Fetal goiter identified in a pregnant woman with triiodothyronine-predominant graves’ disease: a case report

Abstract

Background: Approximately 10% of all Graves' disease cases are triiodothyronine (T3)-predominant. T3predominance is characterized by higher T3 levels than thyroxine (T4) levels. Thyroid stimulating hormone receptor autoantibody (TRAb) levels are higher in T3-predominant Graves' disease cases than in non-T3-predominant Graves' disease cases. Treatment with oral drugs is difficult. Here, we report a case of fetal goiter in a pregnant woman with T3-predominant Graves' disease. Case presentation: A 31-year-old woman had unstable thyroid function during the third trimester of pregnancy, making it impossible to reduce her dosage of antithyroid medication. She was admitted to our hospital at 34 weeks of gestation owing to hydramnios and signs of threatened premature labor, and fetal goiter (thyromegaly) was detected. The dose of her antithyroid medication was reduced, based on the assumption that it had migrated to the fetus. Subsequently, the fetal goiter decreased in size, and the hydramnios improved. The patient underwent elective cesarean delivery at 36 weeks and 5 days of gestation. The infant presented with temporary symptoms of hyperthyroidism that improved over time. Conclusions: The recommended perinatal management of Graves' disease is to adjust free T4 within a range from the upper limit of normal to a slightly elevated level in order to maintain the thyroid function of the fetus. However, in T3-predominant cases, free T4 levels may drop during the long-term course of the pregnancy owing to attempts to control the mother's symptoms of thyrotoxicosis. Little is known about the perinatal management and appropriate therapeutic strategy for T3-predominant cases and fetal goiter. Therefore, further investigation is necessary.

Penanganan Kasus Kehamilan 32 Minggu dengan Hipertiroid Janin-Fetal Goiter

“…Meski demikian, kardiomiopati yang diindukis tiroksin bersifat reversibel. 21,22 Pada pasien, tatalaksana yang diberikan adalah asam folat, kalsium karbonat, vitamin D, Propylthiouracil, folamil dan ferrous sulfat. Propylthiouracil bekerja dengan menghambat konversi T4 ke T3 dan lebih sulit melintasi plasenta dibandingkan methimazole.…”

“…Status tiroid bayi pascapartum dan penilaian perkembangan neuro-psikomotor adalah wajib, dengan dimulainya penggantian levotiroksin segera setelah melahirkan. 21 Rencana selanjutnya pada ibu dengan hipertiroid berkaitan dengan persalinan, pilihan kontrasepsi dan rencana kehamilan selanjutnya.…”

Adverse outcome of T3-predominant maternal Grave’s disease during pregnancy in the mother and the offspring

“…This condition is known as T3-predominant GD. Approximately 10-12% of GD patients are T3-predominat GD [1][2][3].…”

“…In our case, treatment with antithyroid drugs (ATDs) adjusted the FT4 level to the normal range; however, the mother presented clinical signs of thyrotoxicosis probably associated with a high FT3 level. Unlike MMI, PTU suppresses D1 activity, leading to T4-to-T3 conversion [1,2]. With PTU not recommended in children due to PTU-induced severe hepatitis, its administration is sometimes necessary to normalize the thyroid function [3,4].…”

“…GD occurrence in pregnancy deserves particular attention. Foetal/neonatal hyperthyroidism develops due to transplacental passage of maternal TRAbs [1,3]. The TRAb level may increase and remain elevated for months/years in women with a history of ablative therapy [3].…”