A Rare Phenomenon of Hashimoto's Thyroiditis Converting to Graves' Disease

The document reported a rare case of a 67-year-old female with Hashimoto's thyroiditis converting to Graves disease. Initially diagnosed with Hashimoto's in 2015, she was treated with Levothyroxine, which was gradually reduced as her symptoms improved. However, in 2018, she presented with symptoms of hyperthyroidism, and tests confirmed Graves disease. She was treated with Methimazole and eventually underwent a total thyroidectomy in 2019, after which she resumed Levothyroxine. The case highlighted the importance of close monitoring and regular thyroid function tests, as the conversion from Hashimoto's to Graves disease, though rare, could be mistaken for over-replacement of Levothyroxine.