Clinical Topic
Acquired Hypothyroidism in Children:
A Guide for Families
What is the thyroid?
The thyroid gland is a butterfly-shaped organ usually located in the lower front of the neck. The thyroid gland makes the thyroid hormones which are released into the bloodstream to be carried to other tissues in the body. The thyroid hormones are thyroxine (T4) and triiodothyronine (T3). The pituitary gland releases thyroid stimulating hormone (TSH) that directs the thyroid gland to release thyroid hormones. The thyroid hormones help the body to grow, to maintain body temperature, to use energy, and to keep other organs such as the brain, heart, and gut working properly.
What is hypothyroidism?
Hypothyroidism refers to a condition in which the thyroid gland does not make enough thyroid hormone for the body’s needs. Hypothyroidism can be present at birth or develop anytime during childhood, adolescence, or adulthood. Hypothyroidism present at birth is called congenital hypothyroidism and is discussed separately. Hypothyroidism that develops after birth is called acquired hypothyroidism. Acquired hypothyroidism occurs in about 1 in 1,250 children. In most cases, the condition is permanent and will require treatment for life. This handout focuses on acquired hypothyroidism.
What Causes Acquired Hypothyroidism?
Acquired hypothyroidism can arise from the changes to the thyroid gland itself or to the pituitary gland. The thyroid can be damaged by an autoimmune process during which thyroid cells are damaged. The damage occurs because the body’s immune system mistakenly identifies the healthy thyroid as being foreign. Radiation to the neck or surgical removal of the thyroid can also cause acquired hypothyroidism.
Rarely, the pituitary gland does not function correctly which can interfere with TSH secretion and lead to acquired hypothyroidism. The pituitary gland can be damaged due to brain tumors, severe traumatic brain injury, radiation therapy, or pituitary surgery. Certain medications and substances can interfere with thyroid hormone production. For example, too much or too little iodine in the diet can lead to hypothyroidism.
The most common cause of hypothyroidism in children and teens is autoimmune thyroiditis which is also known as Hashimoto thyroiditis. Some children with certain conditions have a greater risk of developing hypothyroidism. These conditions include Trisomy 21, Turner syndrome, other autoimmune diseases such as type 1 diabetes, Individuals who received radiation therapy for cancer treatment may also develop hypothyroidism.
What Are the Signs and Symptoms of Hypothyroidism?
Signs and symptoms of hypothyroidism include:
- Tiredness
- Modest weight gain (no more than 5–10 pounds)
- Feeling cold
- Dry skin
- Hair loss
- Constipation
- Poor growth
- Struggling with learning at school
Sometimes, your child’s doctor will be able to palpate an enlarged thyroid
gland in the neck. This is called a goiter.
How is Hypothyroidism Diagnosed?
Blood tests are used to diagnose hypothyroidism. These tests involve measurement of hormones produced by the thyroid (T4) and pituitary glands (TSH). Your doctor can order these tests and direct you to a laboratory for obtaining the blood sample.
Primary hypothyroidism is diagnosed when the level of stimulating hormone from the pituitary gland (TSH) in the blood is high and the T4 level produced is low. Secondary hypothyroidism occurs if there is not enough TSH being produced by the pituitary gland; both TSH and T4 will be low. Normal reference ranges for T4 and TSH values differ in children compared to adults. Consultation with a pediatric endocrinologist to confirm the diagnosis and help with management is beneficial.
How is Hypothyroidism Treated?
Hypothyroidism is treated using a synthetic thyroid hormone called levothyroxine. The active ingredient in this medication is chemically identical to T4. This is once-daily pill is usually given for life (for more information on thyroid hormone, see the Thyroid Hormone Administration: A Guide for Families handout). Side effects are rare. If side effects occur, they are usually the result of substantial overtreatment or undertreatment.
Your child’s doctor will prescribe the medication and then perform repeat blood testing. The repeat blood testing will not happen for at least 6 to 8 weeks because it takes time for the body to adjust to new hormone levels. If the medication is working as anticipated, the blood testing results will show normal levels of TSH and T4. The dose of the medication will be adjusted by regular monitoring of thyroid function laboratory tests.
You should contact your child’s doctor if your child experiences difficulty falling asleep, restless sleep, or difficulty concentrating in school. These may be signs that your child’s current thyroid hormone dose may be too high and your child is being overtreated.
There is no cure for acquired hypothyroidism; however, hormone replacement is safe and effective. With daily medication and close follow-up with your pediatric endocrinologist, your child can live a healthy life.
—————————————————————–
Updated in July 2024
Pediatric Endocrine Society/American Academy of Pediatrics Section on Endocrinology Patient Education Committee
Copyright © 2018 American Academy of Pediatrics and Pediatric Endocrine Society. All rights reserved. The information contained in this publication should not be used as a substitute for the medical care and advice of your pediatrician. There may be variations in treatment that your pediatrician may recommend based on individual facts and circumstances.