Earlier onset of treatment or increment in LT4 dose in screened congenital hypothyroidism: which as the more important factor for IQ at 7 years?

Analysis of motor, cognitive and language performance of infants undergoing treatment for congenital hypothyroidism

OBJECTIVE

Investigate the association between the age of treatment onset and confirmatory TSH level (as an indicator of severity) with a greater risk of developmental delay in infants with congenital hypothyroidism (CH).

METHOD

The authors conducted a cross-sectional, observational, unmatched case-control study at a Brazilian neonatal screening reference center. Seventy-seven infants with CH (mean age: 12 ± 6.4 months) were examined. The authors evaluated their performance using the Bayley-III Screening Test and categorized them as "LOWER RISK" (competent category) or "GREATER RISK" (combined at-risk + emergent categories) for developmental delay based on the 25th percentile cutoff.

RESULTS

Infants with CH are at a higher risk of non-competent performance in cognition, receptive language, fine motor skills, and gross motor skills when compared to infants without CH. This risk is more pronounced in infants with more severe indications of CH (TSH > 30 μUI/L in the confirmatory test) for cognition (OR = 5.64; p = 0.01), receptive language (OR = 14.68; p = 0.000), fine motor skills (OR = 8.25; p = 0.000), and gross motor skills (OR = 5.00; p = 0.011).

CONCLUSION

The level of TSH in the confirmatory test can be a good indicator for identifying infants with CH who are at a higher risk of non-competent performance in cognition, receptive language, and motor skills. Monitoring development, early detection of delays, and intervention programs are particularly important for infants with CH.

Congenital hypothyroidism in Bogotá, Colombia: a current description (2015-2021)

OBJECTIVES

Congenital hypothyroidism (CH) is a decrease in thyroid hormone function in newborns, being one of the leading causes of neurological deficits and long-term metabolic complications. This study aims to determine the prevalence and characteristics of CH cases in Bogotá, Colombia, between 2015 and 2021, as notified through the mandatory report to the Public Health Surveillance System (PHSS).

METHODS

A retrospective cross-sectional study was conducted. All live births (LB) with a weight ≥500 g, diagnosed with CH with or without goiter (ICD-10 codes E030 and E031, respectively) in Bogotá during 2015-2021 were analyzed.

RESULTS

For a total of 201 cases, the prevalence rate was 3.29 cases per 10,000 LB. 92.54 % were classified as isolated cases of CH, 4.48 % syndromic, and 2.98 % polymalformated. A total of 16.92 % was small for gestational age. The mean gestational age was 37.38 weeks (SD 2.76), 26.87 % were preterm births. Among the mothers, 8.96 % suffered from pregnancy-related or chronic diseases, the most common being hypertensive disorders of pregnancy and pre-existant hypothyroidism (without clarity concerning etiology). A total of 66.67 % of cases did not receive treatment after diagnosis. Treatment was established by an average age of 27 days after birth (SD 36.02) and 17 days after case notification to the PHSS (SD 36.13).

CONCLUSIONS

Observed prevalence is similar to the rate reported by health authorities in Colombia but inferior to reports from high-income countries, highlighting the importance of improvements in the Colombian LB's screening program. Time to diagnosis and treatment was observed to be prolonged, suggesting that new pathways are required for timely CH treatment.

Primary congenital hypothyroidism: challenges in a low-income country without paediatric endocrinologist and universal newborn screening

Due to the lack of public awareness, congenital hypothyroidism (CH) remains an overlooked challenge in Cambodia. This disease should be screened routinely at birth because, though asymptomatic, it can lead to mental retardation in the absence of early treatment. Since 2013, our unit has been the only centre that implements routine screening and provides treatment and follow-up. This case report highlights a long and tough journey of a girl who, after being diagnosed by routine newborn screening, came for follow-up at our centre. Since the screening has yet to be recognised nationally, we want to raise not only awareness of CH but also the difficulties faced by parents because their children are in need of life-long treatment in a low-resource country. Thus, the key to successful management of paediatric patients is their parental involvement, which can be influenced by their educational, cultural, geographical and financial background.

