Endocrine Abstracts

Methods: We retrospectively reviewed the medical notes of 39 patients who received radioiodine treatment (RAI) for thyrotoxicosis from 2004 until February 2010.

Results: Thirty (76.9%) patients were females and the median age of diagnosis was 59.5 years. 17.9% had positive family history of thyrotoxicosis; current smokers (31%), ex-smokers (18%); Graves’ disease (56.4%), Multinodular goitre (41%), and unspecified diagnosis (2.6%). 18% of patients had history of thyroid eye disease(TED); mild (15%), moderate (3%), severe (0%) and two patients were given steroids as per our guidelines; TED worsening(o%) while one patient developed new TED post RAI. At diagnosis, Free T4 (mean, 38.3, median 32.8, NR 11–23 pmol/L); patients (46.2%) had thyroid ultrasound versus radio isotope scan (5.1%). Patients received Carbimazole (77%), Propylthiouracil (21%), none (3%) prior to RAI. 69.2% became hypothyroid post-RAI, euthyroid (20.5%) while 10.3% had further relapse of thyrotoxicosis and required a second dose of RAI. All patients achieved cure after second dose of RAI. All patients with toxic nodular goitre were cured; only 80% of patients with Graves’ disease achieved cure after first RAI treatment. Females were more likely to achieve cure after first RAI (92%) versus males (78%). Both thyroid receptor antibody (TRAB) and Thyroid peroxidise antibody (TPO) positivity were associated with a higher cure rate in our study. Higher Free T4 and T3 levels at diagnosis were associated with further relapse of thyrotoxicosis; however, only FT3 association was statistically significant. We also observed higher Thyroxine dose needed post-RAI associated with TRAB positivity; higher relapse rates in males and longer duration of anti-thyroid treatment but these three factors were not significant. High TRAB was associated with high FT4 levels at diagnosis and this was significant.

Conclusion: Various clinical, demographic factors and careful patient selection should be considered in predicting response to radioiodine treatment in order to achieve good outcomes.

Declaration of interest: There is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.

Funding: No specific grant from any funding agency in the public, commercial or not-for-profit sector.