Related Experiment Videos
[Thyroid function in healthy premature infants and in premature infants with the hyaline membrane syndrome ]
Insights
Premature infants with respiratory distress syndrome exhibit a "low T3 syndrome" and increased conversion of thyroxine (T4) to reverse triiodothyronine (rT3). Thyroid hormone levels did not correlate with lung maturity but were linked to ventilation duration.
Area of Science:
- Neonatalogy
- Endocrinology
- Pediatric Respiratory Medicine
Background:
- Thyroid hormone levels are critical for neonatal development and adaptation.
- Premature infants, especially those with respiratory distress syndrome (RDS), often exhibit altered thyroid hormone profiles.
Purpose of the Study:
- To investigate serum concentrations of thyroid-stimulating hormone (TSH), thyroxine (T4), triiodothyronine (T3), and reverse triiodothyronine (rT3) in premature infants.
- To explore the relationship between thyroid hormones, respiratory distress syndrome, and artificial ventilation in neonates.
Main Methods:
- Longitudinal follow-up of thyroid hormone levels in healthy premature infants and those with RDS requiring mechanical ventilation during the first 4 weeks of life.
- Analysis of TSH, T4, T3, and rT3 serum concentrations, correlating them with clinical parameters like respiratory compliance and ventilation duration.
Main Results:
- TSH and T4 levels remained stable in both groups. T3 levels were significantly lower in sick premature infants on days 1 and 3.
- The rT3/T3 ratio was elevated in both groups, higher in sick infants, and decreased during the first week.
- A
- low T3 syndrome
- was observed in all premature infants postnatally. RDS increased T4 to rT3 conversion.
Conclusions:
- Premature infants with RDS demonstrate a distinct
- low T3 syndrome
- and altered peripheral thyroid hormone metabolism.
- Thyroid hormone levels, particularly T3 and rT3, are influenced by respiratory distress and ventilation duration, but not directly by lung maturity.
- Current findings do not support thyroid hormone substitution therapy for premature infants with RDS.
Abstract:
The serum concentrations of thyrotropin (TSH), thyroxine (T4), trijodothyronine (T3) and of 3,3',5', trijodothyronine (reverse T3, rT3) were followed up during the first 4 weeks of life in 5 healthy premature infants and in 6 premature infants with hyaline membrane syndrome and artificial ventilation. TSH and T4 concentrations remained unchanged in both groups. T3 levels increased during the observation period and were significantly lower in the sick prematures on days 1 and 3 (p less than 0,02). T3 and the rT3/T3 ratio was increased in healthy and in the sick prematures, the sick prematures showing higher values, and decreased in both groups during the first week of life. We found no significant correlation between TSH and the peripheral thyroid hormone levels as well as no relation between the respiratory compliance-indicating degree of lung maturity-and the T3 or T4 concentrations. Postpartal T3 or T4 serum levels were correlated significantly with the duration of artificial ventilation. Our data indicate that a "low T3 syndrome" was present in all prematures after birth and that respiratory distress syndrome increased conversion of T4 to rT3. From our results we cannot conclude that substitution therapy with thyroid hormones may be useful in premature infants with the hyaline membrane syndrome.