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Thyroid Disease


What Is the Thyroid?

The thyroid is a small gland located below the skin and muscles at the front of the neck, just at the spot where a bow tie would rest.

It's brownish red, with left and right halves (called lobes) that look like a butterfly's wings. It usually weighs less than an ounce, but helps the body do many things, such as get energy from food, grow, and go through sexual development.

What Does the Thyroid Do?

Though it's small, the thyroid has a very important job to do, especially for teens. It makes the hormones that help control metabolism and growth.

To do its job, the thyroid needs a chemical element called iodine. The body absorbs iodine from the foods we eat and the water we drink. The entire body contains about 50 milligrams of iodine. Much of that supply (10 to 15 milligrams) is stored in the thyroid. The thyroid combines the iodine with tyrosine (an essential amino acid) to make important hormones.

What Do Thyroid Hormones Do?

Thyroid hormones are released from the gland and travel through the bloodstream to the body's cells. They help control the growth and the structure of bones, sexual development (puberty), and many other body functions.

By helping cells convert oxygen and sugar and other body fuels into the energy they need to work properly, these hormones are important in helping a child's body mature as it should.

Thyroid hormones also directly affect how most organs function. So a thyroid that isn't operating properly can cause problems in many other parts of the body.

What Is Thyroid Disease?

Thyroid disease is when the thyroid gland doesn't supply the proper amount of hormones needed by the body.

  • If the thyroid is overactive, it releases too much thyroid hormone into the bloodstream, causing hyperthyroidism. The body use up energy more quickly than it should, and chemical activity (like metabolism) in the cells speeds up. Graves' disease, an autoimmune disease, is the most common cause of hyperthyroidism.
  • If the thyroid is underactive, it makes too little thyroid hormone, causing hypothyroidism. The body uses up energy more slowly, and chemical activity (metabolism) in the cells slows down. Hashimoto's thyroiditis is an autoimmune disease that causes most cases of hypothyroidism in kids and teens.

Both hypothyroidism and hyperthyroidism can make the thyroid larger than normal. An enlarged thyroid gland is a lump that can be felt under the skin at the front of the neck. When it is large enough to see easily, it's called a goiter.

A goiter can also develop with other thyroid problems, such as infections of the thyroid or thyroid cysts, tumors, or thyroid cancer. People who don't get enough iodine in their diets also can get an enlarged thyroid, but this is rare in the United States because foods here usually supply enough iodine.

What Problems Can Happen?

Puberty puts the body through some very noticeable changes. Because thyroid hormones play an important role in this process, thyroid disease may slow down or interfere with that physical development. Girls with a thyroid problem may have changes in their periods, such as a decrease or increase in menstrual flow, or shorter or longer time between periods. 

People with mild hypothyroidism may feel just fine, but if the problem gets worse they can start to feel sluggish and weak. Hypothyroidism can hold back growth and puberty in kids and teens. People with the condition may notice dry skin, hair loss, constipation, and feeling colder than others. They can also have trouble concentrating and forget things easily.

Hyperthyroidism can cause tremors, sweating, fast heartbeat, weight loss, and bulging eyes. In some kids with hyperthyroidism, the thyroid gland can swell up, causing a goiter.

How Is Thyroid Disease Diagnosed?

Both hyperthyroidism and hypothyroidism are diagnosed with a physical examination and blood tests.

In hyperthyroidism, the levels of thyroid hormones in the blood usually are high and can be measured directly with blood tests. In hyperthyroidism, a blood test is done to measure the level of TSH (thyroid stimulating hormone), which is made by the pituitary gland. 

What Else Should I Know?

It's important to remember that not all kids grow or develop at the same age or at the same rate. If one child seems to grow 4 inches overnight and another hasn't had a growth spurt yet, it doesn't mean there's something wrong with the thyroid.

Because girls who are just starting to menstruate often have irregular periods for the first year or so, changes in periods are usually nothing to worry about and don't mean a girl has thyroid disease.

If you're concerned that your child might have a thyroid problem, call your doctor. Chances are, the problem is something simpler. And if it is thyroid disease, diagnosing and treating it properly — including bringing the blood levels of thyroid hormones back to normal — will usually prevent or correct any problems.

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