Congenital Hypothyroidism

Other Names

Primary congenital hypothyroidism

Cretinism

Congenital myxedema

Diagnosis Coding

E03.1, congenital hypothyroidism without goiter

Disorder Category

An endocrine disorder

Screening

Finding

Elevated thyroid stimulating hormone (TSH) and low free thyroxine (T4)

Tested By

TSH and T4

Overview

Congenital hypothyroidism is a common and treatable cause of mental retardation. Most patients with congenital hypothyroidism are asymptomatic at birth making newborn screening essential for timely diagnosis and treatment. While untreated congenital hypothyroidism results in mental retardation and poor linear growth, with early treatment patients have normal IQ and normal linear growth. Most cases are permanent and require life-long treatment. Newborn screening identifies cases of primary congenital hypothyroidism, in which there is a problem with the thyroid gland itself. Most cases (~85%) of primary congenital hypothyroidism are caused by thyroid dysgenesis, in which the thyroid is either completely absent (agenesis) or ectopic in location. Most of these cases are sporadic and are only diagnosed by lab testing. Other causes include 1) dyshormonogenesis, in which there is a defect in thyroid hormone biosynthesis (very often these children have a goiter at birth and a family history) and 2) TSH receptor resistance. Newborn screening may also identify transient problems which are usually secondary to maternal/intrauterine issues or prematurity.

Incidence

Congenital hypothyroidism occurs in about 1:2000 to 1:4000 live births making it a very common birth defect.

Inheritance

Most cases are sporadic, but about 15% are inherited as autosomal recessive. Several gene mutations are known to cause congenital hypothyroidism.

Other Testing

Newborn screening results may be normal in infants with clinical symptoms. Additional testing is recommended when clinical symptoms are present. False-positive testing may result from samples taken within the first 48 hours of life. Retesting is suggested.

Clinical Characteristics

Most patients with congenital hypothyroidism are asymptomatic at birth. In fact, only about 5% of infants have detectable physical findings or symptoms at birth that may include:
  • post-dates delivery
  • macrosomia
  • open posterior fontanelle
  • umbilical hernia
  • Large tongue
Without treatment, affected individuals may develop the following signs and symptoms over the subsequent weeks:
  • prolonged jaundice
  • constipation
  • poor feeding
  • increasing sleepiness
  • dry and mottled skin
  • hoarse cry
  • puffy face (myxedematous appearance)

Follow-up Testing after Positive Screen

Serum TSH and free T4.

Primary Care Management

Upon Notification of the + Screen

  • Contact the family and evaluate the infant for poor feeding, lethargy, jaundice.
  • Provide urgent treatment/referral if indicated for jaundice, poor feeding, constipation (see the ACT Sheet for Elevated TSH (ACMG) (PDF Document 349 KB) for additional information).
  • To confirm the diagnosis, work with the following service(s): we currently have no Newborn Screening Services service providers listed, please search our Services database for related services.
    • If a second screen is routine in your state, assuring that is performed in a timely manner may be sufficient
    • False positive screens may result from a normal postnatal TSH surge. Depending on the result, a repeat screen or confirmatory testing with TSH and free T4 may be recommended
    • False-negative screens may occur in low birth weight or premature infants due to delayed TSH surge. Additional testing with TSH and T4 is recommended.
  • For evaluation and ongoing collaborative management, consult the following service(s): see all Pediatric Endocrinology services providers (13) in our database.

If the Diagnosis is Confirmed

  • Develop a treatment plan with a pediatric endocrinologist. Early treatment is essential for normal growth and development.
  • Levothyroxine is indicated for affected children and should be monitored and adjusted in collaboration with a pediatric endocrinologist. Typical starting dose is 10-15 µ/kg/day. Liquid formulations are not stable and should not be used. The family needs to be instructed to dissolve a tablet and administer it in 10 ml of water or formula at the beginning of a feeding. There is no role for T3 therapy in infants with hypothyroidism.
  • Lab testing (TSH and free T4) is recommended every 3-4 months for the first 3 years of life as doses can change frequently during infancy and early childhood. After age 3, this can be re-evaluated.
  • Monitor cognitive development of the child and refer if indicated. But reassure parents that newborn screening for hypothyroidism is a success story. Most practitioners today have never seen the consequences of untreated congenital hypothyroidism (cretinism) and the child will will very likely grow up with normal cognitive development.

Specialty Care Collaboration

Initial consultation and ongoing collaboration, particularly for medication management. Due to rapid growth during infancy and early childhood, we recommend frequent follow up for the first few years of life. Genetic counseling for the family may be indicated.

Resources

Information & Support

For Professionals

ACT Sheet for Elevated TSH (ACMG) (PDF Document 349 KB)
Contains short-term recommendations for clinical follow-up of the newborn who has screened positive; American College of Medical Genetics.

ACT Sheet for Low T4 and/or Elevated TSH (ACMG) (PDF Document 348 KB)
Contains short-term recommendations for clinical follow-up of the newborn who has screened positive; American College of Medical Genetics.

Congenital Hypothyroidism: Initial Workup (PES) (Word Document 68 KB)
Guideline from the Pediatric Endocrine Society on the initial work-up of an infant suspected of having congenital hypothyroidism.

For Parents and Patients

Congenital Hypothyroidism (Genetics Home Reference)
Excellent, detailed review of condition for patients and families; U.S. National Library of Medicine.

Congenital Hypothyroidism (The Magic Foundation)
Information about congenital hypothyroidism from The Magic Foundation, a nonprofit organization, providing support services for families of children with a wide variety of chronic and/or critical disorders, syndromes, and diseases that affect growth. Offers patient assistance programs.

Services in Rhode Island

Select services for a different state: ID, MT, NM, NV, UT
Pediatric endocrinology providers throughout the US can be found through Find a Doctor (Pediatric Endocrine Society).

Newborn Screening Services

We currently have no Newborn Screening Services service providers listed; search our Services database for related services.

Pediatric Endocrinology

See all Pediatric Endocrinology services providers (13) in our database.

For other services related to this condition, browse our Services categories or search our database.

Studies

Clinical Trials in Congenital Hypothyroidism (clinicaltrials.gov)
A list of clinical trial maintained by the National Library of Medicine, National Institutes of Health.

Helpful Articles

PubMed search for congenital hypothyroidism in children, last 2 years.

Rose SR, Brown RS, Foley T, Kaplowitz PB, Kaye CI, Sundararajan S, Varma SK.
Update of newborn screening and therapy for congenital hypothyroidism.
Pediatrics. 2006;117(6):2290-303. PubMed abstract

Léger J, Olivieri A, Donaldson M, Torresani T, Krude H, van Vliet G, Polak M, Butler G.
European Society for Paediatric Endocrinology consensus guidelines on screening, diagnosis, and management of congenital hypothyroidism.
J Clin Endocrinol Metab. 2014;99(2):363-84. PubMed abstract / Full Text

Authors & Reviewers

Initial publication: September 2007; last update/revision: December 2018
Current Authors and Reviewers:
Author: Zoe Raleigh, MD
Senior Author: Mary A. Murray, MD
Authoring history
2007: first version: Nicola Longo, MD, Ph.D.R
AAuthor; CAContributing Author; SASenior Author; RReviewer