Endocrine disorders in childhood and adolescence. Natural history of subclinical hypothyroidism in children and adolescents and potential effects of replacement therapy: a review

Prevalence of Associated Endocrine Diseases in Patients with Neurofibromatosis Type 1

Background  Neurofibromatosis type 1 (NF-1) is an autosomal dominant neurocutaneous disorder that increases the risk of developing benign and malignant tumors. Several associated endocrine diseases in NF-1 patients have been explained in the literature. Thus, this study aims to assess the endocrine manifestations as there no previous local data have discussed this association.

Methods  A retrospective cross-sectional study was conducted at KAMC and KASCH, Riyadh, Saudi Arabia by including all patients genetically confirmed with NF1 from 2004 until 2019 using a consecutive non-probability sampling technique. The included data were demographics, consanguinity, genetic variant mutations as well as associated endocrine diseases.

Results  The prevalence of patients with associated endocrine diseases was estimated to be 19.4%. Short stature showed the highest frequency of associated endocrine diseases followed by subclinical hypothyroidism. Positive consanguinity, sporadic mutation, and pathogenic variant showed high frequencies.

Conclusion  The coexistence of endocrine diseases was found in NF-1 patients. Therefore, screening for endocrine abnormality in patients with NF-1 by comprehensive history and physical exam as well as investigations to minimize complications and the late presentation should be considered; however, further studies are necessary to address the need.

The association between subclinical hypothyroidism and metabolic syndrome: an update meta-analysis of observational studies

The association between subclinical hypothyroidism (SCH) and metabolic syndrome (MetS) has been widely discussed. This study aimed to conduct an update and comprehensive meta-analysis to reveal the risk of MetS and its components in SCH. PubMed, Embase and ISI Web of Knowledge were searched to identify relevant studies through February 20^th, 2020. Review Manager 5.3 and Stata 14.0 were used to conduct the meta-analysis. Both fixed-effects and random-effects models were used. In total, 18 articles (19 studies) incorporating 79,727 participants were included. The pooled OR for MetS comparing subjects with SCH with euthyroid subjects was 1.28 (95% CI: 1.19 to 1.39, p = 0.04, I² = 40%). Subgroup analysis results showed significant associations of SCH and MetS in the adult subgroup (OR = 1.28, 95% CI: 1.18-1.40), Asian population subgroup (OR = 1.30, 95% CI: 1.19-1.42) and cross-sectional study design subgroup (OR = 1.31, 95% CI: 1.16-1.47). Significant associations of SCH and MetS also existed in all MetS definition criteria subgroups except the Chinese Diabetes Society (CDS) subgroup. SCH was correlated with MetS and was not affected by the subgroup analysis stratified by the proportion of females in the total population, the TSH cutoff value in SCH diagnostic criteria, or the adjustment for confounding factors. SCH was identified to be associated with an increased risk of obesity, hypertension, high triglyceride (TG) levels and low high-density lipoprotein cholesterol (HDL-C) levels. In conclusion, SCH is significantly associated with an increased risk of MetS and four out of five components of MetS.

The effect of ketogenic diet on thyroid functions in children with drug-resistant epilepsy

BACKGROUND

Ketogenic diet (KD) remains a valuable treatment option for children with drug-resistant epilepsy. However, it may cause many well-known adverse effects such as dyslipidemia or kidney stones. But, its effects on thyroid functions are largely unknown.

PURPOSE

The aim of this study was to investigate the effects of the KD on thyroid functions in children with drug-resistant epilepsy.

METHOD

A total of 66 children (35 females) aged 3-193 months (median, 52 months) with drug-resistant epilepsy who received a KD for at least 12 months were enrolled in the study. All children were started on KD with 3:1 ratio which was then adjusted as clinically necessary. Serum free-thyroxine (FT4) and thyroid stimulating hormone (TSH) concentrations were measured before starting treatment and at the first, sixth and twelfth months of treatment. Changes in FT4 and TSH concentrations over 12 months were analyzed.

RESULTS

Median serum FT4 and TSH concentrations, and the frequencies of patients with low FT4 and high TSH concentrations did not change significantly in the study sample over the 12-month study period. Serum FT4 levels increased significantly and TSH concentrations decreased insignificantly in four patients receiving L-thyroxine replacement therapy. During the 12-month treatment period, BMI-SDS increased, and the number of antiepileptic drugs decreased significantly.

CONCLUSION

It appears that KD therapy does not impair thyroid functions in children with drug-resistant epilepsy. KD can be used safely along with L-thyroxine replacement even in children with pre-existing subclinical hypothyroidism.

The Prevalence of Thyroid Autoimmunity in Children with Developmental Dyslexia

Methods

We enrolled pediatric subjects with developmental dyslexia and, as a control group, healthy age- and sex-matched subjects without developmental dyslexia. Thyroid function was evaluated in subjects with developmental dyslexia measuring serum concentrations of thyroid-stimulating hormone (TSH), free triiodothyronine (fT3), and free thyroxine (fT4). Thyroid autoimmunity was evaluated in all subjects measuring antithyroid peroxidase (TPO-Ab) and antithyroglobulin (TG-Ab) antibodies. In subjects with developmental dyslexia, thyroid ultrasonography (US) was also performed.

Results

We enrolled 51 subjects with developmental dyslexia (M : F = 39 : 12, mean age 12.4 ± 9 years) and 34 controls (M : F = 24 : 10, mean age 10.8 ± 4 years). TPO-Ab positivity was significantly higher in subjects with developmental dyslexia compared to controls (60.8% vs. 2.9%, p < 0.001), while no significant difference was found in TG-Ab positivity (16% vs. 5.8%). Thyroid US performed in 49 subjects with developmental dyslexia revealed a thyroiditis pattern in 60%.

Conclusions

We found an extremely high prevalence of thyroid autoimmunity in children with developmental dyslexia. Further studies are needed to confirm our observations, but our findings may change the approach to this disorder and eventually lead to a systematic determination of thyroid autoimmunity in children with developmental dyslexia.

Subclinical hypothyroidism in childhood, treatment or only follow-up?

Background

Subclinical hypothyroidism (SH) is defined as serum levels of thyroid-stimulating hormone (TSH) above the upper limit with normal concentrations of free T4 (fT4). Its management remains challenging. The aim of the study was to evaluate clinical and laboratory findings as well as the clinical course of children with SH followed in a third level hospital. Sixty-five patients aged between 2 and 18 years old were retrospectively studied.

Methods

The patients were followed for a median period of 9 months (range 6 months to 24 months). Those who normalized TSH levels were discharged (Group 1). If TSH persisted mildly elevated (5-10μUI/mL) with normal fT4 and negative TPOAb/TgAb, they were classified as Group 2 and followed semi-annually without treatment. Those patients whose TSH raised ≥10μUI/mL or who maintained TSH 5-10μUI/mL and positive TPOAb/TgAb were considered suitable for thyroxin therapy (Group 3, G3).

Results

In 89% of our patients, TSH concentrations spontaneously reverted to normality or remained stable without treatment (Groups 1 and 2), whereas less than 11% progressed to clinical hypothyroidism (Group 3). Baseline TSH was significantly lower in group 1 than in group 3. In group 3 the prevalence of female sex (71%) was higher and TPO antibodies were present in 85% of patients. The risk of developing overt hypothyroidism in patients with positive anti-thyroid antibodies respect to those who normalized TSH was 45 (95%CI 6.5–312.5).

Conclusion

Baseline TSH, female sex and the presence of thyroid autoimmunity were the best predictors of the evolution to SH over time.

The effect of subclinical hypothyroidism on body composition parameters in children

BACKGROUND

It's known that overt hypothyroidism increases body fat content and weight. There's limited research about the effect of subclinical hypothyroidism (SH) on body composition in children and the effect of LT4 treatment. We aimed to evaluate body composition parameters in healthy subjects and in children with mild SH (MSH) and determine the effect of LT4 treatment.

METHODS

Sixty-four healthy children and 32 children with MSH were included. Anthropometric measurements and hormonal parameters were evaluated. Body composition was evaluated using bioelectric impedance analysis (BIA). Patients were put on LT4 treatment. BIA was performed again after 12 months of therapy.

RESULTS

There was no significant difference between the anthropometric parameters and basal metabolic rate of the healthy children and the MSH group. The percentage of trunk muscle mass (TMM) in the MSH group was lower than in the control group (P < .05). After 12 months of LT4 treatment, the percentage of total fat-free mass (FFM), TMM and trunk fat-free mass (TFFM) were increased and percentage of total body fat mass and trunk fat mass were decreased (P < .05). The difference between the percentage of TMM in the MSH group and control group was insignificant after LT4 treatment (P > .05).

