The Differing Outcomes of Hyperthyrotropinaemia

Cody, Declan; Kumar, Y; Ng, Sze May; Didi, Mo; Smith, Colin

doi:10.1515/jpem.2003.16.3.375

Cited by 17 publications

(17 citation statements)

References 9 publications

(3 reference statements)

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“…The etiology is probably heterogeneous and can be either a transient or permanent thyroid abnormality [43][44][45][46] or delayed maturation of the hypothalamic-pituitary axis. Inactivation mutations in the TSH-R cause compensated, mild (subclinical) primary hypothyroidism in the neonatal period.…”

Section: Normal T 4 and Elevated Tsh Valuesmentioning

confidence: 99%

Update of Newborn Screening and Therapy for Congenital Hypothyroidism

Rose¹,

Brown²

2006

Pediatrics

582

301

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Unrecognized congenital hypothyroidism leads to mental retardation. Newborn screening and thyroid therapy started within 2 weeks of age can normalize cognitive development. The primary thyroid-stimulating hormone screening has become standard in many parts of the world. However, newborn thyroid screening is not yet universal in some countries. Initial dosage of 10 to 15 g/kg levothyroxine is recommended. The goals of thyroid hormone therapy should be to maintain frequent evaluations of total thyroxine or free thyroxine in the upper half of the reference range during the first 3 years of life and to normalize the serum thyroid-stimulating hormone concentration to ensure optimal thyroid hormone dosage and compliance.Improvements in screening and therapy have led to improved developmental outcomes in adults with congenital hypothyroidism who are now in their 20s and 30s. Thyroid hormone regimens used today are more aggressive in targeting early correction of thyroid-stimulating hormone than were those used 20 or even 10 years ago. Thus, newborn infants with congenital hypothyroidism today may have an even better intellectual and neurologic prognosis. Efforts are ongoing to establish the optimal therapy that leads to maximum potential for normal development for infants with congenital hypothyroidism.Remaining controversy centers on infants whose abnormality in neonatal thyroid function is transient or mild and on optimal care of very low birth weight or preterm infants. Of note, thyroid-stimulating hormone is not elevated in central hypothyroidism. An algorithm is proposed for diagnosis and management.Physicians must not relinquish their clinical judgment and experience in the face of normal newborn thyroid test results. Hypothyroidism can be acquired after the newborn screening. When clinical symptoms and signs suggest hypothyroidism, regardless of newborn screening results, serum free thyroxine and thyroidstimulating hormone determinations should be performed. INTRODUCTIONCongenital hypothyroidism (CH) is one of the most common preventable causes of mental retardation. In most cases, the disorder is permanent and results from an All clinical reports from the American Academy of Pediatrics automatically expire 5 years after publication unless reaffirmed, revised, or retired at or before that time.The guidance in this report does not indicate an exclusive course of treatment or serve as a standard of medical care. Variations, taking into account individual circumstances, may be appropriate.Key Words congenital hypothyroidism, thyroid hormone, thyroid-stimulating hormone, newborn screening Abbreviations CH-congenital hypothyroidism TH-thyroid hormone T 4 -thyroxine T 3 -triiodothyronine TSH-R-thyrotropin receptor TRBAb-thyrotropin receptor-blocking antibody FT 4 -free thyroxine TSH-thyroid-stimulating hormone TBG-thyroid-binding globulin LBW-low birth weight VLBW-very low birth weight L-T 4 -levothyroxine TRH-thyrotropin-releasing hormone PEDIATRICS (ISSN Numbers: Print, 0031-4005; Online, 1098-4275).

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Section: Normal T 4 and Elevated Tsh Valuesmentioning

confidence: 99%

Update of Newborn Screening and Therapy for Congenital Hypothyroidism

Rose¹,

Brown²

2006

Pediatrics

582

301

View full text Add to dashboard Cite

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“…Given the transient nature of many cases of hyperthyrotropinemia, there is controversy whether thyroid hormone therapy should be initiated. 7,8 However, for those neonates started on treatment with levothyroxine, a trial off therapy at 3 years of age is recommended to distinguish those with transitory forms of hypothyroidism from those with true CH who require lifetime treatment. 4,9 Authors of many surveillance or research studies do not distinguish between transient hypothyroidism and transient hyperthyrotropinemia and have defined all such cases as transient hypothyroidism.…”

