Influence of severity of congenital hypothyroidism and adequacy of treatment on school achievement in young adolescents: a population-based cohort study

Chronic health conditions and school performance in first graders: A prospective cohort study

Objective

Children with chronic health conditions may perform poorer at school. Associations may be confounded by numerous social factors. We aimed to estimate the effects of a chronic health condition on overall school performance in first graders with an emphasis on rigorous adjustment for potential confounders.

Methods

A population-based cohort study was performed in the area of Mainz-Bingen (Germany). In 2015 all preschoolers were approached and the presence of a chronic health condition was assessed by parental questionnaires and preschool health examination data. The identification of a chronic health condition was based on special health care needs and presence of a doctor’s diagnosis out of 24 school-relevant diseases. At the end of the first school year, overall school performance was assessed by teachers and rated on a 5-item scale ranging from -10 to +10.

Results

Of 3683 children approached, 2003 were enrolled. Overall school performance was available for 1462 children (51% boys). Of these, 52% suffered from a chronic health condition. Compared to children without a chronic health condition, children with special health care needs (15%) performed worse at school (adjusted mean difference: -0.95, 95% CI: [-1.55; -0.35], P = 0.002). Children with a doctor’s diagnosis but without special health care needs (37%) did not perform worse at school. The effect was further analysed considering the extent of special health care needed.

Conclusions

Chronic health conditions affect overall school performance early in primary school. To identify academically at-risk children, a chronic health condition identification based on special health care needs may be used.

Clinical course of infants with congenital heart disease who developed thyroid dysfunction within 100 days

PURPOSE

We investigated the clinical course of infants with congenital heart disease (CHD) who experienced thyroid dysfunction within 100 days of birth.

METHODS

We performed retrospective medical reviews of 54 CHD patients (24 male patients) who underwent a thyroid function test (TFT) between January 2007 and July 2016. Data were collected on birth history, diagnosis of CHD, underlying chromosomal or genetic abnormalities, medication history, surgery, ventilator care, and exposure to iodine contrast media (ICM). Results of neonatal screening tests (NSTs) and TFTs were reviewed.

RESULTS

A total of 36 patients (29 transient, 7 permanent) showed thyroid dysfunction. Among the seven patients with permanent hypothyroidism, three had an underlying syndrome, three showed abnormal NST results, and one was admitted to the intensive care unit for macroglossia and feeding cyanosis. We found that infants with transient thyroid dysfunction had a lower birth weight and were more commonly exposed to thyroid disrupting medication and/or ICM. However, these risk factors were not significant. A total of 8 patients with a history of ICM exposure showed thyroid dysfunction. Excluding 3 patients with elevated thyroid stimulating hormone before ICM exposure, 5 patients recovered from transient thyroid dysfunction.

CONCLUSIONS

We observed thyroid dysfunction in two-thirds of CHD infants (53.7% transient, 13.0% permanent) who had risk factors and received TFT screening within 100 days, despite normal NSTs. Further studies with larger sample sizes are required to revise the criteria for TFT screening in CHD infants.

Liothyronine Improves Biochemical Control of Congenital Hypothyroidism in Patients with Central Resistance to Thyroid Hormone

OBJECTIVE

To assess whether adding liothyronine (LT3) to levothyroxine (LT4) monotherapy normalizes serum thyrotropin (TSH) and thyroxine (T4) concentrations in children with congenital hypothyroidism and central resistance to thyroid hormone.

STUDY DESIGN

We retrospectively studied 12 patients with congenital hypothyroidism and central resistance to thyroid hormone (6 treated with LT3+LT4 combined therapy and 6 treated with LT4 monotherapy). In patients receiving combined therapy, we compared serum concentrations of TSH, T4, and triiodothyronine before and after addition of LT3. We used repeated measures analysis to compare thyroid function in participants receiving combined therapy vs monotherapy, while accounting for age and intrasubject correlation.

RESULTS

In patients receiving combined therapy, the addition of LT3 was associated with normalization of mean TSH (9.2 vs 4.5 mIU/L, P = .002), a lower proportion of TSH values greater than 10 mIU/L (35% vs 8%, P = .03), and a decrease in mean serum T4 by 23 ± 9% (P < .001). Compared with patients receiving LT4 monotherapy, patients receiving combined therapy had lower mean TSH (8.5 ± 0.9 vs 4.3 ± 0.4, P < .001), lower odds of TSH elevation greater than 10 mIU/L (OR 0.20, 95% CI 0.10-0.41, P < .001), and lower odds of T4 elevation (OR 0.21, 95% CI 0.04-1.09, P = .06). LT3 treatment did not increase serum T3 levels significantly.