CONCLUSIONS

The percentage of TMM in children with MSH was found lower than healthy control group. After LT4 treatment, the percentage of the FFM, TMM and TFFM were increased and the difference between percentage of TMM in children with MSH and healthy controls was insignificant. Our data indicated that MSH might be associated with early changes in body composition parameters.

Cardiovascular risk factors in children and adolescents with subclinical hypothyroidism: A protocol for meta-analysis and systematic review

INTRODUCTION

Subclinical hypothyroidism (SH) is serum thyrotropin (TSH) slightly increased, while serum free thyroxine (FT4) levels are normal, and patients may have no abnormal symptoms, or only slight hypothyroidism, there are many studies proving that SH does increase cardiovascular risk in adults. However, there are few studies in children and adolescents. In order to explore whether children with subclinical hypothyroidism have a higher cardiovascular risk, we designed this meta-analysis.

METHODS

The protocol of this systematic review and meta-analysis was registered on the NPLASY (No. 202040182). The following electronic databases will be searched from the inception through the present to find studies that live up to our standard: PubMed, EMBASE, Web of Science, Cochrane Library, CNKI, Wanfang, and VIP. And we will include case-control studies, cohort studies, and cross-sectional studies. For including study, we will use the Newcastle-Ottawa Scale to evaluate their quality. Then 2 researchers will independently extract the required information. I statistics and subgroups will be used to analyze heterogeneity. We conduct a sensitivity analysis by excluding literature successively. When the system review contains >10 articles, Egger test will be conducted to evaluate publication bias.

RESULTS

From this study, we will assess the cardiovascular risk of children and adolescents with SH from multiple perspectives.

CONCLUSION

The conclusion of this paper will provide evidence for cardiovascular risk of SH children and provide basis for prevention and treatment of SH.

ETHICS AND DISSEMINATION

This meta-analysis does not collect personal primary data, so there is no need for formal moral recognition. The results of the system review will be presented to national and international conferences for publication.

Effect of TSH on Non-Alcoholic Fatty Liver Disease (NAFLD) independent of obesity in children of predominantly Hispanic/Latino ancestry by causal mediation analysis

Background

Nonalcoholic Fatty Liver Disease (NAFLD) is a common co-morbidity of obesity. Elevated TSH levels (eTSH), also associated with obesity, may contribute to the dysmetabolic state that predisposes to NAFLD.

Objective

To assess the relationship between TSH levels and NAFLD in children with biopsy-proven NAFLD compared to controls.

Design and methods

In this retrospective study of children with biopsy-proven NAFLD and age-matched controls, the association of eTSH with NAFLD was investigated and the role of TSH as a mediator between obesity and NAFLD was assessed.

Results

Sixty-six cases and 4067 controls (69.7 vs 59% Hispanic/Latino ancestry, p = 0.1) of the same age range seen in the same time duration at an urban Children’s Hospital were studied. Children with NAFLD were more likely to be male (74.6 vs 39.4%, p < 0.001), have higher modified BMI-z scores (median 2.4 (IQR 1.7) vs 1.9 (IQR 1.7), p < 0.001), and abnormal metabolic parameters (TSH, ALT, HDL-C, non-HDL-C, and TG). Multivariate analyses controlling for age, sex and severity of obesity showed significant association between the 4^th quartile of TSH and NAFLD. Causal mediation analysis demonstrates that TSH mediates 33.8% of the effect of modified BMI-z score on NAFLD. This comprises of 16.0% (OR = 1.1, p = 0.002) caused by the indirect effect of TSH and its interaction with modified BMI-z, and 17.7% (OR = 1.1, p = 0.05) as an autonomous effect of TSH on NAFLD. Overall, 33.8% of the effect can be eliminated by removing the mediator, TSH (p = 0.001).

Conclusions

The association of eTSH and biopsy-proven NAFLD is demonstrated in children of Hispanic/Latino ancestry. Further, a causal mediation analysis implicates an effect of TSH on NAFLD, independent of obesity.

Influence of subclinical hypothyroidism on metabolic parameters in obese children and adolescents

BACKGROUND

Subclinical hypothyroidism (SH) is a common condition in obese children. However, its effect on glucose and lipid metabolism in obese children remains controversial.

PURPOSE

The present study aimed to investigate the association between SH and metabolic parameters.

METHODS

A total of 215 obese children and adolescents aged 6-18 years were included in this retrospective cross-sectional study. The patients' anthropometric measurements such as thyrotropin (TSH), free thyroxine (fT4), fasting plasma glucose, and insulin levels, as well as homeostasis model assessment for insulin resistance (HOMA-IR) index, and lipid profiles were evaluated. The patients were allocated to the SH group (fT4 normal, TSH 5-10 mIU/L) (n=77) or the control group (fT4 normal, TSH<5 mIU/L) (n=138). The glucose and lipid metabolisms of the 2 groups were compared.

RESULTS

SH was identified in 77 of 215 patients (36%). Mean body mass index was similar in both groups. The mean serum insulin, HOMA-IR, and triglyceride (TG) levels were higher and the mean high-density lipoprotein cholesterol level was lower in the SH group than in the control group (P=0.007, P=0.004, P=0.01, and P=0.02, respectively). A positive correlation was observed between TSH level and insulin level, HOMA-IR, and TG level.

CONCLUSION

SH was identified in some of the obese children and adolescents. A clear association was observed between SH, insulin resistance, and dyslipidemia in obese children.

Cognitive Function in Children With Idiopathic Subclinical Hypothyroidism: Effects of 2 Years of Levothyroxine Therapy

BACKGROUND

Long-term consequences of mild subclinical hypothyroidism (SH) in children are still unclear, and the need for levothyroxine (L-T4) supplementation remains controversial. We designed a 2-year, case-control, prospective study of a cohort of children with SH to evaluate the effects of L-T4 therapy on neurocognitive outcome.

METHODS

Thirty-four children, age 9.1 ± 2.6 years, with long-lasting, idiopathic, and mild SH, and 34 healthy matched controls, were enrolled. Twenty SH children underwent a 2-year L-T4 treatment (group A), whereas 14 refused treatment and were reevaluated after a 2-year-follow-up (group B). IQ and specific cognitive domains were evaluated in all children at study entry and after 2 years of therapy (group A) or observation (group B) in SH individuals.

RESULTS

In SH children baseline IQ scores were normal and comparable to controls (full-scale IQ [FSIQ] 100.4 ± 11.3 vs 101.8 ± 14.2, verbal IQ [VIQ] 99.7 ± 13.7 vs 98.3 ± 14.9 and performance IQ [PIQ] 101.2 ± 10.4 vs 105 ± 10.4).In group A, L-T4 treatment was associated with normalization of thyrotropin (6.3 ± 1.0 mIU/L at baseline vs 2.8 ± 1.4 mIU/L at 2 years, P < .001). However, 2-year L-T4 therapy was not associated with a change in IQ scores (FSIQ 104.4 ± 13.8 vs 102.7 ± 11.0; VIQ 101.8 ± 14.9 vs 102.3 ± 11.9; and PIQ 106.5 ± 13.9 vs 102.7 ± 10.7) or in verbal or performance subtest scores. No significant differences were found in IQ scores after 2 years of treatment in group A compared to group B after a 2-year follow-up.

CONCLUSIONS

Our data suggest neurocognitive function in children is not impaired by persistent, mild, untreated SH and is not significantly modified by 2-year L-T4 supplementation.

Referrals for Elevated Thyroid Stimulating Hormone to Pediatric Endocrinologists

Objective

We aimed to determine the reproducibility of TSH testing in pediatric patients referred to pediatric endocrinologists and to identify the threshold TSH levels that would predict the presence of antithyroid autoantibodies and inform decisions by pediatric endocrinologists to initiate or continue treatment with levothyroxine.

Study Design

We analyzed a retrospective case series of 325 children aged 1 to 18 years referred for hypothyroidism to the endocrinology clinic at a tertiary care children’s hospital. The receiver operating characteristic area under curve (AUC) determined the ability of the initial TSH level to predict pediatric endocrinologists’ treatment decisions, presence of thyroid autoantibodies, and reproducibility of elevated TSH on repeat testing.

Results

Of 325 patients, 191 were treated. The treated patients were more likely to have had a higher referral TSH, positive autoantibodies, and abnormal thyroid gland examination findings. An initial TSH of 5 had a specificity of only 14% for a repeat TSH of ≥5. An initial TSH level of 11 had a specificity of 90% for a repeat TSH of ≥11, with sensitivity of 90%. TSH was a relatively poor predictor (AUC, 0.711) of the presence of autoantibodies with optimal classification at TSH >8.8 mIU/L. It was better (AUC, 0.878) at predicting whether endocrinologists started or continued treatment with levothyroxine, with optimal classification at 8.2 mIU/L. TSH levels combined with antibody status and thyroid examination findings had the best ability to predict treatment (AUC, 0.930).

