Endocrine Abstracts

Audit was performed to identify outcomes of patients from our department referred for RAI for thyrotoxicosis over 14 month period. Follow-up data of atleast 6 months was required for inclusion. Forty-eight patients were identified; four were excluded due to insufficient follow-up. Diagnoses were: Graves’ disease (n=35; 79.5%), multinodular disease (MND) (n=8; 18.2%) and Amiodarone induced thyrotoxicosis (AIT) (n=1; 0.02%).

Graves’ disease: Anti-TPO antibodies positive in 15 patients and negative or unmeasured in 21 patients. All antibody unknown or negative patients had clinical features of Graves’. Antithyroid drug therapy (ATDT) of choice was block and replace (B+R) (n=19; 56%), followed by Carbimazole titration (n=12; 32%). Two patients received Propylthiouracil (PTU). Despite some variation, mean treatment duration was 18 months. One patient required no ATDT. Our RAI standard dose (400 MBq) and given to 27 patients, with higher doses in selected cases (600 MBq n=6; 800 MBq n=2). Cure (hypothyroidism or euthyroidism) was achieved in 77.8% (n=21) of the standard dose group, with 15 requiring thyroid replacement therapy (68%). Two patients required thyroidectomy and 3 had repeat RAI.

MND: Eight cases identified. Carbimazole titration was preferred ATDT (n=7) to B+R (n=1) and no treatment (n=1). Standard dose RAI was received by seven patients and cure achieved in 57.1% (n=4; 2=euthyroid, 2=hypothyroid).

AIT: This patient commenced Carbimazole titration and RAI 800 MBq was administered after 15 months. The patient was rendered euthyroid.

Despite some variation, our practices followed standard recommendations and although this audit precedes propylthiouracil drug warnings, use was very limited. Overall cure was achieved in 73.5% using standard dose RAI, and is comparable with other centres. Formulating a diagnosis is useful as optimal ATDT management differs between causes.