In hyperthyroidism, the thyroid gland makes too much thyroid hormone. An overactive thyroid gland pushes the body’s metabolism to unhealthy levels. This bow tie-shaped gland in the throat, at the bottom of the neck, wraps around the windpipe (trachea), near nerves important to the voice.
The thyroid hormone affects almost every tissue and cell in the body and controls many metabolic processes. The hormone influences physical growth, energy and mental development. When the gland sends out too much thyroid hormone, the body’s processes speed up, affecting:
In children, hyperthyroidism can affect growth, puberty development and the bones.
Hyperthyroidism is very rare in a baby. A newborn boy or girl may have trouble breathing if the thyroid gland is enlarged and pressing on the windpipe. The main signs are failure to thrive and gain weight, even though the baby has an enormous appetite.
Untreated hyperthyroidism can lead to heart problems, including rhythm disturbances. If it isn’t detected for a long time, it can weaken the bones. If a newborn with hyperthyroidism isn’t treated, the condition can affect the growth and development of the nervous system.
Almost all cases of hypothyroidism in children and teens are caused by the autoimmune disease known as Graves’ disease. Among children, we see hyperthyroidism most often in adolescent girls. It may come and go throughout life, needing treatment for months or years at a time and then not needing treatment for some time.
Thyroid nodules, inflammation of the thyroid (thyroiditis), consuming too much iodine and overmedicating with synthetic thyroid hormone (the treatment for underactive thyroid) are far less common causes of hyperthyroidism in children. With thyroiditis, hyperthyroidism lasts about six to eight weeks instead of two to three years.
Hyperthyroidism in newborns occurs only when a thyroid-stimulating antibody passed through the placenta from a mother who has or had Graves’ disease. In newborns, hyperthyroidism is temporary (transient) and requires medication for just a few months.
The condition is very treatable. The endocrinologist starts the child on oral medication and carefully adjusts the doses. Anti-thyroid medication, thyroidectomy (surgery to remove the thyroid gland) and radioactive iodine ablation (to destroy the gland) can also be used to treat the condition.
At your first visit, the endocrinologist will get your child’s medical history, do a physical exam and decide if a blood test is needed.
Other tests are sometimes needed to confirm the diagnosis, find the cause or guide treatment, such as:
The diagnosis can quickly be confirmed in newborns.
Treatment varies based on the child’s age and other medical conditions. Hyperthyroidism can be treated in three ways:
The child may be given additional medication to reduce the symptoms and must be monitored to see how the treatment is working:
Typically, treatment starts with an anti-thyroid medication. The medication slows down the production of thyroid hormone. It doesn’t usually have permanent results, and it doesn’t work for thyroiditis. Methimazole is a good choice because the child may only need to take it once a day and it causes fewer liver abnormalities. Another choice is propylthioracil (PTU).
Usually, the medication can be taken once or twice a day. Typically, thyroid hormone levels return to the normal range in several weeks or months. The average treatment time is about one to two years, but treatment can continue for many years if needed.
“The strongest reason we like this treatment, versus radiating the thyroid or surgically removing it, is that Graves’ disease very frequently goes into remission,” says Donald Zimmerman, MD, head of our Division of Endocrinology (also the Mae and Benjamin Allen Founder's Board Professor in Endocrinology and Professor of Pediatrics at Northwestern University Feinberg School of Medicine). “Remission happens most often in milder cases. When the disease goes into remission, the child can stop treatment. We then use tests to be sure the thyroid hormone is in the normal range.”
Anti-thyroid medications can cause side effects in some children. Allergic reactions such as rashes and itching are common, and headaches may occur. The body has fewer white blood cells and lower resistance to infection because of the medication. Liver failure is a side effect in rare cases.
“With anti-thyroid medication, a child is more susceptible to infection. We tell families that if the child seems to be coming down with an infectious illness — for example, a sore throat or fever — they need to get the child’s white blood cell count tested,” says Dr. Zimmerman.
A thyroidectomy removes all or part of the thyroid gland. Surgery is considered when medication doesn’t work or the child has trouble with the medication (for example, the child develops a liver abnormality). The surgery leaves a scar but eliminates the hyperthyroidism. The child takes a thyroid hormone replacement tablet once a day throughout life.
You’ll want a surgeon with specialized training and appropriate experience. The surgeon must be careful of the nerves for the vocal cords and of the parathyroid gland that regulates calcium in the blood. Lurie Children’s has personnel and technology in the operating room especially to protect the vocal nerve from injury.
To permanently stop hyperthyroidism, the child can be given a capsule to swallow that has a small amount of radioactive iodide. The thyroid gland absorbs most of the radioactive iodide. Over several weeks or months, the radiation destroys part or all of the gland. Some children, not many, need a second dose or may need surgery to remove the gland. If the thyroid gland then produces no thyroid hormone, the child takes a hormone replacement tablet once a day throughout life.
“We tend to use radioiodine in older adolescents, rather than younger children. We’re mindful that young people have a greater risk of radiation-induced cancer,” explains Dr. Zimmerman. “All over the world and country, there’s a push to minimize radiation, to avoid changing the genetic material.”
Radioactive iodide and surgery are hospital-based treatments that offer a permanent solution to hyperthyroidism, but with increased risks. Medication is inexpensive, poses fewer risks and may eventually or at times be discontinued. Some children have trouble taking their medication on time if they have to take it more than once a day. This jeopardizes their health.
Our pediatric endocrinologists will talk with you about the plusses, minuses and appropriateness of each option in your child’s situation. We try to minimize the risks of radiation and surgery as much as possible. The goal is to return the child to wellness.
If you're concerned your child may have hyperthyroidism, you can make an appointment with one of our pediatric endocrinologists to have your child examined. To request an appointment with one of our endocrinologists, call 1.800.543.7362 (1.800.KIDS DOC®).
Learn more about hyperthyroidism by visiting the following physician-recommended websites: