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Congenital hypothyroidism.

Rastogi MV, LaFranchi SH - Orphanet J Rare Dis (2010)

Bottom Line: Common symptoms include decreased activity and increased sleep, feeding difficulty, constipation, and prolonged jaundice.Frequent laboratory monitoring in infancy is essential to ensure optimal neurocognitive outcome.Studies show that a lower neurocognitive outcome may occur in those infants started at a later age (> 30 days of age), on lower l-thyroxine doses than currently recommended, and in those infants with more severe hypothyroidism.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pediatrics, Division of Endocrinology, Oregon Health & Science University, 707 SW Gaines Street, Portland, OR, USA.

ABSTRACT
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. Common symptoms include decreased activity and increased sleep, feeding difficulty, constipation, and prolonged jaundice. On examination, common signs include myxedematous facies, large fontanels, macroglossia, a distended abdomen with umbilical hernia, and hypotonia. CH is classified into permanent and transient forms, which in turn can be divided into primary, secondary, or peripheral etiologies. Thyroid dysgenesis accounts for 85% of permanent, primary CH, while inborn errors of thyroid hormone biosynthesis (dyshormonogeneses) account for 10-15% of cases. Secondary or central CH may occur with isolated TSH deficiency, but more commonly it is associated with congenital hypopitiutarism. Transient CH most commonly occurs in preterm infants born in areas of endemic iodine deficiency. In countries with newborn screening programs in place, infants with CH are diagnosed after detection by screening tests. The diagnosis should be confirmed by finding an elevated serum TSH and low T4 or free T4 level. Other diagnostic tests, such as thyroid radionuclide uptake and scan, thyroid sonography, or serum thyroglobulin determination may help pinpoint the underlying etiology, although treatment may be started without these tests. Levothyroxine is the treatment of choice; the recommended starting dose is 10 to 15 mcg/kg/day. The immediate goals of treatment are to rapidly raise the serum T4 above 130 nmol/L (10 ug/dL) and normalize serum TSH levels. Frequent laboratory monitoring in infancy is essential to ensure optimal neurocognitive outcome. Serum TSH and free T4 should be measured every 1-2 months in the first 6 months of life and every 3-4 months thereafter. In general, the prognosis of infants detected by screening and started on treatment early is excellent, with IQs similar to sibling or classmate controls. Studies show that a lower neurocognitive outcome may occur in those infants started at a later age (> 30 days of age), on lower l-thyroxine doses than currently recommended, and in those infants with more severe hypothyroidism.

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Related in: MedlinePlus

Congenital hypothyroidism: Diagnostic algorithm. Diagnostic algorithm: the diagnosis of congenital hypothyroidism begins with either abnormal newborn screening test results or a clinical suspicion of hypothyroidism, leading to serum thyroid function tests (typically TSH and free T4) to confirm the diagnosis. If a diagnosis of primary or secondary (central) congenital hypothyroidism is confirmed, other diagnostic studies can be undertaken to determine the underlying etiology.
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Figure 4: Congenital hypothyroidism: Diagnostic algorithm. Diagnostic algorithm: the diagnosis of congenital hypothyroidism begins with either abnormal newborn screening test results or a clinical suspicion of hypothyroidism, leading to serum thyroid function tests (typically TSH and free T4) to confirm the diagnosis. If a diagnosis of primary or secondary (central) congenital hypothyroidism is confirmed, other diagnostic studies can be undertaken to determine the underlying etiology.

Mentions: The specimen used for newborn screening tests is blood from a heel-prick collected on special filter paper cards. The specimen is routinely collected between two and five days of age (or at discharge from the hospital, if this occurs earlier); some programs use cord blood for screening. In addition, some programs also routinely obtain a 2 nd specimen between two and six weeks of age. The filter paper cards are then sent to a centralized laboratory for testing. Early in the experience of screening, most programs undertook an initial T4 test, with a follow-up TSH test on infants below a specified T4 cutoff [2]. With increasing accuracy of TSH measurement, many screening programs now carry out an initial TSH test to detect congenital hypothyroidism. Each program must develop its own T4 and TSH cutoff for recall of infants with abnormal test results (see Figure 4, Diagnostic algorithm). As there are rapid changes in TSH and T4 in the first few days of life, many programs have developed age-related cutoffs. Following are examples of typical cutoffs for T4 and TSH:


Congenital hypothyroidism.

