1
|
Zdraveska N, Kocova M. Thyroid function and dysfunction in preterm infants-Challenges in evaluation, diagnosis and therapy. Clin Endocrinol (Oxf) 2021; 95:556-570. [PMID: 33864279 DOI: 10.1111/cen.14481] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 04/08/2021] [Accepted: 04/10/2021] [Indexed: 11/30/2022]
Abstract
Thyroid hormone levels have a crucial role for optimal brain development from gestation through the first 2 postnatal years. However, thyroid hormones vary with gestational age, and their levels vary between term and preterm infants. Preterm newborns are prone to thyroid dysfunction which is now more frequently observed with the advances of neonatal care and improved survival of extremely premature infants. Thus, hypothyroxinaemia of prematurity associated with delayed TSH elevation is very common in low birth weight premature infants most likely due to the immaturity of the hypothalamic-pituitary thyroid axis. Furthermore, postnatal illness, medications and iodine status may contribute to the thyroid dysfunction or affect the interpretation of the thyroid function tests. Despite available guidelines, timing of screening and optimal treatment of thyroid dysfunction in premature infants remains controversial. Furthermore, it is unknown whether untreated thyroid dysfunction in premature babies affects neurodevelopmental outcome. In the vast majority of preterm infants, hypothyroxinaemia is transient; however, permanent hypothyroidism due to thyroid dysgenesis or enzyme defects might also occur. Therefore, careful monitoring of thyroid function and long-term follow-up is needed to assess an appropriate therapeutic approach. This article reviews thyroid physiology in preterm infants, the influences of gestation and other neonatal conditions on thyroid function tests, optimal timing of screening and possible predictors to differentiate transient hypothyroxinaemia from permanent hypothyroidism.
Collapse
Affiliation(s)
- Nikolina Zdraveska
- Medical Faculty, University Ss. Cyril and Methodius Skopje, University Children's Hospital, Skopje, Macedonia
| | - Mirjana Kocova
- Medical Faculty, University Ss. Cyril and Methodius Skopje, University Children's Hospital, Skopje, Macedonia
| |
Collapse
|
2
|
Goel D, Luig M, Maheshwari R, D'Cruz D, Goyen TA. General Movement assessment and neurodevelopmental trajectory in extremely preterm infants with hypothyroxinaemia of prematurity (THOP). Early Hum Dev 2020; 144:104886. [PMID: 31668678 DOI: 10.1016/j.earlhumdev.2019.104886] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 09/06/2019] [Accepted: 09/06/2019] [Indexed: 10/25/2022]
Abstract
BACKGROUND Transient hypothyroxinaemia of prematurity (THOP) has been associated with neurodevelopmental deficits with a paucity of literature leading to variable practice. AIM Evaluation of the relationship between free T4 (fT4) levels at 2 weeks after birth and early markers of neurodevelopmental outcome. STUDY DESIGN A retrospective study of prospectively collected data from infants born <29 weeks' gestation, admitted to NICU between January 2012 and December 2014. The primary outcomes were the relationship between fT4 levels at 2 weeks, Prechtl General Movement Assessment (GMA) at 36 weeks and 3 months postterm age, and Bayley Scales of Infant Development (BSID-III) at 2 years postterm age. Secondary outcomes were survival free of disability and other neonatal morbidities. RESULTS Of 122 infants, 101 infants had normal fT4 levels (No-THOP) and 21 had fT4 levels >1SD below the mean (THOP group). There was increased frequency of abnormal GMA in the No-THOP group compared with the THOP group at 36 weeks (abnormal writhing GMs: 43% vs 21%, p = 0.15) and 3 months corrected age (absent fidgety GMs: 7.6% vs 0%, p = 0.36), though not statistically significant. The neurodevelopmental outcome was worse in the No-THOP group compared with the THOP group with significantly lower mean cognitive and motor scores at 2 year of corrected age (90 ± 13.8 vs 100 ± 8.3, p = 0.01 and 91 ± 15.2 vs 100 ± 13.2, p = 0.04 respectively). CONCLUSIONS This is the first report describing General Movements (GMs) in preterm infants with THOP. We found worse neurodevelopmental outcome in No-THOP infants reflected by significantly worse cognitive and motor outcomes at 2 years corrected age.
Collapse
Affiliation(s)
- Dimple Goel
- Westmead Hospital, Sydney, Australia; University of Sydney, Sydney, Australia.
| | | | - Rajesh Maheshwari
- Westmead Hospital, Sydney, Australia; University of Sydney, Sydney, Australia
| | - Daphne D'Cruz
- Westmead Hospital, Sydney, Australia; University of Sydney, Sydney, Australia
| | | |
Collapse
|
3
|
Hijman AI, Konrad D, Fingerhut R. Determining Reference Ranges for Total T 4 in Dried Blood Samples for Newborn Screening. Int J Neonatal Screen 2020; 6:17. [PMID: 33073014 PMCID: PMC7422970 DOI: 10.3390/ijns6010017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 02/20/2020] [Indexed: 01/27/2023] Open
Abstract
The purpose of this study was to define reference intervals for total thyroxine (tT4) in dried blood samples (DBSs) obtained for newborn screening. The aim of our study was to assess the possible benefit of measuring tT4 concentrations directly in DBSs obtained for newborn screening in premature and term-born infants. In order to have a sufficient number of samples for the extremely premature infants (<30 weeks), we set up a retrospective study, measuring the concentrations in DBSs collected over the previous 21 weeks. This time frame was a result of the included miniature study of tT4 stability in DBSs. We found that tT4 strongly correlated with gestational age (GA) in premature infants, highlighting the need for age-specific reference ranges. For term-born infants, the tT4 ranges did not vary significantly among different gestational ages, allowing for the use of one single reference range.
