Thyroid function in the critically ill newborn and child

Indications for Intravenous T3 and T4

Therapy with thyroid hormones normally is restricted to substitution therapy of patients with primary or secondary hypothyroidism. Typically, thyroid hormones are given orally. There are few indications for intravenous use of thyroid hormones. Indications for parenteral application are insufficient resorption of oral medications due to alterations of the gastrointestinal tract, partial or total loss of consciousness, sedation in the intensive care unit or shock. In almost all cases, levothyroxine is the therapy of choice including congenital hypothyroidism. In preterm infants with an altered thyroid hormone status, studies with thyroid hormones including intravenous liothyronine showed a normalisation of T3 levels and in some cases an amelioration of parameters of ventilation. A benefit for mortality or later morbidity could not be seen. Effects on neurological improvements later in life are under discussion. Decreased thyroid hormone levels are often found after cardiac surgery in infants and adults. Intravenous therapy with thyroid hormones improves the cardiac index, but in all other parameters investigated, no substantial effect on morbidity and mortality could be demonstrated. Oral liothyronine therapy in these situations was equivalent to an intravenous route of application. In myxoedema coma, intravenous levothyroxine is given for 3 to 10 days until the patient can take oral medication and normal resorption in the gastrointestinal tract is achieved by restoring at least peripheral euthyroidism. Intravenous levothyroxine is the standard in treating patients with myxoedema coma. A protective effect on the heart of i.v. levothyroxine in brain-dead organ donors may be possible.

Evaluation of non-thyroidal illness syndrome in shock patients admitted to pediatric intensive care unit in a developing country

During critical illness, children my experience various changes in their thyroid hormone levels. Such changes are termed non-thyroidal illness syndrome (NTI). The extent of change correlates with the severity of the illness and its outcomes in critically ill patients. This study aimed to investigate the correlation between the severity of shock and thyroid hormone derangement. This prospective observational study included forty patients aged one month to five years who were admitted to the pediatric intensive care unit (PICU) with shock. Thyroid function tests were conducted on admission, after shock reversal, and five days later. NTI patterns were observed in 70% of patients. The PIM2 score showed a significant negative correlation with T3 (r =  - 0.353, p = 0.026) and FT3 levels on admission (r =  - 0.417, p = 0.007). Furthermore, after shock reversal, the PIM2 score continued to exhibit significant negative correlations with T4 (r =  - 0.444, p = 0.004), T3 (r =  - 0.329, p = 0.038), FT3 (r =  - 0.355, p = 0.025), and FT4 levels (r =  - 0.379, p = 0.016).    Conclusion: This study underscores the high prevalence of NTI in PICU shock patients and suggests monitoring thyroid hormone levels for outcome prediction and treatment guidance. Further research is needed to optimize NTI management in critically ill children. What is Known: • Non-thyroidal illness syndrome (NTIS) is a condition observed in critically ill patients. • There has been limited research on NTI in children, and existing studies have generated conflicting results regarding the relationship between thyroid hormones and clinical outcomes in cases of sepsis and septic shock. What is New: • The study has revealed dynamic changes in free triiodothyronine (FT3) levels during the process of shock reversal and recovery in children who experienced shock. • A significant negative correlation was found between the Pediatric Index of Mortality 2 (PIM2) score and several thyroid hormone levels, including FT3 on admission and T4, FT3, and FT4 on shock reversal.

Endocrine Dysfunction Criteria in Critically Ill Children: The PODIUM Consensus Conference

CONTEXT

Endocrine dysfunction is common in critically ill children and is manifested by abnormalities in glucose, thyroid hormone, and cortisol metabolism.

OBJECTIVE

To develop consensus criteria for endocrine dysfunction in critically ill children by assessing the association of various biomarkers with clinical and functional outcomes.

DATA SOURCES

PubMed and Embase were searched from January 1992 to January 2020.

STUDY SELECTION

We included studies in which researchers evaluated critically ill children with abnormalities in glucose homeostasis, thyroid function and adrenal function, performance characteristics of assessment and/or scoring tools to screen for endocrine dysfunction, and outcomes related to mortality, organ-specific status, and patient-centered outcomes. Studies of adults, premature infants or animals, reviews and/or commentaries, case series with sample size ≤10, and non-English-language studies were excluded.

