Conjunctivitis and Nasolacrimal Flashcards
what is conjunctivitis?
- inflammation of the conjunctiva
- NO concurrent uveitis or intraocular disease
- chemosis
- hyperemia
- discharge: serous to mucopurulent
what is KCS?
keratoconjunctivitis sicca; inflammation of cornea and conjunctiva and dry eye; most clinically important component of conjunctivitis; deficiency of watery/aqueous portion of tears
clinical signs:
1. ropy, mucopurulent discharge
-NOT bacterial issue; may just be commensal flora!! don’t culture the yellow discharge
-discharge is due to tear deficiency
-WIPE off before STT, don’t flush
- conjunctival hyperemia
- keratitis with superficial neovascularization and pigmentation
- ocular discomfort
- secondary infections
- dry, crusted nares
- non-healing erosions
can ulcerate!!
describe tear film anatomy and physiology
lipid:
-superficial
-stabilize and prevent evaporation
-made by meibomian glands
–located in tarsal plate; aggregates of secretory acini, visible through palpebral conjunctiva
-if inadequate, will get individual spots of evaporation until blink again
aqueous:
-intermediate
-corneal nutrition, remove waste
-made by lacrimal gland and gland of third eyelid
mucus:
-interface of tear film with hydrophobic cornea
-source of secretory IgA
-produced by conjunctival goblet cells
describe diagnosis of KCS
- STT: measures aqueous (crude measure); remember to stick in lateral 1/3 of conjunctival
- values:
-normal: 15-25mm/60 sec
-marginal: 10-15mm/60 sec
-low: <10mm/60 sec
-be sure to interpret in context of clinical signs; if low but eye looks normal you probs messed up
what causes KCS?
- idiopathic/immune mediated: MOST COMMON
- congenital (uncommon unless yorkie)
- drug induced:
-atropine, sulfa drugs, topical/general anesthesia, etogesic - neurologic: loss of parasympathetic innervation (often secondary to ear issue)
- infectious: distemper
- removal or uncorrected prolapse of 3rd gland
- orbital trauma/inflammation
- long lasting otic meds
describe breed dispositions to KCS
- english bulldogs
- westies
- pugs
- yorkies
- american cocker spaniels
- perkingese
- mini schnauzer
- english springer spaniels
describe etiology of KCS
- can be surgically induced due to excision of 3rd eyelid gland; if removed, 50% will develop KCS
- neurogenic: loss of parasympathetic activation of the lacrimal gland
-unilateral; a hallmark sign is a super crusty nose
-many causes, needs workup
-rare side effect of osurnia and claro (otic meds)
-pilocarpaine to treat - qualitative dry eye: tears evaporate too quickly
-dx: all crap
-tear film breakup time
-tear osmolality measurement
-tear ferning
-meibometry to assess lipid
-due to:
–loss of goblet cells: chronic inflammatory cell infiltrates in the conjunctiva
–dysfunction of meibomian glands: seborrhea, autoimmune disease affecting mucocutaneous junctions, post cryotherapy/distichia treatment or eyelid agenesis
describe tear stimulation treatment of KCS
- quantitative: low STT
- qualitative: rapid tear break up time
tear stimulation:
1. cyclosporine A for life (if you stop, glands stop producing tears and dry eye comes back)
-most important KCS treatment! but can take a long time to kick in!
-immunosuppressive
-neurohormonal effect through prolactic receptors
-available in ointment (optimmune) or mixed in corn oil BID or TID
-STT <1mm/min: 50% respond
-STT >2 mm/min: 80% respond
- tacrolimus: similar to cyclosporine but not FDA approved, may be carcinogenic
- pilocarpine: stimulates parasympathetic nervous system; oral or topical
-reserved for cases of neurogenic KCS
-may have SLUD signs
eye drops only last for 2 min to a couple hours; cannot supplement tears with the frequency of natural tear production!! HAVE to use a tear stimulant, can supplement tears until drug takes effect
describe the decrease inflammation treatment of KCS
- cylosporine and tacrolimus: decreases inflam
- topical steroids: use with extreme caution in severe cases, may predispose to corneal meting!!
describe seasonal allergies
- most common in dogs
- bilateral
- follicular enlargement: most notable on bulbar surface (pull eyelid out to see)
- can cause allergic conjunctivitis;
-must rule out KCS proper
-needs anti-inflammatory
-never just antibiotic!!
-use NSAIDs, cyclosporine, tacrolimus, steroids
describe follicular conjunctivitis
- can be age limited (gone by 2 years of age)- bilteral
- benign neglect versus meds versus scraping follicles to treat
describe feline conjunctivitis
- usually infectious
- most common differentials:
-FHV-1
-chamydia psittaci
-mycoplasma
describe feline herpesvirus
- ubiquitous
- primary infection: URI +/- conjunctivitis
-bilateral, hyperemia, serous then mucopurulent discharge, chemosis
-may resolve with no long term effects - symbepharon:
-infection before eyelids open; loss of conjunctival, corneal epithelium: inappropriate adherence of conjunctiva
-difficult to repair; often recurs after excision
-80% of cats latently infected after 1st infection; often no URI in reactivation - treatment: topical trifluridine (reserved for corneal disease) or cidofivir or idoxuridine (antivirals)
-oral too but they’re big pills
describe chlamdyial conjunctivitis
- usually no URI
- starts unilateral then goes bilateral
- hyperemia, chemosis, discharge
- often young cat or after into of new cat
- fluorescein negative
- diagnosis: conjunctival cytology early (intracytaplasmic inclusions), IFA\
- treatment: topical tetracycline, erythromycin, ciprofloxacin +/- oral doxycycline
describe feline mycoplasma
- unilateral or bilateral conjunctivitis, epiphora, hyperemia, chemosis
- diagnosis: inclusions at cell membrane, isolation of organism
- treatment: tetracycline, erythromycin, ciprofloxacin