Conclusions

TSH levels slightly above the reference range should not prompt referral to pediatric endocrinologists unless another basis for clinical concern is present.

Thyroid hormone therapy for subclinical hypothyroidism

Subclinical Hypothyroidism (SCH) is defined as a raised level of serum TSH level in the presence of normal circulating free thyroid hormones. SCH is a highly prevalent condition displaying some peculiarities, both in terms of the diagnostic and therapeutic approach, when specific population and/or concomitant diseases are taken into account. The debate upon whether LT4 therapy should be initiated or not in patients with SCH is a long lasting one and still it remains controversial. Current evidence supports the concept that the clinical consequences of SCH may be profoundly different in relation to several patient-specific characteristics. Aim of the present review is to provide updated indications for SCH treatment in specific clinical settings. These will include the management of SCH in obese and diabetic patients, in pregnant women, and in specific age groups. Treatment modalities, including LT4 doses and recommended follow-up strategy will also be discussed. In the era of "precision medicine" the decision to-treat-not-to-treat SCH should be individualized taking into account risks and beneficial outcomes of LT4 therapy. With this in mind, we reviewed the most relevant studies in the recent literature in order to provide evidence for or against LT4 replacement therapy for SCH in specific clinical settings.

Endocrine consequences of neuroblastoma treatment in children: 20 years' experience of a single center

Background Neuroblastoma (NBL) is a child neoplasia affecting extracranial tissue of neuroectodermal origin. It accounts for 10% of solid malignancies in children and is characterized by a survival rate approaching 70%, confronting physicians with the emergence of an adult survivor population who have been previously exposed to surgery, cytotoxic drugs, radiation therapy or metaiodobenzylguanidine (MIBG) therapy. All these treatments potentially affect the endocrine system. Our study consists in a retrospective review of late endocrine effects arising in survivors treated for NBL during childhood. Methods The medical files of 47 patients (M/F = 26/21) treated for NBL were reviewed. Collected data consisted of age, height, weight and biological hormonal values at diagnosis and at the last follow-up consultation. The incidence of late effects in our sample was compared to the data from the literature. Results Patients were between 0 and 15.8 years of age at diagnosis (median: 1.16 years) and between 1 and 25 years of age at last follow-up (median: 16 years). Twenty-six patients were treated with chemotherapy (CT), 11 underwent CT and radiation therapy and five were treated with CT and MIBG therapy. Ten percent of the patients died before reaching the end of therapy. Late effects occurred in 54% of the patients. Thirty-six percent of patients had non-endocrine complications (musculoskeletal, neurological, hematological or hepatic chronic conditions). Endocrine complications (28%) affected mainly patients treated with CT and consisted of gonadal dysfunction (up to 42% patients of over 12 years of age at follow-up) and hypothyroidism (21%). Our analysis revealed that CT had a significant impact on final height (p < 0.05). Conclusions Treatment for childhood malignancies exposes children to late effects affecting the endocrine system. In children treated for NBL, hypothyroidism, gonadal failure and impaired growth appear to be the main endocrine complications. Close follow-up of survivors is thus appropriate.

Influence of Hashimoto Thyroiditis on the Development of Thyroid Nodules and Cancer in Children and Adolescents

It is unclear whether patients with Hashimoto thyroiditis (HT) are predisposed to develop thyroid nodules and/or thyroid cancer. The objective of our study was therefore to assess the prevalence of thyroid nodules and/or cancer in patients with HT and to look for possible prognostic factors. A retrospective survey of 904 children/adolescents with HT (709 females, 195 males) regularly followed in nine Italian centers of pediatric endocrinology was performed. Median period of follow-up was 4.5 years (1.2 to 12.8 years). We evaluated free T4, TSH, thyroid peroxidase antibody (TPOAb), thyroglobulin antibodies, and thyroid ultrasound yearly. One hundred seventy-four nodules were detected, with an annual incidence rate of 3.5%. Ten nodules were malignant (8 papillary and 2 papillary follicular variant), giving a 5.7% prevalence of cancer among patients with nodules. The severity of hypoechogenity at ultrasound, TPOAb, and free T4 serum concentrations were predictive for the appearance of new nodules. Furthermore, a positive correlation was observed between TPOAb titer and the development of thyroid cancer. In conclusion, HT seems to influence the development of thyroid nodules, but not cancer in children and adolescents.

Hashimoto Thyroiditis and Dyslipidemia in Childhood: A Review

Hashimoto autoimmune thyroiditis (AIT) is the most common cause of acquired hypothyroidism in the pediatric population. Development of AIT is mediated mainly by cellular immune response directed toward thyroid autoantigens, leading to inflammation and impaired function of thyroid gland. Both thyroid dysfunction and inflammation affect the metabolism of plasma lipoproteins. The alterations in lipid profile worsen with the advancement of hypothyroidism, ranging from discrete changes in euthyroid AIT patients, to atherogenic dyslipidemia in the overt hypothyroidism. In this review, characteristics of dyslipidemia in pediatric AIT patients, and the consequences in respect to the risk for cardiovascular disease (CVD) development are discussed. Additionally, benefit of L-thyroxine treatment on serum lipid profile in pediatric AIT patients is addressed. Finally, potential usefulness of novel lipid biomarkers, such as proprotein convertase subtilisin/kexin type 9 (PCSK9), non-cholesterol sterols, low-density lipoprotein particle size and number, and high-density lipoprotein structure and functionality in AIT patients is also covered. Further longitudinal studies are needed in order to elucidate the long-term cardiovascular outcomes of dyslipidemia in pediatric patients with Hashimoto AIT.

Subclinical Hypothyroidism in Children: When a Replacement Hormonal Treatment Might Be Advisable

Aim of this mini review was to analyze the main variables which should be taken into account when the decision regarding a possible treatment with L-T4 has to be considered for a child with subclinical hypothyroidism (SH). The indications of periodical monitoring and vigilance have been also discussed. It was inferred that therapy should be recommended for children with underlying Hashimoto's thyroiditis and progressive deterioration of thyroid status over time, particularly in the cases with goiter and hypothyroid symptoms and in those with associated Turner syndrome or Down's syndrome and/or other autoimmune diseases. Treatment might also be recommended for children with proatherogenic metabolic abnormalities. Treatment is not advisable in children with idiopathic and mild SH, no goiter, no hypothyroid symptoms and negative anti-thyroid autoantibodies. In the absence of any therapeutic intervention, clinical status and thyroid function tests should be periodically monitored, in order to individuate the children who might benefit from treatment. It has been suggested that children with a persistent mild elevation of TSH, who are not treated with L-T4, should undergo biochemical monitoring of thyroid function and re-assessment of clinical status every 6 months. After 2 years with stable thyroid function tests, the interval between monitoring can be extended.

Thyroid-stimulating hormone is not the primary regulator of thyroid development in euthyroid children and adolescents living in an iodine-replete area

OBJECTIVES

It is known that there are multiple factors which can affect thyroid gland development during childhood and adolescence. Our aim was to investigate this issue by examining the relationships between age, sex, several anthropometric parameters, pubertal status, thyroid function tests, and iodine intake status with thyroid volume (TV) in children and adolescents.

STUDY DESIGN

This was a cross-sectional field study conducted in 11 representative cities and villages of Uzbekistan. Six hundred and ten children and adolescents participated. Anthropometric indices and TV were estimated. In addition, thyroid function tests (TFTs) and urinary iodine excretion (UIE) measures were obtained.

RESULTS

Median UIE was 151 μg/L, thus the studied areas were iodine-sufficient. TFTs fluctuated in both genders during childhood and adolescence and the thyroid growth spurt was observed, in both sexes, at the ages of 12 and 13 years, which coincided with the age of menarche in girls. Thyroid volume was positively correlated with body surface area (BSA) (r = 0.800, p < 0.001), age (r = 0.780, p < 0.001), fat-free mass (FFM) (r = 0.797, p < 0.001) and negatively correlated with serum TSH (r = -0.154, p = 0.05). No association between thyroid volume and UIE was observed.

CONCLUSIONS

In euthyroid children and adolescents living in iodine-replete areas, thyroid gland development appears to follow the pattern of linear growth and displays a growth spurt at the onset of puberty, probably due to the abrupt increase of circulating sex steroids. At this age, TSH does not appear to be the main regulator of thyroid gland development.

Advances in pediatrics in 2017: current practices and challenges in allergy, endocrinology, gastroenterology, genetics, immunology, infectious diseases, neonatology, nephrology, neurology, pulmonology from the perspective of Italian Journal of Pediatrics

This review provides an overview of a remarkable number of significant studies in pediatrics that have been published over the past year in the Italian Journal of Pediatrics. We have selected information from papers presented in the Journal that deal with allergy, endocrinology, gastroenterology, genetics, immunology, infectious diseases, neonatology, nephrology, neurology, pulmonology. The relevant epidemiologic findings, and developments in prevention, diagnosis and treatment of the last year have been discussed and placed in context. We think that advances achieved in 2017 will help readers to make the future of patients better.

