What causes the elevated thyroxine levels observed in Hashimoto's thyroiditis during its early stages, when the thyroid gland is still partially functional?

💡 Explanation

Autoimmune-mediated destruction of thyroid follicular cells causes the release of pre-formed thyroxine (T4) into the bloodstream, leading to elevated levels. Therefore, increased thyroxine results from cell destruction rather than changes in TSH sensitivity or T4 conversion because the gland is still actively producing hormones.

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