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Levothyroxine over-replacement — SCE Endocrinology MCQ

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ModerateThyroidLevothyroxine over-replacementSCE Endocrinology

A 66-year-old woman is taking levothyroxine 150 micrograms daily after partial thyroidectomy. She has weight loss and palpitations. TSH is 0.02 mU/L, free T4 is 25 pmol/L and ECG shows atrial fibrillation. DXA last year showed osteoporosis. What is the most appropriate management?

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Correct answer: EReduce levothyroxine dose and treat atrial fibrillation risk

Suppressed TSH with high free T4 indicates over-replacement, which contributes to atrial fibrillation and bone loss. Carbimazole is not the solution when the excess is exogenous levothyroxine. The pearl is that TSH suppression is not benign outside selected thyroid cancer contexts.

Reference: https://www.nice.org.uk/guidance/conditions-and-diseases/diabetes-and-other-endocrinal-nutritional-and-metabolic-conditions