Subclinical hypothyroidism in children: is it always subclinical?

Aim of this commentary is to report current knowledges on the main clinical and metabolic abnormalities which might be observed in children with longstanding and untreated subclinical hypothyroidism (SH) and to comment the most recent views about natural evolution of thyroid function in the cases with either idiopathic or Hashimoto’s thyroiditis-related SH. On the basis of these preliminary remarks, the essential guidelines for an appropriate and tailored management of SH children are also proposed.

Thyroid function test evolution in children with Hashimoto's thyroiditis is closely conditioned by the biochemical picture at diagnosis

ᅟ

Aim of this commentary is to summarize the salient literature views on the relationships between presentation and evolution patterns of thyroid function in children with Hashimoto’s thyroiditis (HT).

According to the most recent reports, children with HT and subclinical hypothyroidism (SH) are more prone to the risk of developing severe thyroid dysfunctions over time, if compared to those presenting with euthyroidism.

In contrast, children presenting with HT and either overt or subclinical hyperthyroidism are incline to exhibit a definitive resolution of the hyperthyroid phase within some months, although there is a wide variability between the different individuals.

The natural history of frank hypothyroidism in the children with HT has never been investigated so far, since in these cases an immediate onset of replacement treatment is mandatory.

Conclusions

1) a deterioration of thyroid status over time may be observed especially in the children presenting with SH, but also in those presenting with euthyroidism; 2) a definitive resolution of the hyperthyroid phase is generally observed in those presenting with either overt or subclinical hyperthyroidism.

Longitudinal Change in Thyroid Hormone Levels in Children with Epilepsy on a Ketogenic Diet: Prevalence and Risk Factors

Background and Purpose

The aim of this study is to evaluate the prevalence of hypothyroidism and the change of thyroid hormone level in the children with epilepsy on a ketogenic diet (KD).

Methods

The levels of serum free thyroxine (fT4) and thyroid-stimulation hormone (TSH) were measured at the start of the KD and at 6- to 12-month intervals in children with intractable epilepsy. Hypothyroidism was defined as fT4 level < 0.8 ng/dL and TSH level > 6.0 μIU/mL.

Results

A total of 28 children (17 boys and 11 girls) were enrolled in the study. The mean age of onset of seizure was 1.4 ± 1.6 years, the mean age of the start of the KD was 3.2 ± 2.4 years, and the mean duration of KD was 1.9 ± 1.5 years. Overall, there was no significant longitudinal change in the mean fT4 (0.99 ± 0.25 vs. 0.94 ± 0.71 ng/dL, p = 0.28) and TSH (2.94 ± 1.32 vs. 3.18 ± 1.21 μIU/mL, p = 0.44) levels from the start of the KD to last follow-up. The patients with a younger age of seizure onset, earlier initiation of KD, and higher serum levels of cholesterol and triglyceride had a significant decrease in fT4 levels and increase in TSH levels during the KD. Sex, duration of the seizure or KD therapy, seizure types, seizure frequency, seizure outcomes, brain lesion, ratio of KD, and being overweight did not affect the longitudinal change of fT4 and TSH levels during KD.

Conclusion

Thyroid function had no significant longitudinal decrease in pediatric epilepsy during KD therapy. However, careful monitoring of the serum levels of fT4/TSH should be recommended in children on KDs, especially in those with earlier seizure onset, earlier start of KD, and higher levels of lipid profiles.

The relationship between hyperthyrotropinemia and metabolic and cardiovascular risk factors in a large group of overweight and obese children and adolescents

PURPOSE

Mild TSH elevations are frequently observed in obese patients, in the absence of any detectable thyroid disease. Our objective is to evaluate the relationship between the raised TSH levels and the biochemical and clinical consequences of obesity.

METHODS

This is a retrospective cross-sectional study of a large population of obese children and adolescents. We evaluated 833 subjects (340 m, 493 f), aged 14.4 ± 2.5 (range 5.2-18.5) years, height SDS 0.27 ± 1.04 (-3.49-4.35), and BMI SDS 2.94 ± 0.59 (1.60-4.68). Body composition, free T4, TSH, anti-TPO antibodies, anti-TG antibodies, inflammation markers (total WBC and the subtypes, ultrasensitive C-reactive protein), and metabolic parameters [AST, ALT, γGT, ALP, glycaemia, insulin, total cholesterol (TC), HDL-cholesterol (HDL-C), and LDL-cholesterol (LDL-C), triglycerides (TG)] were measured, and oral disposition index (ODI) and cardiovascular risk factors (TC/HDL-C and TG/HDL-C) were calculated. After exclusion of the subjects showing anti-thyroid antibodies, the remaining 779 (325 m, 454 f) were then subdivided into two subgroups according to a TSH value below (group A) or above (group B) 4.5 mU/L.

RESULTS

Clinical characteristics and hematological markers of patients with and without positive anti-thyroid antibodies were similar, with the exception of higher TSH levels in the latter group. Using analysis of covariance, the subjects of group B had significantly higher values of TC (170.3 ± 28.7 vs 163.3 ± 32.9 mg/dL; p < 0.05), systolic (125.8 ± 13.5 vs 124.5 ± 13.1 mm/Hg), and diastolic blood pressure (79.2 ± 8.0 vs 77.9 ± 8.2 mm/Hg) than subjects of group A. No difference was observed in body composition, ODI, and the cardiovascular risk factors between these two groups.

CONCLUSION

TSH elevation in overweight and obese children and adolescents, being associated with a higher TC and blood pressure, might negatively influence the cardiac status. Longitudinal studies are requested, however, to confirm this hypothesis and, therefore, to conclude whether a substitutive treatment with l-thyroxine is really needed in these patients.

Mild TSH resistance: Clinical and hormonal features in childhood and adulthood

OBJECTIVE

Mutations in TSH receptor (TSHR) are associated with TSH resistance, a genetic defect characterized by a heterogeneous phenotype ranging from severe hypothyroidism to subclinical hypothyroidism (SCH). We assessed the clinical and hormonal pattern of TSHR variants in a series of pediatric patients, and the long-term outcome of growth, biochemical measurements of metabolism, and neuropsychological functions in TSHR mutations carriers.

DESIGN

Observational, retrospective study.

PATIENTS

Thirty four children (age 7 days to 11 years) and 18 adult carriers of TSHR variants.

MEASUREMENTS

The TSHR gene was sequenced by PCR-amplified direct sequencing in 111 pediatric patients with slight to moderate elevation of TSH and normal FT4 levels. The study focused on the: auxological and biochemical parameters, thyroid ultrasound, bone age, bone mineral density (BMD), and intellectual outcome (IQ) were collected during the long follow-up (1-15 years).

RESULTS

Seventeen different TSHR variants (eight novel) were identified in 34 of the 111 pediatric patients, with a high prevalence of familial cases (27/34). Neonatal screening for congenital hypothyroidism was positive in half of the TSHR carriers. Growth, IQ, BMD, and biochemical parameters were normal in all subjects. Twenty patients received L-T4 replacement therapy, in all cases before genetic analysis. After re-evaluation, six patients resumed L-T4 therapy: they were compound heterozygous, or single heterozygous and with associated conditions at risk of thyroid impairment (SGA). No adults presented clinical features consistent with impaired thyroid function.

CONCLUSIONS

Children carriers of TSHR variants, regardless of L-T4 treatment, show regular growth and neuropsychological development, with no evident biochemical and US alterations.

Subclinical hypothyroidism in paediatric population treated with levothyroxine: a real-world study on 2001-2014 Italian administrative data

OBJECTIVE

To estimate the prevalence of subclinical hypothyroidism (SH) among children, by using levothyroxine low dosage as disease proxy, and to describe prescription pattern.

DESIGN

An historical cohort study was performed through administrative databases of 12 Italian Local Health Units covering 3,079,141 inhabitants. A cohort of children (aged 0-13 years) was selected in the period 2001-2014. A subgroup of new users (aged 0-9 years) was identified and followed up for 5 years.

METHODS

The prevalence was provided as mean value of the whole period, as annual trend, by patient gender and age. Demographic details, information on levothyroxine dosage, comorbidities and co-medications were provided. Therapy duration and medication persistence were evaluated among new users.

RESULTS

644 children treated with levothyroxine low dosage was selected, with a mean annual prevalence of 0.20 per 1000 children. The temporal trend of prevalence was stable, with a slight reduction in the 2005-2008. Prevalence by age showed an increase after 10 years. Patients were treated with an average annual dose of 4290 µg/year and 66.9% of children were affected by comorbidities. Among 197 new users, 62.9% received therapy only for one year, whereas out of those treated two or more years, 89.0% resulted persistent to the therapy.

