Biochemical indicators of euthyroid sick syndrome in critically ill children

Thyroiditis and COVID-19: focus on pediatric age. A narrative review

PURPOSE

In light of the growing concern over the possible link between SARS-CoV2 infection and autoimmune diseases, we conducted a review to investigate the impact of the pandemic outbreak on thyroid diseases.

METHODS

We carried out a narrative review of all pediatric cases described in the literature, mainly focusing on the possible association of COVID-19 with the incidence of autoimmune and post-infective thyroid diseases (namely Hashimoto's Thyroiditis (HT), Grave's Disease (GD) and Sub-Acute Thyroiditis (SAT)). We also felt it was necessary to provide a brief review of Non-thyroidal Illness Syndrome (NTIS) and Multisystem Inflammatory Syndrome in Children (MIS-C) because of their overlap with thyroiditis.

RESULTS

There is currently no conclusive evidence linking SARS-CoV-2 infection with an increased incidence of autoimmune thyroiditis (AT) in pediatric age. However, SAT may be a mild complication of SARS-CoV-2 infection, as is the case with other viral infections. SAT typically resolves on its own and does not require treatment. NTIS may be associated with inflammatory complications, such as MIS-C, and admission to intensive care. It may also be considered a prognostic risk factor for severe disease. The hypothesized pathogenetic mechanisms of thyroid damage in COVID-19 include direct damage due to the significant expression of angiotensin-converting enzyme 2 (ACE2) in the thyroid gland, which is a ligand for the virus, and indirect damage due to immune dysregulation, such as the overproduction of IL-6, which is thought to be part of the pathogenesis of thyroiditis.

CONCLUSION

However, due to the limited evidence available, further prospective longitudinal studies are required to clarify the relationship between COVID-19 and thyroid disease in children and adolescents, as well as to investigate any potential long-term consequences.

Association between dynamic fluctuations in triiodothyronine levels and prognosis among critically ill patients within comprehensive intensive care units

Objective

Decrease in free thyroid hormone T3 (FT3) can be used as an independent prognostic indicator for the risk of death in ICUs. However, FT3 as a predictive marker is hindered by its accuracy. The study introduces the concept of dynamic FT3 data as a means to bolster the value of FT3 as a prognostic tool. Therefore, the aim of this study is to investigate the prognostic value of dynamic FT3 evolution in a comprehensive ICU setting, analyze the consistency between dynamic FT3 changes and variations in disease severity, and explore the feasibility of FT3 as an objective indicator for real-time clinical treatment feedback.

Methods

Employing a single-center prospective observational study, FT3 measurements were taken on multiple days following enrollment, corresponding clinical data were collected. To investigated the pattern of dynamic changes of FT3,its prognostic significance in forecasting the risk of 28-day mortality, the alignment between dynamic FT3 changes and variations in the Sequential Organ Failure Assessment (SOFA) score.

Results

The survival group exhibited higher last FT3 levels compared to the lowest point (p<0.05), while the death group did not show statistically significant differences (p>0.05). The study also identifies the optimal correlation between FT3 and SOFA score at day 5 (optimal correlation coefficient -0.546).The ROC curve for FT3 at day 5 yielded an optimal AUC of 0.88, outperforming the SOFA score. The study categorizes FT3 curve patterns,Kaplan-Meier survival analysis of these patterns highlighted that the descending-type curve was significantly associated with increased risk of death (P<0.001). Additionally, the research explores the consistency between changes in FT3 and SOFA scores. While overall consistency rates were modest, subgroup analyses unveiled that greater disease severity led to higher consistency rates.

Conclusions

This study introduces the concept of dynamic FT3 changes to augment its prognostic utility in comprehensive ICU settings. The research identifies day 5 as the optimal time point for predictive efficacy, the descending FT3 curve as indicative of poor prognosis. While overall consistency with SOFA scores is modest, the correlation strengthens with greater disease severity.

Thyroid dysfunction in children and adolescents affected by undernourished and overnourished eating disorders

Eating disorders (ED) are one of the most prevalent chronic disorders in adolescents and young adults, with a significantly increasing prevalence in younger children, particularly in girls. Even if obesity in essence is not framed as an eating disorder and has always been considered a separate pathology, ED and obesity could be considered part of a continuum. It has become evident that one condition can lead to another, such as binge eating disorder (BED) and bulimia nervosa, and that they share the same repercussions in terms of psychosocial, metabolic, and nutritional health. This narrative review aims to investigate the hypothalamic-pituitary-thyroid axis in undernourished and overnourished patients with ED, including obesity, in order to highlight the relationship between weight control and thyroid function and its effects and to consider therapeutic and preventive strategies in children and adolescents. Literature data report that thyroid alterations occur in patients with ED, both underweight and overweight, and represent a continuum of changes depending on the severity and time course of the disease involving the endocrine system. Considering the relevant role thyroid hormones (TH) play not only in energy expenditure (EE) but also in metabolic control and cardiovascular risks related to dysmetabolism and mood regulation, continuous monitoring of thyroid homeostasis in patients with ED is mandatory to prevent severe complications and to start early treatment when necessary.

Non-thyroidal illness syndrome and its relationship with mortality risk in critically ill children

Introduction

Non-thyroidal illness syndrome (NTIS) is considered to be associated with adverse outcomes in critically ill children.The hypothesis that thyroid hormones and inflammatory markers are associated with increased prediction of mortality risk scores is tested in this paper.

Methods

A prospective observational study was set up in a pediatric intensive care unit (PICU). One hundred and three patients were included. NTIS was defined as a low free triiodothyronine (FT3) value for the patient's age. Thyroid hormones levels and inflammatory markers were determined at admission: FT3, FT4 (free thyroxine), TSH (thyroid-stimulating hormone), rT3 (reverse triiodothyronine), CRP (C-reactive protein) and PCT (Procalcitonin). They were compared between children with a pediatric risk of mortality score PRISM-III >75th percentile (group A, n= 25) and the rest (group B, n = 78).

Results

A FT4 value lower than 16.6 pmol/L showed an area under the curve (AUC) of 0.655 (0.56-0.78, p = 0.02), with 76% sensitivity and 61.5% specificity to detect a high risk of mortality. A multiple regression analysis revealed that a FT4 lower than 16.6 pmol/L [OR: 4.92 (1.60-18.19), p = 0.009] and having NTIS [OR: 6.04 (1.45-27.93), p = 0.016] could predict a high risk of mortality.

Conclusions

In unselected critically ill children, FT4 and FT3 values at admission could be used as a good predictor of a high mortality risk. We have not achieved a predictive model that combines hormones with inflammatory markers.