Collapse
Affiliation(s)
| | - Daniel Konrad
- Department of Endocrinology & Diabetology, Children’s Research Center, University Children’s Hospital Zurich, 8032 Zurich, Switzerland
| | - Ralph Fingerhut
- Swiss Newborn Screening Laboratory, Children’s Research Center, University Children’s Hospital Zurich, 8032 Zurich, Switzerland
| |
Collapse
|
4
|
Shi R, Zhang M, Chen Y, Han M, Xu P, Li M, Ding Y, Zhang X, Kou Y, Xu H, Zong F, Liu X, Wang H, He H, Liu Q, Kong W, Niu S, Li X, Huang L, Lu Q, Wang X, Deng L, Yang Z, Zhang X, Sun R, Zhao R, Shi J, Peng F, Sun X, Zhao G, Zhao X, Ge Y, Zhang N, Zhu R, Li J, Li H, Hao H, Yu Y. Dynamic Change of Thyroid Hormones With Postmenstrual Age in Very Preterm Infants Born With Gestational Age <32 Weeks: A Multicenter Prospective Cohort Study. Front Endocrinol (Lausanne) 2020; 11:585956. [PMID: 33859613 PMCID: PMC8043151 DOI: 10.3389/fendo.2020.585956] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 12/30/2020] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND At present, the relationship between thyrotropin (TSH) and free thyroxine (FT4) in relation to postmenstrual age (PMA) in preterm infants is still unclear, and there is no reliable standard thyroid hormone reference ranges, resulting in different diagnostic criteria for congenital hypothyroidism been used by different newborn screening programs and different countries. OBJECTIVES To investigate the relationship between TSH/FT4 and PMA in very preterm infants (VPIs) born with gestational age (GA) <32 weeks and to derive thyroid function reference charts based on PMA. METHODS A prospective cohort study was performed on VPIs born with GA<32 weeks and born in or transferred to the 27 neonatal intensive care units from January 1, 2019 to December 31, 2019. Serial TSH and FT4 values were measured at the end of each week during the first month after birth and also at PMA36 weeks, PMA40 weeks and at discharge, respectively. The 2.5th, 5th, 50th, 95th, and 97.5th percentiles of TSH and FT4 of different PMA groups were calculated to draw the percentile charts based on PMA. RESULTS 1,093 preterm infants were included in this study. The percentile charts of TSH and FT4 levels based on PMA were drawn respectively, and the result indicated that the percentile charts of TSH values were gradually increased initially and then decreased with increasing PMA. The 97.5th percentile chart reached the peak at PMA30 weeks (17.38μIU/ml), and then decreased gradually, reaching the same level as full-term infants (9.07μIU/ml) at PMA38-40 weeks. The 2.5th percentile chart of FT4 was at its lowest point at PMA26-27 weeks (5.23pmol/L), then increased slowly with PMA and reached the same level as full-term infants at PMA38-40 weeks (10.87pmol/L). At PMA36 weeks, the reference intervals of the 2.5th to 97.5th percentiles of TSH and FT4 were 1.18-12.3μIU/ml and 8.59-25.98pmol/L, respectively. CONCLUSION The percentile charts of TSH and FT4 in VPIs showed characteristic change with PMA. The results prompt that age-related cutoffs, instead of a single reference range, might be more useful to explain the thyroid function of VPIs. And repeated screening is necessary for preterm infants.
Collapse
Affiliation(s)
- Ranran Shi
- Department of Neonatology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
- Department of Neonatology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Ming Zhang
- Department of Neonatology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
- Department of Neonatology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Yao Chen
- Department of Neonatology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
- Department of Neonatology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Meiying Han
- Department of Neonatology, Liaocheng People’s Hospital, Liaocheng, China
| | - Ping Xu
- Department of Neonatology, Liaocheng People’s Hospital, Liaocheng, China
| | - Min Li
- Department of Neonatology, Linyi Maternal and Child Health Hospital, Linyi, China
| | - Yanjie Ding
- Department of Neonatology, Yantai Yuhuangding Hospital, Yantai, China
| | - Xiaohui Zhang
- Department of Neonatology, Yantai Yuhuangding Hospital, Yantai, China
| | - Yan Kou
- Department of Neonatology, Shandong Provincial Qianfoshan Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Haiyan Xu
- Department of Neonatology, Shandong Provincial Qianfoshan Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Fangru Zong
- Department of Neonatology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Xinjian Liu
- Department of Neonatology, Hebei PetroChina Central Hospital, Langfang, China
| | - Hui Wang
- Department of Neonatology, Hebei PetroChina Central Hospital, Langfang, China
| | - Haiying He
- Department of Neonatology, Baogang Third Hospital of Hongci Group, Baotou, China
| | - Qiang Liu
- Department of Neonatology, Linyi People’s Hospital, Linyi, China
| | - Weikang Kong
- Department of Neonatology, Linyi People’s Hospital, Linyi, China
| | - Shiping Niu
- Department of Neonatology, Zibo Maternal and Child Care Hospital, Zibo, China
| | - Xia Li
- Department of Neonatal Intensive Care Unit, Jinan Maternity and Child Care Hospital, Jinan, China
| | - Lei Huang
- Department of Neonatology, Shandong Maternal and Child Health Hospital, Jinan, China
| | - Qinghua Lu
- Department of Neonatology, Shandong Maternal and Child Health Hospital, Jinan, China
| | - Xiaofang Wang
- Department of Neonatology, Heze Municipal Hospital, Heze, China
| | - Liping Deng
- Department of Neonatology, Heze Municipal Hospital, Heze, China
| | - Zhenying Yang
- Department of Neonatology, Taian Maternal and Child Health Care Hospital, Tai’an, China
| | - Xiao Zhang
- Department of Neonatology, Taian Maternal and Child Health Care Hospital, Tai’an, China
| | - Rongrong Sun
- Department of Neonatology, Dongying People’s Hospital, Dongying, China
| | - Riming Zhao
- Department of Neonatology, Juxian People’s Hospital, Rizhao, China
| | - Jing Shi
- Department of Neonatology, Second People’s Hospital of Liaocheng, Liaocheng, China
| | - Fudong Peng
- Department of Neonatology, Second People’s Hospital of Liaocheng, Liaocheng, China
| | - Xueming Sun
- Department of Neonatology, Yidu Central Hospital of Weifang, Weifang, China
| | - Guoying Zhao
- Department of Neonatology, Binzhou Medical University Hospital, Binzhou, China
| | - Xinfeng Zhao
- Department of Neonatology, Maternal and Child Health Care Hospital of Zaozhuang, Zaozhuang, China
| | - Yonghong Ge
- Department of Neonatology, Liaocheng Dongchangfu Maternal and Child Health Care Hospital, Liaocheng, China
| | - Nan Zhang
- Department of Neonatology, Jinan Central Hospital Affiliated to Shandong University, Jinan, China
| | - Renxia Zhu
- Department of Neonatology, Linzi District People’s Hospital, Zibo, China
| | - Jing Li
- Department of Neonatology, The Second Affiliated Hospital of Shandong First Medical University, Jinan, China
| | - Haiyan Li
- Department of Neonatology, Yantaishan Hospital, Yantai, China
| | - Huijuan Hao
- Department of Neonatology, Jinan Second Maternal and Child Health Hospital, Jinan, China
| | - Yonghui Yu
- Department of Neonatology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
- Department of Neonatology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
- *Correspondence: Yonghui Yu,
| |
Collapse
|
5
|
Establishment of reference intervals for thyroid hormones in premature infants beyond the first week of life using Beckman Coulter Unicel DxI 800. Clin Biochem 2019; 74:19-23. [PMID: 31499031 DOI: 10.1016/j.clinbiochem.2019.09.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 08/19/2019] [Accepted: 09/05/2019] [Indexed: 11/21/2022]
Abstract
BACKGROUND This 4-year retrospective cohort study aimed to establish reference intervals for free triiodothyronine (FT3), free thyroxine (FT4), and thyrotropin (TSH) in premature infants using the Beckman Coulter Unicel DxI 800 automated immunoassay system. METHODS Study subjects included 605 preterm infants with a gestational age of 26-36 weeks (corrected: 29-38 weeks). Pearson correlation was used to evaluate the association between hormone levels and gestational and corrected gestational ages. A nonparametric method was used to establish reference intervals based on corrected gestational age. RESULTS FT3 and FT4 levels were positively correlated with gestational and corrected gestational ages, respectively. TSH levels were slightly negatively correlated with gestational and corrected gestational ages. FT3 significantly differed according to corrected gestational age (29-33 weeks vs 34-38 weeks); however, the difference was smaller than the reference change value (RCV) for the FT3 test. Thus, we combined the FT3 reference intervals into a single reference interval: 2.65-4.93 pmol/L (29-38 weeks). The reference intervals of FT4 and TSH were 11.20-24.97 pmol/L (29-38 weeks) and 1.01-10.14 mIU/L (29-38 weeks), respectively. CONCLUSIONS Unlike those of full-term infants or adults, the reference intervals established in this study are applicable in premature infants. These results highlight the importance and complexity of establishing instrument-specific thyroid hormone reference intervals for preterm infants.
