pediatrics
Congenital Goiter
Etiology of Congenital Goiter
Congenital goiter may be caused by dyshormonogenesis (abnormal thyroid hormone production), transplacental passage of maternal antibodies, or transplacental passage of goitrogens. Some causes of congenital goiter are hereditary. Genetic defects in thyroid hormone production result in increased levels of thyroid-stimulating hormone (TSH), which in turn can cause congenital goiter. Goiter is present in about 15% of cases of Congenital hypothyroidism . There are a number of gene abnormalities that cause dyshormonogenesis (eg, Dyshormonogenesis can result from a defect in any of the steps in thyroid hormone biosynthesis, including Failure to concentrate iodide Defective organification of iodide due to an abnormality in the thyroid peroxidase enzyme or in thehydrogen peroxide–generating system Defective thyroglobulin synthesis or transport Abnormal iodotyrosine deiodinase activity have mild Hypothyroidism in Infants and Children or euthyroidism, goiter, and Women with an autoimmune thyroid disorder produce antibodies that may cross the placenta during the third trimester. Depending on the disorder, the antibodies either block thyroid-stimulating hormone receptors, causing hypothyroidism, or stimulate them, causing Hyperthyroidism in Infants and Children . Typically, in affected infants, the changes in hormone secretion and the associated goiter resolve spontaneously within 3 to 6 months. Goitrogens, such asamiodarone, iodine, or antithyroid drugs (eg,propylthiouracil,methimazole), taken by the mother can cross the placenta, sometimes causing hypothyroidism and rarely causing goiter. 