CONCLUSIONS

This study provides real-world epidemiology of SH among children, and it depicts the clinical and therapeutic characteristics of these subjects. Its findings showed that the SH treatment of this disorder was widely variable, also due to lack of evidence concerning paediatric population.

Former Very Preterm Infants Show Alterations in Thyroid Function at a Preschool Age

Preterm birth is frequently associated with altered thyroid hormone levels in the newborn period. Recent data suggest a role of prematurity independent of birth size also in childhood thyroid dysfunction. Whether the high-risk population of former very preterm infants (VPI) is particularly susceptible to thyroid hormone alterations is currently unknown. The aim of the present study was to assess whether former VPI display changes in thyroid hormone status in comparison to term-born controls at a preschool age. Free triiodothyronine (fT3), free thyroxine (fT4), and thyroid stimulating hormone (TSH) concentrations were determined in former VPI and same-aged children born at term at five to seven years of age. 31 former term infants and 82 former VPI were included in the study. In comparison to children born at term, former VPI had lower fT4 (16.1 ± 1.8 versus 17.0 ± 2.1 pmol/l), higher fT3 (6.8 ± 0.7 versus 6.5 pmol/l), and higher TSH levels (3.0 ± 1.4 versus 2.3 ± 1.0 μU/l), independent of major neonatal morbidities. As subclinical changes in thyroid hormone status are potentially associated with adverse health profiles, close follow-up of these children is warranted.

Endocrinological Evaluations of a Neurofibromatosis Type 1 Cohort: Is it Necessary to Evaluate Autoimmune Thyroiditis in Neurofibromatosis Type 1?

Background:

Neurofibromatosis type 1 is an autosomal dominant neurocutaneous disorder in which the coexistence of autoimmune thyroiditis and thyroid gland tumours has been reported previously.

Aims:

To determine the thyroid function and autoimmune thyroid diseases in neurofibromatosis type 1 patients in order to identify the possible association between neurofibromatosis type 1 and thyroid diseases.

Study Design:

Case-control study.

Methods:

The study includes 78 consecutive patients diagnosed with neurofibromatosis type 1 between June 2010 and June 2014 and 50 healthy controls. Baseline demographic data were generated from patient examination record forms, including age, sex, height, and weight, as well as levels of free triiodothyronine, free thyroxine, thyroid-stimulating hormone, anti-thyroid peroxidase and anti-thyroglobulin levels.

Results:

Mean age, sex, and body mass index were similar in both groups (p>0.05). The mean levels of free triiodothyronine, free thyroxine, and thyroid-stimulating hormone were not statistically different between the neurofibromatosis type 1 and control groups. Similarly, no statistically significant difference was observed between the neurofibromatosis type 1 and control groups for anti-thyroid peroxidase and anti-thyroglobulin positivity (2.5% vs 0%, p>0.05).

Conclusion:

Screening for autoimmune thyroid disease and thyroid function seems to be unnecessary in patients with neurofibromatosis type 1.

Thyroid function in children and adolescents with Hashimoto's thyroiditis after l-thyroxine discontinuation

OBJECTIVE

Thyroid function may recover in patients with Hashimoto's thyroiditis (HT).

DESIGN

To investigate thyroid function and the need to resume l-thyroxine treatment after its discontinuation.

SETTING

Nine Italian pediatric endocrinology centers.

PATIENTS

148 children and adolescents (25 m and 123 f) with HT on treatment with l-thyroxine for at least one year.

INTERVENTION AND MAIN OUTCOME MEASURE

Treatment was discontinued in all patients, and serum TSH and fT4 concentrations were measured at the time of treatment discontinuation and then after 2, 6, 12 and 24 months. Therapy with l-thyroxine was re-instituted when TSH rose >10 U/L and/or fT4 was below the normal range. The patients were followed up when TSH concentrations were between 5 and 10 U/L and fT4 was in the normal range.

RESULTS

At baseline, TSH was in the normal range in 139 patients, and was between 5 and 10 U/L in 9 patients. Treatment was re-instituted after 2 months in 37 (25.5%) patients, after 6 months in 13 patients (6.99%), after 12 months in 12 patients (8.6%), and after 24 months in an additional 3 patients (3.1%). At 24 months, 34 patients (34.3%) still required no treatment. TSH concentration >10 U/L at the time of diagnosis was the only predictive factor for the deterioration of thyroid function after l-thyroxine discontinuation.

CONCLUSIONS

This study confirms that not all children with HT need life-long therapy with l-thyroxine, and the discontinuation of treatment in patients with a TSH level <10 U/L at the time of diagnosis should be considered.

Analysis of the factors affecting the evolution over time of subclinical hypothyroidism in children

Aim of this commentary is to report the most recent views about natural history of subclinical hypothyroidism (SH) according to the different etiologies. In children with idiopathic SH the natural evolution is often favourable, with a high percentage of cases reverting to euthyroidism or remaining SH even after a prolonged follow-up. By contrast, the risk of a significant deterioration of thyroid status is distinctly higher in the SH children with Hashimoto’s thyroiditis (HT). This risk is even higher in the cases with both HT-related SH and chromosomal abnormalities, such as Turner or Down’s syndrome.

Pediatric TSH Reference Intervals and Prevalence of High Thyroid Antibodies in the Lebanese Population

The aims of this study are to establish reference values for TSH in Lebanese schoolchildren; to look at the relationship between TSH and age, gender, BMI, socioeconomic status (SES), and thyroid antibodies (TAb); and to investigate the prevalence of abnormal TAb in this population. 974 Lebanese schoolchildren aged 8-18 years were recruited from 10 schools of different SES. Third-generation TSH, TPO-Ab, and Tg-Ab measurements were performed using the IMMULITE chemiluminescent immunoassay. The mean TSH is 2.06 ± 1.05 μUI/ml. TSH values are inversely correlated with age (p < 0.0001), are higher in boys than in girls (resp., 2.14 ± 1.10 and 1.98 ± 0.99 μUI/ml, p = 0.017), and are positively correlated with BMI (p < 0.0001). They are also significantly higher in subjects from low-SES schools (p = 0.03) and in girls with positive TAb (p = 0.026). In boys, TSH is independently associated with age, BMI, and schools' SES (p = 0.01, p = 0.03, and p = 0.026, resp.) while in girls, the association is only significant for age and TAb (p = 0.0001 and p = 0.015, resp.). The prevalence of TAb is 4.3% (3% for TPO-Ab and 2.1% for Tg-Ab). Our results showed higher TSH values in the pediatric Lebanese population compared to western populations. TSH varies according to age, gender, BMI, and SES and is associated in girls with TAb.

Unfavorable Course of Subclinical Hypothyroidism in Children with Hashimoto's Thyroiditis Compared to Those with Isolated Non-Autoimmune Hyperthyrotropinemia

Subclinical hypothyroidism (SCH) is a common problem in pediatric population, and the natural history of SCH varies depending on its etiology. Whether Hashimoto's thyroiditis (HT) negatively affects the natural course of SCH was investigated in pediatric patients without concomitant diseases. Predictors for levothyroxine medication were also evaluated. Medical records of 109 children with SCH (91 girls, 5?18 years) diagnosed between 2005 and 2014 were retrospectively reviewed. Patients were classified into HT (n = 37) and isolated non-autoimmune hyperthyrotropinemia (iso-NAHT, n = 72). During median 2 years of follow-up, only 10.1% of SCH patients eventually initiated levothyroxine, and HT patients showed a higher probability of requiring levothyroxine medication than iso-NAHT patients (21.6% vs. 4.2%). Underlying HT independently predicted deterioration of thyroid function, leading to levothyroxine medication (hazard ratios [HRs], 4.6 vs. iso-NAHT, P = 0.025). High titers of anti-thyroglobulin antibodies (TGAbs) predicted later medication in the HT group (HRs, 28.2 vs. normal TGAbs, P = 0.013). Most pediatric SCH showed benign and self-remitting courses. Underlying HT significantly increases the risk for levothyroxine medication, especially with high titers of TGAbs.

Subclinical hypothyroidism in childhood - current knowledge and open issues

Subclinical hypothyroidism is defined as serum levels of TSH above the upper limit of the reference range, in the presence of normal concentrations of total T₄ or free T₄. This biochemical profile might be an indication of mild hypothyroidism, with a potential increased risk of metabolic abnormalities and cardiovascular disease recorded among adults. Whether subclinical hypothyroidism results in adverse health outcomes among children is a matter of debate and so management of this condition remains challenging. Mild forms of untreated subclinical hypothyroidism do not seem to be associated with impairments in growth, bone health or neurocognitive outcome. However, ongoing scientific investigations have highlighted the presence of subtle proatherogenic abnormalities among children with modest elevations in their TSH levels. Although current findings are insufficient to recommend levothyroxine treatment for all children with mild asymptomatic forms of subclinical hypothyroidism, they highlight the potential need for assessment of cardiovascular risk among children with this condition. Increased understanding of the early metabolic risk factors associated with subclinical hypothyroidism in childhood will help to improve the management of affected individuals.