Collapse
|
6
|
Kaluarachchi DC, Allen DB, Eickhoff JC, Dawe SJ, Baker MW. Thyroid-Stimulating Hormone Reference Ranges for Preterm Infants. Pediatrics 2019; 144:peds.2019-0290. [PMID: 31311840 DOI: 10.1542/peds.2019-0290] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/30/2019] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND AND OBJECTIVES Many newborn screening (NBS) programs now perform repeat or serial NBS to detect congenital hypothyroidism. There is wide variation in thyroid-stimulating hormone (TSH) cutoffs used by NBS programs. Data on TSH reference ranges in preterm infants at increasing postnatal age are limited. Our study objective was to determine TSH reference ranges for preterm infants born at <32 weeks' gestation. METHODS We analyzed serial TSH levels on NBS performed on infants born between 22 and 31 weeks' gestation from 2012 to 2016 in Wisconsin. The study cohort was divided into 2 groups (22-27 and 28-31 weeks), and TSH percentiles were defined from birth to the term equivalent gestational age. RESULTS The study cohort consisted of 1022 and 2115 infants born at 22 to 27 and 28 to 31 weeks' gestation, respectively. The 95th percentile TSH level for the group born at 22 to 27 weeks' gestation gradually decreased and reached a nadir at ∼10 to 11 weeks. In contrast, for the group born at 28 to 31 weeks' gestation, the 95th percentile TSH level reached a nadir at ∼5 to 6 weeks. At 3 to 4 weeks after birth, the 95th percentile TSH level ranged from 11 to 11.8 μIU/mL for the group born at 22 to 27 weeks' gestation and ranged from 8.2 to 9 μIU/mL for the group born at 28 to 31 weeks' gestation. CONCLUSIONS Using a statewide cohort of preterm infants, we constructed TSH reference charts from birth to the term equivalent gestation for preterm infants born at <32 weeks' gestation. Use of a single cutoff for all preterm infants might lead to misdiagnosis. The differences in TSH levels according to gestational-age categories might explain the increased frequency in congenital hypothyroidism diagnoses among preterm infants. These data are useful for defining age-adjusted NBS TSH cutoffs for preterm infants.
Collapse
Affiliation(s)
| | | | | | - Sandra J Dawe
- Wisconsin State Laboratory of Hygiene, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin
| | - Mei W Baker
- Departments of Pediatrics and.,Wisconsin State Laboratory of Hygiene, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin
| |
Collapse
|
7
|
Chung HR. Screening and management of thyroid dysfunction in preterm infants. Ann Pediatr Endocrinol Metab 2019; 24:15-21. [PMID: 30943675 PMCID: PMC6449615 DOI: 10.6065/apem.2019.24.1.15] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 03/15/2019] [Indexed: 12/18/2022] Open
Abstract
Preterm infants can suffer various thyroid dysfunctions associated with developmental immaturity of the hypothalamic-pituitary-thyroid axis, postnatal illness, medications, or iodine supply. The incidence of thyroid dysfunction among preterm infants is higher than that among term infants and has been increasing with improvement in the survival of preterm infants. Hypothyroxinemia is frequently observed during the first week of life in extreme preterm neonates, and the incidence of delayed thyrotropin elevation is high at the age of 2-6 weeks. Although the necessity of routine rescreening remains controversial, recent guidelines on screening for congenital hypothyroidism have recommended rescreening of all preterm neonates. Thyroid hormone replacement is recommended for persistent thyrotropin elevation with or without hypothyroxinemia. Hypothyroxinemia without thyrotropin elevation does not require treatment, and some potential risks of levothyroxine supplementation have been reported. Although most thyroid dysfunctions are transient, careful follow-up after discontinuation of levothyroxine is considered so as to avoid missing persistent hypothyroidism.