Rastogi MV, LaFranchi SH - Orphanet J Rare Dis (2010)

Congenital hypothyroidism: Diagnostic algorithm. Diagnostic algorithm: the diagnosis of congenital hypothyroidism begins with either abnormal newborn screening test results or a clinical suspicion of hypothyroidism, leading to serum thyroid function tests (typically TSH and free T4) to confirm the diagnosis. If a diagnosis of primary or secondary (central) congenital hypothyroidism is confirmed, other diagnostic studies can be undertaken to determine the underlying etiology.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2903524&req=5

Figure 4: Congenital hypothyroidism: Diagnostic algorithm. Diagnostic algorithm: the diagnosis of congenital hypothyroidism begins with either abnormal newborn screening test results or a clinical suspicion of hypothyroidism, leading to serum thyroid function tests (typically TSH and free T4) to confirm the diagnosis. If a diagnosis of primary or secondary (central) congenital hypothyroidism is confirmed, other diagnostic studies can be undertaken to determine the underlying etiology.
Mentions: The specimen used for newborn screening tests is blood from a heel-prick collected on special filter paper cards. The specimen is routinely collected between two and five days of age (or at discharge from the hospital, if this occurs earlier); some programs use cord blood for screening. In addition, some programs also routinely obtain a 2 nd specimen between two and six weeks of age. The filter paper cards are then sent to a centralized laboratory for testing. Early in the experience of screening, most programs undertook an initial T4 test, with a follow-up TSH test on infants below a specified T4 cutoff [2]. With increasing accuracy of TSH measurement, many screening programs now carry out an initial TSH test to detect congenital hypothyroidism. Each program must develop its own T4 and TSH cutoff for recall of infants with abnormal test results (see Figure 4, Diagnostic algorithm). As there are rapid changes in TSH and T4 in the first few days of life, many programs have developed age-related cutoffs. Following are examples of typical cutoffs for T4 and TSH:

Bottom Line: Common symptoms include decreased activity and increased sleep, feeding difficulty, constipation, and prolonged jaundice.Frequent laboratory monitoring in infancy is essential to ensure optimal neurocognitive outcome.Studies show that a lower neurocognitive outcome may occur in those infants started at a later age (> 30 days of age), on lower l-thyroxine doses than currently recommended, and in those infants with more severe hypothyroidism.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pediatrics, Division of Endocrinology, Oregon Health & Science University, 707 SW Gaines Street, Portland, OR, USA.

ABSTRACT
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. Common symptoms include decreased activity and increased sleep, feeding difficulty, constipation, and prolonged jaundice. On examination, common signs include myxedematous facies, large fontanels, macroglossia, a distended abdomen with umbilical hernia, and hypotonia. CH is classified into permanent and transient forms, which in turn can be divided into primary, secondary, or peripheral etiologies. Thyroid dysgenesis accounts for 85% of permanent, primary CH, while inborn errors of thyroid hormone biosynthesis (dyshormonogeneses) account for 10-15% of cases. Secondary or central CH may occur with isolated TSH deficiency, but more commonly it is associated with congenital hypopitiutarism. Transient CH most commonly occurs in preterm infants born in areas of endemic iodine deficiency. In countries with newborn screening programs in place, infants with CH are diagnosed after detection by screening tests. The diagnosis should be confirmed by finding an elevated serum TSH and low T4 or free T4 level. Other diagnostic tests, such as thyroid radionuclide uptake and scan, thyroid sonography, or serum thyroglobulin determination may help pinpoint the underlying etiology, although treatment may be started without these tests. Levothyroxine is the treatment of choice; the recommended starting dose is 10 to 15 mcg/kg/day. The immediate goals of treatment are to rapidly raise the serum T4 above 130 nmol/L (10 ug/dL) and normalize serum TSH levels. Frequent laboratory monitoring in infancy is essential to ensure optimal neurocognitive outcome. Serum TSH and free T4 should be measured every 1-2 months in the first 6 months of life and every 3-4 months thereafter. In general, the prognosis of infants detected by screening and started on treatment early is excellent, with IQs similar to sibling or classmate controls. Studies show that a lower neurocognitive outcome may occur in those infants started at a later age (> 30 days of age), on lower l-thyroxine doses than currently recommended, and in those infants with more severe hypothyroidism.

Show MeSH
Related in: MedlinePlus