Genotype-phenotype correlations of dyshormonogenetic goiter in children and adolescents from South India

BACKGROUND

Dyshormonogenetic goiter is one of the most common causes of hypothyroidism in children and adolescents in iodine nonendemic areas. The exact genotype-phenotypic correlations (GPCs) and risk categorization of hypothyroid phenotypes of dyshormonogenetic mutations are largely speculative. The genetic studies in pediatric dyshormonogenesis are very sparse from Indian sub-continent. In this context, we analyzed the implications of TPO, NIS, and DUOX2 gene mutations in hypothyroid children with dyshormonogenetic hypothyroidism (DH) from South India.

MATERIALS AND METHODS

This is interdisciplinary prospective study, we employed eight sets of primers and screened for 142 known single nucleotide polymorphisms in TPO, NIS, and DUOX2 genes. The subjects were children and adolescents with hypothyroidism due to dyshormonogenetic goiter. Congenital hypothyroidism, iodine deficiency, and Hashimoto's thyroiditis cases were excluded.

RESULTS

We detected nine mutations in 8/22 (36%) children. All the mutations were observed in the intronic regions of NIS gene and none in TPO or DUOX2 genes. Except for bi-allelic, synonymous polymorphism of TPO gene in child number 14, all other mutations were heterozygous in nature. GPCs show that our mutations significantly expressed the phenotypic traits such as overt hypothyroidism, goiter, and existence of family history. Other phenotypic characters such as sex predilection, the age of onset and transitory nature of hypothyroidism were not significantly affected by these mutations.

CONCLUSION

NIS gene mutations alone appears to be most prevalent mutations in DH among South Indian children and these mutations significantly influenced phenotypic expressions such as severity of hypothyroidism, goiter rates, and familial clustering.

Five-Year Prospective Evaluation of Thyroid Function Test Evolution in Children with Hashimoto's Thyroiditis Presenting with Either Euthyroidism or Subclinical Hypothyroidism

BACKGROUND

Whether the course of thyroid function in Hashimoto's thyroiditis (HT) differs in children who present with either euthyroidism or subclinical hypothyroidism (SH) has been incompletely investigated.

AIM

Using a five-year prospective evaluation of 234 children with HT and no prognostic risk factors, this study investigated whether the evolution of the thyroid status is influenced by the biochemical pattern at initial diagnosis.

RESULTS

In the entire series, thyrotropin values significantly increased during follow-up, while free thyroxine values decreased and the proportion of children with a thyroid dysfunction increased from 27.3% to 47.4% (p = 0.0001). An increasing proportion of cases with severe thyroid dysfunction was identified, especially among the 64 patients presenting with SH (group B), but also among the 170 children presenting with euthyroidism (group A) at initial diagnosis. At the end of follow-up, the prevalence of children with overt hypothyroidism was 12.3% in group A compared with 31.2% in group B (p = 0.0007). In the overall population, however, the majority of patients (52.6%) exhibited biochemical euthyroidism at the end of follow-up.

CONCLUSIONS

Children with HT may develop a deterioration of thyroid status during the first five years of disease. Such a trend may be observed, even in the patients who initially present with a mild biochemical picture (either SH or euthyroidism). A total of 57.1% of initially euthyroid children remain euthyroid, and 40.6% of patients with initial SH normalize thyroid function within five years after HT diagnosis. The patients presenting with SH are more prone to the risk of developing severe thyroid dysfunction over time.

Serum TSH levels are associated with cardiovascular risk factors in overweight and obese adolescents

OBJECTIVE

To investigate the relationship between serum thyrotropin (TSH), insulin resistance (IR), and cardiovascular risk factors (CRF) in a sample of overweight and obese Brazilian adolescents.

METHODS

A retrospective, longitudinal analysis of 199 overweight and obese pubescent adolescents was performed. The TSH and free T4 (fT4) levels, anthropometric measurements, and laboratory test results of these patients were analyzed.

RESULTS

27 individuals (13.56%) presented with TSH levels above the normal level (subclinical hypothyroidism [SCH]). Their waist circumference (WC) was significantly higher than those of euthyroid individuals. Serum TSH was positively correlated with the homeostasis model assessment of insulin resistance (HOMA-IR) index, triglycerides (TG) and high-density lipoprotein cholesterol (HDL-C). Using TSH and BMI as independent variables, TSH levels were shown to be independently related to HOMA-IR (p=0.001) and TG (p=0.007). Among euthyroid subjects, individuals with TSH values <2.5mIU/mL exhibited statistically significant decreases in waist-to-hip ratio, HDL-C levels, and HOMA-IR scores and a tendency toward lower WC values.

CONCLUSION

SCH in overweight and obese adolescents appears to be associated with excess weight, especially visceral weight. In euthyroid adolescents, there appears to be a direct relationship between TSH and some CRF. In conclusion, in the present sample of overweight and obese adolescents, TSH levels appear to be associated with IR and CRF.

Subclinical Hypothyroidism in Childhood Cancer Survivors

PURPOSE

In childhood cancer survivors, the most common late effect is thyroid dysfunction, most notably subclinical hypothyroidism (SCH). Our study evaluated the risk factors for persistent SCH in survivors.

MATERIALS AND METHODS

Survivors (n=423) were defined as patients who survived at least 2 years after cancer treatment completion. Thyroid function was assessed at this time and several years thereafter. Two groups of survivors with SCH were compared: those who regained normal thyroid function during the follow-up period (normalized group) and those who did not (persistent group).

RESULTS

Overall, 104 of the 423 survivors had SCH. SCH was observed in 26% of brain or nasopharyngeal cancer survivors (11 of 43) and 21.6% of leukemia survivors (35 of 162). Sixty-two survivors regained normal thyroid function, 30 remained as persistent SCH, and 12 were lost to follow-up. The follow-up duration was 4.03 (2.15-5.78) years. Brain or nasopharyngeal cancer and Hodgkin disease were more common in the persistent group than in the normalized group (p=0.002). More patients in the persistent group received radiation (p=0.008). Radiation to the head region was higher in this group (2394±2469 cGy) than in the normalized group (894±1591 cGy; p=0.003). On multivariable analysis, lymphoma (p=0.011), brain or nasopharyngeal cancer (p=0.039), and head radiation dose ≥1800 cGy (p=0.039) were significant risk factors for persistent SCH.

CONCLUSION

SCH was common in childhood cancer survivors. Brain or nasopharyngeal cancer, lymphoma, and head radiation ≥1800 cGy were significant risk factors for persistent SCH.

Effects of L-thyroxine treatment on early markers of atherosclerotic disease in children with subclinical hypothyroidism

OBJECTIVE

To investigate the effect of levothyroxine (L-T4) treatment on early markers of atherosclerotic disease in children with mild idiopathic subclinical hypothyroidism (SH).

DESIGN

Two-year, open, case-control prospective study.

METHODS

A total of 39 children, aged 9.18±3.56 years, with SH and 39 healthy controls were enrolled in the study. Waist-to-height ratio (WHtR), blood pressure, triglycerides, total cholesterol (total-C), HDL-C, LDL-C, non-HDL-C, triglycerides/HDL-C, atherogenic index (AI), homocysteine (Hcy), asymmetric dimethylarginine (ADMA), flow-mediated dilation (FMD) and intima-media thickness (IMT) were evaluated at baseline and after 2 years of L-T4 treatment in SH children and after 2 years of follow-up in controls.

RESULTS

At study entry WHtR was higher in SH subjects compared with controls (0.56±0.08 vs 0.49±0.07, P=0.04) and significantly decreased after 2 years of treatment (0.50±0.06, P<0.0001). Mean HDL-C levels (50.47±11.43 vs 61.06±13.83mg/dL, P=0.002) were lower, while triglycerides/HDL-C (1.63±1.07 vs 1.19±0.69, P=0.05), AI (3.32±0.90 vs 2.78±0.68, P=0.005), and Hcy (9.35±2.61 vs 7.71±1.94μmol/L, P=0.01) were higher in SH subjects compared with controls and improved after 2 years of treatment (HDL-C 56.26±13.76mg/dL, P<0.0001; triglycerides/HDL-C 1.23±0.78, P=0.006; AI 2.82±0.68, P<0.0001; and Hcy 8.25±2.09μmol/L, P=0.06). ADMA concentrations at baseline were higher in SH subjects compared with controls (0.77±0.21 vs 0.60±0.16μmol/L, P=0.001) and decreased after therapy (0.58±0.13μmol/L, P<0.0001). FMD, IMT and other metabolic parameters were not different among SH subjects and controls at baseline and after 2 years.