Collapse
Affiliation(s)
- Hye Rim Chung
- Department of Pediatrics, Seoul National University Bundang Hospital, Seongnam, Korea,Address for correspondence: Hye Rim Chung, MD Department of Pediatrics, Seoul National Universit y Bundang Hospital, 82, Gumi-ro 173 Beongil, Bundang-gu, Seongnam 13620, Korea Tel: +82-31-787-7289 Fax: +82-31-787-4054 E-mail:
| |
Collapse
|
8
|
Hashemipour M, Hovsepian S, Ansari A, Keikha M, Khalighinejad P, Niknam N. Screening of congenital hypothyroidism in preterm, low birth weight and very low birth weight neonates: A systematic review. Pediatr Neonatol 2018; 59:3-14. [PMID: 28811156 DOI: 10.1016/j.pedneo.2017.04.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 01/09/2017] [Accepted: 04/12/2017] [Indexed: 11/30/2022] Open
Abstract
Evidence from different screening programs indicated that the rate of congenital hypothyroidism (CH) was higher in pre-term and low-birth-weight (LBW) newborns than normal ones. Incomplete development of hypothalamic-pituitary axis in this group of neonates results in the delayed rise of TSH and missing cases with CH. Hence, there is a great need for a practicable systematic screening method for proper diagnosis of CH in this group of neonates. In this review, we systematically reviewed papers with the following key words ([Congenital Hypothyroidism AND Screening AND Thyroxine AND Thyroid Stimulating Hormone AND Low Birth Weight AND Premature]) in international electronic databases including PubMed, Scopus, and Google Scholar. After quality assessment of selected documents, data of finally included papers were extracted. In this review, 1452 papers (PubMed: 617; Scopus: 714; Google scholar: 121) were identified through electronic database search. One hundred and ninety four articles were assessed for eligibility, from which 36 qualified articles were selected for final evaluation. From the reviewed articles, 38.9%, 11.11% and 8.3% recommended rescreening in this group of neonates, lowering the screening cutoff of TSH and using cutoffs according to the gestational age, respectively. Some of them (13.9%) recommended using both TSH and T4 for screening of preterm infants. After reviewing available data, we recommend repeating the screening test in pre-term, LBW and very-low- birth-weight (VLBW) infants at age of two, six and ten weeks by measuring TSH and FT4 levels simultaneously and considering TSH = 10 mU/L as the cutoff level for positive and suspicious cases.
Collapse
Affiliation(s)
- Mahin Hashemipour
- Isfahan Endocrine and Metabolism Research Center, Isfahan University of Medical Sciences, Isfahan, Iran; Department of Pediatrics, Child Growth and Development Research Center, Research Institute for Primordial Prevention of Non-Communicable Disease, Emam Hossein Children's Hospital, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Silva Hovsepian
- Child Growth and Development Research Center, Research Institute for Primordial Prevention of Non Communicable Disease, Isfahan University of Medical Sciences, Isfahan, Iran.
| | - Arman Ansari
- Students Research Committee, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mojtaba Keikha
- Department of Epidemiology, Child Growth and Development Research Center, Research Institute for Primordial Prevention of Non Communicable Disease, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Pooyan Khalighinejad
- Students Research Committee, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Negar Niknam
- Students Research Committee, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| |
Collapse
|
9
|
Mitchell ML, Hsu HW, Brown RS, Cohen LE, Lee MM, Levitsky LL, Sadeghi-Nejad A, Soyka LA, Tonyushkina K, Wolfsdorf JI. Unresolved Issues in the Wake of Newborn Screening for Congenital Hypothyroidism. J Pediatr 2016; 173:228-231.e1. [PMID: 27056453 DOI: 10.1016/j.jpeds.2016.03.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 02/23/2016] [Accepted: 03/07/2016] [Indexed: 10/22/2022]
Affiliation(s)
- Marvin L Mitchell
- New England Newborn Screening Program, University of Massachusetts Medical School, Jamaica Plain, MA
| | - Ho-Wen Hsu
- New England Newborn Screening Program, University of Massachusetts Medical School, Jamaica Plain, MA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Nomogram-based evaluation of thyroid function in appropriate-for-gestational-age neonates in intensive care unit. J Perinatol 2015; 35:204-7. [PMID: 25297003 DOI: 10.1038/jp.2014.181] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Revised: 08/20/2014] [Accepted: 08/21/2014] [Indexed: 11/08/2022]
Abstract
OBJECTIVE The objective of this study was to help neonatologists to interpret the thyroid hormone results accurately, and also to provide reference ranges and/or nomograms of FT4 (free thyroxine) and thyrotropin against gestational age at postnatal 1 week and 1 month in order to assess thyroid function in AGA (appropriate for gestational age) neonates in intensive care unit. STUDY DESIGN This is a retrospective study. We included a total number of 515 AGA neonates between 24 and 42 weeks of gestation. Routine results of serum FT4 and TSH that had been analyzed with an immunoassay were collected from existing laboratory data. Least square regression analyses were used to estimate both the mean and the s.d. curves as polynomial functions of gestational age. RESULT Free T4 levels were correlated with gestational age both at postnatal 1 week (r=0.39, P<0.001) and 1 month (r=0.26, P<0.001). Serum TSH levels at postnatal 1 week and 1 month did not show any correlation with gestational age. Scatterplots of FT4 levels against gestational age at 1 week and 1 month, showing the predicted 2.5th, 50th and 97.5th percentiles and central 95% reference ranges for TSH were provided. CONCLUSION Gestational age-specific nomograms for FT4 and reference ranges for TSH at postnatal 1 week and 1 month in AGA neonates have been developed. This can help neonatologists to interpret the thyroid hormone results accurately. Further studies providing reference ranges/nomograms for thyroid function in small-for-gestational-age neonates are needed.
Collapse
|
11
|
Oh KW, Koo MS, Park HW, Chung ML, Kim MH, Lim G. Establishing a reference range for triiodothyronine levels in preterm infants. Early Hum Dev 2014; 90:621-4. [PMID: 25150803 DOI: 10.1016/j.earlhumdev.2014.07.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 07/16/2014] [Accepted: 07/29/2014] [Indexed: 10/24/2022]
Abstract
OBJECTIVES Thyroid dysfunction affects clinical complications in preterm infants and older children. However, thyroid hormone replacement in preterm infants has no proven benefits, possibly owing to the lack of an appropriate reference range for thyroid hormone levels. We aimed to establish a reference range for triiodothyronine (T3) levels at 1-month postnatal age (PNA) in preterm infants. METHODS This retrospective study included preterm infants born at a tertiary referral neonatal center at gestational age (GA)<35 weeks with no apparent thyroid dysfunction, for 6 consecutive years, with follow-up from PNA 2 weeks to 16 weeks. Using thyroid function tests (TFT), the relationships between T3 levels and thyrotropin (TSH) and free thyroxine (fT4) levels, birth weight, GA, postmenstrual age (PMA), and PNA were examined. The conversion trend for fT4 to T3 was analyzed using the T3/fT4 ratio. RESULTS Overall, 464 TFTs from 266 infants were analyzed, after excluding 65 infants with thyroid dysfunction. T3 levels increased with fT4 levels, birth weight, GA, PMA, and PNA but not with TSH levels. The T3/fT4 ratio also increased with GA, PNA, and PMA. The average T3 level at 1 month PNA was 72.56 ± 27.83 ng/dL, with significant stratifications by GA. CONCLUSIONS Relatively low T3 and fT4 levels in preterm infants were considered normal, with T3 levels and conversion trends increasing with GA, PMA, and PNA. Further studies are required to confirm the role of the present reference range in thyroid hormone replacement therapy.
