Ultrasound and Functional Thyroid Evaluation

Study Overview
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Brief Summary
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Thyroid disorders are most commonly concomitant with prematurity and still remains a controversial topic. The incidence of a temporary form of hypothyroidism among preterm neonates is higher than in the general population. Transient prematurity hypothyroxinemia is defined as a temporary reduction in FT4 values without increase in TSH values. Currently, there is no consensus about normal thyrotropine (TSH) and free thyroxine (FT4) values in preterm infants. The aim of this study is to determine the volume of the thyroid gland in preterm infants born between 24 and 32 weeks of gestation inborn or admitted to the unit within 14 days from birth and compare it with the results of TSH and FT4 blood concentration. Besides, the objective of the study is to determine values of thyroid hormones in premature infants born before 33 wk gestation to help neonatologist to interpreter the thyroid hormone results

Detailed Description
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Thyroid disorders are most commonly concomitant with prematurity and still remains a controversial topic. Preterm infants are susceptible to thyroid disorders due to many reasons including immaturity of hypothalamopituitary-thyroid axis, non-thyroidal illness, impaired synthesis and metabolism of thyroid hormones, medication administration like dopamine, steroids, caffeine.The incidence of a temporary form of hypothyroidism among preterm neonates is higher than in the general population. Transient prematurity hypothyroxinemia is defined as a temporary reduction in FT4 values without increase in TSH values. It is a diagnostic challenge in order to differentiate it from thyroid disfunction in the critically ill patient. Currently, there is no consensus about normal thyrotropine (TSH) and free thyroxine (FT4) values in preterm infants. Given the delayed appearance of TSH value increase in preterm newborns additional thyroid evaluation methods are sought. We believe the thyroid ultrasound might prove helpful. The aim of this study is to determine the volume of the thyroid gland in preterm infants born between 24 and 32 weeks of gestation inborn or admitted to the unit within 14 days from birth and compare it with the results of TSH and FT4 blood concentration. We will performed the thyroid ultrasound to estimate the thyroid volume to aid in the comparative evaluation of infants with suspected thyroid disease. The value of sonography thyroid volume will give specialists possibility to identify a gland as normal, small or enlarged. Besides, the objective of the study is to determine value of thyroid hormones in premature infants born before 33 wk gestation to help neonatologist to interpreter the thyroid hormone results

Official Title
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Ultrasound and Functional Thyroid Evaluation in Preterm Infants Born Between 24 and 32 Weeks of Gestation

Conditions
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Thyroid, Gland; Functional Disturbance

Intervention / Treatment
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* Diagnostic Test: thyroid ultrasound


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: preterm infants born between 24 and 32 weeks of gestation (estimated by ultrasound) in born or admitted to the unit within one week from birth randomization within 7 days from birth parental consent Exclusion Criteria: preterm delivery <23 weeks of gestation or > 32 weeks (estimated by ultrasound) major congenital abnormalities no parental consent medications used after birth: steroids, vasopressors (up to 12 hours after end of treatment) positive thyroid stimulating antibodies (TSAb) in the mother mothers with thyroid disease treated with antythyroid drugs mothers treated with amiodarone

Ages Eligible for Study
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Minimum Age: 1 Week
Maximum Age: 12 Weeks

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Diagnostic Test: thyroid ultrasound|After meeting enrolment criteria the thyroid ultrasound will be performed at 32 and 36 weeks of gestation, blood test for TSH and FT4 will be obtained at 14-21 day of life, at 32 and 36 weeks of gestation|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Determination of FT4 and TSH values in preterm infants born at 24-28 weeks of gestation | FT4 and TSH - blood concentration | 14-21 days of life, at 32 and 36 weeks of PCA | 
| Determination of FT4 and TSH values in preterm infants born at 29-32 weeks of gestation | FT4 and TSH - blood concentration | at 14-21 day of life, at 32 and 36 weeks of PCA | 
| Determination of ultrasound thyroid volume in both groups of preterm infants (i.e., those born at 24-28 weeks of gestation and those born at 29-32 weeks of gestation) | The thyroid volume | at 32 and 36 weeks of PCA | 
| Evaluation of correlations between circulating thyroid hormone concentrations and thyroid volume | comparison of values of FT4, TSH and thyroid volume | at 32 and 36 weeks of PCA | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Comparison of changes in FT4 evaluated at 32 and 36 weeks of PCA in each group of preterm infants | comparison of results | at 14-21 day of life, at 32 and 36 weeks of PCA | 
| Comparison of changes in TSH evaluated at 32 and 36 weeks of PCA in each group of preterm infants | comparison of results | 14-21 days of life, at 32 and 36 weeks of PCA | 
| Analysis of TSH values over time (to determine the optimal time for TSH measurement) | Intervention time | at 14-21 day of life, at 32 and 36 weeks of PCA | 
| Evaluation of changes in ultrasound thyroid volume examined at 32 and 36 weeks of PCA in each group of preterm infants | comparison of results | at 32 and 36 weeks of PCA | 
| Evaluation of the correlation between thyroid volume and circulating thyroid hormone concentrations with the head circumference and body mass at 32 and 36 weeks of PCA | correlation of results with the body mass and the head circumference | at 32 and 36 weeks of PCA | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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thyroid volume, ultrasound, preterm infants, thyroid hormone