ESPE Abstracts (2016) 86 P-P1-931

Radioiodine Therapy for Graves' Disease - the Experience of a Portuguese Single Centre

Nuno Vicentea, Luís Cardosoa, Inês Diasc, Joana Serra-Caetanob, Rita Cardosob, Isabel Dinisb, Gracinda Costad, Luísa Barrosa, Francisco Carrilhoa & Alice Miranteb


aEndocrinology, Diabetes and Metabolism Department, Centro Hospitalar Universitário Coimbra, Coimbra, Portugal; bPaediatric Endocrinology Department, Centro Hospitalar Universitário Coimbra, Coimbra, Portugal; cPaediatric Department, Centro Hospitalar Leiria, Leiria, Portugal; dNuclear Medicine Department, Centro Hospitalar Universitário Coimbra, Coimbra, Portugal


Background: Besides surgery, radioactive iodine therapy (RAI) is an effective and safe option to treat children with hyperthyroidism from Graves disease (GD) who cannot achieve euthyroidism with antithyroid drugs.

Objective and hypotheses: To present the experience of a Portuguese paediatric unit with the use of RAI in children with GD.

Method: The authors performed a review of 7 cases of Graves disease of age under 18 years treated with RAI between 2010 and 2015. A previous trial on methimazole (“block and replace”) was attempted in all patients. Indications for RAI were uncontrolled hyperthyroidism with thyroid mass less than 80 g and absence of active eye disease. The goal of RAI was achieving a hypothyroid state, after which therapy with levothyroxine would be started. Methimazole was routinely stopped 1 week before RAI and therapeutic activity was calculated based on 24 h radioiodine uptake and thyroid mass.

Results: Patients, who were all female, had a median time of onset of 10.1years (9.9–10.8). RAI was administered after a long period under methimazole (41months (33–52)) to achieve an euthyroid state, at median age of 13.9 years (13.5–15.1), with a median activity of 10 mCi (9–13). After RAI, hypothyroidism was achieved after a median of 6 months (5.25–11.5) in 5 patients. The remaining two needed a second RAI dose of 7.6 and 10.9 mCi and became hypothyroid 1 month later. Globally, the 1-session RAI group were offered a 11 mCi (10–13) activity, compared to 17 mCi (15.1–19.0) of the 2-session group. There is also a trend in progressively higher activities of RAI, with better results. No side effects were related by any patients.

Conclusion: RAI has been safely used in our unit with good results. Hypothyroidism is achieved 6 months later after RAI and 1 month later, when a second treatment is needed. Higher activities of RAI also seem to be associated with better results (more rapid onset of hypothyroidism).