Журнал заболеваний щитовидной железы и терапии
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ISSN: 2167-7948
ISSN: 2167-7948
Isabela M. Benseñor, Paulo A. Benseñor
Thyroid disorders are common diseases in worldwide. This chapter provides information on embryology, anatomy, and physiology of the thyroid gland, foetal and neonatal thyroid metabolism, and definition and classification of thyroid disorders. It shows the normal values for the commonly measured thyroid function tests. Hypothyroidism is defined as a state in which the hypothalamic-pituitary-thyroid axis is failing, or is in danger of failing, to produce sufficient T4. Classification is according to: site of abnormality: primary (thyroid), secondary (pituitary), and tertiary (hypothalamus); onset of abnormality: congenital (prenatal) or acquired (postnatal); severity: compensated hypothyroidism and decompensated hypothyroidism. Goitre refers to thyroid gland enlargement [1]. Thyroid is sub-classified according to thyroid function: hypothyroid, hyperthyroid, or euthyroid. The chapter additionally includes information on future developments, when to involve a specialist centre, controversial points, common pitfalls, case histories and further reading, and useful information for patients and parents. Chronic diseases are the leading cause of death and hospitalization in Brazil [2]. In this regard, consideration has been attracted to cardiovascular, neoplastic, respiratory, digestive and mental diseases, but not to thyroid disorders. In such manner, consideration has been attracted to cardiovascular, neoplastic, respiratory, stomach related and mental illnesses, yet not to thyroid issue. This inconsistency between the group and individual approach probably arises because diagnosis, treatment, screening and prevention of thyroid diseases have been outstanding actions of both public health and medicine over the last two centuries. Nowadays, occurrences of patients with myxedematous facies and Graves's disorder are less frequent because of the combination of awareness among physicians of the symptoms and signs of thyroid dysfunction, accessibility of thyroid tests and utilization of reasonable medicines for thyroid substitution or for blocking hyper function of the thyroid organ. Thyroid hormones are vital to the regulation of multiple cellular and organ functions, including affecting the activity of enzymatic processes, regulation of hormone function, and maintenance of metabolism. Diseases of the thyroid gland are among the most frequently diagnosed endocrinopathies of small animals. Hyperthyroidism is most commonly diagnosed in geriatric cats and the aetiology is unknown. Various therapies can be effective in managing or curing this disease and earlier recognition has led to improved outcomes. Hypothyroidism is more commonly diagnosed in dogs and may be diagnosed in dogs of any age. Hypothyroidism is most often caused by either lymphocytic thyroiditis or idiopathic atrophy, although other causes such as drug