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Hypoechoic thyroid nodules on ultrasound 4 years after prenatal exposure to radioiodine: resolution with thyroxine therapy
Author(s) -
Perry Rebecca J,
Ainine Ahmad,
Butler Sandra,
Donaldson Malcolm DC
Publication year - 2008
Publication title -
acta pædiatrica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 115
eISSN - 1651-2227
pISSN - 0803-5253
DOI - 10.1111/j.1651-2227.2008.00725.x
Subject(s) - medicine , thyroid , gestation , in utero , pregnancy , hormone , fetus , endocrinology , obstetrics , genetics , biology
We describe an infant inadvertently exposed to radioiodine at 17 weeks gestation. His mother had received 400 MBq of 131 I for hyperthyroidism (total T4 178 nmol/L, thyroid stimulating hormone (TSH) <0.1 mU/L, 4‐h 131 I uptake 16%). Following cordocentesis at 27 weeks (free T4 12.7 pmol/L, TSH 35.4 mU/L) intra‐amniotic thyroxine was withheld and a male infant was born at 39 weeks gestation, birthweight 3520 g. Cord TSH was low (0.1 mU/L), total T4 151 nmol/L on day 4, the mother having received no medication during pregnancy. Postnatal follow‐up showed mild TSH elevation (11.0–19.4 mU/L) but normal free T4 (9–12.7 pmol/L) during the first 2 years of life following which the child was discharged still untreated. On recall at 4.3 years, TSH elevation persisted (15.4 mU/L) and ultrasound showed several hypoechoic thyroid nodules within the left lobe that disappeared after thyroxine treatment. Conclusion: In the event of inadvertent exposure to radioiodine in utero , the infant should receive thyroxine therapy from birth in order to protect the thyroid gland from TSH over‐stimulation, however mild.