Hypothyroid Newborns Research Articles

Interlaboratory surveys of the quantitation of thyroxin and thyrotropin (thyroid-stimulating hormone) in dried blood spot specimens.

Screening of newborns for hypothyroidism is mandated by law in most states. The screening usually consists of measuring thyroxin in dried blood spot specimens followed by measurement of thyrotropin if the results for thyroxin are suggestive of hypothyroidism. The first nationwide interlaboratory surveys designed to assess the proficiency of screening laboratories in the identification of euthyroid and hypothyroid specimens are reported here. Each survey consisted of three specimens mailed quarterly from late 1979 through 1980. A total of 88 laboratories participated in at least one of the four surveys. More than 17 different methods or diagnostic kits were used by participants in the surveys. Coefficients of variation ranged from 20% to 41% for thyroxin data and from 23% to 63% for thyrotropin. Despite the large analytical interlaboratory variation, most participants assigned clinical classifications consistent with the survey design. The incidence of mis-classifications was low.

Thyroxine treatment and recovery of hypothyroidism-induced pyramidal cell damage

We have previously shown that changes occur in pyramids of area 17 of the rat visual cortex both after thyroidectomy( T ¯ ) at 10 21,24 and at 40 22 days of age. To assess the effects of thyroxine treatment, instituted at different ages after T ¯ , two series of experiments were performed. A: rats were T ¯ at 10 days of age and either left untreated, or injected once daily with 1.5 μg thyroxine (T 4)/100 g body weight. Treatment was started at 12, 15, 20, 30 or 40 days of age. Groups of untreated and T 4-treated T ¯ -treated T ¯ rats and of age-paired intact controls were killed at different ages, ranging from 40 to 80 days. B: rats were T ¯ at 40 days of age, a group being treated with the same T 4 dose starting 30 days after T ¯ . These animals, solvent-treated T ¯ rats and intact age-paired controls were killed at 90 days of age. The number and distribution of spines along the shaft of Golgi-stained pyramidal cells of the visual cortex were measured and fitted by a mathematical model developed previously 19. Body weights, pituitary growth hormone contents, plasma thyrotropic hormone, thyroxine and triiodothyronine levels were measured to assess the degree of hypothyroidism. It was found that treatment with T 4 of rats T ¯ at 10 days of age prevented the alterations of pyramidal cells, provided treatment was started by 12 days of age and euthyroidism was maintained. In rats T ¯ at 40 days of age, treatment with T 4 had an ameliorating effect despite a delay in onset of treatment of 30 days after T ¯ . Whatever the mechanisms which are involved, the present results stress once more the importance of very early treatment of hypothyroid newborns, if permanent cortical brain damage is to be prevented.

Screening of newborns for hypothyroidism.

Journal Article Screening of newborns for hypothyroidism. Get access A Hamfelt A Hamfelt Search for other works by this author on: Oxford Academic Google Scholar Clinical Chemistry, Volume 28, Issue 4, 1 April 1982, Page 722, https://doi.org/10.1093/clinchem/28.4.722 Published: 01 April 1982

Methodische Untersuchungen verschiedener Filterpapierqualitäten im Rahmen der radioimmunologischen Thyrotropinbestimmung bei Neugeborenen

In the screening of newborns for congenital hypothyroidism, filter paper cards act as sample carriers for capillary blood specimens, and for reference quantities of the measured hormones. Therefore, the quality of the filter paper is especially important and must be taken into account. Different types of filter paper and different guide marks on the paper surface for spotting blood specimens were investigated. The hormone distribution within the dried blood spot and the time necessary to extract the hormones were examined in relation to the sensitivity and yield of the test kit.

Adverse effect of iodide containing contrast agents on newborn thyroid function

Administration of iodine containing antiseptic agents during perinatal life is known as the most frequent reason for transient hypothyroidism in newborns. Since we have detected one newborn infant who developed transient hypothyroidism after angiocardiography(ACG), we investigated thyroid function in 30 babies with congenital heart disease before and after ACG. Informed consent was given by the parents. RESULTS: After ACG with 20 ml diatrizoate 76%(iodide content 200-400 ug) 6 newborns developed transient hypothyroidism within 5 days. In 3 of them renal function was reduced for a few days. Thyroid function returned to normal within 2 weeks in 4 newborns and after 2 weeks in 2 infants. All infants with transient hypothyroidism were less than 4 weeks of age.Infants older than 4 weeks did not develop hypothyroidism, but showed a slight increase of their T4- and T3-serum concentrations 2 to 4 weeks after ACG. CONCLUSION: Newborn infants develop transient hypothyroidism after ACG in more than 80%.Even the administration of relatively small doses of iodide may be followed by an acute Wolff-Chaikoff-Effect. This may be due to immaturity of thyroid autoregulative function.

