Diagnosis and Medical Management of Keratoconjunctivitis Sicca (KCS) in the Dog

Abstract

Keratoconjunctivitis sicca (KCS) is a common ophthalmic disorder in the dog. The diagnosis and medical management of 50 dogs suffering from KCS were studied and reviewed. The sex ratio of the 50 KCS affected patients between males and females was 1:1. The mean age of affected dogs was 6.1 years old. The leading KCS affected breeds were Shih-Tzu (20%), Cocker Spaniel (16%), and Yorkshire Terrier (16%). On physical examination, the most commonly concurrent diseases are dermatological disorders associated with imbalanced immune response, such as atopy and demodicosis. Tear production and ocular lesions were assessed by Schirmer tear test (STT), slit-lamp biomicroscope, ophthalmoscope, fluorescein stain, and microbiological cultures. Following ophthalmic examination, 30 dogs showed bilateral disease and 20 dogs had unilateral disease. Bilateral KCS cases tend to have more severe clinical lesions compared with the unilateral ones. Among the 17 KCS bilaterally affected dogs with STT readings, 10 eyes were mild or early KCS (STT: 11 to 14 mm/min), 4 eyes were moderate KCS (6 to 10 mm), 20 eyes were severe KCS (0-5 mm). Among the 10 dogs with unilateral disease, 6 eyes were moderate KCS (6 to 10 mm) , 4 eyes were severe KCS (0-5 mm). Abnormal ocular findings included mucoid or mucopurulent discharge, loss of normal corneal luster, conjunctival hyperemia, pigmentary keratitis, ulcerative keratitis, corneal vascularization, and vision loss. Pigmentary change of cornea were found in 21 dogs (42%), corneal vascularization in 16 dogs (32%), 19 dogs with ulcerative keratitis (38%), and 10 dogs with vision loss (20%). Microbiological cultures, obtained by conjunctival sac sampling of infected KCS cases, revealed that Staphylococcus spp. (aureus or intermedius) was the leading bacterial pathogen. Medical management of the KCS cases included the use of tear replacement ointment (all 50 cases), 1%-2% cyclosporine solution (80% cases), antibiotics (40% cases), and 1% pilocarpine in food (4 cases). Twenty (79%) of 38 follow-up cases showed improvement of corneal and conjunctival lesions , while 22 dogs (58%) of 38 follow-up cases showed improved tear production. AII improved cases have been treated by topical cyclosporine solution. The improvement of corneal and conjunctival lesions was significant and dramatic within a couple of weeks particularly following treatment by topical cyclosporine solution.