DATA EXTRACTION

Data extraction and risk-of-bias assessment for each eligible study were performed by 2 independent reviewers.

RESULTS

The systematic review supports the following criteria for abnormal glucose homeostasis (blood glucose [BG] concentrations >150 mg/dL [>8.3 mmol/L] and BG concentrations <50 mg/dL [<2.8 mmol/L]), abnormal thyroid function (serum total thyroxine [T4] <4.2 μg/dL [<54 nmol/L]), and abnormal adrenal function (peak serum cortisol concentration <18 μg/dL [500 nmol/L]) and/or an increment in serum cortisol concentration of <9 μg/dL (250 nmol/L) after adrenocorticotropic hormone stimulation.

LIMITATIONS

These included variable sampling for BG measurements, limited reporting of free T4 levels, and inconsistent interpretation of adrenal axis testing.

CONCLUSIONS

We present consensus criteria for endocrine dysfunction in critically ill children that include specific measures of BG, T4, and adrenal axis testing.

Surviving sepsis campaign international guidelines for the management of septic shock and sepsis-associated organ dysfunction in children

OBJECTIVES

To develop evidence-based recommendations for clinicians caring for children (including infants, school-aged children, and adolescents) with septic shock and other sepsis-associated organ dysfunction.

DESIGN

A panel of 49 international experts, representing 12 international organizations, as well as three methodologists and three public members was convened. Panel members assembled at key international meetings (for those panel members attending the conference), and a stand-alone meeting was held for all panel members in November 2018. A formal conflict-of-interest policy was developed at the onset of the process and enforced throughout. Teleconferences and electronic-based discussion among the chairs, co-chairs, methodologists, and group heads, as well as within subgroups, served as an integral part of the guideline development process.

METHODS

The panel consisted of six subgroups: recognition and management of infection, hemodynamics and resuscitation, ventilation, endocrine and metabolic therapies, adjunctive therapies, and research priorities. We conducted a systematic review for each Population, Intervention, Control, and Outcomes question to identify the best available evidence, statistically summarized the evidence, and then assessed the quality of evidence using the Grading of Recommendations Assessment, Development, and Evaluation approach. We used the evidence-to-decision framework to formulate recommendations as strong or weak, or as a best practice statement. In addition, "in our practice" statements were included when evidence was inconclusive to issue a recommendation, but the panel felt that some guidance based on practice patterns may be appropriate.

RESULTS

The panel provided 77 statements on the management and resuscitation of children with septic shock and other sepsis-associated organ dysfunction. Overall, six were strong recommendations, 49 were weak recommendations, and nine were best-practice statements. For 13 questions, no recommendations could be made; but, for 10 of these, "in our practice" statements were provided. In addition, 52 research priorities were identified.

CONCLUSIONS

A large cohort of international experts was able to achieve consensus regarding many recommendations for the best care of children with sepsis, acknowledging that most aspects of care had relatively low quality of evidence resulting in the frequent issuance of weak recommendations. Despite this challenge, these recommendations regarding the management of children with septic shock and other sepsis-associated organ dysfunction provide a foundation for consistent care to improve outcomes and inform future research.

Surviving Sepsis Campaign International Guidelines for the Management of Septic Shock and Sepsis-Associated Organ Dysfunction in Children

OBJECTIVES

To develop evidence-based recommendations for clinicians caring for children (including infants, school-aged children, and adolescents) with septic shock and other sepsis-associated organ dysfunction.

DESIGN

A panel of 49 international experts, representing 12 international organizations, as well as three methodologists and three public members was convened. Panel members assembled at key international meetings (for those panel members attending the conference), and a stand-alone meeting was held for all panel members in November 2018. A formal conflict-of-interest policy was developed at the onset of the process and enforced throughout. Teleconferences and electronic-based discussion among the chairs, co-chairs, methodologists, and group heads, as well as within subgroups, served as an integral part of the guideline development process.

