Screening for congenital hypothyroidism: the value of retesting after four weeks in neonates with low and very low birth weight.

OBJECTIVES: Thyroid-stimulating hormone (TSH), normally a reliable screening test for congenital hypothyroidism (CH), may fail to detect cases among infants who have low and very low birth weight. The purpose of this study was to identify neonates with false-negative screening results. SETTING: A province in Poland in which 3,854 neonates had body weight or= 10 mIU/L in 19 of the 3,854 low birth weight neonates. The final diagnosis in these neonates was permanent CH in two, transient CH in five, possible compensated CH in six and transient high TSH in six. Of the 19, 16 (84%) required iodine and/or thyroxine replacement therapy. CONCLUSIONS: In neonates with low and very low birth weight, normal TSH levels measured between the third and sixth day of life do not exclude thyroid dysfunction, but a repeat TSH measurement after the fourth week of life identifies the false-negative results. In our data, the prevalence of primary and secondary hypothyroidism (both permanent and transient) was about 0.5%.

[Incidence of Graves disease in children in some regions of south-eastern Poland]. / Zapadalnosc dzieci na chorobe Gravesa-Basedowa w wybranych regionach Polski poludniowo-wschodniej.

The aim of the studies was the assessment of Graves disease (G-D) incidence in children aged 0-15 years who inhabited the Krakowskie (K), Nowosadeckie (N) and Rzeszowskie (Rz) provinces in the years 1989-1996. The incidence of G-D was evaluated depending on the age, sex and place of residence (urban vs. rural area). The analyses for particular years were carried out separately for each province and for three provinces combined. The mean incidence coefficient (I.C.) for three provinces in the years 1989-1996 was 1.83. The highest incidence of G-D was noted in the group of 10-15 year old patients (I.C.=3.81). In the youngest children the disease was sporadic (I.C.=0.12). A significantly higher incidence rate was observed in girls, in whom the I.C. value was the highest in the oldest age group, amounting to 6.92. In boys the incidence of G-D was 8 times lower and the I.C. value in the 10-15 year group was 0.79. It was also demonstrated that the incidence of Graves disease in the entire group showed no significant differences in urban and rural areas. The incidence of Graves disease in subsequent years of the analyzed period was diversified. The linear regression analysis demonstrated a growing tendency in the years 1989-1996. In the period under investigation, the highest incidence was noted in the Rz region, where the standardize incident coefficient was 2.4. In the K and N provinces the incidence was lower and both cases amounted to 1.6 after standardization. The incidence of Graves disease showed a seasonal variation, associated with a significantly more frequent diagnosis established in autumn months.

[TSH levels in newborn with low and very low birth weight vs rescreening for congenital hypothyroidism]. / Analiza poziomów hormonu tyreotropowego u dzieci z niska i bardzo niska urodzeniowa masa ciala a celowosc przeprowadzenia powtórnego badania przesiewowego noworodków w kierunku wrodzonej niedoczynnosci tarczycy.

UNLABELLED: A disorder of thyroid function, as stated by various references, is very common among children with low and very low body weight. Also, the concentration of thyroid hormones in this group differs from that of neonates full term with the adequate body weight. In 1998, in southeastern Poland, a repeated screening for TSH level in blood spots on filter paper was introduced among neonates with low and very low birth-weight. The purpose of this work was the exclusion of late appearing transient hypothyroidism, as well as the verification of falsely positive results in the basic test. Newborns with low and very low birth-weight comprise nearly 5% of live births in the region. During 1998-2001, 4,445 children with body weight below 2500 g were tested. Tests for TSH level in blood on filter paper were carried out in neonates between three and six days of age and also at the end of the first month of life. TSH levels in blood on filter paper were estimated using the LIA method (Byk Sangtec Diagnostica). The results were divided into two groups: those with correct TSH, that is < 15 mIU/L, and those with a raised level 3 15 mIU/L. The repeated test confirmed the correct result in nearly 100% of the neonates, while in 20 (0.5%) showed the increase of TSH level above 15 mIU/L. TSH and fT4 monitoring followed by serum determinations during treatment showed primary hypothyroidism in 10 children and hyperthyrotropinemia in 5 cases. CONCLUSION: 1) It would appear advisable to introduce a repeated routine screening for hypothyroidism in the group of low and very low birth-weight neonates, as this permits the identification of cases with raised values requiring verification. 2) In addition, thanks to the repeated screening we avoid false negative pitfalls in low and very low birth-weight neonates, i.e. primary congenital and transient hypothyroidism.