Congenital hypothyroidism with delayed rise in serum TSH missed on newborn screening

Abstract

We report on a female patient with congenital hypothyroidism (CH) missed on a newborn screening test. She is now 10 years old with retarded development. The patient was born premature at 34 weeks of gestation with birth‐weight of 1515 g, and was judged to be normal in the screening programme of Niigata Prefecture. However, she gradually suffered from poor weight gain and retarded development with stridor at breathing. Serum thyroid stimulating hormone (TSH) levels were rechecked and showed high values with normal T3 and T4 levels. She was referred to our hospital at the age of 13 months. She was diagnosed as having CH (ectopic thyroid) with a delayed rise in blood TSH concentration, probably due to the prematurity of the hypothalamic‐pituitary‐thyroid axis. l‐thyroxine therapy brought a decline in TSH levels with partial improvement of her symptoms. Regardless of the result of newborn screening, infants with elevated serum TSH levels should be carefully examined for possible CH, even when T3, T4 and free T4 values are in the normal range.

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

“…[1][2][3] This may result in false-negative TSH screening results and thus failure to detect late-onset forms of CH, which become manifest somewhat later in low and very low birth weight infants than in those born at term with normal birth weight. 4 It is therefore necessary to repeat TSH measurements in low and very low birth weight infants 2-4 weeks after birth. The thyroid dysfunction usually resolves spontaneously within several weeks, but this is not the case for permanent or transient CH, which require thyroxine replacement therapy to ensure normal development of the central nervous system.…”

Short Report: False-negative primary neonatal thyroid screening: the need for clinical vigilance and secondary screening

“…Hypothalamic-pituitary hypothyroidism, which has a prevalence of 1/50,000 to 1/100,000, 8,12,13 results in low or low-normal serum T4 concentration with normal or low or even slightly elevated TSH concentration, which would be missed by primary TSH screening. 9 Cases of primary hypothyroidism with dyshormonogenesis 8,14 or thyroid dysgenesis (ectopia, aplasia and hypoplasia) 15,16 may have low T4 and delayed TSH elevation (1/100,000), which may be missed on neonatal TSH screening. 8,11 Transient TSH elevation is known to occur in association with iodine contamination, 17 maternal anti-thyroid antibodies or endemic iodine de ciency.…”

“…Physical examination at the age of two weeks was unremarkable except for jaundice. The total serum bilirubin was 244.5 mmol/l (normal for age [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] and the direct bilirubin 6.8 mmol/l (normal for age <3.4). Her leukocyte count was 14.1 ´10 9 cells/l (normal for age 5-21 10 9 ), haemoglobin was 180 g/l (normal for age 150-200), haematocrit was 0.55 (normal for age 0.46-0.62), platelets were 425 ´10 9 /l (normal for age 150-400 ´10 9 ), reticulocyte count was 0.001 (normal for age 0-0.1) and she did not have any reducing substances in the urine.…”

Neonatal Thyroid Function: Effect of a Single Exposure to Iodinated Contrast Medium in Utero

“…Another potential limitation is the fact that infants with central hypothyroidism and those with a delayed increase in TSH concentration can be identifi ed only with the initial T 4 and follow-up TSH assay method (38)(39)(40), whereas infants with subclinical hypothyroidism (high blood TSH level, normal blood T 4 level) are identifi ed only with TSH testing. The clinical importance of subclinical hypothyroidism in newborns is not entirely clear, and its management is controversial.…”