Hypothyroidism in Infants and Children

Hypothyroidism in Infants and Children: Frequently Asked Questions

Here are some frequently asked questions related to hypothyroidism in children.

Q: Our daughter was recently diagnosed with hypothyroidism. She was late entering puberty (all of her friends had had menstrual periods for awhile but she didn’t) and she had begun to have real problems at school. She had also complained she always felt cold. I didn’t realize those things could mean you had something serious going on. Should I have had her see a doctor sooner?

A: Don’t feel bad. Many of the symptoms of hypothyroidism found in older children and adults are subtle and appreciated far more with hindsight after the hypothyroidism is diagnosed. It’s good your daughter’s condition was diagnosed and that she began treatment. Many of the symptoms that bother her will improve markedly or disappear after she has taken thyroid hormone for several months.

Q: I was confused when I asked my doctor about my child’s thyroid hormone level and she talked about T3 and T4 values. What do these have to do with thyroid hormone?

A: Two slightly different forms of thyroid hormone are found in the blood. One is abbreviated as T3 (thyroid hormone with 3 attached iodines) and the other as T4 (thyroid hormone with 4 attached iodines). Both are considered as thyroid hormone. The form of thyroid hormone found in replacement tablets is T4. The body naturally converts T4 into T3.

Q: The doctor said my son’s hypothyroidism isn’t due to a problem in the thyroid gland, but instead something wrong in another gland, one in his head. What does that mean?

A: Although the vast majority of cases of childhood hypothyroidism result from a problem in the thyroid gland, about 5% of cases are due to a problem in the pituitary gland. This tiny endocrine gland located under brain tissue produces and releases the hormone TSH, which stimulates the thyroid gland to produce thyroid hormone. In your son’s case, his thyroid gland isn’t making enough thyroid hormone because it isn’t receiving enough TSH to stimulate it to do so. Treatment is the same as for any other case of hypothyroidism: replacement of the missing thyroid hormone with synthetic hormone taken in tablet form.

Q: I was diagnosed with Graves’ disease in my late 20s. I took an antithyroid medicine to control my hyperthyroidism during pregnancy. When my daughter was born, she had hypothyroidism, but it was mild and went away when she was a baby. Now she is in her early 30s, and she was just diagnosed withHashimoto’s thyroiditis and hypothyroidism. Are these things related?

A: Your daughter’s temporary bout with hypothyroidism in infancy was probably due to the medication that you took for your hyperthyroidism, and that is not directly related to her developing Hashimoto’s thyroiditis. However, there is a genetic factor in developing both Graves’ disease and Hashimoto’s thyroiditis, and there is often a familial tendency toward both thyroid disorders. Individuals with Graves’ disease are at higher risk to develop Hashimoto’s thyroiditis, and persons with Hashimoto’s thyroiditis are at higher risk to develop Graves’ disease. You and your daughter can discuss this with your doctors and have any remaining questions answered.

Q: We adopted a baby from another country and brought him home when he was about four months old. Our pediatrician sent us to an endocrinologist, and he says our little boy has hypothyroidism. He also used the terms congenital hypothyroidism and cretinism. What do those terms mean?

A: Congenital hypothyroidism is hypothyroidism that is present at birth. You may see it abbreviated as CH. Cretinism is a term for hypothyroidism that appears in infancy or early childhood. Neither term is associated with any specific cause of hypothyroidism. The doctor will determine what is the cause of the hypothyroidism. You will begin to feel better as you learn more about the particulars of your son’s condition and as he begins to respond to thyroid hormone treatment.

Q: Our 3-year-old daughter was just diagnosed with hypothyroidism that her doctor says is due to defective development of the thyroid gland before birth. She was right on target developmentally until this past year. Why would something that was wrong at birth take so long to show up?

A: You should raise this question with her doctor to get the specifics of her case. Doctors do know that some infants are born with thyroid glands that are not capable of producing much thyroid hormone. Sometimes these children develop hypothyroidism when they have grown up enough that their bodies’ needs for thyroid hormone exceed the amount that the gland can make. This may be the cause of your daughter’s condition. Fortunately, thyroid hormone treatment is simple and will replace the thyroid hormone that her gland cannot make.