Page 1144 - Cote clinical veterinary advisor dogs and cats 4th

Keratoconjunctivitis Sicca 569

• Increased predisposition reported for • Iatrogenic: removal of the gland of the third (conjunctivitis and nonulcerative keratitis),
castrated male and spayed female dogs eyelid increases risk of KCS, especially in secondary bacterial infections, and corneal
VetBooks.ir GENETICS, BREED PREDISPOSITION • Infectious disease (e.g., canine distemper, Acute General Treatment Diseases and Disorders
predisposed breeds.
ulceration if present.
FHV-1)
Predisposed breeds (dogs): English bulldog,
West Highland white terrier, Lhasa apso, pug,
hyperadrenocorticism, diabetes mellitus)
American cocker spaniel, Pekingese, Yorkshire • Metabolic disease (e.g., hypothyroidism, • Lacrimostimulants
○ Cyclosporine 0.2% ointment or 0.5%-2%
terrier, shih tzu, miniature schnauzer, Boston • Neurogenic: may occur with facial nerve solution topically to affected eye(s) q 12h
terrier, dachshund, Chihuahua, German paralysis and denervation of parasympathetic • Lacrimomimetics (tear substitutes and
shepherd, Doberman pinscher fibers innervating the gland or after ocular stabilizers such as hyaluronic acid 0.4%, gels
proptosis. or ointments) applied topically to affected
RISK FACTORS • Chronic blepharoconjunctivitis due to eye(s) q 4-6h
• Medications, metabolic disorders, dysauto- obstruction of lacrimal ductules secondary • Antimicrobials if secondary bacterial con-
nomia, and infectious diseases (see Etiology to chemosis or ascending infection into junctivitis and/or corneal ulceration
and Pathophysiology below) lacrimal gland ○ Topical broad-spectrum antibiotic (e.g.,
• Removal of gland of the third eyelid • Chronic conjunctivitis may cause ductules bacitracin-neomycin-polymyxin antibiotic
• Systemic immune-mediated disease (e.g., to scar (e.g., FHV-1). solution) to affected eye(s) q 6-8h
systemic lupus erythematosus [p. 955]) • Irradiation: when primary beam near or on • Antiinflammatories if severe conjunctivitis
periocular region and/or corneal vascularization/pigmentation
CONTAGION AND ZOONOSIS but only in the absence of corneal ulceration
Infectious causes (e.g., canine distemper; feline DIAGNOSIS ○ Dexamethasone 0.1% solution topically
herpesvirus type 1 [FHV-1]) are contagious. to affected eye(s) q 6-8h
Diagnostic Overview • Pilocarpine 1 drop 2% pilocarpine/10 kg
ASSOCIATED DISORDERS The diagnosis is suspected based on the body weight on food q 12h, gradually and
Conjunctivitis and ulcerative and nonulcerative presence of conjunctivitis or ulcerative and/ cautiously increasing by 1-drop increments
keratitis or nonulcerative keratitis. The confirma- until increased tearing or systemic side effects
tory test of choice is the Schirmer tear test (e.g., vomiting, diarrhea, anorexia, saliva-
Clinical Presentation (STT). tion, bradycardia; if systemic effects occur,
HISTORY, CHIEF COMPLAINT decrease dose or discontinue immediately);
• Red eye (p. 870) Differential Diagnosis effective only in some with neurogenic
• Ocular pain Dogs: other causes of keratoconjunctivitis: KCS
• Mucoid to mucopurulent ocular discharge • Conjunctivitis (p. 200)
• Corneal vascularization or pigmentation (e.g., Chronic Treatment
PHYSICAL EXAM FINDINGS pannus [pp. 212 and 748]) Lacrimostimulants:
• Systemic: unremarkable unless associated • Corneal exposure (e.g., lagophthalmos); • Cyclosporine 0.2% ointment or 0.5%-2%
with systemic disease common cause of misdiagnosis of KCS solution topically to affected eye(s) q 8-24h
• Ophthalmic: any of the following • Corneal ulceration (p. 209) (typically q 12h)
○ Mucoid to mucopurulent ocular discharge • Blepharitis ○ For STT values that remain 10 mm/
○ Conjunctival hyperemia and chemosis Cats: other causes of keratoconjunctivitis: min or less after 3-4 weeks of treat-
○ Blepharospasm • FHV-1 conjunctivitis/keratitis (p. 464) ment, dosage may be increased to
○ Protrusion of the third eyelid • Proliferative keratoconjunctivitis: eosinophilic q 8h.
○ Dry/lackluster corneal appearance ○ Dose frequency should not be decreased
○ Corneal ulceration: range from superficial Initial Database until STT values are ≥ 20 mm/min.
ulceration to corneal perforation Complete ophthalmic exam (p. 1137): ○ Dosage may be decreased to q 24h in rare
○ Signs of chronicity • STT cases if very favorable response occurs.
Corneal vascularization ○ Normal: ≥ 15 mm/min in dogs; varies in • Tacrolimus 0.02%-0.03% ointment or
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Corneal pigmentation cats aqueous suspension q 12h
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Corneal keratinization ○ Early or subclinical KCS: 11-14 mm/min ○ Used if no response to cyclosporine after
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○ Blepharitis ○ Mild to moderate KCS: 6-10 mm/min 3-6 weeks of treatment
○ Periocular dermatitis secondary to exudates ○ Severe KCS: ≤ 5 mm/min ○ 51% of dogs that fail to respond to
and/or self-trauma • Fluorescein dye application: secondary cyclosporine respond to tacrolimus.
○ Vision impairment secondary to chronic corneal ulceration is common. ○ Studies evaluating long-term safety have
keratitis • Intraocular pressure (IOP): normal IOP not been performed.
• Cats often show fewer clinical signs than values; normal IOP range is 15-25 mm Hg • Some ophthalmologists advocate increasing
dogs. (dogs and cats) the concentration of the lacrimostimulant if
there is no response (i.e., 0.2% cyclosporine
Etiology and Pathophysiology Advanced or Confirmatory Testing ointment to 2% solution).
• Immune-mediated adenitis: most common • Other quantitative test: phenol red-thread • Continue pilocarpine only if effective in
(dogs) tear test neurogenic cases until the condition has
• Congenital: lacrimal gland hypoplasia or ○ Dogs: normal 34.15 ± 4.45 mm/15 sec resolved.
aplasia (usually toy breeds) ○ Cats: normal 23.04 ± 2.23 mm/15 sec • Consider parotid duct transposition if no
• Drug-induced: general or topical anesthesia response to lacrimostimulants.
and atropine (transient keratoconjunctivitis TREATMENT
sicca [KCS]) Possible Complications
• Drug toxicity: some systemic medications Treatment Overview • Corneal ulceration
(e.g., sulfonamides; phenazopyridine; 5- Treatment goals are to stimulate tear produc- • Vision impairment from progressive corneal
aminosalicylic acid; etodolac) may cause tion, stabilize the tear film, and eliminate vascularization/pigmentation (uncontrolled
transient or permanent KCS. ocular pain by controlling ocular inflammation KCS)

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