Children's Hospital Colorado

Hyperthyroidism in Children

What is hyperthyroidism in children?

Hyperthyroidism happens when a child's thyroid gland makes more thyroid hormone than they need. The thyroid gland is butterfly-shaped and is located in the neck, just below the Adam's apple. Its job is to release thyroid hormone into the blood to control the body's heart rate, temperature and metabolism. An overactive thyroid gland can get big and it may look and feel like a lump in the throat, especially when the child swallows.

When the thyroid gland releases too much hormone, this speeds up a child's metabolism and causes problems such as anxiousness, weight loss and tremors. It can also affect their growth and development. However, pediatric hyperthyroidism is treatable and is rare compared to hypothyroidism. Hypothyroidism happens when the thyroid gland does not produce enough thyroid hormone.

Treatment is important because hyperthyroidism can cause cognitive delay in children under 3 years old, which affects their ability to think and learn. In newborns, it can be life-threatening if it isn't diagnosed soon after birth. Untreated hyperthyroidism can also cause children to grow quickly at first, and then stop growing early. This can cause short stature.

What causes hyperthyroidism in children?

The main causes of pediatric hyperthyroidism include the following:

  • Graves' disease is the most common cause of hyperthyroidism in children. It is an autoimmune disorder that happens when the body's immune system gets confused, and in addition to attacking germs, attacks the thyroid gland. It uses cells called antibodies, which cause the thyroid gland to release extra thyroid hormone. These antibodies may also attack the muscles behind the eyes, which can cause the eyes to bulge. Graves' disease is also called autoimmune hyperthyroidism.
  • Taking too much thyroid hormone medicine can cause hyperthyroidism. For children taking thyroid hormone medicine to treat a low thyroid problem, it is possible to take too much of the medicine and develop hyperthyroidism instead.
  • Taking in too much dietary iodine can also cause hyperthyroidism. Iodine is an important building block for thyroid hormone production, which is why the World Health Organization recommends using iodized salt. However, it is possible to eat too much iodine. This can happen through excessive consumption of iodine-rich foods like seaweed. Taking iodine supplements is the cause of most cases of iodine overdose.
  • Thyroid nodules are growths in the thyroid gland that sometimes produce extra hormones. If we find a nodule in your child's neck, we may recommend a biopsy. This is a procedure in which we remove a small piece of thyroid tissue and look at it under a microscope to check for cancer cells. Thyroid nodules are not usually cancerous, but when they are, we can surgically remove them.
  • Thyroiditis is a condition in which the thyroid gland becomes inflamed and leaks extra hormones into the blood. This is typically a self-limited condition, which means it will stop on its own. A thyroid gland injury or infection can cause thyroiditis, or it can happen in the early stages of autoimmune diseases such as Hashimoto's thyroiditis.
  • Neonatal Graves' disease, while rare, is the most common form of hyperthyroidism in newborns. It happens when a mother with a history of Graves' disease has antibodies that cross the placenta and stimulate the baby’s thyroid gland.

Who gets pediatric hyperthyroidism

Hyperthyroidism is more common in adolescents than in young children. It is also more common in females than in males. Some risk factors include:

  • A personal or family history of thyroid disease or thyroid nodules
  • A personal or family history of autoimmune diseases
  • Trauma to the thyroid gland
  • For newborns: a mother with a history of Graves' disease

Contact the Endocrinology department

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