What is hypothyroidism in a child?

Hypothyroidism is when the thyroid gland doesn't make enough thyroid hormone. The condition is more common in adults. But it’s the most common thyroid disorder in children. Not enough thyroid hormone leads to signs, such as slow growth, lack of activity, and poor performance in school. In children, it’s often referred to as acquired hypothyroidism.

What causes hypothyroidism in a child?

The most common cause of acquired hypothyroidism is an autoimmune reaction called Hashimoto thyroiditis. This is when the body's immune system slowly destroys the thyroid gland.

Which children are at risk for hypothyroidism?

A child is at risk for hypothyroidism if they have any of these:

• A chromosomal disorder, such as Down syndrome, Williams syndrome, or Turner syndrome

• An autoimmune disorder, such as type 1 diabetes, Addison disease or celiac disease

• Not enough or too much iodine intake

• Injury to the thyroid gland

• Radiation to the head and neck

• Premature birth

What are the symptoms of hypothyroidism in a child?

The signs in children are different from those in adults. The most common sign in children is slowed or delayed growth. This may occur years before other signs occur. Other signs can occur a bit differently in each child and can vary by age.

Signs in younger children (juvenile hypothyroidism) can include:

• Slow growth that may cause short limbs

• Delayed tooth development

• Impaired school performance

• Lack of energy

• Inactivity

• Slow bowel movements (constipation)

• Dry skin

• Feeling cold

Signs in older children and teens (adolescent hypothyroidism) can include:

• Slow growth

• Delayed puberty

• Hoarse voice

• Slow speech

• Droopy eyelids

• Puffy and swollen face

• Brittle hair, hair loss

• Dry skin

• Slow pulse

• Weight gain

• Impaired school performance

• Lack of energy

• Inactivity

• Slow bowel movements (constipation)

The symptoms of hypothyroidism are nonspecific and can be seen in other health conditions. Make sure your child sees their healthcare provider for a diagnosis.

How is hypothyroidism diagnosed in a child?

The healthcare provider will ask about your child’s symptoms and health history. They may also ask about your family’s health history and will give your child a physical exam. Your child will need blood tests to confirm a diagnosis of hypothyroidism.

• Blood test. These are done to check the levels of thyroid hormones. A child may have low levels of T4. This is the main hormone released from the thyroid. A child with hypothyroidism will usually have high levels of thyroid-stimulating hormone (TSH). TSH is released into the blood from the pituitary gland. TSH increases the size, number, and activity of thyroid cells. TSH also stimulates the release of hormones that affect a person's metabolism.

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• Ultrasound. This test uses sound waves to learn about the structure of organs, such as the thyroid gland.

How is hypothyroidism treated in a child?

Your child's healthcare provider will consider your child's age, overall health, and other factors when advising treatment. Your child may need to see a pediatric endocrinologist. This is a healthcare provider with extra training in treating children with hormone problems.

The goal of treatment is to restore hormone levels to normal and stimulate normal growth and development. Treatment may include taking thyroid hormones to increase the level of hormones in the body. Your child will need to take hormones at least until growth and puberty are complete. For some, this may mean taking hormones for life. Other children may be able to stop hormone therapy. Your child’s healthcare provider will check your child’s blood regularly during treatment. This will help to show if the treatment is working and how long treatment needs to continue.     

What are possible complications of hypothyroidism in a child?

Hypothyroidism can affect a child's normal growth and development. This includes sexual development. If untreated, the condition can also lead to:

• Low red blood cell levels in the blood (anemia)

• Low body temperature

• Low heart rate

• Heart failure

• Nervous system problems, such as lower IQ and difficulties with motor skills.

Helping a child live with hypothyroidism

Hypothyroidism can impair a child's normal growth and development. It’s important for a child to continue treatment until after puberty. This will help ensure a child reaches their normal adult height. Some children do not need to continue treatment into adulthood. Work with your child's healthcare providers to create an ongoing plan to manage your child’s condition.

When should I call my child's healthcare provider?

Call your child's healthcare provider if you’re concerned about your child's growth, or if they have any signs of hypothyroidism.

Key points about hypothyroidism in a child

• Hypothyroidism is when the thyroid gland doesn't make enough thyroid hormone. It’s the most common thyroid disorder in children.

• Not enough thyroid hormone leads to signs such as slow growth, lack of activity, and poor performance in school.

• The most common cause is an autoimmune reaction that destroys the thyroid gland.

• Treatment may include taking thyroid hormones to increase the level of hormones in the body. Some children will need to take hormones for life. Other children may outgrow the disorder.

• Hypothyroidism can impair a child's normal growth and development. It’s important for a child to continue treatment until after puberty. This will help ensure a child reaches their normal adult height.

Next steps

Tips to help you get the most from a visit to your child’s healthcare provider:

• Know the reason for the visit and what you want to happen.

• Before your visit, write down questions you want answered.

• At the visit, write down the name of a new diagnosis and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you for your child.

• Know why a new medicine or treatment is prescribed and how it will help your child. Also know what the side effects are.

• Ask if your child’s condition can be treated in other ways.

• Know why a test or procedure is recommended and what the results could mean.

• Know what to expect if your child does not take the medicine or have the test or procedure.

• If your child has a follow-up appointment, write down the date, time, and purpose for that visit.

• Know how you can contact your child’s provider after office hours. This is important if your child becomes ill and you have questions or need advice.