(See also Simple Nontoxic Goiter Simple Nontoxic Goiter Simple nontoxic goiter, which may be diffuse or nodular, is noncancerous hypertrophy of the thyroid without hyperthyroidism, hypothyroidism, or inflammation. Except in severe iodine deficiency... read more in adults and Overview of Thyroid Function Overview of Thyroid Function The thyroid gland, located in the anterior neck just below the cricoid cartilage, consists of 2 lobes connected by an isthmus. Follicular cells in the gland produce the 2 main thyroid hormones... read more .)
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 Congenital hypothyroidism Hypothyroidism is thyroid hormone deficiency. Symptoms in infants include poor feeding and growth failure; symptoms in older children and adolescents are similar to those of adults but also... read more . There are a number of gene abnormalities that cause dyshormonogenesis; they commonly have an autosomal recessive form of inheritance, and many are single-gene defects.
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 the hydrogen peroxide–generating system
Defective thyroglobulin synthesis or transport
Abnormal iodotyrosine deiodinase activity
Children with Pendred syndrome have mild hypothyroidism Hypothyroidism in Infants and Children Hypothyroidism is thyroid hormone deficiency. Symptoms in infants include poor feeding and growth failure; symptoms in older children and adolescents are similar to those of adults but also... read more or euthyroidism, goiter, and sensorineural hearing loss Pathophysiology Worldwide, about half a billion people (almost 8% of the world's population) have hearing loss (1). More than 10% of people in the US have some degree of hearing loss that compromises their... read more due to a genetic abnormality of a protein (pendrin) involved in iodine transport and cochlear function. Although Pendred syndrome is caused by a genetic defect, it rarely manifests in the newborn period.
Transplacental passage of maternal antibodies
Women with an autoimmune thyroid disorder produce antibodies that may cross the placenta during the 3rd trimester. Depending on the disorder, the antibodies either block thyroid-stimulating hormone receptors, causing hypothyroidism, or stimulate them, causing hyperthyroidism Hyperthyroidism in Infants and Children Hyperthyroidism is excessive thyroid hormone production. Diagnosis is by thyroid function testing (eg, free serum thyroxine, thyroid-stimulating hormone). Treatment is with <span class="... read more . Typically, in affected infants, the changes in hormone secretion and the associated goiter resolve spontaneously within 3 to 6 months.
Transplacental passage of goitrogens
Goitrogens, such as amiodarone or antithyroid drugs (eg, propylthiouracil, methimazole), taken by the mother can cross the placenta, sometimes causing hypothyroidism and rarely causing goiter.
Symptoms and Signs of Congenital Goiter
The most common manifestation of congenital goiter is firm, nontender enlargement of the thyroid. Enlargement is most often diffuse but can be nodular. It may be noticeable at birth or detected later. In some patients, enlargement is not directly observable, but continued growth can cause deviation or compression of the trachea, compromising breathing and swallowing. Many children with goiters are euthyroid, but some present with hypothyroidism or hyperthyroidism.
Diagnosis of Congenital Goiter
If the diagnosis of congenital goiter is suspected, thyroid size is typically assessed by ultrasonography. Free thyroxine Thyroxine (T4) measurement The thyroid gland, located in the anterior neck just below the cricoid cartilage, consists of 2 lobes connected by an isthmus. Follicular cells in the gland produce the 2 main thyroid hormones... read more (T4) and thyroid-stimulating hormone Thyroid-stimulating hormone (TSH) measurement The thyroid gland, located in the anterior neck just below the cricoid cartilage, consists of 2 lobes connected by an isthmus. Follicular cells in the gland produce the 2 main thyroid hormones... read more levels are measured.
Treatment of Congenital Goiter
Surgical treatment of enlargement causing symptoms related to compression
Sometimes thyroid hormone
Hypothyroidism is treated with thyroid hormone.
Goiters that compromise breathing and swallowing can be treated surgically.
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