Avaliação clínica, laboratorial e ecocardiográfica de gatos domésticos hipertireóideos no período entre 2007 e 2008

Abstract

Hyperthyroidism is the most common endocrine disorder of older cats. Due to the progressive nature of the disease, the identification of a sublcinical stage is essential in order to have a better control of the disease. The present study was a survey of the frequency of feline hyperthyroidism in Rio de Janeiro, from March, 2007 to April, 2008. The purpose of this study was to perform an evaluation of the clinical, laboratorial and echocardiographic aspects in a feline population of naturally acquired hyperthyroidism. Moreover, this study wants to emphasize the palpation and classification of thyroid lobes. This is the first report in Brazil that classifies the thyroid lobes in a standardized scale. A total of 51 cats coming from 20 different districts of Rio de Janeiro and also from Niterói were evaluated in a feline practice in Botafogo. The selection of the cats was done by the documentation of an elevation of total T4 levels by radioimmunoassay. The animals were dividided in two groups according to the thyroid palpation: group I (nonpalpable thyroid lobe) and group II (palpable thyroid lobe). Laboratorial and complete clinical evaluation were performed in all cats. The clinical evaluation included behavioral evaluation, body weight, body condition, dermatologic, cardiopulmonary auscultation, thyroid palpation and systolic blood pressure reading. Besides the total T4, the following exams were performed: urea, creatinine, alanine aminotransferase (ALT), alkaline phosphatase (ALP) and glucose. Thirty one cats had an echocardiogram performed. This study concluded that the clinical, laboratorial and echocardiographic parameters were similar between the two groups. However, the T4 levels were significantly lower in the nonpalpable thyroid group. Vocalization, tachypnea, changes in cardiopulmonary auscultation, hypertension, increase in alanine aminotransferase and echocardiographic changes observed in cats from group I emphasizes the importance of an early diagnosis before the disease attacks organs as liver, kidneys and heart.