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Neonatal hypothyroidism
Cretinism; Congenital hypothyroidism
Neonatal hypothyroidism is decreased thyroid hormone production in a newborn. In very rare cases, no thyroid hormone is produced. The condition is also called congenital hypothyroidism. Congenital means present from birth.
Causes
Hypothyroidism in the newborn may be caused by:
- A missing or poorly developed thyroid gland
- A pituitary gland that does not stimulate the thyroid gland
- Thyroid hormones that are poorly formed or do not work
- Medicines the mother took during pregnancy
- Lack of iodine in the mother's diet during pregnancy
-
Antibodies
made by the mother's body that block the baby's thyroid function
Antibodies
An antibody is a protein produced by the body's immune system when it detects harmful substances, called antigens. Examples of antigens include micr...
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A thyroid gland that is not fully developed is the most common defect. Girls are affected twice as often as boys.
Symptoms
Most affected infants have few or no symptoms. This is because their thyroid hormone level is only slightly low. Infants with severe hypothyroidism often have a unique appearance, including:
- Dull look
- Puffy face
- Thick tongue that sticks out
This appearance usually develops as the disease gets worse.
The child may also have:
- Choking episodes
- Constipation
- Dry, brittle hair
-
Jaundice
Jaundice
Newborn jaundice occurs when a baby has a high level of bilirubin in the blood. Bilirubin is a yellow substance that the body creates when it replac...
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- Low hairline
- Poor feeding
- Short height
- Sleepiness
- Sluggishness
Exams and Tests
A physical exam may show:
- Decreased muscle tone
- Slow growth
- Hoarse-sounding cry or voice
- Short arms and legs
- Very large soft spots on the skull (fontanelles)
- Wide hands with short fingers
-
Widely separated skull bones
Widely separated skull bones
Separated sutures are abnormally wide spaces in the bony joints of the skull in an infant.
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Blood tests are done to check thyroid function. Other tests may include:
-
Thyroid ultrasound scan
Thyroid ultrasound scan
A thyroid scan uses a radioactive iodine tracer to examine the structure and function of the thyroid gland. This test is often done together with a ...
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X-ray
of the
long bones
X-ray
X-rays are a type of electromagnetic radiation, just like visible light. An x-ray machine sends individual x-ray particles through the body. The im...
Read Article Now Book Mark ArticleLong bones
Long bones are hard, dense bones that provide strength, structure, and mobility. The thigh bone (femur) is a long bone. A long bone has a shaft and...
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Treatment
Early diagnosis is very important. Most of the effects of hypothyroidism are easy to reverse. For this reason, most US states require that all newborns be screened for hypothyroidism.
Thyroxine is usually given to treat hypothyroidism. Once the child starts taking this medicine, blood tests are regularly done to make sure thyroid hormone levels are in a normal range.
Outlook (Prognosis)
Getting diagnosed early usually leads to a good outcome. Newborns diagnosed and treated in the first month or so usually have normal intelligence.
Untreated mild hypothyroidism can lead to severe intellectual disability and growth problems. The nervous system goes through important development during the first few months after birth. Lack of thyroid hormones can cause damage that cannot be reversed.
Intellectual disability
Intellectual disability is a condition diagnosed before age 18 that includes below-average intellectual function and a lack of skills necessary for d...
When to Contact a Medical Professional
Call your health care provider if:
- You feel your infant shows signs or symptoms of hypothyroidism
- You are pregnant and have been exposed to antithyroid drugs or procedures
Prevention
If a pregnant woman takes radioactive iodine for thyroid cancer, the thyroid gland may be destroyed in the developing fetus. Infants whose mothers have taken such medicines should be observed carefully after birth for signs of hypothyroidism. Also, pregnant women should not avoid iodine-supplemented salt.
Most states require a routine screening test to check all newborns for hypothyroidism. If your state does not have this requirement, ask your provider if your newborn should be screened.
Screening test
Newborn screening tests look for developmental, genetic, and metabolic disorders in the newborn baby. This allows steps to be taken before symptoms ...
References
LeFranchi SH, Huang SA. Hypothyroidism. In: Kliegman RM, Stanton BF, St. Geme, Schor NF, eds. Nelson Textbook of Pediatrics . 20th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 565.
Van Vliet G, Deladoëy J. Disorder of the thyroid in the newborn and infant. In: Sperling MA, ed. Pediatric Endocrinology . 4th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 7.
Review Date: 4/27/2015
Reviewed By: Kimberly G Lee, MD, MSc, IBCLC, Associate Professor of Pediatrics, Division of Neonatology, Medical University of South Carolina, Charleston, SC. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.