Collapse
Affiliation(s)
- Ki Won Oh
- Department of Pediatrics, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, South Korea
| | - Mi Sung Koo
- Department of Pediatrics, Maryknoll Medical Center, Busan, South Korea
| | - Hye Won Park
- Department of Pediatrics, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, South Korea
| | - Mi Lim Chung
- Department of Pediatrics, Haeundae Paik Hospital, College of Medicine, Inje University, Busan, South Korea
| | - Min-ho Kim
- Biomedical Research Center, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, South Korea
| | - Gina Lim
- Department of Pediatrics, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, South Korea.
| |
Collapse
|
12
|
Levy-Shraga Y, Tamir-Hostovsky L, Boyko V, Lerner-Geva L, Pinhas-Hamiel O. Follow-up of newborns of mothers with Graves' disease. Thyroid 2014; 24:1032-9. [PMID: 24472020 DOI: 10.1089/thy.2013.0489] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Overt neonatal Graves' disease is rare, but may be severe, even life threatening, with deleterious effects on neural development. The main objective of this study was to describe the course of thyrotropin (TSH) and free thyroxin (fT4) levels, as well as postnatal weight gain in relation to fT4 levels, in neonates born to women with Graves' disease without overt neonatal thyrotoxicosis. Such information is important to deduce the optimal schedule for evaluation. METHODS We conducted a retrospective chart review of neonates born to mothers with Graves' disease between January 2007 and December 2012. The records were reviewed for sex, gestational age, birth weight, maternal treatment during pregnancy, and maternal thyroid stimulating immunoglobulin (TSI) level. For each visit in the clinic, the data included growth parameters, presence of symptoms suspected for hyperthyroidism, blood test results (levels of TSH, fT4, and TSI), and treatment. RESULTS Ninety-six neonates were included in the study (49 males), with a total of 320 measurements of thyroid function tests (TSH and fT4). Four neonates (4%) had overt neonatal Graves' disease; one of them along with nine others were born preterm. In 77 (92.9%) of the remaining 83 neonates (the subclinical group), fT4 levels were above the 95th percentile on day 5. All had normal fT4 on day 15. A negative association was found between fT4 and weight gain during the first two weeks. CONCLUSIONS In this cohort, most neonates born to mothers with Graves' disease had a subclinical course with abnormal fT4 levels that peaked at day 5. After day 14, all measurements of fT4 returned to the normal range, although measurements of TSH remained suppressed for up to three months. Elevated fT4 was associated with poor weight gain.
Collapse
Affiliation(s)
- Yael Levy-Shraga
- 1 Pediatric Endocrine and Diabetes Unit, Edmond and Lily Safra Children's Hospital, Sheba Medical Center , Ramat Gan, Israel
| | | | | | | | | |
Collapse
|
13
|
Chan DKL, Tagamolila V, Ardhanari J, Lim XY, Wong J, Yeo CP. Reference range of thyroid hormones in very low birth weight infants at the time of discharge. Thyroid 2014; 24:73-7. [PMID: 23879206 DOI: 10.1089/thy.2012.0580] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AIM There is little information regarding the reference range for thyroid hormones in preterm babies, especially those with very low birth weight (VLBW) of less than 1500 g. The objective of our study was to evaluate the relationship between thyroid hormone levels and postmenstrual age in a cohort of stable VLBW infants. METHOD An observational cohort study of VLBW infants preparing for discharge from a high-dependency nursery in Singapore. The infants' free thyroxine (fT4) and thyrotropin (TSH) levels were assayed just before discharge and correlated with postmenstrual age, calculated as the sum of the duration of gestation at birth and chronological age in weeks. RESULTS fT4 and TSH levels were sampled in 129 ex-VLBW babies at a mean postmenstrual age of 38.5 (±4.6) weeks. The babies were born at a mean±SD gestation of 28.9±2.4 weeks (median 29.0 weeks, range 24.0-34.5 weeks) with mean±SD birth weight of 1081±268 g (median 1090 g, range 490-1490 g). Linear regression analysis revealed negative and fair correlation between fT4 and postmenstrual age (r=-0.302). The mean±SD fT4 level was 16.8±3.2 pmol/L (median 16.8 pmol/L, range 8.5-28.9 pmol/L). However, there was only a very weak negative correlation between TSH levels and postmenstrual age, both with (r=-0.116) or without logarithmic transformation. The mean±SD TSH was 4.56±2.50 mIU/L (median 4.42 mIU/L, range 1.0-13.5 mIU/L). CONCLUSION Our study shows a fair and inverse correlation of fT4 with postmenstrual age in a large cohort of growing ex-VLBW infants, in keeping with maturation of the hypothalamic-pituitary-thyroid axis. It suggests that fT4 levels in growing infants are best compared to postmenstrual age-specific norms instead of a single reference interval.
Collapse
Affiliation(s)
- Daisy K L Chan
- 1 Departments of Neonatal and Developmental Medicine, Singapore General Hospital , Singapore
| | | | | | | | | | | |
Collapse
|
14
|
Sun X, Lemyre B, Nan X, Harrold J, Perkins SL, Lawrence SE, Barrowman N. Free thyroxine and thyroid-stimulating hormone reference intervals in very low birth weight infants at 3–6 weeks of life with the Beckman Coulter Unicel DxI 800. Clin Biochem 2014; 47:16-8. [DOI: 10.1016/j.clinbiochem.2013.10.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 09/27/2013] [Accepted: 10/02/2013] [Indexed: 11/26/2022]
|
15
|
Zhu L, Zhang X, He X, Yang X, Wang Y, Wang C, Feng Z. Reference intervals for serum thyroid hormones in preterm hospitalized infants. J Pediatr Endocrinol Metab 2013; 26:463-7. [PMID: 23412903 DOI: 10.1515/jpem-2012-0277] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2012] [Accepted: 01/16/2013] [Indexed: 11/15/2022]
Abstract
OBJECTIVE In our study, the reference intervals of serum thyroid hormones were established in 247 hospitalized preterm infants from 28 to 36 weeks of gestation at 8-15 postnatal days. The thyroid hormones were serum triiodothyronine (T3), free triiodothyronine (FT3), thyroxine (T4), free thyroxine (FT4), and thyrotropin (TSH). METHODS Electrochemiluminescence immunoassay was used to examine the thyroid hormone levels of serum samples from 247 preterm infants, who were grouped on sampling by gestational age. SPSS 16.0 was used to calculate the population-based reference intervals, in comparison to the manufacturer's suggested reference intervals. RESULTS Kruskal-Wallis H tests could not determine the difference in TSH levels among groups, which allowed us to develop a single interval for the study population. ANOVA determined the differences in T3, FT3, T4, and FT4 levels among groups, which allowed us to define reference intervals for preterm infants according to their gestational age. CONCLUSION Developed reference intervals are useful for clinical diagnosis; however, there is a lack of consensus. These values could be used to assess the thyroid status of preterm infants and provide a foundation for clinical therapy. The results emphasized the importance of establishing gestational age-based reference intervals for the clinical laboratory.
