Development of primary hypothyroidism with the appearance of blocking-type antibody to thyrotropin receptor in Graves' disease in late pregnancy.
Spontaneous remission of Graves' disease with a decrease of thyroid stimulating antibody (TSAb) activity is commonly observed in pregnancy. In this article, however, a Graves' patient who developed primary hypothyroidism with an appearance of thyroid stimulation-blocking antibody (TSBAb) activity in late pregnancy is reported. A 25-year-old woman presented with clinical and biochemical hyperthyroidism with an elevation of 99mTcO4- thyroid uptake (4.7%; normal range, 0.7%-3.0%) and mildly elevated activity of thyrotropin-binding inhibitory immunoglobulin (TBII; 30.4%). She was euthyroid with normal TBII (8.0%) and TSAb (126%) before pregnancy, when the patient was taking a 5-mg daily dose of methimazole (MMI). MMI was stopped by the patient when she became pregnant. Subsequently, the patient progressed into primary hypothyroidism with a marked elevation of TBII activity (78.4%) in the third trimester of the pregnancy (at that time, TSAb activity was not detected). TSBAb measured 2 weeks later was detected at the activity of 85.0%. Replacement therapy was initiated with levothyroxine (LT4) (0.05-0.1 mg/day), which was discontinued on the 55th day postpartum because of the onset of mild thyrotoxicosis followed by short-term euthyroid state despite high TSBAb activity. Subsequently, because the patient developed primary hypothyroidism 5 months after delivery, replacement therapy with LT4 (0.1-0.125 mg/day) was readministered. Thus, it is suggested that the development of hypothyroidism with the appearance of TSBAb in Graves' patients can occur even in late pregnancy.
Ueta
Y
Y
First Department of Internal Medicine, Faculty of Medicine, Tottori University, Yonago, Japan.
Fukui
H
H
Murakami
H
H
Yamanouchi
Y
Y
Yamamoto
R
R
Murao
A
A
Santou
Y
Y
Taniguchi
S
S
Mitani
Y
Y
Shigemasa
C
C
D000328:Adult; D013956:Antithyroid Agents / Q000627:therapeutic use; D001323:Autoantibodies / Q000097:blood*; D005260:Female; D006111:Graves Disease / Q000150:complications / Q000188:drug therapy / Q000276:immunology; D006801:Humans; D007037:Hypothyroidism / Q000188:drug therapy / Q000276:immunology*; D018828:Immunoglobulins, Thyroid-Stimulating / Q000097:blood*; D008297:Male; D008713:Methimazole / Q000627:therapeutic use; D011247:Pregnancy; D011248:Pregnancy Complications; D011263:Pregnancy Trimester, Third; D011989:Receptors, Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000627:therapeutic use
D013956:Antithyroid Agents; D001323:Autoantibodies; D018828:Immunoglobulins, Thyroid-Stimulating; D011989:Receptors, Thyrotropin; C118905:thyroid stimulation-blocking antibody; C094372:thyrotropin-binding inhibitory immunoglobulin; D008713:Methimazole; D013974:Thyroxine