A patient with chronic kidney disease exhibits elevated serum TSH despite normal T4 levels. Why does this thyroid hormone dysregulation occur in this context?

💡 Explanation

The elevated TSH occurs because chronic kidney disease impairs the kidneys' ability to clear T3, leading to increased T3 levels and feedback inhibition of TSH secretion, thus maintaining normal T4. Therefore, the pituitary gland isn't exposed to the right level of the thyroid hormone, rather than altered conversion or uptake which would cause differing T4 levels.

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