Collapse
Affiliation(s)
- Lina Zhu
- Department of Pediatrics, BaYi Children's Hospital of The General Military Hospital of Beijing PLA, Beijing 100700, PR China
| | | | | | | | | | | | | |
Collapse
|
16
|
Lem AJ, de Rijke YB, van Toor H, de Ridder MAJ, Visser TJ, Hokken-Koelega ACS. Serum thyroid hormone levels in healthy children from birth to adulthood and in short children born small for gestational age. J Clin Endocrinol Metab 2012; 97:3170-8. [PMID: 22736771 DOI: 10.1210/jc.2012-1759] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
CONTEXT Age-appropriate reference ranges for thyroid hormones are required for detecting pediatric thyroid dysfunction. Data on thyroid hormones and peripheral thyroid metabolism in short children born small for gestational age (SGA) before and during GH treatment are lacking. OBJECTIVES Our objectives were to obtain pediatric thyroid hormone reference ranges; to investigate thyroid hormones in short SGA children before puberty, during puberty, and during postponement of puberty by GnRH analog; and to evaluate thyroid hormones during GH treatment. PATIENTS AND DESIGN In 512 healthy children (225 females; 0-18 yr), free T(4) (FT(4)), TSH, total T(4), T(3), rT(3), and T(4)-binding globulin were determined. Reference ranges were calculated using the linearity, median, and skewness method. In 125 short SGA children (62 females; mean age 11.3 yr), thyroid hormones were analyzed before and after 2 yr of GH treatment and additional GnRH analog. RESULTS Thyroid references showed wide ranges postnatally and age-specific patterns thereafter, similar in boys and girls. Untreated short SGA children had similar FT(4) and T(4) levels as the reference population but significantly higher T(3), rT(3), and T(4)-binding globulin levels. During puberty and during GH treatment, FT(4) and rT(3) significantly decreased, whereas T(3) significantly increased. CONCLUSION Age-specific thyroid reference ranges are presented. Puberty and GH treatment both induce changes in peripheral thyroid metabolism, resulting in more biologically active T(3) at the expense of less inactive rT(3), possibly mediated by IGF-I. GH treatment induces altered peripheral thyroid metabolism but does not result in thyroid dysfunction.
Collapse
Affiliation(s)
- Annemieke J Lem
- Dutch Growth Research Foundation, P.O. Box 23068, 3001 KB Rotterdam, The Netherlands.
| | | | | | | | | | | |
Collapse
|
17
|
Williams F, Hume R. The measurement, definition, aetiology and clinical consequences of neonatal transient hypothyroxinaemia. Ann Clin Biochem 2010; 48:7-22. [PMID: 20930033 DOI: 10.1258/acb.2010.010174] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This review focuses on neonatal transient hypothyroxinaemia, a condition characterized by temporary postnatal reductions in concentrations of Total T4 or Free T4, with normal or low concentrations of thyroid stimulating hormone (TSH). There is neither an agreed quantitative definition, nor an agreed mode of measurement for the condition. Transient hypothyroxinaemia is not routinely monitored yet it is thought to affect about 50% of preterm infants; it was thought to be without long-term sequelae but observational studies indicate that neurodevelopment may be compromised. The aetiology of transient hypothyroxinaemia is complex. There are significant contributions from the withdrawal of maternal-placental thyroxine transfer, hypothalamic-pituitary-thyroid immaturity, developmental constraints on the synthesis and peripheral metabolism of iodothyronines and iodine deficiency. It is not possible to distinguish clinically, or from laboratory measurements, whether transient hypothyroxinaemia is an independent condition or simply a consequence of non-thyroidal illness and/or drug usage. An answer to this question is important because studies of thyroid hormone replacement have been instigated, with mixed results. Until the aetiology of transient hypothyroxinaemia is better understood it would seem prudent not to routinely supplement preterm infants with thyroid hormones. Iodine deficiency, non-thyroidal illness and drug usage are the most modifiable risk factors for transient hypothyroxinaemia and are the clear choices for attempts at reducing its incidence. We suggest that transient hypothyroxinaemia in preterm infants is defined as a normal or low TSH concentration in conjunction with a concentration of Total T4, that is ≤10th percentile of cord Total T4 of the equivalent gestational age had the infant remained in utero.
Collapse
Affiliation(s)
- Fiona Williams
- Clinical and Population Sciences and Education, Human Brain Development Group, Mackenzie Building, Ninewells Hospital and Medical School Campus, Kirsty Semple Way, Dundee DD2 4BF, UK.
| | | |
Collapse
|
18
|
Silva SAB, Chagas AJ, Goulart EMA, Silva GAB, Marçal LV, Gomes MNA, Alves VMD. Screening for congenital hypothyroidism in extreme premature and/or very low birth weight newborns: the importance of a specific protocol. J Pediatr Endocrinol Metab 2010; 23:45-52. [PMID: 20432805 DOI: 10.1515/jpem.2010.23.1-2.45] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Neonatal screening for congenital hypothyroidism (CH) in premature infants is not as well established as in term newborns regarding age and number of samples. AIMS 1. To evaluate the effectiveness of the protocol recommended by the Neonatal Screening Program of the State of Minas Gerais (PETN-MG) for CH neonatal screening in very low birth weight premature infants. 2. To estimate the prevalence of delayed TSH elevation and thyroid function alterations in the target population. METHODS TSH was assessed by ELISA on the 5th, 10th and 30th days of life in all newborns with gestational age <32 weeks and/or very low birth weight (VLB) (<1,500 g) in the period from October 2004 to September 2006. RESULTS Out of the 14,462 newborns screened, 2,647 were premature with gestational age <32 weeks and/or VLB. Forty-four cases of altered TSH were found and 11 infants underwent treatment. Delayed TSH elevation was detected in 66% of altered cases. Five out of the 11 cases were detected in the second sample and five cases were only detected in the third sample. CONCLUSION The high prevalence of thyroid function alterations that demanded treatment (1:242) and delayed TSH elevation in VLB premature infants reinforce the need for a specific protocol, based on retesting procedures, for CH neonatal screening.