[Newborn screening for congenital hypothyroidism and congenital adrenal hyperplasia: Benefits and costs of a successful public health program]

Newborn screening is an important public health program and a triumph of preventive medicine. Economic analyses show that the benefits of newborn screening clearly outweigh the costs for certain diseases, but not necessarily for other ones. This is due to the great diversity of the natural history of the diseases detected, to the fact that each of these diseases considered individually is rare, and to differences in the effectiveness of interventions. In addition, the benefit-cost ratio of screening for a particular disorder may differ between countries, specifically between high-income and low- and middle-income countries. The burden of a disorder may also be alleviated by increased clinical awareness and effective clinical services, even in the absence of newborn screening. In this article, we focus on economic analyses of newborn screening for primary congenital hypothyroidism, which has been in place in high-income countries for roughly 40 years, and for classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency. Screening for the latter is not yet universal, even in high-income countries, although the lack of universal implementation may reflect factors other than economic considerations.

Effect of Thyroid Hormones on Neurons and Neurodevelopment

This review focuses on the current knowledge of the effects of thyroid hormones on central nervous system differentiation and development in animals and the human fetal brain. The outcomes of children with congenital hypothyroidism and of newborns with hypothyroid pregnant mothers are emphasized, focusing on how therapies could affect and especially improve the outcomes.

Trends in Scottish newborn screening programme for congenital hypothyroidism 1980-2014: strategies for reducing age at notification after initial and repeat sampling

OBJECTIVES

To determine ages at first capillary sampling and notification and age at notification after second sampling in Scottish newborns referred with elevated thyroid-stimulating hormone (TSH).

SUBJECTS AND METHODS

Referrals between 1980 and 2014 inclusive were grouped into seven 5-year blocks and analysed according to agreed standards.

RESULTS

Of 2 116 132 newborn infants screened, 919 were referred with capillary TSH elevation ≥8 mU/L of whom 624 had definite (606) or probable (18) congenital hypothyroidism. Median age at first sampling fell from 7 to 5 days between 1980 and 2014 (standard 4-7 days), with 22, 8 and 3 infants sampled >7 days during 2000-2004, 2005-2009 and 2010-2014. Median age at notification was consistently ≤14 days, range falling during 2000-2004, 2005-2009 and 2010-2014 from 6 to 78, 7-52 and 7-32 days with 12 (14.6%), 6 (5.6%) and 5 (4.3%) infants notified >14 days. However 18/123 (14.6%) of infants undergoing second sampling from 2000 onwards breached the ≤26-day standard for notification. By 2010-2014, the 91 infants with confirmed congenital hypothyroidism had shown favourable median age at first sample (5 days) with start of treatment (10.5 days) approaching age at notification.

CONCLUSION

Most standards for newborn thyroid screening are being met by the Scottish programme, but there is a need to reduce age range at notification, particularly following second sampling. Strategies to improve screening performance include carrying out initial capillary sampling as close to 96 hours as possible; introducing 6-day laboratory reporting and use of electronic transmission for communicating repeat requests.

Intellectual development in preschool children with early treated congenital hypothyroidism

PURPOSE

Delayed treatment of congenital hypothyroidism (CH) is a common cause of mental retardation. The aim of the present study was to evaluate intellectual outcomes in preschool children with treated CH.

METHODS

We retrospectively reviewed the clinical records of 43 children (age range: 13 to 60 days of life; 22 girls and 21 boys) diagnosed with CH. Children aged 5 to 7 years were examined using the Korean Wechsler Intelligence Scale for Children or the Korean Wechsler Preschool and Primary Scale of Intelligence.

RESULTS

The patients started treatment between 13 and 60 days of age. The mean intelligence quotient (IQ) of patients tested at age 5 to 7 years was 103.14±11.68 (IQ range: 76-126). None had intellectual disability (defined as an IQ <70). Twenty-one subjects were treated with a low dose (6.0-9.9 µg/kg/day) and 22 with a high dose of levothyroxine (10.0-16.0 µg/kg/day). There was no significant difference in the mean full-scale IQ (FSIQ), verbal IQ (VIQ), and performance IQ (PIQ) scores between the 2 groups. FSIQ, PIQ, and VIQ scores were not significantly correlated with initial dose of L-T4, initial fT4, age at treatment in multivariate analysis.

