Congenital Hypothyroidism: Screening and Management.

Untreated congenital hypothyroidism (CH) leads to intellectual disabilities. Newborn screening (NBS) for CH should be performed in all infants. Prompt diagnosis by NBS leading to early and adequate treatment results in grossly normal neurocognitive outcomes in adulthood.

Congenital Hypothyroidism: Screening and Management.

Untreated congenital hypothyroidism (CH) leads to intellectual disabilities. Prompt diagnosis by newborn screening (NBS) leading to early and adequate treatment results in grossly normal neurocognitive outcomes in adulthood. However, NBS for hypothyroidism is not yet established in all countries globally.

History of the Thyroid.

The history of the thyroid dates from 2697 BCE when the "Yellow Emperor" Hung Ti described the use of seaweed to treat goiter. The English name "thyroid" was coined by Thomas Wharton in 1656 from the Greek word for a shield. Bernard Courtois discovered iodine in 1811 when he noted a residual purplish ash while burning seaweed.

Thyroid Function in Preterm/Low Birth Weight Infants: Impact on Diagnosis and Management of Thyroid Dysfunction.

Maternal thyroid hormone crosses the placenta to the fetus beginning in the first trimester, likely playing an important role in fetal development. The fetal thyroid gland begins to produce thyroid hormone in the second trimester, with fetal serum T4 levels gradually rising to term. Full maturation of the hypothalamic-pituitary-thyroid (HPT) axis does not occur until term gestation or the early neonatal period.

Outcome of Newborn Screening for Congenital Adrenal Hyperplasia at Two Time Points.

Background/aims: Screening newborns for congenital adrenal hyperplasia (CAH) is problematic owing to the dynamic changes in serum 17-hydroxyprogesterone (17-OHP) levels following birth. Our study objectives were to determine the accuracy of screening, severity of CAH, and biochemical and clinical outcomes of cases detected by our program which collects specimens at 2 time periods following birth.

Methods: We reviewed all CAH cases detected in the Northwest Regional Newborn Screening Program from 2003 through 2017.

Newborn Screening in the US May Miss Mild Persistent Hypothyroidism.

Objective: To determine if newborn screening (NBS) programs for congenital hypothyroidism in the US use thyroid-stimulating hormone (TSH) cutoffs that are age adjusted to account for the physiologic 4-fold reduction in TSH concentrations over the first few days of life.

Study Design: All NBS programs in the US were contacted and asked to provide information on their NBS protocols, TSH cutoffs, and whether these cutoffs were age adjusted.

Results: Of 51 NBS programs, 28 request a repeat specimen if the initial eluted serum TSH concentration is mildly increased (between the cutoff and a median upper limit of 50 mU/L), whereas 14 programs perform a routine second screen in all infants.

Characterization of Thyroid Abnormalities in a Large Cohort of Children with Down Syndrome .

Background/aims: Thyroid disease is a common comorbidity in individuals with Down syndrome (DS), but historical studies have multiple limitations. We assessed thyroid abnormalities in a large cohort of children with DS.

Methods: Retrospective records review from a single institution.

Transient versus Permanent Congenital Hypothyroidism after the Age of 3 Years in Infants Detected on the First versus Second Newborn Screening Test in Oregon, USA.

Background/aims: The newborn screening (NBS) program in Oregon, USA, collects two routine specimens in all infants. The aim of our study was to determine the incidence of permanent versus transient congenital hypothyroidism (CH) in infants detected on the first versus second screening test.

Methods: Thyroid function was determined in infants after the age of 3 years diagnosed with CH and born in Oregon between 2005 and 2011.

Detection of neonates with mild congenital hypothyroidism (primary) or isolated hyperthyrotropinemia: an increasingly common management dilemma.

Anywhere from 10% to 40% of neonates detected by newborn screening programs have mild congenital hypothyroidism (thyroid-stimulating hormone [TSH] 6 to 20 mU/l with borderline low free T4) or isolated hyperthyrotropinemia. The increasing frequency of such cases appears to be chiefly the result of lowering screening TSH cutoffs. In some cases, the etiology is a mild form of dysgenesis or dyshormonogenesis; most cases, however, on imaging have gland in situ of unexplained etiology.

Screening for congenital hypothyroidism: a worldwide view of strategies.

