A significant number of cases with permanent CH are missed when a TSH threshold of 20 mU/liter is applied. Almost 40% of the missed CH cases were premature. A mild increase of TSH at screening is not a predictor of transient CH. The increase in recall rate constitutes a serious drawback and should be balanced against the possible consequences of thyroid dysfunction at this important developmental stage.

The neonatal screening program for congenital hypothyroidism (CH) in Greece shows an overall incidence of the disease of 1:2321. The cases with permanent CH have an incidence of 1:2542, whereas the transient forms of CH account for 8.7% of all cases diagnosed as CH. Transplacental passage of maternal thyrotropin receptor-blocking antibodies is a rare cause of transient CH. In our program, a retrospective analysis of 508,358 screened newborns revealed 6 infants with transient CH caused by maternal thyroid autoimmunity, representing 2.7% of all cases of CH. All the newborns with transient CH, due to maternal autoimmune thyroid disease, had high serum TSH concentration (ranging from 98 to 689 mU/L), whereas serum thyroxine (T4) values were low normal to normal in 3 of them. Replacement therapy with L-thyroxine was initiated at a mean age of 6.5 days. The newborns with transient CH belonged to 4 families, one of which had 4 and another 2 children with the same pathology. Thyrotropin-receptor antibodies (TSH-R Abs), present at the initial examination in newborns serum, had disappeared from the infants circulation by the third month of life. One mother carried the Abs for at least 8 years during which period she delivered four babies. The diagnosis of transient CH should be suspected if the mother has autoimmune thyroid disease, if there are siblings with transient CH or if there is no need for an increase in L-thyroxine dose with advancing age. The diagnosis is very important for genetic counseling, early treatment initiation of subsequent offspring and adequate control of the mothers thyroid function during subsequent pregnancies so that any neurodevelopmental abnormality of the fetus could be avoided.

An earlier adiposity rebound, suggestive of adult obesity, has been reported in children with congenital hypothyroidism. We undertook this study to evaluate the effect of congenital hypothyroidism on: 1) the timing of adiposity rebound, 2) the long-term prognosis of BMI status, and 3) the factors potentially affecting adiposity in subjects with congenital hypothyroidism. We found that in children with congenital hypothyroidism the BMI values were higher during the first years of life compared to normal population, but subsequently normalized. After the initial rise of BMI, the decline (nadir) and subsequent rise (adiposity rebound), usually occurring in normal children at an age greater than 30 months, was less evident in our group of children with congenital hypothyroidism. The severity of hypothyroidism affected BMI values at 6 and 12, but not at 36 months of age. In conclusion, in children with congenital hypothyroidism, 1) the high BMI values in early childhood normalize in adolescence, and 2) the normally expected BMI fluctuations during the first years of life are attenuated. These findings constitute indirect evidence that thyroid function during fetal and neonatal life affects BMI status during the first years of life.

The aim of the work was to assess thyroid function in children and adolescents in an iodine replete area and to explore possible effects of age, gender, puberty, and adiposity. Thyrotropin (TSH), total triiodothyronine (T (3)), total thyroxine (T (4)), free thyroxine (FT (4)), and the T (4)/T (3) ratio were determined for 440 schoolchildren (200 boys and 240 girls), aged 5-18 years, living in an iodine replete region. Body Mass Index (BMI), BMI standard deviation score (BMI-SDS), and Body Surface Area (BSA) were calculated. In girls there was a negative correlation of TSH, T (3), and FT (4) values with age. In boys there was a negative correlation only of T (3) values with age. Girls had lower TSH, T (4), and T (3) values, whereas boys had only lower T (3) values at puberty compared to the prepubertal stage. Girls had lower TSH values than boys (p<0.03) only at puberty. BMI-SDS in boys and girls were 0.21 and 0.03, respectively. BMI-SDS was not related to TSH, T (4), or T (3) in either gender, whereas it was negatively related to T (4)/T (3) ratio in boys and to FT (4) in girls. We conclude that estrogens may exert a suppressive effect on the pituitary-thyroid axis after puberty. TSH values are not correlated with BMI-SDS, whereas T (4)/T (3) ratio in boys and FT (4) in girls are negatively correlated with BMI-SDS.

Transient hyperprolactinaemia has been reported to follow unprovoked seizures, a finding proposed to be useful in the differential diagnosis of epilepsy. There is also evidence that patients with unprovoked seizures may have high baseline prolactin levels, which could be of value in detecting those predisposed to epilepsy after a first convulsive attack. The purpose of this study was to examine whether prolactin levels are elevated: (1) postictally in febrile seizures and (2) interictally in afebrile seizures. In 17 children with simple febrile seizures, mean postictal prolactin value (370 +/- 160 mU/l, mean +/- SD) was significantly higher (approximately 0.001) than the mean baseline value of 18 seizure-free controls (202 +/- 136 mU/l). The mean baseline prolactin values were not significantly different: (1) in ten children with afebrile versus ten seizure-free controls and (2) in 18 children with febrile seizures associated with high risk for subsequent afebrile seizures versus 23 children with febrile seizures but unlikely to suffer from afebrile seizures. CONCLUSION. Postictal prolactin levels may be a useful marker of recent febrile seizures, while baseline prolactin levels do not appear to have any prognostic significance in afebrile seizures.