Children's Hospital Colorado

Hypothyroidism in Children

What is hypothyroidism in children?

Hypothyroidism happens when the thyroid gland doesn't produce enough thyroid hormones. We call these hormones triiodothyronine (T3) and thyroxine (T4). They are important because they control the body's heart rate, temperature and metabolism. Hypothyroidism can be present at birth, which we call congenital hypothyroidism. It can also occur at a later age, which we call acquired hypothyroidism.

Pediatric hypothyroidism is a common and treatable condition that affects about one in 1,250 children. It can happen when there is a problem with the thyroid gland. This gland is located in the neck, just below the Adam's apple, and is shaped like a butterfly. We call this primary hypothyroidism. In rare cases, a problem with the pituitary gland, which is located in the brain, can cause it. The pituitary gland controls thyroid hormone production by releasing a hormone called thyroid stimulating hormone (TSH).

If left untreated, low thyroid hormone levels can cause problems, such as impaired growth and development. Other risks include anemia, which is a shortage of healthy red blood cells, and heart failure, a condition in which the heart doesn't pump as well as it should.

Types of hypothyroidism in children

  • Transient hypothyroidism happens when a baby is born with low thyroid hormone levels. It is temporary and usually stabilizes on its own or with short-term treatment. It can be due to a problem during pregnancy, such as iodine deficiency. It can also happen if the mother is taking anti-thyroid medicine or she has thyroid antibodies, which are cells in the blood that attack the thyroid gland.
  • Congenital hypothyroidism happens when a child is born producing too few thyroid hormones. This usually happens because the baby's thyroid gland is underdeveloped, or it did not develop at all. Sometimes, the baby's thyroid gland has developed, but it cannot produce enough hormones. This condition tends to run in families. It is common in newborns, though it's not always noticeable at first. That's why it is part of standard newborn screening procedures in the U.S. Treatment is important to avoid serious problems with brain development, which can lead to learning difficulties.
  • Autoimmune thyroiditis is a condition in which a child's immune system attacks and weakens the thyroid gland. This is the most common form of acquired hypothyroidism in children and teens. We also know it as Hashimoto's thyroiditis, or chronic lymphocytic thyroiditis.
  • Central hypothyroidism happens when a child's pituitary gland does not produce enough TSH. Without TSH, the thyroid gland doesn't get stimulated to produce thyroid hormones.
  • Iatrogenic hypothyroidism is caused by damage to the thyroid gland or removal of the thyroid gland. This can occur through radiation or surgery to treat thyroid cancer and other conditions.

Who gets pediatric hypothyroidism?

Autoimmune thyroiditis, the most common kind of acquired hypothyroidism in children, is more common in adolescents than young children. It is also more common in girls than boys. Children with other autoimmune disorders, such as type 1 diabetes, are at higher risk. So, we recommend that children with type 1 diabetes get regular screenings. Children with congenital syndromes, especially Down syndrome, are also at higher risk, as are children who have received cancer treatments.

Our team may also recommend screening for children with a history of radiation for cancer treatment, and those with a history of brain injury or abnormal brain development. We may also screen children with poor growth or other pediatric hypothyroidism symptoms.

What are the signs and symptoms of pediatric hypothyroidism?

Pediatric hypothyroidism symptoms may be hard to notice because they can develop slowly, and they can seem normal to your child and family. Some children may have no symptoms at all, while others may have many.

Symptoms of hypothyroidism in newborns may include:

  • A larger than normal soft spot on the head (fontanel)
  • Low body temperature
  • Jaundice (a yellow tone in the eyes and skin)
  • Poor eating
  • Constipation (trouble pooping)
  • Sleepiness
  • Hoarse cry

Symptoms of hypothyroidism in children and adolescents may include:

  • Slowed growth and/or short stature
  • Delayed puberty
  • An enlarged thyroid gland, which may feel like a lump in the neck
  • Tiredness
  • Modest weight gain, such as 5 to 10 pounds
  • Feeling cold
  • Constipation
  • Dry skin
  • Hair loss
  • Delayed tooth eruption
  • Slow pulse
  • Heavy or irregular menstrual periods

How does Children's Hospital Colorado diagnose hypothyroidism in children?

