctivitis?
- is keratitis present or ever been present? (look for dendritic ulcers & ghost vessels)
- history of URTI?
- is there a positive response to anti-viral therapy?
- have you ruled out other causes of red eye using fluorescein dye & tonometry?
what is the current gold standard for treating FHV-1 conjunctivitis? what topical therapy is another treatment option?
oral famciclovir - topical option of cidofovir 0.5% (compounded & given twice daily)
what supportive care is recommended for FHV-1 conjunctivitis?
topical erythromycin - wide spectrum macrolide antibiotic used 3-4X daily
what cats are affected by chlamydial conjunctivitis?
young & stressed cats
what type of agent causes chlamydial conjunctivitis?
obligate intracellular bacteria!!
does chlamydial conjunctivitis cause corneal or conjunctival ulceration in cats?
nope!
what is a more specific clinical sign associated with chlamydial conjunctivitis in cats?
chemosis - less specific signs include blepharospasm, epiphora, mucoid/mucopurulent discharge, & hyperemia
what is seen on cytology that is used to diagnose chlamydial conjunctivitis in cats?
intracytoplasmic inclusion bodies
how is chlamydial conjunctivitis diagnosed in cats?
PCR, history, clinical signs, cytology, & ruling out other causes
what kind of antibiotic do you need for treating chlamydial conjunctivitis in cats? what are your options?
need one that has intracellular penetration!!! tetracyclines (oxytetracycline - terramycin), macrolides (erythromycin), fluoroquinolones as a last resort (ofloxacin & ciprofloxacin), or oral tetracyclines (doxycycline) for 3 weeks
what is seen on cytology that supports mycoplasma conjunctivitis?
membrane associated bacteria
how is mycoplasma conjunctivitis diagnosed?
PCR, compatibile clinical signs, cytology, & ruling out other causes of feline conjunctivitis
what are some clinical signs seen with mycoplasma conjunctivitis?
nonspecific signs - blepharospasm, epiphora, mucoid/mucopurulent discharge, hyperemia, & +/- chemosis
does mycoplasma conjunctivitis cause corneal or conjunctival ulceration?
nope!
what treatment is used for mycoplasma conjunctivitis?
similar sensitivity to chlamydial organisms - same treatment protocol with intracellular penetration antibiotics
what cats are affected by calicivirus conjunctivitis?
shelter environments & catteries
what are some very specific signs that indicate calicivirus conjunctivitis? what are some other less specific signs?
very specific - tongue/oral ulceration (pathognomonic when present!!!) less specific - conjunctival ulceration but no corneal ulceration, blepharospasm, mucoid/mucopurulent discharge, & hyperemia
T/F: calicivirus conjunctivitis can cause conjunctival ulceration but not corneal ulceration
TRUE
what treatment is used for calicivirus conjunctivitis?
supportive topical therapy - erythromycin ointment applied 3-4X daily
how is calicivirus conjunctivitis diagnosed?
challenging diagnosis to make - use PCR, compatible history, compatible clinical signs, & rule out other causes of feline conjunctivitis