Collapse
Affiliation(s)
- S A B Silva
- Postgraduate Program, Minas Gerais Federal University Medical School, Brazil.
| | | | | | | | | | | | | |
Collapse
|
19
|
Abstract
Pragmatic criteria are required for defining transient hypothyroxinemia and to permit entry to clinical trials of thyroxine substitution of only those extreme preterm infants who are hypothyroxinemic. The purpose of this article is to suggest that transient hypothyroxinemia is defined by postnatal serum T(4) levels, which are cord levels corrected to an equivalent gestational age had the fetuses remained in utero, and that those levels are adjusted for the significant prenatal and intrapartum factors. Lowered serum FT(4) levels are not a consistent pathognomonic feature of transient hypothyroxinemia as postnatal FT(4) levels in this large series of preterm infants are within or above the cord values of equivalent gestational age, irrespective of severity of illness. Although serum T(3) and thyroid-stimulating hormone levels do not contribute to the diagnosis of transient hypothyroxinemia, measurement of their levels is nevertheless required for trial monitoring involving thyroxine substitution to avoid inadvertent suppression of the developing hypothalamic-pituitary-thyroid axis by excess T(4) substitution.
Collapse
Affiliation(s)
- Fiona L R Williams
- Community Health Sciences, University of Dundee, Ninewells Hospital and Medical School, Dundee, Scotland
| | | |
Collapse
|
20
|
Abstract
During the functional ontogenesis of the thyroid gland an increasing number of transcription factors play fundamental roles in thyroid-cell differentiation, maintenance of the differentiated state, and thyroid-cell proliferation. The early growth and development of the fetal thyroid appears to be generally independent of thyroid-stimulating hormone (TSH). TSH and thyroxine (T4) levels increase from the 12th week of gestation until delivery, whereas triiodothyronine (T3) levels remain relatively low. At birth, a cold-stimulated short-lived TSH surge is observed, followed by a TSH decrease until day 3 or 4 of life by T4 feedback inhibition. Disorders of thyroid gland development and/or function are relatively common, affecting approximately one newborn infant in 2000-4000. The most prevalent disease, congenital hypothyroidism, is frequently caused by genetic defects of transcription factors involved in the development of the thyroid or pituitary gland. A major cause of congenital hyperthyroidism is the transplacental passage of stimulating thyrotropin antibodies from the mother to the fetus. Hypothyroxinaemia or hypotriiodthyroninaemia is frequently observed in preterm infants with or without severe non-thyroidal illness. Whereas congenital hypo- and hyperthyroidism may be treated successfully with T4 or thyrostatic drugs, there is still insufficient evidence on whether the use of T4 for treatment of the latter condition results in changes in neonatal morbidity or reductions in neurodevelopmental impairment.
Collapse
Affiliation(s)
- Juergen Kratzsch
- Institute of Laboratory Medicine, Clinical Chemistry and Molecular Diagnostics, University Hospital, Paul-List-Str. 13-15, D-04103 Leipzig, Germany.
| | | |
Collapse
|
21
|
Deming DD, Rabin CW, Hopper AO, Peverini RL, Vyhmeister NR, Nelson JC. Direct equilibrium dialysis compared with two non-dialysis free T4 methods in premature infants. J Pediatr 2007; 151:404-8. [PMID: 17889078 DOI: 10.1016/j.jpeds.2007.03.046] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2006] [Revised: 02/15/2007] [Accepted: 03/20/2007] [Indexed: 10/23/2022]
Abstract
OBJECTIVE To compare the incidence of low free T4 values reported by a direct equilibrium dialysis method to their incidence reported by 2 non-dialysis methods. STUDY DESIGN Ninety-five infants, < or = 33 weeks gestational age at birth, admitted to Loma Linda University Children's Hospital before day 3 of life were studied. Infants were grouped by gestational age ranges: < or = 27, 28-30, and 31-33 weeks. Free T4 determinations were measured at 3, 7, and 14 days of life with 3 different free T4 methods. Gestational age-specific newborn reference ranges were available for the direct equilibrium dialysis method only. The only reference ranges available for the non-dialysis free T4 methods were not gestational age specific. Using available reference ranges we classified free T4 values as either low or not low. The incidence of low free T4 values was compared at 3, 7, and 14 days of life. RESULTS Low direct equilibrium dialysis free T4 values were substantially less frequent than non-dialysis free T4 values. CONCLUSION Substantial free T4 inconsistencies occur between dialysis and non-dialysis free T4 methods in preterm infants. It is unclear how much of this inconsistency is method dependent and how much is reference range dependent.
Collapse
Affiliation(s)
- Douglas D Deming
- Department of Pediatrics, Loma Linda University School of Medicine, Loma Linda, CA 92354, USA.
| | | | | | | | | | | |
Collapse
|
22
|
Cartault Grandmottet A, Cristini C, Tricoire J, Rolland M, Tauber MT, Salles JP. Évaluation des taux de TSH, T4L, T3T des nouveau-nés prématurés et à terme hospitalisés. Arch Pediatr 2007; 14:138-43. [PMID: 17140778 DOI: 10.1016/j.arcped.2006.10.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2006] [Accepted: 10/12/2006] [Indexed: 10/23/2022]
Abstract
UNLABELLED Thyroid hormones are essential for foetus and newborn development. Preterm newborns present low levels for thyroid hormones. These low levels are related with disorder in psychomotor and neurological development. In the literature, several studies concerning newborns treated with thyroid hormone have been realized in different conditions; however, there is no consensus about preterm newborn supplementation benefit. OBJECTIVE The aim of the study was to defined hormonal values used for normal and preterm newborns. MATERIAL AND METHODS We reported TSH, T3T and T4L levels for 195 normal or preterm newborns, eutrophic or small for gestational age (SGA). RESULTS A positive correlation was found between hormonal level and gestational age. This work allowed us to define a threshold for preterm newborn according to their gestational age. CONCLUSION Owing to lack of consensus, those values are useful for clinical and biological follow-up of thyroid function for newborns at risk (SGA and preterm before 32 weeks) during the first year of life. Finally, it would be interesting to study systematic supplementation of thyroid hormone for those infants in a prospective study.
Collapse
Affiliation(s)
- A Cartault Grandmottet
- Unité d'endocrinologie, pathologie osseuse, gynécologie et génétique, hôpital des Enfants, CHU de Toulouse, TSA 70034, 31059 Toulouse, France.
| | | | | | | | | | | |
Collapse
|
23
|
|
24
|
Abstract
Thyroid hormones are required for normal development of the brain. Transient hypothyroxinaemia is the most common thyroid dysfunction in preterm infants and is defined by temporary low levels of T4, T3 and normal or low TSH. Low T4 levels in preterm infants are associated with persistent neurodevelopmental deficits in cognitive and motor function. Thyroid hormone substitution trials to date are underpowered and show inconsistent results; the question remains -- are low T4 levels simply an epiphenomenon? The aetiology of transient hypothyroxinaemia is multifactorial and the components amenable to correction form the basis of the therapeutic strategy: rectification of iodine deficiency in parenteral nutrition; a reduction of non-thyroidal illnesses and attenuation of their severity; and substitution of drugs that interfere with the hypothalamic-pituitary-thyroid axis. Thyroxine substitution therapy should only be done in the context of clinical trials and only in those infants who are hypothyroxinaemic.
