Exam 3 - Keratoconjunctivitis Sicca Flashcards
successful diagnosis & treatment of KCS depend on what 2 things?
- highly magnified view of ocular structures
- appreciation of depth within the eye paying special attention to the quality of the specular reflection
what is the ‘classic’ quantitative KCS?
dog presenting for ‘red eyes with film’
what is the ‘diversion’ KCS?
animal is presented for another issue causing KCS to be overlooked in the other eye!!!
what is the ‘nose’ presentation of KCS?
neurogenic KCS - animal presents for red eye & itching
what is the treatment failure patient of KCS?
refractory & absolute KCS
what is the ‘puzzle’ patient of KCS?
patient that has multifactorial qualitative KCS that presents for squinting & discharge
what ocular lesion is shown in this photo?
pigmentary keratitis
what makes up the 3 layers of the tear film?
- oil/lipid production through meibomian gland
- aqueous middle layer - lacrimal gland (65%) & 3rd eyelid gland (35%)
- mucinous, innermost, conjunctival goblet cells - connects the aqueous layer to the cornea
what is the function of the tear film of the eye?
to nourish, cleanse, & protect the ocular surface
what defines quantitative KCS? how is it diagnosed?
aqueous deficiency!!!!
diagnosed by schirmer tear test < 15 mm/min + clinical signs
T/F: quantitative KCS is the ONLY common cause of bacterial conjunctivitis in dogs
true
what does the schirmer tear test do?
quantifies the aqueous portion of the tear film
what are the guidelines for performing a schirmer tear test?
performed before any other drops or ointments!!!
performed before sedation or anesthesia
performed for 60 SECONDS
what is the normal test result for a schirmer tear test in a dog? what about a cat?
> 15 mm of wetting/min including basal & reflex tearing
unpredictable in cats!!!
what is the most common cause of quantitative KCS?
immune-mediated destruction
what causes neurogenic quantitative KCS?
loss of parasympathetic input to tears
apart from immune-mediated & neurogenic causes of KCS, what are some other causes of this condition?
trauma causing proptosis, congenital alacrima, iatrogenic (removal of the gland of the 3rd eyelid), drugs (sulfonamides & atropine), & infectious (canine distemper virus)
what signalment of animals are commonly affected by KCS?
toy breeds - yorkies, pomeranians
brachycephalic breeds - bulldogs, pugs, shih tzus
cocker spaniels
what is the common presenting complaint of animals with quantitative KCS?
mucoid discharge!!!!!!
red eyes & squinting
what is seen in this photo that is evidence of keratitis?
superficial corneal neovascularization
what is seen on ocular exam & schirmer tear testing that diagnoses quantitative KCS?
STT < 15 mm/min + evidence of keratitis & conjunctivitis
what is seen in this photo that is evidence of conjunctivitis?
mucopurulent discharge
what is seen in this photo that is evidence of conjunctivitis?
conjunctival hyperemia
T/F: for patients with corneal ulceration, the ulcer is often infected & often requires emergent care
true
what is seen in this photo that is evidence of keratitis?
superficial corneal pigment
what is seen in this photo that is evidence of keratitis?
corneal ulceration
what is seen in this photo that is evidence of keratitis?
corneal fibrosis & faint edema
what lesion is seen here? what should you think is going on?
superficial corneal neovascularization
evidence of keratitis - think about early quantitative KCS
where does superficial corneal neovascularization most often start?
dorsal limbus of the eye
what are the 4 objectives of KCS treatment?
- replace the tears - lubricate the eye with artificial tears 2-6X a day
- temporary antibiotic therapy - need to clear the initial bacterial infection while the tear film recovers
- stimulate more tears - use of cyclosporine or tacrolimus indefinitely!!!!
- anti-inflammatory therapy - topical cyclosporine or similar
how is neurogenic KCS diagnosed?
diagnosed by the presence of ipsilateral xeromycteria (dry nose)
unilateral disease that can resolve spontaneously - unpredictable, can take years
T/F: neurogenic KCS typically disrupts motor function to CN VII
false - usually doesn’t
what is the typical age of patients affected by neurogenic KCS?
average age of 9 years
presents with unilateral KCS with a dry nose
what do you think is wrong with these two dogs?
unilateral quantitative KCS with dry nose - neurogenic KCS
what is the mechanism of action of topical pilocarpine? how is topical 1% pilocarpine used?
indirect parasympathomimetic
patients with neurogenic KCS - 1 drop per 10 lbs given twice daily until the patient develops signs of toxicity!!!
what are signs of toxicity associated with topical 1% pilocarpine?
vomiting, diarrhea, increased salivation, bronchiolar spasm, & pulmonary edema
if you’re treating a KCS patient that you think may be refractory, and you see no improvement at 4-6 weeks of therapy, what should you do next?
increase concentration/frequency of cyclosporine - use COMPOUNDING
add additional tear stimulant - for example, tacrolimus
continue topical lubrication
introduce the idea of surgical options
recheck in another 4-6 weeks
what are the two largest veterinary compounding pharmacies nationally that you can use for compounding cyclosporine?
stokes pharmacy
wedgewood pharmacy
what is level 1 for treating a refractory KCS patient?
change optimmune (0.2% cyclosporine) to 2% cyclosporine OU BID until recheck
add on 0.3% tacrolimus OU BID
continue puralube OU QID until recheck
recheck in 4-6 weeks
what is level 2 (max) for treating a refractory KCS patient?
2% cyclosporine OU TID until recheck
1% tacrolimus OU TID
discuss warnings in increasing the doses of cyclosporine/tacrolimus
pulse therapy topical antibiotics for 1 week to 1 month
continue puralube OU QID until recheck
recheck in 4-6 weeks
what surgical therapy may be used for a refractory KCS patient that fails to recover tear production with persisting clinical signs?
parotid duct transposition
what are some newer therapies/ideas being used for treating KCS?
- oral cyclosporine - 10 mg/kg
- subconjunctival cyclosporine implant
- buccal mucosal graft
what is qualitative KCS?
lipid or mucin deficiency (something is going on with the goblet cells or meibomian glands)
how is qualitative KCS diagnosed?
schirmer tear test >/= 15 mm/minute + clinical signs
what are the acceptable first line therapies used for qualitative KCS?
topical cyclosporine twice daily for life!!!!
topical lubricant as needed
address underlying cause if possible