CONCLUSION

The addition of LT3 to LT4 monotherapy facilitates normalization of both serum TSH and T4 in patients with congenital hypothyroidism and central resistance to thyroid hormone. Larger prospective studies are needed to confirm these findings and to determine the effect of combined therapy on neurodevelopmental outcomes.

Guidelines for Mass Screening of Congenital Hypothyroidism (2014 revision)

Purpose of developing the guidelines: Mass screening for congenital hypothyroidism started in 1979 in Japan, and the prognosis for intelligence has been improved by early diagnosis and treatment. The incidence was about 1/4000 of the birth population, but it has increased due to diagnosis of subclinical congenital hypothyroidism. The disease requires continuous treatment, and specialized medical facilities should make a differential diagnosis and treat subjects who are positive in mass screening to avoid unnecessary treatment. The Guidelines for Mass Screening of Congenital Hypothyroidism (1998 version) were developed by the Mass Screening Committee of the Japanese Society for Pediatric Endocrinology in 1998. Subsequently, new findings on prognosis and problems in the adult phase have emerged. Based on these new findings, the 1998 guidelines were revised in the current document (hereinafter referred to as the Guidelines). Target disease/conditions: Primary congenital hypothyroidism. Users of the Guidelines: Physician specialists in pediatric endocrinology, pediatric specialists, physicians referring patients to pediatric practitioners, general physicians, laboratory technicians in charge of mass screening, and patients.

Congenital hypothyroidism: a clinical update of long-term outcome in young adults

Congenital hypothyroidism (CH) is the most common congenital endocrine disorder. The early treatment of CH patients has successfully improved the prognosis and management of this disorder. Optimal treatment and management throughout the patient's life, beginning in the neonatal period, are required to ensure long-term health. Affected patients should be offered assessments of associated medical conditions and provided with accurate information about their condition throughout their lives, but particularly during the transition from pediatric to adult services. This review provides a summary of current knowledge about the long-term outcomes of these patients and appropriate management into early adulthood. We carried out a systematic search of the Medline database to identify relevant articles. Despite major improvements in prognosis, the impact of CH is clearly not uniform, and management should take into account a broader range of relevant indicators, including CH severity, associated comorbid conditions and the adequacy of treatment during childhood and adulthood. The early diagnosis and management of associated medical conditions, and better educational strategies to improve compliance with treatment, should improve the long-term prognosis. Further studies are required to explore changes with aging.

Iodine-induced hypothyroidism in full-term infants with congenital heart disease: more common than currently appreciated?

CONTEXT

Iodine is a micronutrient essential for thyroid hormone synthesis. Thyroid hormone is critical for normal neurocognitive development in young infants, and even transient hypothyroidism can cause adverse neurodevelopmental outcomes. Both iodine deficiency and excess can cause hypothyroidism. Although iodine-induced hypothyroidism is well recognized in premature infants, full-term neonates have received less attention. Infants with congenital heart disease (CHD) are commonly exposed to excess iodine from administration of iodinated contrast agents during cardiac catheterization as well as topical application of iodine-containing antiseptics and dressings; hence, this is a vulnerable population.

OBJECTIVE

We report three cases of iodine-induced hypothyroidism in full-term neonates with CHD after cardiac angiography and topical application of iodine-containing antiseptics and dressings in the operative setting.

RESULTS

Three neonates with CHD and normal thyroid function at birth developed hypothyroidism after exposure to excess iodine. Two of these infants had transient hypothyroidism, and one had severe hypothyroidism requiring ongoing thyroid replacement therapy. All infants were asymptomatic, with hypothyroidism detected incidentally in the inpatient setting due to repeat newborn screening mandated by the long duration of hospitalization in these infants.

CONCLUSIONS

Iodine-induced hypothyroidism may be under-recognized in infants with CHD exposed to excess iodine. Systematic monitoring of thyroid function should be considered to avoid potential long-term adverse neurodevelopmental effects of even transient thyroid dysfunction in this susceptible population.

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.

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.

Audit of initial management of congenital hypothyroidism in the United Kingdom--comparison of UK practice with European and UK guidelines

BACKGROUND

Prompt and adequate management of newly diagnosed congenital hypothyroidism (CH) has been shown to optimise intellectual outcome.

METHODS

A questionnaire survey of the British Society for Paediatric Endocrinology and Diabetes (BSPED) membership was undertaken, examining current clinical practice in neonatal CH. Results were compared with published management guidelines from Europe and the UK.

RESULTS

The response rate was 86%. The majority were largely compliant with both guidelines. 43% review newly referred infants on the day of notification. However, 26% treat severe CH with < 10 microg/kg/day thyroxine and nearly 20% do not follow up until at least 14 days after initiating treatment, in contrast to both guidelines. Despite a new liquid T4 preparation being licensed, respondents preferred tablet T4.