Detection by newborn screening (NBS) and treatment of babies with congenital hypothyroidism (CH) has largely eliminated the intellectual disability caused by this disorder. Lowering of the screening TSH cutoff and changes in birth demographics have been associated with an approximate doubling of the incidence of CH, from 1:3500 to 1:1714. The additional cases detected by lowering of the TSH cutoff tend to have milder hypothyroidism, with imaging often demonstrating a eutopic, "gland in-situ", and some cases turn out to have transient CH.

Novel microcephalic primordial dwarfism disorder associated with variants in the centrosomal protein ninein.

Context: Microcephalic primordial dwarfism (MPD) is a rare, severe form of human growth failure in which growth restriction is evident in utero and continues into postnatal life. Single causative gene defects have been identified in a number of patients with MPD, and all involve genes fundamental to cellular processes including centrosome functions.

Objective: The objective of the study was to find the genetic etiology of a novel presentation of MPD.

Congenital hypothyroidism caused by excess prenatal maternal iodine ingestion.

We report the cases of 3 infants with congenital hypothyroidism detected with the use of our newborn screening program, with evidence supporting excess maternal iodine ingestion (12.5 mg/d) as the etiology. Levels of whole blood iodine extracted from their newborn screening specimens were 10 times above mean control levels.

Approach to the diagnosis and treatment of neonatal hypothyroidism.

Congenital hypothyroidism, occurring in 1:3000 newborns, is one of the most common preventable causes of mental retardation. Neurodevelopmental outcome is inversely related to the age of diagnosis and treatment. Infants detected through newborn screening programs and started on l-T(4) in the first few weeks of life have a normal or near-normal neurodevelopmental outcome.

Congenital hypothyroidism.

Congenital hypothyroidism (CH) occurs in approximately 1:2,000 to 1:4,000 newborns. The clinical manifestations are often subtle or not present at birth. This likely is due to trans-placental passage of some maternal thyroid hormone, while many infants have some thyroid production of their own.

Newborn screening strategies for congenital hypothyroidism: an update.

It is the purpose of this article to briefly review the initial development and subsequent evolution of newborn screening programs to detect infants with congenital hypothyroidism (CH) and then to provide an update of the advantages and disadvantages of the main test strategies. Pilot programs began screening newborn populations in North America in the mid-1970s using either primary thyroxine (T4)-follow-up thyroid stimulating hormone (TSH) or primary TSH testing. Many programs in the United States and around the world continue to prefer a primary T4-follow-up TSH test strategy.

Fetal and neonatal thyroid function: review and summary of significant new findings.

Purpose Of Review: The purpose of this review is to briefly summarize current knowledge of fetal and neonatal thyroid function, and then to summarize the most significant new findings over the last year that add to our knowledge of the cause, diagnosis, and management of fetal and neonatal thyroid disorders.

Recent Findings: Significant findings from publications in the last year include a report that inadequate iodine intake during pregnancy exists in many parts of the world. Conversely, maternal exposure to iodinated contrast agents did not affect neonatal thyroid function.

Should the levothyroxine starting dose be tailored to disease severity in neonates with congenital hypothyroidism?

Early levothyroxine treatment is crucial to minimize neurocognitive impairment associated with congenital hypothyroidism. In this Practice Point commentary, I discuss the findings, implications, and limitations of the study of Mathai et al. in which neonates with congenital hypothyroidism were treated with variable initial doses of levothyroxine.

Pediatric thyroid testing issues.

Thyroid problems are common in children. While serum thyroid function tests lead to an accurate diagnosis in most patients, unique patient situations can produce misleading results. Total T4 measurements can incorrectly suggest hypothyroidism in congenital thyroid binding globulin (TBG) deficiency and hyperthyroidism in TBG excess, as seen in high estrogen states.

How should we be treating children with congenital hypothyroidism?

Early detection by newborn screening and appropriate L-thyroxine treatment leads to normal or near-normal neurocognitive outcome in infants with congenital hypothyroidism. Many newborns with congenital hypothyroidism have some residual thyroid hormone production, and even in those with athyreosis, transplacental passage of maternal thyroid hormone offers some protection for a time. Given the serum T4 half-life of 6 days, the neonatal T4 level will fall and disappear over the first 2-3 weeks of life.