METHODS

The panel consisted of six subgroups: recognition and management of infection, hemodynamics and resuscitation, ventilation, endocrine and metabolic therapies, adjunctive therapies, and research priorities. We conducted a systematic review for each Population, Intervention, Control, and Outcomes question to identify the best available evidence, statistically summarized the evidence, and then assessed the quality of evidence using the Grading of Recommendations Assessment, Development, and Evaluation approach. We used the evidence-to-decision framework to formulate recommendations as strong or weak, or as a best practice statement. In addition, "in our practice" statements were included when evidence was inconclusive to issue a recommendation, but the panel felt that some guidance based on practice patterns may be appropriate.

RESULTS

The panel provided 77 statements on the management and resuscitation of children with septic shock and other sepsis-associated organ dysfunction. Overall, six were strong recommendations, 52 were weak recommendations, and nine were best-practice statements. For 13 questions, no recommendations could be made; but, for 10 of these, "in our practice" statements were provided. In addition, 49 research priorities were identified.

CONCLUSIONS

A large cohort of international experts was able to achieve consensus regarding many recommendations for the best care of children with sepsis, acknowledging that most aspects of care had relatively low quality of evidence resulting in the frequent issuance of weak recommendations. Despite this challenge, these recommendations regarding the management of children with septic shock and other sepsis-associated organ dysfunction provide a foundation for consistent care to improve outcomes and inform future research.

Non-Thyroidal Illness Syndrome in Critically Ill Children: Prognostic Value and Impact of Nutritional Management

INTRODUCTION

Non-thyroidal illness (NTI), which occurs with fasting and in response to illness, is characterized by thyroid hormone inactivation with low triiodothyronine (T3) and high reverse T3 (rT3), followed by suppressed thyrotropin (TSH). Withholding supplemental parenteral nutrition early in pediatric critical illness (late-PN), thus accepting low/no macronutrient intake up to day 8 in the pediatric intensive care unit (PICU), accelerated recovery compared to initiating supplemental parenteral nutrition early (early-PN). Whether NTI is harmful or beneficial in pediatric critical illness and how it is affected by a macronutrient deficit remains unclear. This study investigated the prognostic value of NTI, the impact of late-PN on NTI, and whether such impact explains or counteracts the outcome benefit of late-PN in critically ill children.

METHODS

This preplanned secondary analysis of the Early versus Late Parenteral Nutrition in the Pediatric Intensive Care Unit randomized controlled trial quantified serum TSH, total thyroxine (T4), T3, and rT3 concentrations in 982 patients upon PICU admission versus 64 matched healthy children and in 772 propensity score-matched early-PN and late-PN patients upon admission and at day 3 or last PICU day for shorter PICU stay. Associations between thyroid hormone concentrations upon admission and outcome, as well as impact of late-PN on NTI in relation with outcome, were assessed with univariable analyses and multivariable logistic regression, linear regression, or Cox proportional hazard analysis, adjusted for baseline risk factors.

RESULTS

Upon PICU admission, critically ill children revealed lower TSH, T4, T3, and T3/rT3 and higher rT3 than healthy children (p < 0.0001). A more pronounced NTI upon admission, with low T4, T3, and T3/rT3 and high rT3 was associated with higher mortality and morbidity. Late-PN further reduced T4, T3, and T3/rT3 and increased rT3 (p ≤ 0.001). Statistically, the further lowering of T4 by late-PN reduced the outcome benefit (p < 0.0001), whereas the further lowering of T3/rT3 explained part of the outcome benefit of late-PN (p ≤ 0.004). This effect was greater for infants than for older children.

CONCLUSION

In critically ill children, the peripheral inactivation of thyroid hormone, characterized by a decrease in T3/rT3, which is further accentuated by low/no macronutrient intake, appears beneficial. In contrast, the central component of NTI attributable to suppressed TSH, evidenced by the decrease in T4, seems to be a harmful response to critical illness. Whether treating the central component with TSH releasing hormone infusion in the PICU is beneficial requires further investigation.

