ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Endocrine Abstracts (2017) 51 P002 | DOI: 10.1530/endoabs.51.P002

Radioactive Iodine therapy for the management of hyperthyroidism in children and adolescents

Ingrid C E Wilkinson Wilkinson1, Muriel Meso2, Victoria Rowse3, Emily Joel3, Elizabeth Morris3, Leanne Price3, Helen L Storr1 & William M Drake1

1Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, First Floor, John Vane Science Centre, Charterhouse Square, London, UK; 2Department of Paediatric Endocrinology, Royal London Hospital, Whitechapel Road, Whitechapel, London, UK; 3Department of Nuclear Medicine, St Bartholomew’s Hospital, West Smithfield, London, UK.

Background: Radioactive iodine therapy (RAI) is established as a safe and effective treatment for adults with Grave’s disease. As thyrotoxicosis in children is rare, it is difficult to obtain high quality evidence about the safety and efficacy of RAI. We present data from our centre between 2007 and 2017.

Methods: 20 paediatric patients with hyperthyroidism (16F), median age 15.7 years (range 10.8–19.3) had RAI in our centre either one or two doses. Median follow-up for all patients was 1.4 years (0–9 years).

Results: All patients received an initial median iodine-131 (I-131) dose of 607 MBq (419–803 MBq). The primary indications were: definitive treatment following antithyroid drug treatment (ATD) (16/20; 80%), intolerance/sensitivity to ATD (2/20; 10%), poor compliance to ATD (1/20; 5%) and acute psychosis secondary to thyrotoxicosis (1/20; 5%). Following one dose of I-131, 15/20 (75%) patients became hypothyroid in median 3.5 months (1–20 months), 3/20 (15%) relapsed median 7 months (range 1–19 months) following RAI. Two (10%) were lost to follow up. The 3 relapsed patients had a second dose of RAI median 600 MBq (421–618 MBq). One had allergic hypersensitivity to ATD and her presenting FT4 was >150 pmol/l. A second RAI dose was given 9 weeks after the first and the fT4 normalised. However, one year later she relapsed and required definitive treatment with surgical thyroidectomy. Another patient had a large goitre and went hypothyroid after 9 years. The final patient was rendered hypothyroid within one month following second RAI. Fifteen patients who were hypothyroid initially remain well on thyroxine replacement median 100 μm (50–200 μm) following RAI.

Discussion: Whilst our cohort is small, our data suggest that RAI is a safe and effective definitive treatment for hyperthyroidism in children and adolescents. Long term follow up data is difficult to obtain due to the rarity of hyperthyroidism in paediatric patients but can be achieved by collaboration between centres.