Today's Veterinary Practice

JUL-AUG 2014

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July/August 2014 Today's veterinary Practice 21 Diagnosis & TreaTmenT of KeraToconjuncTiviTis sicca in Dogs | Anti-Inflammatory Agents Anti-inflammatory therapy may be useful if conjunctival inflammation is severe, possibly occluding lacrimal excre- tory ducts. Corticosteroids can be used on a short-term basis (1–4 weeks); discontinue if patient is nonresponsive. Only consider using them, though, in animals with no uptake of fluorescein dye. Apply topical prednisolone acetate 1% or dexamethasone 0.1% topically Q 6 to 8 H. Use caution when using topical corticosteroids because dogs with KCS can develop ulcer- ative keratitis, infection, and keratomalacia. Mucolytics If a patient with KCS has copious mucopurulent discharge, acetylcysteine 5% is often administered; however, its use is not common due to its expense and toxicity to the epithe- lium. In addition, the mucous layer provides some protec- tion to the cornea. Frequent flushing with sterile eyewash, instead, simply removes mucus without side effects. SURGICAL MANAGEMENT OF KCS After 3 to 6 months of medical therapy with no response, surgical treatment for KCS can be considered. Surgery is not always successful and, even when it is, patients often need ongoing topical therapy. 29 Treatment of Choice Parotid duct transposition—in which the parotid duct and papilla are dissected free of the oral mucosa, mobilized, and transposed to the inferior cul-de-sac—is the surgical treatment of choice. Open and closed methods have been described. Challenges This surgery is often performed by a board-certified oph- thalmologist due to the difficulty of the procedure in some dogs and often complicated aftercare. Potential complica- tions include severance of the duct, occlusion of the duct secondary to scar formation, development of white miner- al crystalline corneal deposits, facial dermatitis, periocular pyoderma, and excessive saliva production. PROGNOSIS & MONITORING Prognosis depends on the underlying etiology of KCS and the patient's response to treatment (Table 2). If KCS does not respond to medical therapy, the prognosis is worse for vision retention. In addition, most patients will require life- long therapy with topical immunosuppressive medications. Recently, chronic keratitis treated long-term with tacroli- mus or CsA has been tenuously associated with increased risk for corneal squamous cell carcinoma. 30 However, because the study was retrospective, clinical data are lack- ing, and KCS alone may have resulted in a predisposition to this condition. While this study is interesting, KCS should be treated as described in this article. Dogs with a diagnosis of KCS should be evaluated every 6 to 12 months to assess effect of treatment and progres- sion of disease. n csa = cyclosporine a; Kcs = keratoconjunctivitis sicca; PTf = precorneal tear film; sTT = schirmer tear test; sTT1 = schirmer tear test 1; TBuT = tear film breakup time References 1. King-Smith PE, Fink BA, Fogt N, et al. The thickness of the human precorneal tear film: Evidence from reflection spectra. Invest Ophthalmol Vis Sci 2000; 41(11):3348-3359. 2. Prydall JI, Artal P, Wood H, Campbell FW. Study of human precorneal tear film thickness and structure using laser interferometry. Invest Ophthalmol Vis Sci 1992; 33(6):2006-2011. 3. Franzco IC. Fluids of the ocular surface: Concepts, functions, and physics. Clin Exp Ophthalmol 2012; 40(6):634-643. 4. Herring IP, Pickett JP, Champagne ES, Marini M. Evaluation of aqueous tear production in dogs following general anesthesia. JAAHA 2000; 36(5):427- 430. 5. Dodam JR, Branson KR, Martin DD. Effects of intramuscular sedative and opioid combinations on tear production in dogs. Vet Ophthalmol 1998; 1(1):57-59. 6. Sanchez RF, Mellor D, Mould J. Effects of medetomidine and medetomidine-butorphanol combination on Schirmer tear test 1 readings in dogs. Vet Ophthalmol 2006; 9(1):33-37. 7. Kaswan RL, Martin CL, Chapman WL. Keratoconjunctivitis sicca: Histopathologic study of nictitating membrane and lacrimal glands from 28 dogs. Am J Vet Res 1984; 45(1):112-118. 8. Martin CL, Kaswan R. Distemper-associated keratoconjunctivitis sicca. JAAHA 1985; 21(3):355-359. 9. Matheis FL, Walder-Reinhardt L, Spiess BM. Canine neurogenic keratoconjunctivitis sicca: 11 cases (2006-2010). Vet Ophthalmol 2012; 15(4):288-290. 10. Naranjo C, Fondevila D, Leiva M, et al. Characterization of lacrimal gland lesions and possible pathogenic mechanisms of keratoconjunctivitis sicca in dogs with leishmaniosis. Vet Parasit 2005; 133(1):37-47. 11. Westermeyer HD, Ward DA, Abrams K. Breed predisposition to congenital alacrima in dogs. Vet Ophthalmol 2009; 12(1):1-5. 12. Klauss G, Giuliano EA, Moore CP, et al. Keratoconjunctivitis sicca associated with administration of etodolac in dogs: 211 cases (1992-2002). JAVMA 2007; 230(4):541-547. 13. Trepanier LA, Danhoff R, Troll J, Watrous D. Clinical findings in 40 dogs with hypersensitivity associated with administration of potentiated sulfonamides. J Vet Intern Med 2003; 17(5):647-652. 14. Bryan GM, Slatter DH. Keratoconjunctivitis sicca induced by ULCER ThERAPy While superficial, uncomplicated ulcers can be treated with triple antibiotic ointment, csa, and lubricants, ulcers secondary to Kcs are usually complicated and require more intensive therapy. 1. Perform culture and cytology on stromal ulcers and ulcers with a cellular infiltrate. 2. Apply topical antibiotics Q 2 H to infected ulcers until the cornea stabilizes. appropriate antibiotics include: • ciprofloxacin 0.03% ophthalmic solution, or other ophthalmic fluoroquinolones, used alone or • Tobramycin 0.03% ophthalmic solution and cefazolin (33 mg/mL in artificial tear solution). 3. Use topical atropine to dilate the pupil and decrease ciliary spasm, even though it is associ- ated with decreased tear production. if the patient remains uncomfortable while on atropine therapy, the addition of oral nsaiDs may be considered. 4. Consider conjunctival graft placement in addition to Kcs therapy and frequent antibiotic therapy for deep ulcers.

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