VETgirl Q1 2020 Beat e-Newsletter

MANAGEMENT OF NON-HEALING CORNEAL ULCERS DR. SHELBY REINSTEIN, DACVO Veterinary Specialty & Emergency Center, Levittown, PA

In the VETgirl Real-Life Rounds webinar, “What’s the deal, it just won’t heal: Management of non-healing corneal ulcers,” Dr. Shelby Reinstein, DVM, DACVO reviewed non-healing corneal ulcers.

KEY HIGHLIGHTS

(KCS, dry eye) is exceedingly common in dogs, and both quantitative and qualitative tear film abnormalities will interfere with normal corneal healing and result in a refractory corneal ulcer. A variety of primary corneal diseases will prevent or delay normal cell healing. Lipid, cholesterol, or calcium deposition in the cornea will inhibit the formation of strong cellular attachments. Corneal edema can lead to the formation of bullae, or fluid pockets, in the anterior corneal stroma. These areas are predisposed to ulceration that is often refractory in nature. The excessive stromal fluid inhibits normal epithelial cell attachment to the underlying stroma. Finally, superficial refractory ulceration that has no discernable underlying cause is known as spontaneous chronic corneal epithelial defects, or SCCEDs (“Boxer ulcers”, indolent ulcers). 2 SUPERFICIAL CHRONIC CORNEAL EPITHELIAL DEFECTS (SCCEDS) The boxer is the most common breed to develop SCCEDs, comprising approximately 25% of cases. Other breeds that have been reported to have an increased incidence of SCCEDs include poodle and poodle crosses, Welsh Corgis, Labrador retrievers, and German Shepherds and their crosses. The average age of dogs affected with SCCEDs is 7-9 years with

Refractory Corneal Ulcers Refractory corneal ulcers are superficial ulcerations that are not progressive but yet, also fail to heal within 5-7 days. The most common type of refractory corneal ulcers in dogs is a chronic corneal epithelial defect (CCED), otherwise known as an indolent ulcer. CCEDs are due to a failure of the epithelial cells to develop normal attachments to the underlying basement membrane. Any condition that interferes with normal The first step in the management of a refractory corneal ulcer is to determine the underlying etiology. A thorough physical and ophthalmic examination is essential to identify factors that could be contributing to the refractive healing state. Refractory corneal ulcers can be caused by primary corneal disease or secondary to other processes. Eyelid abnormalities are quite common and may lead to a non-healing corneal ulcer. Specifically, persistent corneal trauma from distichia, ectopic cilia, entropion, or eyelid masses will interfere with normal cellular healing. Abnormalities that preclude normal blinking can predispose to refractory ulceration; lagophthalmos (incomplete blinking) may be associated with poor eyelid conformation, buphthalmos, exophthalmos, or cranial nerve deficits. Keratoconjunctivitis sicca epithelialization or epithelial cell adhesion can result in a CCED. 1 CAUSES OF REFRACTORY CORNEAL ULCERS

no dramatic sex predilection. SCCEDs are often easily diagnosed by recognizing the typical clinical appearance of a superficial ulcer with a non-adherent epithelial border. Fluorescein stain can be classically seen diffusing under this loose lip of epithelial cells and appears as a less intense ring of stain uptake. SCCEDs are most often located in the axial or paraxial cornea and are vascularized approximately 60% of the time. Without proper treatment, SCCEDs may persist for months to even years with an average time to referral of 7.5 weeks. (continued)

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