Endocrine Abstracts

Background: Conventional management for thyrotoxicosis includes anti-thyroid medications, radioactive iodine and/or surgery. However, in some cases patients are resistant to first line drugs and need second line treatment to normalize thyroid function tests (TFTs) before considering definitive therapy. We present a case of Grave’s disease where patient didn’t respond to first line anti-thyroid medications and required Lithium and Cholestyramine to achieve euthyroid status prior to surgery.

Case: A 29 years old lady was referred with 1 year history of tiredness, on and off loose stools and weight loss of 26 kg. She also reported getting sweaty easily, shaking of hands and palpitations. She had never smoked and was working as a support worker. On examination, she was tachycardic with heart rate of 110, had a fine tremor and a World Health Organization (WHO) grade 2 smooth goiter with an audible bruit. There were no signs of thyroid eye disease and no neck lymphadenopathy. She had significant family history of thyroid disease on her maternal side (Mother, Aunts, Uncle and Grandfather - hypothyroid). Her initial TFTs showed a fT4 34.1 pmol/l, fT3 >30 pmol/land TSH <0.01mU/l, with thyroid receptor antibodies (TRAb) level>68 IU/land anti-thyroid peroxidase (TPO) antibodies level of 1118 IU/ml. Patient was commenced on carbimazole 30 mg and propranolol for symptomatic relief. After 6 months of treatment, despite being on maximum dose of carbimazole (60 mg) and good compliance, she had fully suppressed TSH, elevated fT3 and fT4 and she remained symptomatic. Patient declined radioactive iodine due to work commitments and agreed for surgery as definitive treatment. To prepare her for surgery, she was started on Lithium and Cholestyramine which showed an improvement in her TFTs. She was also planned to receive Lugol’s iodine 2 weeks before surgery.

Conclusion: Thionamide resistant thyrotoxicosis is uncommon but can be life-threatening. Surgery and/or radio-iodine remains the mainstay of treatment. This case highlights the approach and importance of considering second line treatments to achieve euthyroid status before definitive therapy.