Conparative kinetics of levothyroxine and total thyroid extracts in newborns selected by the screening for the hypothyroidism

1 - Detected as hypothyroid newborns were given either levothyroxine (1 T4) 5 mcg/kg, or bovine thyroid extract (BTE) 1ctg/kg in a single oral dose. With parental approuval, five controls subjects were choosen. TSH, T4, T3, free T4 and TBG were measured in the serum before and 1/2, 1, 1 1/2, 6, 12, 24, and 48 hours after ingestion of the drug. 2 - Before intake of the drug and compaired with controls, TSH was strongly elevated TBG was in the normal range, T3 in the lower limit of the normal and T4 and F. T4 were wery low. 3 - After levothyroxine, T4 reached to a normal value within 30 mn, increased at a maximal peak at 9th hour and decreased slowly until 24 hours remaining in the normal range. T3 concentration increased progressively and remained elevated, TSH demonstrated no changes. 4 - After BTE, serum T4 remained below the normal values for 24 hours, and Increased slowly to on optimal concentration reached only at the of the first week of daily therapy.T3 concentration was normal within 1 hour. TSH remained an change. 5 - TSH concentration continued to be very elevated during several months of therapy with BTE, but returned to normal values within two weeks with levothyroxine.These data are discussed with regards of T4/TBG binding, peripheral T4/T3 conversion and suggest that levothyroxine must be prefered as neonatal substitutive therapy.

Studies on the required analytical quality of TSH measurements in screening for congenital hypothyroidism.

In the present study analytical reliability has been evaluated from the point of view of medical practice. The data were obtained from a screening program for congenital hypothyroidism in newborns using measurements of TSH. The aim of the investigation has been to evaluate the optimal analytical quality of the TSH determinations in the classification of children into two groups, with and without hypothyroidism. Evaluation of analytical quality was attempted at four different levels: (i) the numbers of misclassifications at a certain fixed value of the cutoff point, (ii) the numbers of false positives when the percentage of false negatives is fixed, (iii) the total costs of the screening program, and (iv) the social costs. When the evaluations are performed at level (i) and (ii) the results indicate a need for a high analytical quality. At level (iii) a lower analytical quality is acceptable from consideration of costs only. When social costs (iv) are considered, the acceptable analytical quality will depend on the weights given to the different factors. Finally the results point to a close relationship between the imprecision and the cutoff point chosen.

Serum 3,5,3′-Triiodothyronine, Thyroxine, and Thyrotropin in Hypothyroid Infants with Congenital Goiter and the Response to Iodine

Iodine deficiency in adults caused preferred synthesis of T3; this observation has not been reported in iodine-deficient hypothyroid newborns. Serum total T4, total T3, and TSH have been determined in nine full term newborns with congenital hypothyroid goiter before and after cutaneous application of iodine. The mothers of these infants had untreated euthyroid goiter and lived during pregnancy in the area of Göttingen, West Germany, known as an iodine-deficient region. Mean total T4 in the newborns was 6.3 +/- 1.6 (mean +/- SD) micrograms/dl compared to 16.6 +/- 3.4 micrograms/dl in normal newborns at 3-4 days of age. Mean T3 in the goitrous newborns was 2.74 +/- 0.66 ng/ml compared to 1.58 +/-0.41 ng/ml in the control group of the same age. Serum TSH remained elevated during the first week of life, with a concentration of 40.9 +/- 28.7 microU/ml (control group, 4.16 +/- 1.43 microU/ml). The cutaneous application of iodine resulted in rapid disappearance of goiter and normalization of T4 and TSH within 5 days. After 30 days of iodine treatment, T3 decreased slowly but remained elevated (2.0 +/- 0.42 ng/ml vs. 1.67 +/- 0.36 ng/ml in the control group). The present findings confirm preferential T3 secretion in newborns with hypothyroid goiter. The goiter is thought to be caused by intrauterine iodine deficiency, because hypothyroid values of T4 and TSH normalized during iodine treatment. General iodine prophylaxis of the population is recommended.

