Thyroid Hormone Administration Pediatric Endocrine Society

Children confirmed to have central hypothyroidism should have MRI of the brain and pituitary to rule out central nervous system lesions. Alternatively this pattern of thyroid dysfunction develops in children who use certain medications (eg, antiseizure medications, immune checkpoint inhibitors) or who have certain illnesses (euthyroid sick syndrome). For children with euthyroid sick syndrome, thyroid function normalizes as the clinical status improves. Even when treated promptly, severe congenital hypothyroidism may still cause subtle developmental problems and hearing loss. Hearing loss may be so mild that it is not detected during the routine newborn screening, but it may still interfere with language learning.

Conditions & Treatments

Severe congenital hypothyroidism, even when treated promptly, may still cause subtle developmental problems and sensorineural hearing loss (3, 4). Hearing loss may be so mild that initial screening misses it, but it may still interfere with language acquisition. For babies and small children, because there is no reliable liquid preparation, the pill should be crushed just before administration and mixed with a small volume of water, human (breast) milk, or formula. This mixture can be given to the baby or small child using a spoon, dropper, or infant syringe.

Children who have Down syndrome are at increased risk of congenital hypothyroidism. Eventually, infants may develop dry, cool, mottled skin, coarse facial features (such as a flat, broad nasal bridge and a puffy face), and a slightly open mouth with an synthroid france enlarged tongue. Hypothyroidism can occur in a developing fetus or newborn or during childhood or adolescence. Once-daily administration and close follow-up with your endocrinologist is needed to ensure the best possible results. Dyshormonogenesis has multiple types, which can result from a defect in any of the steps of thyroid hormone biosynthesis (see Congenital Goiter). Copyright © 2018 American Academy of Pediatrics and Pediatric Endocrine Society.

What Are the Side Effects of Thyroid Hormone Medication?

To date, there is limited experience with these liquid formulations in congenital hypothyroidism, and it is unclear whether dosing is the same as for crushed tablets. If levothyroxinemust be given intravenously, 75% of the oral dose should be used. Although T3 is the biologically active thyroid hormone, levothyroxine (T4) is usually given as monotherapy and it is not necessary to use T3 because the majority of brain T3 arises through enzyme conversion of T4 to T3. In children and adolescents with suspected hypothyroidism (elevated TSH and low T4/free T4), thyroid antibody titers (to thyroid peroxidase and thyroglobulin) should be measured to evaluate for autoimmune thyroiditis.

• For those who have an illness, thyroid function becomes normal once the illness goes away.
• Autoimmune thyroiditis occurs most commonly during adolescence, but it also occurs in younger children, typically after the first few years of life.
• However, pregnant women in the United States can develop mild iodine deficiency because their bodies need more iodine when they are pregnant.
• To date, there is limited experience with these liquid formulations in congenital hypothyroidism, and it is unclear whether dosing is the same as for crushed tablets.

In the United States, acquired hypothyroidism is most commonly caused by Hashimoto thyroiditis (autoimmune thyroiditis). In Hashimoto thyroiditis, the body’s immune system attacks the cells of the thyroid gland, causing chronic inflammation and decreased production of thyroid hormones. About 50% of affected children have a family history of autoimmune thyroid disease. Hashimoto thyroiditis occurs most commonly during adolescence, but it can also occur in younger children, typically after the first few years of life. Children who have Down syndrome or Turner syndrome are at increased risk of Hashimoto thyroiditis. Children who have other genetic conditions (such as DiGeorge syndrome or Prader-Willi syndrome) are at increased risk of acquired hypothyroidism that is not autoimmune.

Thyroid hormone is the medication prescribed by your child’s doctor to treat hypothyroidism, also known as an underactive thyroid gland. The body makes 2 forms of thyroid hormone, levothyroxine (T4) and triiodothyronine (T3). Generally, prescribed thyroid hormone comes in the form of T4, which is converted by the body to the active form, T3. Brand names you may encounter for this medication include Levothroid, Levoxyl, Synthroid, and Unithroid. Babies who need thyroid hormone because of hypothyroidism must be given this medication on a regular basis so that their brains will develop normally.

Treatment regimens

There is controversy regarding treatment of patients with subclinical hypothyroidism. Treatment can be considered if patients have a goiter, positive thyroid antibodies, decreased growth velocity, or hyperlipidemia. If not treated, thyroid function should be monitored every 6 to 12 months for a period of time to make sure function does not worsen. Thyroid testing should be repeated in patients with subclinical hypothyroidism because the majority of patients will have normalized TSH levels on repeat testing (1).

For those who have an illness, thyroid function becomes normal once the illness goes away. Routine newborn screening detects hypothyroidism before clinical signs are evident (1). If screening is positive, confirmation is necessary with thyroid function tests, including measurement of free serum thyroxine (free T4) and thyroid-stimulating hormone (TSH) (2). Free T4 is a better measure of thyroid function than total T4 in these patients because the levels of thyroid-binding proteins (thyroid-binding globulin, transthyretin, and albumin) affect total T4 levels. It is particularly important to measure free T4 rather than total T4 in preterm or low birthweight infants in whom alterations in binding proteins lead to low total T4 levels despite normal free T4 levels.

What is Thyroid Hormone?

• In another rare cause, the pituitary gland is abnormally formed and fails to stimulate the thyroid gland to produce thyroid hormones.
• After a dose adjustment in older children, TSH and free T4 levels are measured in 6 to 8 weeks.
• Other less common causes of acquired hypothyroidism include radiation therapy to the head and neck for certain cancers and the use of certain medications (for example, lithium or amiodarone).
• A good way to keep track of your child’s doses is to get a 7-day pillbox and fill it at the beginning of the week.

Thyroid function tests are also done in older children and adolescents in whom hypothyroidism is suspected. Levothyroxine is typically given in tablet form because of the inconsistent delivery of compounded liquid formulations prepared by individual pharmacists. Tablets can be crushed, mixed with a small amount (1 to 2 mL) of water, breast milk, or non–soy-based formula, and given orally by syringe. The absorption oflevothyroxine may be decreased if it is given with soy formula, iron, or calcium. Commercial oral liquid formulations are available for children of any age and are available as single-dose ampules in different strengths or as 100-mL bottles with the dose selected by syringe volume.

Babies and older children also need thyroid hormone for normal growth, among other important body functions. In some countries, congenital hypothyroidism occurs when the mother does not get enough iodine in her diet while pregnant (iodine deficiency), and a woman’s body needs more iodine when she is pregnant. Iodine deficiency is rare in areas of the world where iodine is added to table salt but is more common in areas where people do not get enough iodine in their diet.