Patologia ocular em animais domésticos

Abstract

This doctoral thesis involved the study of ocular and periocular diseases affecting domestic animals, and included one manuscript about lesions of surgical pathology and one manuscript about hyphema in dogs and cats submitted to necropsy. In the first part, 33,075 reports of hystopathological exams performed in a veterinary pathology diagnostic laboratory in the Central Region of the State of Rio Grande do Sul, Brazil, over 50 years. From the total amount, 540 (1.6%) concerned ocular and periocular lesions. For various reasons ninety specimens were excluded from the study, 450 remaining. More than half of all cases consisted of samples from dogs (53.5%), followed by cattle (28.2%), cats (11.1%), horses (5.1%) sheep (1.3%), rabbits (0.4%), and pig (0.2%). The eyelids were the most prevalent (248/450) site of lesions in each of the species studied, followed by third eyelid (73/450), and conjunctiva (27/450). In dogs lesions in sebaceous glands were the most common findings (75/241), followed by melanocytic tumors and nonspecific conjunctivitis. In cattle, anatomical sites affected by ocular and periocular lesions, in decreasing order of frequency, were eyelid, cornea and third eyelid. Squamous cell carcinoma (SCC) alone accounted for 80.3% of all lesions diagnosed in cattle. Neoplasia accounted for most of the lesions diagnosed in cats (39/50 cases); all of these were malignant, and SCC, hemangiosarcoma and fibrosarcoma were the most common types diagnosed. In horses, 19 out of 23 submissions were neoplasms and most were sarcoid (8/23) and SCC (8/23). In sheep, all samples represented SCC of the eyelids (5) and third eyelid (1). For the second manuscript, cases of hyphema in dogs and cats submitted to necropsy were examined. Twenty cases, 14 dogs and six cats of several ages and breeds and of both sexes were included in the study. Hyphema presented as a unilateral (14 cases out of 20) or bilateral (6/20) disorder in dogs and cats and extension of hemorrhage varied from minimal to diffuse. Hyphema was secondary to systemic disease (15/20) or occurred as a primary ocular lesion (5/20) in four dogs and one cat. Primary hyphema was always unilateral. In four of these cases, the cause of hyphema was trauma and remaining case was caused by phacoclastic uveitis in a dog with bilateral hypermature cataract. Various causes of bleeding disorders were found related to secondary hyphema: in decreasing order of frequency, they included vasculitis (8/15), systemic hypertension (5/15), and acquired coagulopathies (2/15).