Serum Thyroglobulin Changes in Patients with Graves’ Disease Treated withLong Term Antithyroid Drug Therapy

Abstract

In 29 patients with thyrotoxic Graves' disease treated with conventional long term antithyroid drug therapy, serum thyroglobulin (Tg) was serially determined by RIA and compared with clinical course, goiter shrinkage, and 131I uptake suppression. Those subjects with Tg autoantibody-negative sera comprised 46% of the patients with Graves' disease. They were divided into a remission group (G I) and an exacerbation group (G II). G I was subdivided into G Ia, who were in remission for 7-40 months, and G Ib, who relapsed more than 15 months after therapy. G II was still on therapy 27-62 months after its initiation, because these subjects exacerbated on reduction of the drugs. Goiter shrinkage occurred in 60% and 0%, and 131I uptakes were suppressed by T3 in 50% and 0% in G I and G II, respectively. Serum Tg in G I declined progressively and reached 48 +/- 5 (+/-SE) ng/ml on discontinuation of therapy, in sharp contrast with serum Tg in G II which remained high throughout (154 +/- 29 ng/ml at the last examination; P less than 0.001). Results of goiter shrinkage, 131I uptake suppressibility, and serum Tg levels were similar in G Ia and G Ib on cessation of therapy. Serum Tg levels less than 68 or more than 140 ng/ml on discontinuation of therapy were helpful in predicting the outcome of therapy. On the other hand, Tg levels were low and goiters were small in size in euthyroid Graves' disease. Tg levels were not clearly correlated with goiter weight or serum T4 and T3 levels before treatment. In conclusion, serial determinations of serum Tg reflect thyroid activity and provide information useful in the decision to discontinue therapy and observation after that.

Serum thyroglobulin concentration in normal pregnancy.

“…Recently, it has been shown that determinations of serum Tg concentrations could provide useful information concerning the recurrence of thyroid carcinoma (Van Herle and Uller, 1975;Shlossberg et al, 1979;Pacini et al, 1980) and the decision to discontinue antithyroid drug in the treatment of Graves' disease (Kawamura et al, 1983). From the results of the present study, it is concluded that pregnancy per se does not likely cause misinterpretation of the evaluation of the Tg level in patients with thyroid disease, since (1) the serum Tg level in pregnant females at the first, second, and early third trimesters is not different from that of controls and (2) the mean serum Tg level in pregnant females at the late third trimester is only slightly higher than that of controls when compared with the clearly elevated Tg level in patients with thyroid disease (Van Herle et al, 1973 andIzumi and Laysen 1978;Gardner et al, 1979;Shlossberg et al, 1979;Pacini et al, 1980).…”

Drug discontinuation after treatment with minimum maintenance dose of an antithyroid drug in Graves' disease: a retrospective study on effects of treatment duration with minimum maintenance dose on lasting remission

“…The timing of ATD cessation is difficult to determine because there are no measures for accurately evaluating the activity of Graves' disease. For this purpose, the triiodothyronine (T3) suppression test [10,11], thyroid releasing hormone test [12,13], T3/thyroxine (T4) ratio [14] and serum thyroglobulin [15,16] and thyroid stimulating hormone (TSH) receptor antibody (TRAb) [2,3,[17][18][19][20][21][22][23][24] levels have been used, but acceptable results have not been obtained.…”

Serum Thyroid-Stimulating Antibody, Thyroglobulin Levels, and Thyroid Suppressibility Measurement as Predictors of the Outcome of Combined Methimazole and Triiodothyronine Therapy in Graves' Disease

“…Discordant results in the predictive value of serum Tg may derive from the different dietary iodine intake of the patients studied. Interestingly, most reports of good prognostic value of serum Tg levels were from countries with a high iodine intake (8)(9)(10)(11). This parameter was not of predictive value in populations with comparatively low dietary iodine intake (11)(12)(13)(14).…”

“…The correlation between serum thyroglobulin (Tg) levels and either TSAb or T3 suppressibility in patients who remitted after ATD therapy suggested that the serum Tg could substitute for TSAb or T3 suppression tests (7). A higher risk of relapse was reported in patients with elevated serum Tg concen¬ trations at the end of ATD treatment (8)(9)(10), but these data have been contradicted (11)(12)(13)(14). Van Herle et al (15) proposed the combined measurement of serum TSAb and Tg as an ideal prognostic index.…”