Section: Definitions Of Transient Hypothyroidismmentioning

confidence: 99%

The Impact of Transient Hypothyroidism on the Increasing Rate of Congenital Hypothyroidism in the United States

et al. 2010

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The reported incidence rate of primary congenital hypothyroidism (CH) has been increasing in the United States over the past 2 decades. We have considered the possibility that the inclusion of cases of transient hypothyroidism has inflated the reported incidence rate of CH. Assessing the effects of cases of transient hypothyroidism on the incidence rate is problematic, because the definitions, diagnostic criteria, and differentiation from transient hyperthyrotropinemia vary widely among state newborn screening programs. Among the 4 etiologies for transient hypothyroidism (maternal thyrotropin receptor-blocking antibodies, exposure to maternal antithyroid medications, iodine deficiency, and iodine excess), there is little evidence of increases in the incidence rate from thyrotropin receptor-blocking antibodies. Exposure to antithyroid drugs could contribute significantly to the incidence rate of transient CH, given the high estimated incidence of active maternal hyperthyroidism. Iodine deficiency or excess in the United States seems unlikely to have contributed significantly to the incidence rate of CH, because the secular trend toward lower iodine intake among women of reproductive age in the 1980s and 1990s seems to have plateaued, and perinatal iodine exposure has presumably declined as a result of recommendations to discontinue using iodinecontaining disinfectants. Although the female-to-male sex ratio among newborns with thyroid agenesis or dysgenesis (the most common causes of CH) is typically 2:1, analysis of the sex ratio of newborns diagnosed with presumed CH in the United States suggests that a substantial proportion might have transient hypothyroidism or hyperthyrotropinemia, because the sex ratio has been well below the expected 2:1 ratio. Combined ultrasonography and 123 I scintigraphy of the thyroid gland are effective tools for identifying cases of thyroid agenesis and dysgenesis and can help to differentiate cases of transient hypothyroidism from true CH. Imaging is also a vital component in evaluating children who, at 3 years of age, undergo a trial of discontinuation of levothyroxine treatment to test for persistence of hypothyroidism. Ultimately, thyroid gland imaging, in conjunction with longterm follow-up studies that appropriately assess and report whether there was permanence of hypothyroidism, will be necessary to address the true incidence rate of CH and any contribution to the observed rate by transient cases of hypothyroidism or hyperthyrotropinemia.

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“…Low basal metabolic rate in these patients suggests that this can be a form of compensated hypothyroidism (4). Permanent and subclinical hypothyroidism can occur in long-lasting cases (5)(6)(7). However, information in the literature about this issue is scarce.…”

Section: Introductionmentioning

confidence: 99%

l-thyroxin treatment in infants with hyperthyrotropinaemia: 4-year experience

Demirel

Bideci

Çamurdan

et al. 2006

International Journal of Clinical Practice

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Hyperthyrotropinaemia, in which normal levels of T4 occur in association with raised thyroid stimulating hormone (TSH), is usually picked up on neonatal screening. High TSH level can continue for a long time in some of the cases. There is no consensus concerning the follow-up or treatment plan for hyperthyrotropinaemia. In this study, results of a 4-year follow-up of 36 cases who had been medically treated are discussed. Low-dose (5 microg/kg/day) L-thyroxin treatment was carried out in 36 cases that had 5 mU/l or higher TSH and showed exaggerated response to TRH test. Dose was decreased to 2-3 microg/kg/day in 24 of these patients during 6 months follow-up. The drug was stopped in three cases because of the development of biochemical hyperthyroidism. Denver developmental assessment test was applied to all cases at the end of the third year. All patients showed a normal development in relation to their age. According to our results, cases with hyperthyrotropinaemia need to be followed regularly for a long time and a need for low-dose L-thyroxin treatment may exist at ages varying from patient to patient.

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The Differing Outcomes of Hyperthyrotropinaemia

Cited by 17 publications

References 9 publications

Update of Newborn Screening and Therapy for Congenital Hypothyroidism

Update of Newborn Screening and Therapy for Congenital Hypothyroidism

The Impact of Transient Hypothyroidism on the Increasing Rate of Congenital Hypothyroidism in the United States

l-thyroxin treatment in infants with hyperthyrotropinaemia: 4-year experience

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