CONCLUSION

Rapidity of assessment and adequate follow up of suspected CH is critical to outcome. Existing European and UK guidelines should be reviewed and expanded to incorporate new evidence, together with increased advice on preparation and administration of T4.

Neonatal screening for congenital hypothyroidism in Hessen, Germany: efficiency of the screening program and school achievement of 129 children at an age of 8-12 years

Status and school achievement of 129 children born in Hessen between 1988 and 1992 and notified by a repeatedly elevated concentration of TSH in neonatal screening were evaluated. Interviews of mothers, teachers and pediatricians were used to score the development and educational achievements, respectively. A total of 298,175 newborns were screened and the incidence of permanent congenital hypothyroidism (PCH) was 1: 3,313 (n = 90). The female/male ratio was 1.37:1. In the 69 PCH cases with complete data, athyreosis (52%), hypoplasia (32%), dyshormogenesis (9%) and ectopia (7%) were identified as etiologies. The mean age at start of therapy decreases from day 15 in 1988 to day 9 in 1992; however, 27% of PCH children showed reduced psychomotor development as scored by their pediatrician and 11% attended a special school for educationally subnormal children. Approximately 25% of the children had lower educational achievements irrespective of the school type. Our finding of a relatively high percentage of PCH children with subnormal development points to a failure in disease management. A follow-up program including repeated serum TSH monitoring and yearly examinations by pediatric endocrinologists and supervision by the regional screening center is necessary to ensure the long-term efficacy of neonatal screening for congenital hypothyroidism.

Congenital hypothyroidism: developmental outcome in relation to levothyroxine treatment variables

Neonatal screening programs for congenital hypothyroidism (CH) were initiated in the 1970s to ensure early treatment in order to prevent mental retardation. With screening, developmental prognosis is considerably improved, but follow-up studies still report developmental delay compared to controls. To explain the delay, most studies have focused on effects of CH severity, supposedly caused by prenatal hypothyroidism. Nonoptimal treatment could also be an explanatory factor. Treatment guidelines have changed; now, a higher levothyroxine starting dose is recommended. In this review, we first summarize outcome studies in CH versus controls and in mild versus severe CH. Second, we report results on the association between levothyroxine treatment variables and developmental outcome. Six research groups have reported results on the association between levothyroxine starting dose and intelligence, and eight groups on the association between circulating thyroid hormones and intelligence. Most studies found a positive association between a high level of treatment, primarily treatment during the first year and later intelligence. However, negative associations between high-dose treatment and outcome have been reported, and the question of optimal treatment in relation to developmental outcome has not been answered. Effects of high levothyroxine dosage should be documented in samples that have been treated according to recent recommendations.

Congenital hypothyroidism: a review of current diagnostic and treatment practices in relation to neuropsychologic outcome

Because thyroid hormone is essential for normal brain development, children born with congenital hypothyroidism who lack thyroid hormone during a circumscribed period of early development are at risk of brain damage and mental retardation. Since the advent of newborn screening programs in the 1980s, the diagnosis and treatment of this condition are now provided in the first 2-3 weeks of birth in most regions. While this is usually sufficient to prevent mental retardation, the children so identified attain mildly reduced IQs from expectation, and may still experience subtle and specific neurocognitive deficits. Their particular deficits are related to the brief period of thyroid hormone insufficiency they undergo, especially factors reflecting the severity of hypothyroidism at the time of diagnosis, the duration of hypothyroidism in infancy, and thyroid hormones at time of testing. In this article, we review the specific kinds of deficits demonstrated by children with congenital hypothyroidism who were diagnosed by screening and treated early, as well as the factors associated with their disease and its management that contribute to these deficits. The disease-related factors that will be reviewed will include the etiology of hypothyroidism and severity of disease at the time of diagnosis, while the treatment-related factors will include age at onset of therapy, starting and subsequent dose levels, compliance, and treatment-adequacy issues. Also examined will be the effects of hormone levels at the time of testing. In addition, the role of moderating variables such as social, genetic, and environmental influences, as well as the child's gender, will be discussed. Furthermore, several new issues including the quality of subsequent management, ultimate outcome, and pregnancy will be additionally reviewed. In conclusion, while outcome in congenital hypothyroidism is substantially improved by screening, affected children do still experience mild neuropsychologic deficits. To reduce the impact of persisting deficits, further research is needed to determine the optimal starting dose for the different etiologies, guidelines for subsequent management, and alternative therapies. Moreover, now that the original samples are reaching adulthood and, in females, childbearing age, further research is also needed regarding treatment during pregnancy in women with congenital hypothyroidism, as is research to determine how this population ultimately fares in adulthood.