The complex aetiology of cerebral palsy

Cerebral palsy (CP) is the most prevalent, severe and costly motor disability of childhood. Consequently, CP is a public health priority for prevention, but its aetiology has proved complex. In this Review, we summarize the evidence for a decline in the birth prevalence of CP in some high-income nations, describe the epidemiological evidence for risk factors, such as preterm delivery and fetal growth restriction, genetics, pregnancy infection and other exposures, and discuss the success achieved so far in prevention through the use of magnesium sulfate in preterm labour and therapeutic hypothermia for birth-asphyxiated infants. We also consider the complexities of disentangling prenatal and perinatal influences, and of establishing subtypes of the disorder, with a view to accelerating the translation of evidence into the development of strategies for the prevention of CP.

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.

Are preterm newborns who have relative hyperthyrotropinemia at increased risk of brain damage?

BACKGROUND

We sought to disentangle the contributions of hyperthyrotropinemia (an indicator of thyroid dysfunction) (HTT) and intermittent or sustained systemic inflammation (ISSI) to structural and functional indicators of brain damage.

METHODS

We measured the concentrations of thyroid-stimulating hormone (TSH) on day 14 and of 25 inflammation-related proteins in blood collected during the first 2 postnatal weeks from 786 infants born before the 28th week of gestation who were not considered to have hypothyroidism. We defined hyperthyrotropinemia (HTT) as a TSH concentration in the highest quartile for gestational age on postnatal day 14 and ISSI was defined as a concentration in the top quartile for gestational age of a specific inflammation-related protein on 2 separate days a week apart during the first 2 postnatal weeks. We first assessed the risk of brain damage indicators by comparing 1) neonates who had HTT to those without (regardless of ISSI) and 2) neonates with HTT only, ISSI only, or HTT+ISSI to those who were exposed to neither HTT nor ISSI.

RESULTS

In univariable models that compared those with HTT to those without, HTT was not significantly associated with any indicator of brain damage. In models that compared HTT only, ISSI only, and HTT+ISSI to those with neither, children with ISSI only or with HTT+ISSI were at significantly higher risk of ventriculomegaly [odds ratios (ORs) 2-6], whereas those with HTT only were at significantly reduced risk of a hypoechoic lesion (ORs 0.2-0.4). Children with HTT only had a higher risk of quadriparesis and those with ISSI alone had a higher risk of hemiparesis (ORs 1.6-2.4). Elevated risk of a very low mental development score was associated with both ISSI only and HTT+ISSI, whereas a very low motor development score and microcephaly were associated with HTT+ISSI.

CONCLUSIONS

The association of HTT with increased or decreased risk of indicators of brain damage depends on the presence or absence of ISSI.

Endocrine physiology in the newborn

Evaluation of suspected endocrine pathology in newborn infants requires knowledge of the dynamic changes that characterize normal hormonal function in the neonatal period. This article reviews normal endocrine physiology as it pertains to common clinical scenarios encountered in neonatal surgical patients. Topics covered include thyroid and adrenal function as well as glucose and calcium metabolism.

The role of interleukin-6 and C-reactive protein in non-thyroidal illness in premature infants followed in neonatal intensive care unit

OBJECTIVE

To investigate the role of interleukin-6 (IL-6) and C-reactive protein (CRP) in non-thyroidal illness (NTI) in premature infants.

METHODS

Serum levels of IL-6 and CRP, thyroid-stimulating hormone (TSH), total thyroxine (T4), free T4 (fT4), total triiodothyronine (T3), and free T3 (fT3) were determined at the 1st, 2nd and 4th weeks of postnatal life in 148 premature infants born before 33 weeks of gestation.

RESULTS

At the 1st week, serum T3 was negatively correlated with IL-6 (r= -0.33, p= 0.001) and CRP (r= -0.17, p= 0.03). Serum T3 was negatively and more strongly correlated with IL-6 (r= -0.49, p= 0.001) and CRP (r=- 0.33, p= 0.03) at the 2nd week, at which time sepsis frequency and low T3 rates were the highest. At the 4th week, mortality rate was higher among infants with lower T3 levels.

CONCLUSIONS

High IL-6 and CRP values related to neonatal sepsis might have a significant role in the pathogenesis of NTI in premature infants.

Newborn Thyroid Screening

The availability of rapid and robust thyroid stimulating hormone (TSH) and free thyroxine (fT4) assays are important tools for newborn thyroid screening.