Flashcards in 4: conjunctiva - giuliano Deck (75):
what is the conjunctiva?
pink, fleshy structure that coats and lines part of the globe
what are the regions of the conjunctiva?
Nictitans: anterior and posterior surface
where is the palpebral conjunctiva loc?
under the eyelid, facing the globe
where is bulbar conjunctiva?
the conjunctiva that projects on to the surface of the globe
what is the fornix of the conjunctiva?
the space where the conjunctiva folds over itself, loc superior and inferior to the bulbar conjunctiva
what is the fxn of the conjunctiva?
- glove movement [low friction]
- physical barrier [mucus of goblet cells]
- immunologic barrier [conjunctival associated lymphoid tissue, M cells]
what is work up for conjunctival dz?
MODB - minimum ophthalmic data base
what are things to r/o when considering conjunctival dz?
- tear deficiency
- corneal dz
- intraocular dz
what additional diagnostics might be conducted for conjunctival dz?
- NL flush
- rose bengal stain
c/s of conjunctival dz?
what is epiphora?
tearing - inc in serous discharge
what causes epiphora?
- inc prod: pain, irritation
- dec outflow: NL obstruction
what is chemosis?
what causes chemosis?
- allergic rxn
- infectious agents
- tumors [rare]
what infectious agents cause chemosis?
what infectious agents causes hyperemia?
what is hyperemia?
what 2 types of hyperemia that are important to distinguish within the eye?
conjunctival vs scleral hyperemia
what does conjunctival hyperemia look like?
what kind of dz does this suggest is in the eye?
tortorous vessels, branching
move with conjunctiva
blanch with the epithelium
what does scleral hyperemia look like?
what kind of dz does this suggest is in the eye?
DEEP DZ, FROM W/IN THE EYE
what is mucopurulent exudate?
excess mucus with WBCs
what are causes of mucopurulent exudate?
- KCS [dry eye]
- bacT infections
- viral infections
what is emphysema of the eye?
entry of air into the periorbita from surrounding tissues
swelling and crepitus of conjunctiva
what causes emphysema of the eye?
trauma to sinus or tracheostomy
what is the term for hemorrhage inside the eye?
what is the definition of hemorrhage in the eye?
extravasation of blood w/in the conjunctiva
what causes hemorrhage in the eye?
trauma: strangulation, CSF tap / SAH
often a manifestation of systemic dz:
what are 2 categories of tissue proliferation w/in the eye?
follicle formation or swelling/mass
what are 2 reasons for follicle formation w/in the eye?
lymphoid follicles [normal or abnormal location]
what are causes of mass or swelling in the eye?
what are some causes of pruritus of the eye?
2* lesions: alopecia, erythema, stained/matted hair [MC region or periocular]
cats and cows 1* get what type of conjunctivitis?
infectious - bacT and viral
what species MC get non infectious conjunctivitis?
canine and horse
what is common cause of canine conjunctivitis?
KCS*** (2* conjunctivitis)
2* infections may occur
what is common cause of equine conjunctivitis?
conjunctivitis tx goals?
remove all exudates/cleanse the eye
maintain surface moisture
control 1* / 2* infections
what are signs of feline conjunctivitis allergic reactions?
feline conjunctivitis allergic reaction dx?
administration of triple antibiotic (poly-bac, TAB) - suspected neomycin
what is Tx of feline conjunctivitis allergic reactions?
+/- anti inflammatory therapy
what is the MC etiology of feline conjunctivitis?
herpes - viral infection
in addition to the risk of an allergic reaction, why is it typically not appropriate to administer TAB or poly-bac that contains neomycin?
it does not treat the MC etiology of conjunctivitis => herpes virus infection
and it does not treat the more common bacT causes either...
what bacT infections in cats are common causes of conjunctivitis?
c/s of feline conjunctivitis caused by chlamydophila felis?
dx: cytology, PCR
tx: tetracyclines***, azithromycin [oral]
c/s of feline conjunctivitis caused by mycoplasma spp?
90% cats normal
oral doxy or mino
c/s of feline conjunctivitis caused by FHV-1?
sneezing and nasal discharge - MC in kittens
dx: serology, cytology, PCR, IFA, virus isolation
tx: oral L-lysine and anti viral agents
anti viral agents are created among species. acyclovir and valcyclovir, common human anti viral agents, are safe to use in cats
they can kill cats - DO NOT USE THEM
what is most classic lesion you will see in a cat infected with FHV-1?
dentritic corneal lesions - branching ulcers or erosions
what is the major oral anti viral drug given to tx FHV-1 infections?
what are two issues with topical anti viral drugs, such as cidofovir?
must be given often - b/c anti virals are static, NOT cidal
also, they sting - cats are very sensitive
how would a clinician describe FHV-1 latency?
a period of time when a patient does not show any c/s of viral infection
besides stress induced outbreaks, what will reactivate FHV-1 infection?
pharmacologic stress: corticosteroids [or epinephrine]
how do FHV-1 establish latency?
by traveling down the sensory Nn from the site of replication - lies dormant in the sensory ganglia
what type of transport does virus utilize in sensory neurons?
how does stress bring FHV-1 out of latency?
causes viral rep at site of latency w subsequent transport of the virus in the sensory Nn
virus travels to target tissue, replicates, causes clin dz
how does lysine tx inhibit viral replication?
the virus incorporates lysine into its genome, instead or arginine, but then it cannot replicate properly
arginine cannot be removed from diet b/c it is necessary for life but influxes of lysine inc proportion of lysine in the genome
lysine offers a cure to viral infection
dec duration and severity of clin dz - is NOT a cure
what is symblepharon?
adherence of conjunctiva to cornea or itself
what are 3 FHV-1 related conditions?
what is common presentation of corneal sequestrum?
necrotic cornea - looks like a burn in the cornea
corneal sequestrum tx?
what is c/s of calcivirus in cats?
ocular discharge - minimal conjunctivitis, no keratitis
oral ulceration ****
ptyalism (excess salivation)
what is the common signalment of canine conjunctivitis caused by allergy?
large breed dogs
follicles, periocular erthema, chemosis, skin/ears affected
what is the pathogenesis of allergic canine conjunctivitis?
cytology: lymphocytes and plasma cells
Tx of canine allergic conjunctivitis?
flush out allergens w sterile eye wash
corticosteroids: topical, systemic
allergy meds: mast cell stabilizers, anti histamines, eosinophil inhibitors
c/s of canine conjunctivitis caused by KCS?
dx: schirmer tear test
etiology of canine conjunctivitis caused by trauma/irritation?
direct trauma: strangulation, head trauma, CSF tap
tx: remove 1* cause
anti inflammatory medication
trauma should always be at the top of your differential list
trauma is unlikely - so unless it was witnessed, it should be on the bottom of the list
canine viral conjunctivitis common etiologies?
canine distemper #1
what are early and chronic signs of distemper?
early: serous discharge, conjunctival hyperemia, systemic dz
chronic: KCS [viral adenitis], mucopurulent rhinitis
what are some non neoplastic types of conjunctival masses?
nodular granulomatous episcleritis
what type of granulation tissue is MC present in cats?
what kind of parasite commonly affects the eyes?
common conjunctival masses that are neoplastic?
- melanoma, melanocytoma
- adenoma, adenocarcinoma
- HSA, hemangioma
what is the leading presentation of cats with systemic LSA?