[Transitory neonatal hypothyroidism caused by transplacental transfer of anti-receptor antibodies of hypophyseal thyroid simulation. Case report and estimated incidence]. / Hypothyroïdie néonatale transitoire par transfert transplacentaire d'anticorps antirécepteurs de la thyréostimuline hypophysaire. Casuistique et estimation de l'incidence.

Transient neonatal hypothyroidism induced by transplacental transfer of thyrotropin receptor-blocking antibodies is rare, but should be diagnosed early because its course, treatment, and prognosis are different from the other forms of congenital hypothyroidism. Transient neonatal hypothyroidism should be suspected in infants with a history of maternal autoimmune thyroid disease. We describe two siblings whose mother has been treated for idiopathic primary nongoitrous hypothyroidism since adolescence. High levels of thyrotropin receptor-blocking antibodies were first detected in maternal serum at the time of the first child's birth. At the time of the second child's birth antithyroid peroxidase antibodies were found in addition to the thyrotropin receptor-blocking antibodies. Both children were clinically healthy newborns without evidence of congenital malformations. Thyroid suppression, reflected by high levels of TSH during neonatal screening, was transient in both infants. Hormonal substitution was only necessary in one child for a period of 4 months. When tested at the age of 6-7 months, maternal antibodies had completely disappeared from the infants' sera. At ages 7 and 4 years respectively the 2 children do not require treatment and show normal growth and neurodevelopmental skills. In the north-eastern part of Switzerland congenital hypothyroidism has an incidence of one in 3300 live-born infants, the most frequent form being permanent congenital hypothyroidism (1:4500). In this population, analyzed over a period of 16 years, the two cases reported represent the only observations of transient neonatal hypothyroidism due to thyrotropin receptor-blocking antibodies; the incidence can thus be estimated to be approximately 1:310,000 live newborns. In this rare condition, early recognition is pertinent in order to avoid unnecessary treatment and parental anxiety.

Postnatal thyroxine administration for idiopathic respiratory distress syndrome in preterm infants.

Thirty-six preterm infants of less than 34 weeks of gestation with idiopathic respiratory distress syndrome (IRDS) were studied. Eighteen of them were treated with intravenous thyroxine (T4) and compared with 18 control prematures to evaluate the effect of postnatal T4 administration on the course of IRDS. After treatment, serum T4 levels were similar to those of healthy term infants. No statistically significant effect on mortality rate, duration of mechanical ventilation (p greater than 0.3), need of high oxygen environment (p greater than 0.05) and development of bronchopulmonary dysplasia (p greater than 0.2) was observed between the two groups. These observations show that postnatal use of T4 does not carry any benefit for preterm infants with IRDS.

Incidence of retinopathy of prematurity in low birth weight infants with peri-intraventricular hemorrhage.

Data from 80 high-risk low birth infants were analysed to determine whether there is a clinical association between Retinopathy of Prematurity (ROP) and Peri-Intraventricular Hemorrhages (PIVH) in preterm newborns. Diagnosis of retinopathy was made by retinal examination at approximately four weeks of age. All infants were routinely and repeatedly scanned by real-time ultrasound to diagnose the presence of Peri-Intraventricular Hemorrhages. PIVH was clearly present in 41 (51.2%) of them, whereas 39 (48.7%) infants had no evidence of intracerebral bleeding. We found no statistically significant association between cicatricial retinopathy and PIVH (P = 0.1). We suppose therefore, that the sensitivity of retinal vasculature and cerebral vasculature to the various factors considered to be important in the development of PIVH is different.

[Transcutaneous bilirubin determination: correlation in white premature infants weighing less than 1500 gm]. / Mesure transcutanée de la bilirubine: corrélation chez le prématuré de race blanche de moins de 1500 g.

The transcutaneous bilirubinometer (TcB) was evaluated in 24 preterm infants of less than 34 weeks gestation and weight less than 1500 g. A close correlation between the TcB index and serum bilirubin values was obtained with 50 measurements at sternum (R = 0.858, p less than 0.001). From these resultant ratios it is concluded that the TcB-meter is a valuable tool in screening healthy preterm infants less than 34 weeks gestation for hyperbilirubinemia.