A 58-year-old man on long-term amiodarone develops thyrotoxicosis. Colour flow Doppler shows absent thyroid vascularity and radioiodine uptake over 24 hours is nearly zero. Interleukin-6 level is markedly elevated. Which statement about his condition is correct?
- A It is caused by iodine-induced increased hormone synthesis and responds to carbimazole
- B It always resolves spontaneously on stopping amiodarone within 4 weeks
- C It results from destructive thyroiditis and glucocorticoids are the mainstay of treatment ✓
- D It is managed identically to type 1 disease with perchlorate and thionamides
Correct answer: C. It results from destructive thyroiditis and glucocorticoids are the mainstay of treatment
Explanation
Amiodarone-induced thyrotoxicosis type 2 is a destructive process in which the drug damages thyroid follicular cells, releasing preformed hormone. Low or absent vascularity on Doppler, near-zero radioiodine uptake, and high interleukin-6 support type 2 over type 1, which shows preserved or increased vascularity and uptake and responds to thionamides. Glucocorticoids are first-line therapy for type 2. Amiodarone has a very long half-life, so stopping it rarely produces rapid resolution, and near-total thyroidectomy is needed for refractory cases.
Reference: Williams Textbook of Endocrinology, 14th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.