What is hypothyroidism?

Hypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone. If a baby is born with hypothyroidism it is called congenital hypothyroidism. When it starts after a child is born, it is called acquired hypothyroidism. It is more common in girls than in boys.

Having too little thyroid hormone causes many symptoms. A slower rate of growth is the first sign of this problem in children. Your child may also:

• Feel tired all the time.
• Have weak muscles.
• Be constipated.
• Feel cold a lot of the time.

Other problems may include:

• depression
• heavy or long menstrual periods (in young women)
• dry skin
• hoarse voice
• trouble learning or remembering
• puffiness or swelling in the face.

What causes hypothyroidism?

Hypothyroidism is most often caused by a disease that makes the thyroid gland swell. The disease is called Hashimoto's thyroiditis. This disease usually causes low thyroid levels, but may also cause high levels of thyroid hormone (hyperthyroidism). Ask your healthcare provider about the specific cause of your child's low thyroid hormone level. If other members of your family have thyroid disease, it may provide a clue to the cause of your child's condition.

How is it diagnosed?

Your child will have blood tests to measure thyroid hormones.

How is it treated?

Your child will receive thyroid hormone medicine. This will take the place of what the body would normally make. After your child takes the hormone tablets for 2 to 4 weeks, he or she will feel better. After a few weeks, your child should have no symptoms of the disease. Your child should have regular blood tests to make sure she is taking the right amount of hormone. Most likely, your child will need to take thyroid hormone tablets every day for the rest of his or her life.

Children often begin to grow taller very rapidly once they are treated for hypothyroidism. Growth should be carefully monitored by your doctor. Your doctor may refer your child to a hormone specialist (endocrinologist) to help monitor the growth rate and the hormone treatment.

Taking hormone tablets is safe and simple. It's important for your child to:

• Take tablets every day, exactly as prescribed by your child's healthcare provider.
• Have thyroid hormone levels checked regularly.
• Keep follow-up appointments.

See your child's healthcare provider if symptoms come back or get worse.