CONCLUSION

IQ scores of subjects with early treated CH diagnosed through a neonatal screening test were within normal range, regardless of etiology, thyroid function, initial dose of levothyroxine, and age at start of treatment.

Congenital Hypothyroidism: Optimal Initial Dosage and Time of Initiation of Treatment: A Systematic Review

CONTEXT

Appropriate management of neonates, tested positive for congenital hypothyroidism (CH), in particular, the initial dosage of levothyroxine and the time of initiation of treatment is a critical issue. The aim of this study was to assess all current evidence available on the subject to ascertain the optimal initial dose and optimal initiation time of treatment for children with CH.

EVIDENCE ACQUISITION

In this study, all published research related to the initiation treatment dose and the onset time of treatment in congenital hypothyroidism were reviewed. The searched electronic databases included Medline, Science direct, Scopus EMBASE, PsycINFO, Cochrane, BIOSIS and ISI Web of Knowledge. Additional searches included websites of relevant organizations, reference lists of included studies, and issues of major thyroid and pediatrics journals published within the past 35 years. Studies were included if they were written in English and investigated levothyroxine dose or timing of treatment or both, used for the treatment of children with congenital hypothyroidism.

RESULTS

Two thousand three hundred and seventy-four articles (excluding duplicates) were retrieved from the primary search. After reviewing the titles, abstracts and full-texts of studies, eventually, 22 studies were found that met our inclusion criteria. Amongst these, 17 and 12 evaluated outcomes of different treatment doses and treatment timing, respectively. Overall, the majority of these studies emphasized the initial high dose of levothyroxine and early treatment of newborns with hypothyroidism. There were, however, some studies that disagreed with increasing levothyroxine dose at initiation of treatment.

CONCLUSIONS

Considering the results of this review, apparently there is no difference in opinion regarding the early initiation of treatment, whereas determining the optimal dose of levothyroxine for start of treatment in CH patients still remains a controversial issue, demonstrating the need for further studies, despite the fact that use of high doses can lead to rapid normalization of biochemical indices, although this may cause complications.

European Society for Paediatric Endocrinology consensus guidelines on screening, diagnosis, and management of congenital hypothyroidism

OBJECTIVE

The aim was to formulate practice guidelines for the diagnosis and management of congenital hypothyroidism (CH).

EVIDENCE

A systematic literature search was conducted to identify key articles relating to the screening, diagnosis, and management of CH. The evidence-based guidelines were developed with the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system, describing both the strength of recommendations and the quality of evidence. In the absence of sufficient evidence, conclusions were based on expert opinion.

CONSENSUS PROCESS

Thirty-two participants drawn from the European Society for Paediatric Endocrinology and five other major scientific societies in the field of pediatric endocrinology were allocated to working groups with assigned topics and specific questions. Each group searched the literature, evaluated the evidence, and developed a draft document. These papers were debated and finalized by each group before presentation to the full assembly for further discussion and agreement.

RECOMMENDATIONS

The recommendations include: worldwide neonatal screening, approaches to assess the cause (including genotyping) and the severity of the disorder, the immediate initiation of appropriate L-T4 supplementation and frequent monitoring to ensure dose adjustments to keep thyroid hormone levels in the target ranges, a trial of treatment in patients suspected of transient CH, regular assessments of developmental and neurosensory functions, consulting health professionals as appropriate, and education about CH. The harmonization of diagnosis, management, and routine health surveillance would not only optimize patient outcomes, but should also facilitate epidemiological studies of the disorder. Individuals with CH require monitoring throughout their lives, particularly during early childhood and pregnancy.

European Society for Paediatric Endocrinology consensus guidelines on screening, diagnosis, and management of congenital hypothyroidism

OBJECTIVE

The aim was to formulate practice guidelines for the diagnosis and management of congenital hypothyroidism (CH).

