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GOITER. Anatomy. The largest gland of the endocrine system The isthmus of the thyroid connects the right and left lobes The gland lies over the trachea down to cricoid cartilage. Anatomy. Arterial supply : superior thyroid artery from external carotid artery
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Anatomy • The largest gland of the endocrine system • The isthmus of the thyroid connects the right and left lobes • The gland lies over the trachea down to cricoid cartilage
Anatomy Arterial supply : superior thyroid artery from external carotid artery inferior thyroid artery from subclavian artery Venous drainage : to the internal jugular veins to the left brachiocephalic vein Lymphatic drainage: to the deep cervical nodes
Physiology of thyroid gland T3 – triiodothyronine (thyronine) T4 – tetraiodothyronine (thyroxin) Thyrocalcitonin ( calcitonin )
Physiology of thyroid gland Functions of thyroid hormones 1. Bone growth 2. CNS maturation 3. Beta-adrenergic effects
Physiology of thyroid gland 1. Increase cardiac output 2. Increase basal metabolic rate 3. Increase glycogenolysis, gluconeogenesis, lipolysis
Definition Goiter – the enlargement of the thyroid gland (local or diffuse) based on hyperplasia or degeneration
Pathogenesis of diffuse nontoxic goiter • Iodine deficiency results in hypothyroidism • Increasing TSH causes hypertrophy of thyroid
Pathogenesis of multinodular goiter • Follicles may become autonomous; certain follicles will have greater intrinsic growth and functional capability
Pathogenesis of toxic multinodular goiter • Follicles continue to grow and function despite decreasing TSH
Classification • Benign Nontoxic Conditions • Diffuse and Nodular Goiter • Benign Toxic Conditions • Toxic Multinodular Goiter • Graves’ Disease • Toxic Adenoma
Classification • Sporadic goiter • Endemic goiter
Classification • Hyperthyroid goiter • Euthyroid goiter • Hypothyroid goiter
Clinical features enlargement compressive symptoms thyrotoxicosis
Enlargement • 0 – the gland is not palpated • I – some part of the gland can be palpated • II- the gland can be seen although the neck is in a normal shape • III – shape of the neck is being changed • IV – configuration of the neck is being changed • V – an giant goiter with complications
Treatment • Suppressive Therapy • Antithyroid Medications • I-131 • Surgery