Abstract 8

JH is well-known as a long and discouraging disease since only about 25 per cent of the patients go into remission while the others remain hyperthyroid for an extremely long term. MMI proved to be an excellent treatment for JH, but the question that come out is when is the proper time to stop it avoiding the relapse of the disease. In order to find out markers which could be used as predictors of 1) the evolution of the disease and 2) the real underlying thyroid status under MMI, we correlated the natural outcome of the disease (persistence/relapse or remission) with some factors present at the beginning of the disease in 68 new patients collected from 1988 to 1996 (m, 17; f,51; ratio m/f, 1/3), aged 3 to 20 years old (X±sd 11.7 ± 3.9). Sex age, presence or not of exophthalmus, high titles of microsomal and thyroglobulin antibodies were evaluated in all patients. TSH-receptor antibody test (TRab, normal value < 15%) and thyroid fine needle aspiration biopsy were performed during the course of the disease and were also considered. All received MMI as initial treatment. Euthyroidism was reached between 1-2 months and treatment was continued by decreasing doses up to the minimum maintenance doses (X: 1-5 mg/day) achieved after 6 to 12 m of treatment. Compliance with this strategy was excellent and no side effects were observed. Fifty five patients (81% of the whole group were followed for 12 m. to 144m. (X±sd 37.1 ± 31.1); 12/25 (22%) went into remission between 15 and 56 m. (X±sd 33.8 ± 12.6) of treatment; 43/55 (78%) remained hyperthyroid followed during 33.6 ± 29.6m; 9/43 received therapeutic I-131 after 34 to 49 m of treatment. Results: TRab above 15% proved to be the unique significant predictor related to persistence of the disease since 19/19 patients with high TRab under MMI, remained hiperthyroid (Fisher Exact Test, p: 0.006. Sensibility 100%). On the contrary, normal TRab values showed a poor predictive value (Specificity 38.5%) since only 5/13 patients with TRab < 15 values went into remission after withdrawal low dosis of MMI Furthermore, the remaining 8 patients relapsed 15 days after MMI was discontinued, increasing significantly TRab to 32.5 ± 14.5%. None of the other factors were significant to predict neither evolution nor underlying thyroid status. In Conclusion: - No factor examined neither from the beginning of the disease nor under MMI treatment proved to be useful to predict remission - Relapse of the disease and the increment of TRab values soon after withdrawal of low doses of MMI would suggest an “immunosuppressive or restraining“ effect of MMI on the course of the disease. - Since our patients required an average of about 33 months to go into remission, it could be considered a proper time to maintain MMI treatment. Afterwards, the possibility of continuing MMI or selecting I-131 administration should be considered to avoid excessively long treatments of patients in whom remission was not achieved. Ultimately, the decision should be shared among patients, their families and physicians.