Timing, prevalence, and dynamics of thyroid disorders in children and adolescents affected with Down syndrome

Autoimmune Thyroid Disease in Patients with Down Syndrome-Review

Down syndrome develops due to the presence of supernumerary chromosome 21. This diagnosis is made in approximately 1:800 live births. The tendency to develop autoimmune disorders like idiopathic arthritis, celiac disease, diabetes mellitus type 1, vitiligo and autoimmune thyroid disease is strongly expressed in patients with Down syndrome. Autoimmune thyroid diseases consisting of Hashimoto's thyroiditis and Graves' disease are specifically prevalent in patients with Down syndrome. The aim of our study is to collect available data connecting the pathogenesis and clinical course of autoimmune thyroid diseases in patients with Down syndrome of different ages and compare them to control groups. According to published data, the incidence ratio of Hashimoto's thyroiditis diagnosis in patients with Down syndrome is elevated compared to in age-matched controls without this chromosomal aberration, similarly to Graves' disease risk, which is also increased in a group of patients with Down syndrome. What is more, both Hashimoto's thyroiditis and Graves' disease are diagnosed at an earlier age than in the healthy population and are not correlated with gender or a family history of autoimmune diseases.

Cardiac Pre-tamponade Secondary to Generalized Myxedema Due to Neglected Hashimoto's Thyroiditis in a Child With Down Syndrome

Down syndrome (DS) is the most common chromosomal disorder in live-born infants, often associated with intellectual disability and various medical conditions, including thyroid dysfunction. Hashimoto's thyroiditis (HT), an autoimmune subtype, is a leading cause of acquired hypothyroidism in DS children. Severe hypothyroidism can precipitate myxedema, a critical condition linked to complications like pericardial effusion and cardiac tamponade. This case study presents a nine-year-old male with DS who was admitted for acute respiratory distress exhibiting classic signs of myxedema. Initial investigations revealed severe hypothyroidism and significant pericardial effusion. Surgical pericardiotomy drained 800 mL of fluid, confirming myxedema secondary to HT. Levothyroxine therapy led to progressive improvement, resolving myxedematous infiltrate and associated symptoms within a month. Follow-up at 12 months demonstrated sustained improvement with normalized thyroid function and no clinical disease activity. This case highlights an atypical presentation of HT in a DS child with cardiac pre-tamponade.

Hypothyroidism in Patients with Down Syndrome: Prevalence and Association with Congenital Heart Defects

This population-based study aimed to assess the prevalence of congenital hypothyroidism (CH) and overt hypothyroidism (OH) and their association with congenital heart defects (CHDs) in patients with Down syndrome (DS). The population included all live births residing in Tuscany (Italy) diagnosed with DS recorded in the Registry of Congenital Defects and in the Registry of Rare Diseases of Tuscany in the years 2003-2017. The prevalence of CH and OH in DS patients was calculated by sex and by period. The association of CH and OH with CHDs in DS patients was assessed using multivariate logistic regression. The cohort included 228 subjects. The prevalence of CH and OH was 11.4% (95%CI: 7.4-16.7%) and 12.7% (95%CI: 8.5-12.3%), respectively, with no significant difference by sex. A significant increase in the prevalence of CH (p < 0.0001) was found in the years 2010-2017 compared to the previous period, and among preterm infants (p = 0.009). The presence of CH was associated with a higher prevalence of CHDs (adjusted OR = 2.24, p = 0.082). A significant association between ventricular septal defects (VSDs) and the occurrence of OH (adjusted OR = 3.07, p = 0.025) was also observed. This study confirmed the higher prevalence of both CH and OH in DS compared to the general population. Furthermore, the risk of association between DS and CHDs was higher in the presence of CH, while VSDs are associated with OH, providing relevant insights into the epidemiology of hypothyroidism in DS and associated anomalies.

Thyroid function, sensitivity to thyroid hormones, and metabolic syndrome in euthyroid children and adolescents with Down syndrome

PURPOSE

Patients with Down Syndrome (DS) showed multiple comorbidities, including thyroid disorders, obesity, and metabolic derangement. Different thyroid hormone (THs) patterns and sensitivity to thyroid hormone indices (STHI) seem to be associated with metabolic disorders. The study's aim was to evaluate the prevalence of metabolic syndrome (MS) in pediatric patients affected by DS, taking into consideration the relationship between the metabolic parameters, THs and STHI.

METHODS

We enlisted 50 euthyroid patients with DS (9.03 ± 4.46). Clinical parameters, TSH, FT3, FT4 and the presence of MS were recorded. Indexes of peripheral sensitivity (FT3/FT4 ratio) and central sensitivity (TSH index, TSHI; TSH T4 resistance index, TT4RI; TSH T3 resistance index, TT3RI) were also detected. Thirty healthy subjects were included as a control group.

RESULTS

MS was detected in 12% of the subjects with DS. FT3, FT4, and TSH levels were higher in DS than in the control group (p < 0.01); higher levels of FT3/FT4 ratio, TSHI and TT3RI and lower TT4RI values (p < 0.01) were also detected. A significant correlation was detected between FT3 and fasting blood glucose (FBG) (R = 0.46), triglyceride (TG) (r = 0.37), total (r = 0.55) and high density lipoprotein-cholesterol (HDL-C) (r = - 0.38), diastolic blood pressure (DBP) (r = - 0.4); FT3/FT4 ratio and waist circumference (WC) (r = 0.36); TSHI and total (r = 0.30) and HDL cholesterol (r = - 0.31); TT4RI and HDL cholesterol (r = - 0.31); TT3RI and total (r = 0.39) and HDL cholesterol (r = - 032).

CONCLUSION

We confirmed a higher MS prevalence in children with DS compared to the control group. A significant association between THs, STHI, and the glucose and lipid metabolism parameters was detected supporting their role in metabolic alterations related to the DS.

Treatment of hypothyroidism in infants, children and adolescents

In 2014, treatment guidelines from the American Thyroid Association reflected the general consensus that levothyroxine (LT4), adjusted to maintain a normal thyrotropin (TSH) level, is the preferred method for treatment of hypothyroidism. Although this is generally applicable to children, there are subsets of children for whom the diagnosis and treatment of hypothyroidism are problematic. These include children with congenital hypothyroidism (CH), low birth weight (LBW) and very low birth weight (VLBW), Down syndrome (DS), subclinical hypothyroidism, and obesity. In this Review, we focus on the progress and remaining pitfalls in diagnosis and treatment of hypothyroidism in these and other groups.