Onset of Graves’ disease during pregnancy in a woman with established hypothyroidism

Abstract

Background: Pregnancy strongly influences the thyroid gland and its function. Thyroid guidelines recommend a 30 to 50% increase of the preconceptional levothyroxine dose in women with hypothyroidism, when pregnancy is diagnosed. Case: A 33 year-old, 8-week pregnant woman with hypothyroidism, presents with a 2-week history of palpitations, sweating, nervousness and fatigue. Physical examination shows tachycardia (108 bpm), distal tremors and diffuse goiter. After biochemical confirmation of hyperthyroidism, her levothyroxine dose is reduced and finally interrupted. Propylthiouracil is started and maintained until after the delivery of a healthy baby at week 40. Two weeks postpartum, hyperthyroidism worsens and propylthiouracil is replaced by methimazole. Eighteen months after delivery 7.5 mCi 131Iodine was given. Two months later, hypothyroidism developed and levothyroxine was initiated. Conclusion: Although conversion of Hashimoto's hypothyroidism into Graves' disease is exceptional in pregnancy, pregnant women with autoimmune hypothyroidism should ideally have their TSH concentrations measured before empirically increasing their levothyroxine dose

背景: 妊娠强烈影响甲状腺及其功能。甲状腺指南推荐: 甲状腺功能减退的妇女一旦诊断妊娠, 左旋甲状腺素的剂量较孕前增加30到50%。

病例: 一个33岁、妊娠8周的甲状腺功能减退孕妇, 主诉心悸、出汗、紧张、疲劳2周。查体显示心动过速 (108次/分) 、远端震颤和弥漫性甲状腺肿。生化检查明确甲状腺功能亢进后, 降低了她的左旋甲状腺素剂量, 最后中断。并开始丙基硫氧嘧啶治疗, 维持到40周健康婴儿分娩后。产后2周, 甲状腺功能亢进恶化, 丙硫氧嘧啶被甲巯咪唑替代。产后18个月, 给予7.5mCi I131治疗。两个月后, 甲状腺功能减退, 开始左旋甲状腺素治疗。

结论: 虽然妊娠期桥本氏甲状腺功能减退转化为Graves病是个例外, 但合并自身免疫性甲状腺功能减退的孕妇在经验性增加左旋甲状腺素剂量前应该检测TSH的浓度。