SFEIES24 Poster Presentations Thyroid (21 abstracts)
1Cardiff University School of Medicine, Cardiff, United Kingdom; 2University Hospital of Wales, Cardiff, United Kingdom
Introduction: We aimed to characterise clinical and biochemical features, management and outcome in subjects with thyrotoxicosis who presented for definitive treatment with radioactive iodine (RAI) therapy to our unit.
Methods: This retrospective analysis examined patients with Graves disease (GD) and nodular thyroid disease (NTD) who were treated with RAI as definitive treatment for thyrotoxicosis between 2008 2012. A standard activity of RAI (555 MBq) was used for all subjects. We examined previous electronic records and databases for clinical and biochemical data at presentation, details of medical management before and after RAI, and the rate of occurrence of post RAI hypothyroidism in the two groups.
Results: There were 241 GD subjects (goitre recorded in 56%, and orbitopathy in 19.6%) and 156 NTD subjects who had RAI for thyrotoxicosis during this period. GD subjects (a) were younger median age 51 vs. 67 years, P < 0.001; (b) had higher median free T3 (11.95 vs. 7 pmol/l) and free T4 (30.1 vs. 19.7 pmol/l) concentrations at presentation (P < 0.001); (c) a longer duration of treatment with a thionamide before RAI (12 vs. 7 months, P < 0.001); and (d) a higher incidence of post RAI hypothyroidism (88.5% vs. 31%, P < 0.001) compared to NTD subjects. Most GD subjects received RAI for relapse (62.3% vs.15.6%) while the majority of NTD subjects received RAI as first choice treatment (39% vs.4.2%). The median time to post RAI hypothyroidism was 3-3.5 months in both groups.
Conclusions: Our study indicates that subjects with GD presenting for RAI mainly for relapsed disease, (a) were younger, (b) had more severe biochemical thyrotoxicosis compared to those with NDT and (c) a higher percentage of them developed hypothyroidism post RAI although both groups received a standard activity of 555 MBq.