FUNÇÃO TIREOIDIANA DE CÃES COM LEISHMANIOSE VISCERAL

Abstract Several non-thyroid factors such as age, breed, concomitant diseases and use of certain drugs might influence the diagnosis of hypothyroidism in dogs. Changes in the concentrations of thyroid hormones due to non-thyroid illnesses are named euthyroid sick syndrome. The aim of this study was to evaluate the influence of visceral leishmaniasis on thyroid function in dogs without clinical signs of hypothyroidism, with or without azotemia. Positive animals for leishmaniasis were divided into six groups (absence or presence of hypoalbuminemia, normal or increased creatinine, normal or increased urea). The effect on these groups was evaluated on the thyroid-stimulating hormone (TSH), total thyroxine (TT4) and free thyroxine (FT4) concentrations. Dogs that were positive for leishmaniasis, by ELISA test, presented thyroid-stimulating hormone serum concentrations greater than seronegative animals, while total thyroxine and free thyroxine in dogs with leishmanisis were lower (P≤0.01) when compared to healthy dogs. However, the results were within the values for euthyroid animals. In seropositive dogs for leishmaniasis, TT4 showed statistically significant difference (P≤0.04) in the group with hypoalbuminemia compared to the group with normoalbuminemia, respectively, 1,01ug/dL and 1.4 g/dL. Based on this study, we could conclude that positive dogs for visceral leishmaniasis have not presented euthyroid sick syndrome, although when compared to healthy dogs, FT4 and TT4 were reduced and TSH increased.摘要 多种非甲状腺相关因素，包括年龄、品种、伴随疾病及特定药物使用，均可对犬甲状腺功能减退症的诊断造成干扰。由非甲状腺疾病引发的甲状腺激素浓度改变，被定义为正常甲状腺病态综合征（euthyroid sick syndrome）。本研究旨在评估内脏利什曼病（visceral leishmaniasis）对无甲状腺功能减退临床症状、伴或不伴氮质血症（azotemia）的犬甲状腺功能的影响。研究将利什曼病检测阳性的受试犬分为6组：低白蛋白血症（hypoalbuminemia）与否、肌酐水平正常或升高、尿素水平正常或升高。通过检测各组的促甲状腺激素（thyroid-stimulating hormone, TSH）、总甲状腺素（total thyroxine, TT4）及游离甲状腺素（free thyroxine, FT4）浓度，评估上述分组对甲状腺功能的影响。经酶联免疫吸附试验（ELISA）确认利什曼病阳性的犬，其血清促甲状腺激素浓度高于血清阴性个体；而利什曼病阳性犬的总甲状腺素与游离甲状腺素水平均较健康犬更低（P≤0.01），但上述结果仍处于正常甲状腺动物的参考区间内。在利什曼病血清阳性犬中，低白蛋白血症组的总甲状腺素水平与正常白蛋白血症（normoalbuminemia）组相比存在统计学差异（P≤0.04），两组对应数值分别为1.01μg/dL与1.4g/dL。基于本研究结果，可得出如下结论：内脏利什曼病阳性犬并未出现正常甲状腺病态综合征，尽管与健康犬相比，其游离甲状腺素与总甲状腺素水平降低、促甲状腺激素水平升高。