EVIDENCE

A systematic literature search was conducted to identify key articles relating to the screening, diagnosis, and management of CH. The evidence-based guidelines were developed with the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system, describing both the strength of recommendations and the quality of evidence. In the absence of sufficient evidence, conclusions were based on expert opinion.

CONSENSUS PROCESS

Thirty-two participants drawn from the European Society for Paediatric Endocrinology and five other major scientific societies in the field of pediatric endocrinology were allocated to working groups with assigned topics and specific questions. Each group searched the literature, evaluated the evidence, and developed a draft document. These papers were debated and finalized by each group before presentation to the full assembly for further discussion and agreement.

RECOMMENDATIONS

The recommendations include: worldwide neonatal screening, approaches to assess the cause (including genotyping) and the severity of the disorder, the immediate initiation of appropriate L-T4 supplementation and frequent monitoring to ensure dose adjustments to keep thyroid hormone levels in the target ranges, a trial of treatment in patients suspected of transient CH, regular assessments of developmental and neurosensory functions, consulting health professionals as appropriate, and education about CH. The harmonization of diagnosis, management, and routine health surveillance would not only optimize patient outcomes, but should also facilitate epidemiological studies of the disorder. Individuals with CH require monitoring throughout their lives, particularly during early childhood and pregnancy.

Thyroid disease and the nervous system

Thyroid disorders are common in the general population and in hospitalized patients. Thyroid disease may present first with neurological complications or else may occur concurrently in patients suffering other neurological disorders, particularly those with an autoimmune etiology. For this reason neurologists will commonly encounter patients with thyroid disease. This chapter provides an overview of the neurological complications and associations of disorders of the thyroid gland. Particular emphasis is placed on conditions such as thyrotoxic periodic paralysis and myxedema coma in which the underlying thyroid disorder may be occult leading to a first, often emergency, presentation to a neurologist. Information about clinical features, diagnosis, pathogenesis, therapy, and prognosis is provided. Emphasis is placed on those aspects most likely to be relevant to the practicing neurologist and the interested reader is directed to references to good, recent review articles for further information.

Optimising outcome in congenital hypothyroidism; current opinions on best practice in initial assessment and subsequent management

Congenital hypothyroidism (CH), usually of the primary and permanent variety, is an eminently preventable cause of growth retardation and mental handicap whose outlook has been transformed by newborn screening, usually involving the measurement of capillary thyroid stimulating hormone (TSH). Severe primary CH, due for example to athyreosis, may result in subtle cognitive, behavioural and sensori-motor deficits, but the extent to which these can be offset by optimal postnatal diagnosis and management remains uncertain. This is because the available adult follow-up data reflect the outcome of previous management in the 1970's and 1980's, and also because the accurate neuro-psychological assessment of children is difficult, particularly in the preschool population. There is an urgent need to develop new consensus guidelines and to ensure that the children managed according to such guidelines are systematically and prospectively assessed so that good quality outcome data become available. In this review, key recommendations in the management of CH include: screening at day 3 so that severely affected infants can begin treatment within the first 10 days of life; setting the TSH referral cut-off at 8-10 mU/L; adopting a disciplined diagnostic algorithm to evaluate referred cases, with measurement of venous free thyroxine (T4), TSH and thyroglobulin combined with dual ultrasound and radioisotope imaging; initial treatment with a T4 dose of 50 μg daily in infants weighing ≥ 2.5 kg and 15 μg/kg/day in infants weighing < 2.5 kg followed by weekly review until thyroid function is normalised; and maintenance of free T4 levels between 15-26 pmol/L and TSH between 0.5-5 mU/L thereafter to avoid both under- and overtreatment.

Detection and treatment of congenital hypothyroidism

Congenital hypothyroidism is the most frequent endocrine disorder in neonates. Controversy exists regarding the necessity to adjust current screening programs to also diagnose patients with central hypothyroidism or those with mild forms of congenital hypothyroidism, who have high TSH levels but normal T(4) and normal T(3) levels (also known as 'subclinical hypothyroidism'). Thyroid hormone replacement should start as soon as the diagnosis is confirmed by measurement of elevated TSH and low serum thyroid hormone levels. Further diagnostic approaches, such as ultrasonography, scintigraphy and measurement of thyroglobulin levels, to determine the subtype of congenital hypothyroidism, should not delay initiation of treatment. Recommendations regarding the initial dosage of levothyroxine vary considerably, and no general accepted guideline exists with regards to initial dosage or optimal time point for dose adjustment according to biochemical parameters. More than 30 years after the introduction of the first neonatal screening programs, mental retardation can be prevented in the majority of children (>90%) with congenital hypothyroidism if therapy is commenced within the first 2 weeks of life, making neonate screening for this disorder the most successful population-based screening test in pediatrics.