Collapse
|
25
|
Abstract
Use of iodinated skin disinfectants in the perinatal period can result in significant iodine overload of the neonate and transient hypothyroidism. The authors report a case of unusually severe hypothyroidism requiring L-thyroxine (L-T4) replacement therapy in a premature neonate after prolonged use of iodinated skin disinfectants for a complex skin lesion. Neonatal iodine overload should be minimized, and in cases with significant iodine exposure, thyroid-stimulating hormone should be monitored, especially in preterm neonates who are exquisitely sensitive to the antithyroid effects of iodine excess.
Collapse
Affiliation(s)
- Minesh Khashu
- Division of Neonatology, Department of Pediatrics, British Columbia Children's Hospital and University of British Columbia, Vancouver BC V6H 3V4, Canada
| | | | | |
Collapse
|
26
|
Rabin CW, Hopper AO, Job L, Peverini RL, Clark SJ, Deming DD, Nelson JC, Vyhmeister NR. Incidence of low free T4 values in premature infants as determined by direct equilibrium dialysis. J Perinatol 2004; 24:640-4. [PMID: 15306825 DOI: 10.1038/sj.jp.7211109] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND The incidence of transient reductions in serum free T(4) (FT(4)) in premature infants may be overestimated because certain FT(4) analytical methods underestimate FT(4) concentrations. Transient reductions of FT(4) measurements have been reported in the majority of premature newborn infants. Direct equilibrium dialysis (DED) does not underestimate FT(4) concentrations and is the best available technique to measure serum FT(4) in the premature infant. OBJECTIVE To evaluate the incidence of low FT(4) concentrations in premature infants using DED to measure FT(4). DESIGN/METHOD We measured FT(4) by DED in infants with birth weight <1500 g. Infants were excluded if the following conditions were present: congenital anomalies or maternal thyroid disorders. Free T(4) was measured at 14 days of life. Low FT(4) was defined using a statistical definition of FT(4) measurements <10.3 pmol/l (0.8 ng/dl). RESULTS Free T(4) was measured by DED in 114 infants. Low FT(4) levels were seen in nine infants (7.9%). CONCLUSION The incidence of low FT(4) was much lower than previously reported when FT(4) was measured using DED indicating that methodological issues are involved in the variability among estimates of the frequency of transient reduction in FT(4).
Collapse
Affiliation(s)
- Christopher W Rabin
- Department of Pediatrics, Coleman Pavilion Room 11121C, Loma Linda University School of Medicine, 11175 Campus Street, Coleman Pavilion, Suite 11121, Loma Linda, CA 92354, USA
| | | | | | | | | | | | | | | |
Collapse
|
27
|
Carrascosa A, Ruiz-Cuevas P, Potau N, Almar J, Salcedo S, Clemente M, Yeste D. Thyroid function in seventy-five healthy preterm infants thirty to thirty-five weeks of gestational age: a prospective and longitudinal study during the first year of life. Thyroid 2004; 14:435-42. [PMID: 15242570 DOI: 10.1089/105072504323150741] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Thyroid function was evaluated in 75 healthy preterm infants, 30-35 weeks of gestational age. Serum thyrotropin (TSH), thyroxine (T(4)), triiodothyronine (T(3)), free T(4) (immunochemoluminescence) and reverse triiodothyronine (rT(3)) (radioimmunoassay) were measured in the mother and in the cord at delivery and in the preterm infants at 1 hour, 24 hours, 1 week, 3 weeks, 2 months, 4 months, 6 months, and 12 months of postnatal age. These values were compared to those of healthy full-term infants of the same postnatal age (22 at 24 hours from our hospital and from previously reported data at others times). Mean 24-hour TSH values were significantly lower (p < 0.001) in preterm than in full-term infant populations (12.38 +/- 6.13 microIU/mL versus 22.02 +/- 13.28 microIU/mL); however, all TSH values of preterm infants were in the range of the full-term values. Mean 24-hour free T(4) values were similar in preterm and full-term infants (1.88 +/- 0.46 ng/dL versus 2.01 +/- 0.54 ng/dL) and all preterm infants had free T(4) values within the range of those of full-term infants at 24 hours. Mean T(4) and T(3) values were significantly lower in preterm than in full-term neonates at 1 hour and 24 hours of age. Mean 24-hour rT(3) values were significantly higher in preterm than in full-term newborns. From 1 week onwards, all thyroid function values were in the same range in both populations. In conclusion, individual thyroid function was similar in healthy preterms and full-terms from the first 24 hours of life. Normative data in preterm infants during the first year of life applying the latest luminescence techniques currently used worldwide are reported.
Collapse
Affiliation(s)
- Antonio Carrascosa
- Pediatric Endocrine Service, Children's Hospital Vall d'Hebron, Autonomous University of Barcelona, Barcelona, Spain.
| | | | | | | | | | | | | |
Collapse
|
28
|
van Wassenaer AG, Kok JH. Hypothyroxinaemia and thyroid function after preterm birth. ACTA ACUST UNITED AC 2004; 9:3-11. [PMID: 15013471 DOI: 10.1016/s1084-2756(03)00114-3] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2003] [Indexed: 11/25/2022]
Abstract
The concentration of thyroid hormone in preterm infants is lower than that in term infants. This phenomenon is referred to as transient hypothyroxinaemia of prematurity. Low thyroid hormone levels after very preterm birth are associated with worse developmental outcome in childhood, but only one randomized controlled trial has been carried out in the surfactant era to find out whether thyroid hormone supplementation is beneficial for developmental outcome. More studies are required to find out whether thyroid hormone supplementation is beneficial, and if so, for which preterm group.
Collapse
Affiliation(s)
- Aleid G van Wassenaer
- Department of Neonatology, Emma Childrens' Hospital Academic Medical Center, DE Amsterdam, The Netherlands.
| | | |
Collapse
|
29
|
Rapaport R. Evaluation of thyroid status of infants in intensive care settings: recommended an extension of newborn screening. J Pediatr 2003; 143:556-8. [PMID: 14615721 DOI: 10.1067/s0022-3476(03)00550-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|