CONCLUSIONS

Children with SH may have subtle pro-atherogenic abnormalities. Although L-T4 treatment exerts some beneficial effects, the long-term impact of therapy on metabolic outcomes in SH children still remains unclear.

Thyroxine therapy ameliorates serum levels of eicosanoids in Chinese subclinical hypothyroidism patients

AIM

The eicosanoids derived from phospholipids play key roles in inflammation. However, the profiles of serum eicosanoids in subclinical hypothyroidism (SH) patients and the effects of thyroxine replacement therapy (TRT) on these eicosanoids remain unclear. Many studies show that TSH regulates lipid metabolism. As eicosanoids derived from phospholipids play key roles in oxidative stress and immune function and inflammatory process, it was necessary to explore the profiles of serum eicosanoids in SH patients and the effects of thyroxine replacement therapy (TRT) on the eicosanoids.

METHODS

A total of 50 Chinese SH patients and 22 healthy volunteers were recruited. SH patients received TRT (L-T4, 25 and 50 mcg/d for patients with TSH≤10.0 mIU/L and TSH>10.0 mIU/L, respectively) for 3 months. Serum levels of major eicosanoids and cPLA2 were analyzed using LC-MS and clinical biochemical assays.

RESULTS

The serum levels of cPLA2, eicosanoids (8-isoPGF2a, 11-dehydroTXB2 and 12-HETE) and 11-dehydroTXB2/6-Keto-PGF1a were significantly elevated in SH patients. The serum TSH levels were significantly correlated with the levels of cPLA2 (r=+0.65), 11-dehydroTXB2 (r=+0.32) and 11-dehydroTXB2/6-Keto-PGF1a (r=+0.37). After 3-month TRT, the serum levels of TSH, cPLA2 and the above-mentioned eicosanoids in SH patients were significantly decreased.

CONCLUSION

The metabolism of eicosanoids is significantly altered in Chinese SH patients, and TRT can ameliorate the abnormalities of serum eicosanoid levels.

Levothyroxine treatment of mild subclinical hypothyroidism: a review of potential risks and benefits

Subclinical hypothyroidism (SCH) is defined as elevated thyroid stimulating hormone (TSH) with normal levels of free triiodothyronine (FT3) and free thyroxine (FT4). SCH is further classified into a milder condition with TSH levels between 4.0 and 10.0 milli-international units (mIU)/l (mild-SCH) and a severe form with TSH >10.0 mIU/l (severe-SCH). SCH is a common problem (prevalence is greater in women than men), which increases further with increasing age and TSH levels. Even though the risk of progression to overt hypothyroidism is higher in patients with severe-SCH, the risk is also significant in patients having mild-SCH; it has been suggested that every twofold rise in serum TSH would increase the risk from 1 to 4%, which further increases to 38% if thyroid antibodies are positive. Current data have shown increased cardiovascular risk in patients with mild-SCH and have demonstrated some benefits of levothyroxine treatment in reducing these events. However, evidence on the association of mild-SCH and musculoskeletal system, cognitive dysfunction, mood disorders, dyslipidaemia, diabetes and goitre is conflicting. Similarly, the discussion regarding the exact upper limit of normal for serum TSH remains controversial. The data have also shown increased risk of adverse pregnancy outcomes in patient with mild-SCH, with some benefits of thyroxine treatment. The recent available guidelines related to management of patients with serum TSH <10 mIU/l have suggested decisions should be made taking into account the age of the patient, associated risk factors and comorbid conditions. This chronicle review assesses current evidence regarding the risks associated and the recommendations related to benefits of levothyroxine treatment in patients having mild-SCH.

Evaluation of Subclinical Hypothyroidism in Children and Adolescents: A Single-Center Study

The main purpose of our retrospective study was to evaluate the medical care of the patients with subclinical hypothyroidism (sHT) and to investigate the rationale for administering L-thyroxine (LT-4) to young sHT patients. Patients and Methods. Based on a retrospective review of the charts of 261 patients referred to the Endocrinology Outpatient Clinic between 2009 and 2014 with suspicion of sHT, 55 patients were enrolled for further analysis. Data collected was baseline age, anthropometric measurements, serum TSH, fT4, fT3, anti-thyroid autoantibodies, positive family history, absence/presence of clinical symptoms, length of follow-up, and data concerning LT-4 therapy (therapy: T1; no therapy: T0). Results. T1 encompassed 33 (60.0%) patients. There were no differences between T1 and T0 (p > 0.05) with regard to age, TSH concentrations, BMI Z-score, and hSDS values, though follow-up was longer in T1 (p < 0.01). Four (11.8%) children in T1 and none in T0 had a positive family history of thyroid disorders. Fifteen (68.2%) patients in group T0 became euthyroid. One (1.8%) girl (T1) developed overt hypothyroidism. Conclusions. A small percentage of patients can proceed to overt hypothyroidism. Only positive family history seemed to influence the decision to initiate LT-4 therapy. Further prospective studies are warranted in order to establish treatment indications, if any, and the mean recommended dosage of LT-4.

Five-year prospective evaluation of thyroid function in girls with subclinical mild hypothyroidism of different etiology

AIM

To follow-up for 5 years thyroid status evolution in 127 girls with mild (TSH 5-10 mU/l) subclinical hypothyroidism (SH) of different etiologies.

PATIENTS

The population was divided into two age-matched groups of 42 and 85 girls with either idiopathic (group A) or Hashimoto's thyroiditis (HT)-related SH (group B). Group B was in turn divided into three subgroups, according to whether SH was either isolated or associated with Turner syndrome (TS) or Down syndrome (DS).

RESULTS

At the end of follow-up the rate of girls who became euthyroid was higher in group A (61.9% vs 10.6%), whereas the rates of patients who remained SH (55.3% vs 26.2%), became overtly hypothyroid (30.6% vs 11.9%) or required levothyroxine (l-T4) therapy (63.5% vs 23.8%) were higher in group B. Among the girls of group B, the risk of remaining SH or developing overt hypothyroidism was higher in the subgroups with TS or DS than in those with isolated HT.

CONCLUSIONS

Long-term prognosis of mild and idiopathic SH is frequently benign, even though a l-T4 treatment may be needed throughout follow-up in almost a quarter of cases; long-term prognosis is different in the girls with either idiopathic or HT-related SH; and the association with either TS or DS impairs the outcome of HT-related SH.

The association with Turner syndrome significantly affects the course of Hashimoto's thyroiditis in children, irrespective of karyotype

Only few studies have investigated to now whether the association with Turner syndrome (TS) may affect the course of Hashimoto's thyroiditis (HT) in children. Aim of this study was to ascertain whether the presentation and long-term course of HT in TS children may be characterized by a peculiar and atypical pattern. The clinical and biochemical findings at HT diagnosis in 90 TS children (group A) were compared with those recorded in 449 girls with HT but without TS (group B); in group A patients, thyroid function tests were re-evaluated after a median time interval of 4.9 years. At HT diagnosis median TSH levels and the rate of cases presenting with a thyroid dysfunction picture were significantly lower in group A, irrespective of karyotype abnormalities. In group A only 34.8 % of the girls who had initially presented with euthyroidism remained euthyroid even at re-evaluation, whilst 67.7 % of those who had presented with subclinical hypothyroidism became overtly hypothyroid over time; also such evolutive pattern was irrespective of karyotype abnormalities. (1) In TS girls, HT presents with a milder hormonal pattern, which often deteriorates over time; (2) these biochemical features are not necessarily linked with a specific karyotype.

Peculiarities of autoimmune thyroid diseases in children with Turner or Down syndrome: an overview

Aim of this commentary is to summarize the salient literature news on the relationships between autoimmune thyroid diseases (ATDs) and either Down syndrome (DS) or Turner syndrome (TS).According to literature reports both Hashimoto's thyroiditis (HT) and Graves' disease (GD) are more frequent in children with DS or TS than in those without these chromosomopathies.An up-regulation of proinflammatory cytokines might be responsible for the enhanced susceptibility of TS children to ATDs, whereas a dysregulation of immune system may favor the development of ATDs in DS.In TS children biochemical presentation of HT is less severe than in peer controls. In both DS and TS GD picture at the time of diagnosis is not significantly different than in the pediatric general population.The evolution over time of GD in DS and TS does not differ from that observed in the pediatric general population, whereas the evolution of HT in both TS and DS is more severe than in girls without these chromosomopathies.

CONCLUSIONS

The association with TS or DS is able to affect both epidemiology and course of ATDs by conditioning: a) an increased susceptibility to these disorders; b) a less severe biochemical presentation and a more severe evolutive pattern of HT in TS girls; c) a more severe biochemical presentation and evolution of HT in DS patients.