Cord blood reverse T3 in normal, premature, euthyroid low T4, and hypothyroid newborns.

To assess whether 3,3’,5’-triiodothyronine (reverse T3, rT3) can predict neonatal thyroid status we have determined rT3,thyroxine (T4), thyrotropin (TSH), and rT3 /T4 (X1000) ratio in 57 full-term normal (group N), 32 premature (group P) with birth weights 1048 to 2430 g and gestation ages 28 to 37 weeks, 95 hypothyroxinemic (T4 70 /AJ/ml in all. In group H rT3 was low in 50% (of 6) and infants with normal rT3 (false negative) values had iodide-induced myxedema, sepsis, or lingual thyroid. Low rT3 (false positives) were noted in 3.5% N, 3.1% P, and 12.6% L. These observations suggested that (a) an increased rT3/T4 ratio indicates prematurity, (b) a normal rT3 in the hypothyroid infant may indicate either a less severe degree of hypothyroidism or co-existing prematurity and systemic illness, (c) because rT3 varies with fetal maturity and available T4 precursor, rT3 is of limited value in screening for hypothyroidism.

Congenital hypothyroidism in Sweden. Incidence and age at diagnosis.

A total number of 112 children with congenital hypothyroidism were diagnosed in all Children's Hospitals and Pediatric Wards in Sweden during the 7-year period 1969-1975. Since it may be assumed that all cases of congenital hypothyroidism, which were diagnosed during that period were seen in one of these hospitals, the incidence of congenital hypothyroidism in Sweden can be calculated to be 1:6900 live births. In spite of an efficient National Health Care Program for infants the diagnosis was delayed until after an age of three months in 52% of the cases. This fact supports the view that mass screening of newborns for congenital hypothyroidism has to be introduced in Sweden. However, the beneficial effects of such a program cannot be fully elucidated until it has been considered whether earlier instituted treatment would have improved the outcome of children in whom a diagnosis was made after 3 months of age.

176: Lithium intake during pregnancy leading to large goiter and subclinical hypothyroidism in a prematurely born baby

A premature baby with a large goiter was born from a mother treated during the whole gestation with lithium (750 mg/d). Tracheal compression was visible on a lateral neck x-ray. Skeletal maturation was retarded and a hyperbilirubinemia prolonged. On the second day plasma TSH was elevated to 118 uU/ml and total thyroxin was 12,5 ug %. 100 ug of TRH i.v. increased plasma TSH at 30 and 60' above 200 uU/ml. After two weeks treatment with L-thyroxin basal TSH was still elevated. After a further two weeks plasma TSH response to TRH was suppressed and the size of the goiter reduced. Somatic and psychomotor development was slightly retarded. In order to decide on the necessity of continuation of therapy a TRH-test was repeated at the age of 6 months. Substitution was therefore interrupted for 2 weeks and resumed immediately after TRH stimulation until laboratory results were available. As T4, T3 and the pattern of TSH were euthyroid therapy was definitively withdrawn A TRH-test in the mother revealed a borderline hypothyroidism: basal T4 at lower limit of normal TSH rise exaggerated. It is concluded that lithium intake during pregnancy can induce hypothyroidism. TRH-stimulation is a sensitive parameter for borderline hypothyroidism. The test is useful for the decision for withdrawal of replacement therapy started as a preventive measure in suspected cases of hypothyroidism in newborns.

Microdetermination of TSH in dried blood spot--its use in the mass-screening for congenital or juvenile primary hypothyroidism (author's transl)

Blood TSH (Thyroid Stimulating Hormone) was successfully measured by radioimmunoassay in a dried blood spot on filter paper which is obtained in newborn screening for metabolic disorders. By this method, the minimal detectable level of blood TSH was about 10 muU/ml, which is the approximate upper limit of normal values of blood TSH. Good correlation was found between the TSH values obtained from this specimen and from liquid serum samples from the same subjects. The duplication of assay of a single sample was not necessary. A screening program using the method described here was initiated and a 4 year old infant was found to have primary hypothyroidism, later verified by other testing methods. Since the technique is simple and adequately sensitive for the detection of hypothyroidism, it could be a valuable method for use in mass-screening of newborns for congenital hypothyroidism.