Risk factors for neurodevelopmental deficits in congenital hypothyroidism after early substitution treatment

Neurodevelopment in children with congenital hypothyroidism who receive early treatment is generally good. However, subtle neurological deficits still exist in some patients. The aim of this investigation was to evaluate factors that may influence neurodevelopmental outcome in congenital hypothyroidism patients. The developmental quotient (DQ) of 155 children with congenital hypothyroidism was evaluated at 24 months of age, using Gesell Developmental Schedules (GDS), and compared with that of 310 healthy controls. Mean DQ scores in congenital hypothyroidism patients were 7.5 points lower for adaptive behavior than in control patients (p < 0.01). Patients with severe congenital hypothyroidism had the lowest DQ scores compared with two other congenital hypothyroidism subgroups and controls (p < 0.01). Children with congenital hypothyroidism who also had a low level of serum T(4) at diagnosis or exhibited a longer thyroid stimulating hormone (TSH) normalization time had lower adaptive behavior scores (p < 0.0003). Bivariate correlation and multiple regression analyses found that the severity of congenital hypothyroidism and parental socioeconomic status correlated with DQ scores. TSH normalization time was negatively related to adaptive behavior scores (p < 0.01). Neurodevelopmental deficits in children with congenital hypothyroidism correlate with the severity of congenital hypothyroidism, TSH normalization time, and parental socioeconomic status.

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. 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.

Children with congenital hypothyroidism: long-term intellectual outcome after early high-dose treatment

We aim to determine long-term intellectual outcome of adolescents with early high-dose treated congenital hypothyroidism (CH). Sixty-three prospectively followed children with CH were assessed at age of 14 y with the Wechsler Intelligence Scale for Children-Revised and compared with 175 healthy controls. Median age at onset of treatment was 9 d (range 5-18 d) and median starting dose of levothyroxine (L-T4) was 14.7 microg/kg/d (range 9.9-23.6 microg/kg/d). Full-scale intelligence quotient (IQ) was significantly lower than in controls after adjustment for socioeconomic status (SES) and gender (101.7 versus 111.4; p < 0.0001). Children with athyreosis had a lower performance IQ than those with dysgenesis (adjusted difference 7.6 IQ scores, p < 0.05). Lower initial thyroxine (T4) levels correlated with poorer IQ (r = 0.27, p = 0.04). Lower SES was associated with poorer IQ, in particular in children with CH (interaction, p = 0.03). Treatment during childhood was not related to IQ at age 14 y. Adolescents with CH manifest IQ deficits when compared with their peers despite early high-dose treatment and optimal substitution therapy throughout childhood. Those adolescents with athyreosis and lower SES are at particular risk for adverse outcome. Therefore, early detection of intellectual deficits is mandatory in children with CH.

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. Thus, there is a crucial 'window of opportunity' to correct the hypothyroidism and minimize the time the brain is exposed to hypothyroxinemia. While there are few truly prospective, randomized clinical trials investigating treatment parameters, studies measuring IQ outcome support a starting L-thyroxine dose of 10-15 microg/kg/day. Further, studies show that the most severely hypothyroid infants are at risk for a 5-20 point decrease in IQ. Such infants may benefit from a starting dose of 12-17 microg/kg/d, which has been shown to normalize T4 in 3 days and TSH in 2 weeks. Target serum T4 or free T4 levels appear to be higher in the first two weeks of treatment. Infants require more frequent laboratory monitoring, every 1-2 months in the first 6 months and every 3-4 months until age 3 years, as the developing brain has a critical dependence on thyroid hormone in the first 2-3 years of life.