The thyroid is a small gland
below the skin and muscles at the front of the neck, at the spot where a bow tie would
It's brownish red, with left and right halves (called lobes) that look like a butterfly's
wings. It weighs less than an ounce, but helps the body do many things, such as get
energy from food, grow, and go through sexual
development. In younger children, it is also important for brain development.
What Is Hypothyroidism?
Hypothyroidism (or underactive thyroid) is when
the thyroid gland doesn't make enough of some important hormones. This makes the body
use up energy more slowly, and chemical activity (metabolism) in the cells slows down.
Hypothyroidism is a common condition, especially in adult women. But kids can have
it too. Some children are born with it — this is called congenital
hypothyroidism. Others develop it later, usually late in childhood or as teens.
The most common cause of hypothyroidism in kids and teens is the
disease Hashimoto's thyroiditis.
What Are the Signs & Symptoms of Hypothyroidism?
A person with mild hypothyroidism may feel just fine. In fact, it might cause no
symptoms at all.
But if thyroid hormone levels get too low, symptoms can become more obvious. These
Hashimoto's thyroiditis (hah-she-MOE-toes thy-roy-DYE-tiss) is
an autoimmune disease. It causes most cases of hypothyroidism in kids and teens. Hashimoto's
thyroiditis is also called lymphocytic thyroiditis.
What Happens in Hashimoto's Thyroiditis?
Hashimoto's thyroiditis is an ongoing condition in which the immune
system attacks the thyroid. Often, this prevents the thyroid from making enough
thyroid hormone, causing hypothyroidism. The body responds by sending a message to
the thyroid to work harder to make enough hormone.
This, and the swelling the immune system causes as it attacks the gland, can make
the thyroid get bigger, leading to a goiter.
The thyroid can keep changing size over months or years. Surgery is sometimes done
to treat goiters, especially if the thyroid is big enough to cause problems with swallowing.
But this is rarely needed in children.
How Are Hypothyroidism and Hashimoto's Thyroiditis Diagnosed?
To diagnose hypothyroidism and Hashimoto's thyroiditis, doctors ask about a person's
symptoms, do an exam, and order blood tests. The tests measure:
Thyroid hormone levels, particularly thyroxine
(T4) and thyroid-stimulating
hormone (TSH). TSH is a hormone made in the
(a pea-sized gland just beneath the brain). More TSH is released into
the blood when the brain and pituitary sense that the levels of thyroid hormone in
the blood are too low. TSH stimulates the thyroid to work harder to make more thyroid