Doença renal crônica e uremia em gatos domésticos
Ambrosio, Marcella Barrella
This masters dissertation was composed of two different parts, resulting in two scientific articles. The first article consisted of a comparative study between macroscopic, histological and immunohistochemical features changes in 25 cats with chronic kidney disease (CKD) with interstitial fibrosis. The morphological diagnosis of chronic tubular interstitial nephritis (CTIN) was the most commonly observed (20/25) and five cats (5/25) had primary glomerular disease. Reduction of kidney size was observed in 22 of the 25 cases and the reduced kidneys had higher degrees of interstitial fibrosis (p = 0.021) and the reduction in kidney size was correlated with the severity of chronic inflammation (p = 0.0039) and interstitial fibrosis (p <0.001). The rounded gross appearance of the kidneys, observed only in CTIN, was attributed to interstitial fibrosis, tubular atrophy, glomerular obsolescence and reduced thickness of the cortical layer laterally to the renal hilum, a region compatible with the renal poles. Cellular immunostaining for α-smooth muscle actin (α-SMA) was observed in all stages of CKD, demonstrating the role of myofibroblasts in the different processes and degrees of severity of CKD with the development of interstitial fibrosis. The second study aimed to determine the prevalence and clinical aspects of uremia in cats, in addition to the pathological aspects and the anatomical distribution of nonrenal uremic lesions. During the studied period (from January 2000 to October 2019), 1,330 cats were necropsied in LPV-UFSM, of which 78 had nonrenal uremic lesions (6%). In 75% of the cases, prolonged azotemia and uremia were the result of kidney disease. CKD in the form of NTIC was the most commonly observed renal process. The most frequente nonrenal uremic lesions observed in cats were pulmonary edema and hemorrhagic and/or ulcerative gastritis. Soft tissue mineralization and parathyroid hyperplasia were uncommon findings and fibrous osteodystrophy was not observed. The multisystemic presentation of nonrenal uremic lesions was observed only in 24% of the cases, and some uremic lesions usually observed in uremic dogs were not observed in the cats of this study.