Routine newborn screenings include a blood test to diagnose congenital hypothyroidism at birth. When a screening program diagnoses hypothyroidism, it notifies your child's doctor. We then do a second blood test to confirm the diagnosis and begin treatment. Sometimes we also do a thyroid scan to check the size of the thyroid gland.

We also use blood tests to make a pediatric hypothyroidism diagnosis for cases that develop later in childhood. We will check your child's levels of TSH and T4. We diagnose hypothyroidism when TSH is high and T4 is low, or when both are low. The safe ranges for these hormones are different in children than adults, so it's important to have a pediatric endocrinologist review the results. Sometimes we also measure the level of thyroid antibodies in your child's blood.

How is pediatric hypothyroidism treated?

We treat hypothyroidism by replacing your child's missing thyroid hormones. To do this, we prescribe a small pill appropriate for all ages. The pill is a synthetic thyroid hormone called levothyroxine. It is chemically the same as T4, and it brings your child’s thyroid hormones up to a healthy level. Rarely, patients also need to take the synthetic hormone called liothyronine to replace the thyroid hormone T3. This depends on your child's response to treatment.

The pills must be taken every day and they are best absorbed on an empty stomach. You can crush the pills into a tablespoon of food or liquid such as applesauce, water, breast milk or formula, as long as you do this every time. Don't mix it into a full bottle of liquid.

Try to give your child their medicine at the same time each day. Any time of day is ok, though we recommend the morning. Some foods and supplements can block the medicine from working, and shouldn't be taken at the same time, though they can be used at another time of the day. These include soy products (including soy-based formula), high-calcium foods and iron supplements. Tell us about any other supplements or medicines your child is taking. Some medicines may affect dosing, such as birth control pills and supplemental estrogen or testosterone.

If your child misses a dose, you can give it to them later in the day, or you can give them two doses the next day.

We recommend that families avoid changing medicine brands. Switching pill brands can cause your child's hormone levels to go up and down. We also recommend that families avoid liquid preparations of the medicine, which can settle and provide uneven dosing. If your child cannot swallow pills, they can chew them or take them crushed in their food.

After 4 to 6 weeks on this medicine, we will give your child another blood test to make sure their thyroid hormones are at the right levels. If needed, we will adjust their medicine dose. Never change your child's medicine dose on your own. Taking too much thyroid hormone can cause heart and bone problems.

How is hypothyroidism monitored in children?

Thyroid medication needs to be monitored frequently with blood tests. Children under 3 years old, who are growing quickly, need their thyroid levels checked every 3 months. This will be even more frequent for children under 6 months of age. Parents can also watch for symptoms that their baby or toddler's medicine dose needs to change and tell their doctor. If your child is getting too much medicine, you may see irritability, trouble sleeping, weight loss, increased hunger and frequent bowel movements (pooping). If your child is getting too little medicine, you may see excessive sleeping, constipation, weight gain, low energy and cold, dry skin. It is normal for your child to be more awake and active after beginning thyroid medicine.

After the age of 3, children need their thyroid levels checked every 6 months, or when they have any changes in symptoms. Repeat testing is also needed 1 to 2 months after your child’s dose is changed for any reason.

We will need to adjust your child's medicine as they grow. If their dose is too low, it won't resolve their hypothyroidism. If their dose is too high, it will cause hyperthyroidism. Hyperthyroidism is when thyroid hormone levels are too high. We will also monitor your child's growth and development.

Some children may outgrow the need for thyroid hormone replacement. However, most will need treatment throughout their life. Even after your child's brain has finished developing, people need thyroid hormones for normal growth and energy, and normal adolescent and adult development.

In some cases, your pediatrician may be comfortable managing your child's thyroid condition. Otherwise, your child will need to see a pediatric endocrinologist for their follow-up care.

Why Choose Children's Colorado for your child's pediatric hypothyroidism treatment?

We treat your child as an individual and work with your family to determine the best approach for their care. Together, we consider your child’s diagnosis, overall health and preferences to develop a treatment plan. Our multidisciplinary care team includes a nutritionist, a diabetes educator, a clinical social worker and a psychologist to assist with any related health challenges.

Our Department of Pediatric Endocrinology provides a full range of medical, radiologic and surgical therapies. We have nursing and medical support available 24 hours a day, 7 days a week, for Children's Colorado patients and their families.