Outcome of pediatric Graves' disease after treatment with antithyroid medication and radioiodine

Objective: To evaluate the efficacy of antithyroid medication in the initia l treatment of pediatric Graves' disease and the frequency of use and outco me of radioiodine as second-line therapy. Design: Retrospective review. Setting: Tertiary care children's hospital. Patients: Thirty-three patients (29 female, 4 male; mean age 12.7 years) wh o started treatment for hyperthyroidism between Jan. 1, 1990, and Dec. 31, 1994. Interventions: Initial treatment with propylthiouracil or methimazole (with addition of levothyroxine if needed to maintain euthyroidism); subse quent treatment with radioiodine. Outcome measures: 1) Clinical and laboratory features at the time of diagno sis; 2) doses and duration of antithyroid drug treatment and response to tr eatment; 3) need for treatment with levothyroxine to maintain euthyroidism during the trial of antithyroid medication; 4) indications for radioiodine therapy, and the dose and number of treatments with (131)iodine (I-131); 5) thyroid status at last follow-up visit (at least 2 years after diagnosis). Results: All patients were initially treated with antithyroid drugs, and le vothyroxine was added in 16 subjects to maintain euthyroidism. The median d uration of drug treatment was 21 months. Ultimately, 24/33 patients (73%) r eceived radioiodine following a trial of antithyroid drugs because of a) si de effects of antithyroid medication tin 3 patients); b) inadequate respons e to medication (in 8 patients); and c) relapse (in 13 patients), which occ urred at a median of 6 (range 1 to 16) months following cessation of drug t herapy. Five patients required a second dose of radioiodine and 2 patients required 3 doses. Of the 24 patients treated with radioiodine, at last foll ow-up after the most recent treatment (median 18.5, range 3 to 55 months), 6 patients were euthyroid, 16 required thyroxine replacement, and 2 were st ill, or again, hyperthyroid. Conclusion: In our population of children and adolescents, treatment of hyp erthyroidism with antithyroid drugs frequently resulted in either side effe cts, inadequate response to medication or subsequent relapse, all of which led to radioiodine therapy. We conclude, therefore, that radioiodine could be considered as one of the first-line options in older children and adoles cents with hyperthyroidism.