Ten-year longitudinal study of thyroid function in children with Down's syndrome

BACKGROUND/AIMS

The natural history of thyroid function in children with Down's syndrome is relatively unknown. We hypothesized that in these patients the occurrence of thyroid dysfunction rises during development.

METHODS

Thyroid function was assessed yearly in 145 children with Down's syndrome, all followed from birth up to 10 years of age. Heteroskedastic binary and ordinary logistic regression for repeated measures was used to evaluate the relationship of thyroid function with continuous time.

RESULTS

Congenital hypothyroidism was detected in 7% of cases. The probability of acquired thyroid dysfunction increased from 30% at birth to 49% at 10 years (p < 0.001). The subclinical hypothyroidism was nearly stable during the follow-up. The probability of hypothyroidism increased from 7 to 24% at 10 years (p < 0.001). Positive anti-thyroglobulin antibodies were associated with higher odds of more severe hypothyroidism (odds ratio 3.6). Positive anti-thyroid peroxidase antibodies were a better predictor of more severe hypothyroidism (odds ratio 6.1). Diffuse hypoechogenicity on thyroid ultrasound was found in 34 out of 145 children.

CONCLUSION

The probability of thyroid dysfunction increasing during development is higher than previously reported. Such children should be carefully monitored annually to early identify thyroid dysfunction.

Thyroid-related neurological disorders and complications in children

BACKGROUND

Thyroid hormones exert critical roles throughout the body and play an important and permissive role in neuroendocrine, neurological, and neuromuscular function.

METHODS

We performed a PubMed search through June 2014 with search terms including "hypothyroidism," "hyperthyroidism," "neurological complications," "neuropathy," "myopathy," "congenital hypothyroidism," and "encephalopathy." Relevant publications reviewed included case series, individual case reports, systematic reviews, retrospective analyses, and randomized controlled trials. The neurological outcomes of congenital hypothyroidism were reviewed, along with the clinical features of associated neuromuscular syndromes of both hypothyroidism and hyperthyroidism, including other autoimmune conditions. Evidence for, and pathophysiological controversies surrounding, Hashimoto encephalopathy was also reviewed.

RESULTS

The establishment of widespread newborn screening programs has been highly successful in attenuating or preventing early and irreversible neurological harm resulting from congenital thyroid hormone deficiency, but some children continue to display neuromuscular, sensory, and cognitive defects in later life. Acquired disorders of thyroid function such as Hashimoto thyroiditis and Graves' disease are associated with a spectrum of central nervous system and/or neuromuscular dysfunction. However, considerable variation in clinical phenotype is described, and much of our knowledge of the role of thyroid disease in childhood neurological disorders is derived from adult case series.

CONCLUSIONS

Early and aggressive normalization of thyroxine levels in newborn infants with congenital hypothyroidism is important in minimizing neurological sequelae, but maternal thyroid hormone sources are also critically important to the early developing brain. A spectrum of neurological disorders has been reported in older children with acquired thyroid disease, but the frequency with which these occur remains poorly defined in the literature, and much must be extrapolated from adult data. A high index of suspicion for acquired thyroid disease is paramount in the investigation of many neurological disorders of youth, as many reported sequelae of hypothyroidism and hyperthyroidism are reversible with appropriate endocrine management.

Underlying Hashimoto's thyroiditis negatively affects the evolution of subclinical hypothyroidism in children irrespective of other concomitant risk factors

BACKGROUND

The pediatric literature does not contain any studies comparing the evolution of Hashimoto's thyroiditis (HT)-related subclinical hypothyroidism (SH) with idiopathic SH longitudinally.

AIM AND DESIGN

In the present study, the two-year evolution of HT-related SH in 32 children with no concomitant risk factors (group A) was compared to that observed in 90 age-matched children with idiopathic SH (group B). The aim was to ascertain whether the association with HT could, per se, affect the evolution of thyroid status over time in SH children irrespective of other coexisting factors, such as thyromegaly, association with other autoimmune diseases, and/or concomitant therapies.

RESULTS

During the two-year follow-up, the percentage of children whose thyrotropin (TSH) values increased >10 mIU/L was significantly higher in group A (p<0.0005), whereas the percentages of those who either maintained a stable TSH (5-10 mIU/L) or normalized the TSH (<5 mIU/L) were significantly higher in group B (p<0.025). Moreover, the percentage of children who developed a pathological thyroid enlargement during follow-up was significantly higher in group A (p<0.0005).

CONCLUSIONS

The association with HT exerts a negative influence on the evolution over time of mild SH, irrespective of other concomitant risk factors. In children with mild and HT-related SH, the risk of a deterioration in thyroid status over time is high (53.1%), while the probability of spontaneous TSH normalization is relatively low (21.9%). In contrast, in children with mild and idiopathic SH, the risk of a deterioration in thyroid status over time is very low (11.1%), whereas the probability of spontaneous TSH normalization is high (41.1%).

Subclinical hypothyroidism in children and adolescents: is it clinically relevant?

Although subclinical hypothyroidism (SH) is a common clinical problem, its diagnosis tends to be incidental. According to the definition, it should be asymptomatic, only detectable by screening. The presence or coincidence of any symptoms leads to L-thyroxine treatment. The clinical presentation, especially in younger patients with subclinical hypothyroidism, is still under dispute. Accordingly, the aim of this paper was to review the literature from the past seven years. The literature search identified 1,594 potentially relevant articles, of which 24 met the inclusion criteria. Few studies focus on the symptomatology of subclinical hypothyroidism, and most of them analyzed a small number of subjects. A significant correlation was found by some authors between subclinical hypothyroidism and a higher risk of hypertension, dyslipidemia, and migraine. No evidence of the impact of subclinical hypothyroidism on weight, growth velocity, and puberty was revealed. As the quality of most studies is poor and no definite conclusions can be drawn, randomized, large-scale studies in children and adolescents are warranted to determine the best care for patients with SH.

Psychiatric Symptoms due to Thyroid Disease in a Female Adolescent

The hypothalamic-pituitary-thyroid axis is involved in the production of thyroid hormone which is needed to maintain the normal functioning of various organs and systems, including the central nervous system. This study reports a case of hypothyroidism in a fifteen-year-old female adolescent who was attended for psychiatric symptoms. This case reveals the importance of evaluating thyroid function in children and adolescents with neuropsychiatric symptoms.

Guidelines for the treatment of hypothyroidism: prepared by the american thyroid association task force on thyroid hormone replacement

BACKGROUND

A number of recent advances in our understanding of thyroid physiology may shed light on why some patients feel unwell while taking levothyroxine monotherapy. The purpose of this task force was to review the goals of levothyroxine therapy, the optimal prescription of conventional levothyroxine therapy, the sources of dissatisfaction with levothyroxine therapy, the evidence on treatment alternatives, and the relevant knowledge gaps. We wished to determine whether there are sufficient new data generated by well-designed studies to provide reason to pursue such therapies and change the current standard of care. This document is intended to inform clinical decision-making on thyroid hormone replacement therapy; it is not a replacement for individualized clinical judgment.

METHODS

Task force members identified 24 questions relevant to the treatment of hypothyroidism. The clinical literature relating to each question was then reviewed. Clinical reviews were supplemented, when relevant, with related mechanistic and bench research literature reviews, performed by our team of translational scientists. Ethics reviews were provided, when relevant, by a bioethicist. The responses to questions were formatted, when possible, in the form of a formal clinical recommendation statement. When responses were not suitable for a formal clinical recommendation, a summary response statement without a formal clinical recommendation was developed. For clinical recommendations, the supporting evidence was appraised, and the strength of each clinical recommendation was assessed, using the American College of Physicians system. The final document was organized so that each topic is introduced with a question, followed by a formal clinical recommendation. Stakeholder input was received at a national meeting, with some subsequent refinement of the clinical questions addressed in the document. Consensus was achieved for all recommendations by the task force.

RESULTS

We reviewed the following therapeutic categories: (i) levothyroxine therapy, (ii) non-levothyroxine-based thyroid hormone therapies, and (iii) use of thyroid hormone analogs. The second category included thyroid extracts, synthetic combination therapy, triiodothyronine therapy, and compounded thyroid hormones.

CONCLUSIONS

We concluded that levothyroxine should remain the standard of care for treating hypothyroidism. We found no consistently strong evidence for the superiority of alternative preparations (e.g., levothyroxine-liothyronine combination therapy, or thyroid extract therapy, or others) over monotherapy with levothyroxine, in improving health outcomes. Some examples of future research needs include the development of superior biomarkers of euthyroidism to supplement thyrotropin measurements, mechanistic research on serum triiodothyronine levels (including effects of age and disease status, relationship with tissue concentrations, as well as potential therapeutic targeting), and long-term outcome clinical trials testing combination therapy or thyroid extracts (including subgroup effects). Additional research is also needed to develop thyroid hormone analogs with a favorable benefit to risk profile.