The most common thyroid diseases in dogs and cats

Štitnjača je endokrina žlijezda u kojoj se sintetiziraju hormoni tiroksin i trijodtironin. Oni su važni za pravilan rast i razvoj organizma. Najčešći poremećaji rada štitnjače u pasa i mačaka su hipotireoidizam i hipertireoidizam. Hipotireoidizam obilježava niska razina hormona štitnjače u krvi zbog smanjenja njezine funkcije. Uzroci hipotireoidizma su manjak joda, T3, TSH ili enzima koji sudjeluje u sintezi hormona, disgeneza štitnjače te limfocitni tireoiditis. Simptomi koji ga obilježavaju jesu letargija, pretilost te dermatološke promjene. Bolest se dijagnosticira na temelju kliničkog pregleda, hematološke i biokemijske pretrage te endokrinološkog testiranja. Koncentracija T4 ispod 15 nmol/L i koncentracija TSH 1-3 μg potvrđuje dijagnozu te se bolest liječi levotiroksinom. Hipertireoidizam obilježava visoka razina hormona štitnjače u krvi i najčešće ga uzrokuje karcinom štitnjače ili hiperplazija štitnjače. Simptomi specifični za hipertireoidizam su mršavljenje uz pojačan apetit, nemir i hiperreaktivnost te tahikardiju i pojavu srčanog šuma. Sumnja se postavlja kod prisutnosti kliničkih znakova ili palpacijom povećanih režnjeva žlijezde. Dijagnostika se temelji na određivanju koncentracije tiroksina u krvi. Terapija se zasniva na antitireoidnim lijekova ili aplikaciji radioaktivnog joda te se u nekim slučajevima preporučuje kirurško uklanjanje štitne žlijezde.The thyroid gland is an endocrine gland in which the hormones thyroxine and triiodothyronine are synthesized. They are important for the proper growth and development of the organism. The most common thyroid disorders in dogs and cats are hypothyroidism and hyperthyroidism. Hypothyroidism is characterized by a low level of thyroid hormone in the blood due to a decrease in its function. The causes of hypothyroidism are a lack of iodine, T3, TSH or an enzyme involved in hormone synthesis, thyroid dysgenezia, and lymphocytic thyroiditis. Most common symptoms are lethargy, obesity and dermatological changes. The disease is diagnosed on the basis of a clinical examination, hematological and biochemical tests, and an endocrinological test. The concentration of T4 below 15 nmol/L and TSH concentration between 1-3 μg confirm the diagnosis and the disease is treated with levothyroxine. Hyperthyroidism is characterized by a high level of thyroid hormone in the blood and is most often caused by thyroid cancer or thyroid hyperplasia. Symptoms specific to hyperthyroidism are weight loss with increased appetite, restlessness and hyperreactivity, as well as tachycardia and heart murmur. Suspicion is raised in the presence of clinical signs or palpation of enlarged lobes of the gland. The diagnosis is based on determining the concentration of thyroxine in the blood. Therapy is based on antithyroid drugs or a radioactive iodine application and in some cases surgical removal of the thyroid gland is recommended