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Elevated thyroid‐stimulating hormone level in a euthyroid neonate caused by macro thyrotropin–IgG complex
Author(s) -
Rix Mariane,
Laurberg Peter,
Porzig Christina,
Kristensen Søren Risom
Publication year - 2011
Publication title -
acta paediatrica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 115
eISSN - 1651-2227
pISSN - 0803-5253
DOI - 10.1111/j.1651-2227.2011.02212.x
Subject(s) - medicine , euthyroid , endocrinology , triiodothyronine , hormone , thyroid stimulating hormone , free thyroxine , thyroid , thyroid function , congenital hypothyroidism
Elevated thyroid‐stimulating hormone (TSH) was discovered by routine neonatal screening in a newborn with no clinical symptoms. Thyroid function tests were repeated and confirmed a high TSH value but normal total thyroxine (T4) and triiodothyronine (T3). However, the mother also had elevated serum TSH with normal levels of T4 and T3. The results suggested a transmitted maternal interfering factor, and no treatment was started while further investigation was performed. Gel filtration chromatography of serum from both the infant and the mother showed a peak TSH with molecular mass consistent with a TSH–IgG complex (macro‐TSH). TSH in the infant decreased to a normal level within 8 months in accordance with a normal rate of elimination of maternal IgG, whereas the TSH level of the mother remained high. Conclusion: This case suggests that interfering macro‐TSH should be considered in a euthyroid neonate with elevated serum TSH and normal T4 and T3 levels to avoid unnecessary treatment.