The Levothyroxine

A 25-year-old woman presents with 6 months of lethargy, sensitivity to cold temperatures, and an elevated serum TSH. What is the most appropriate management for this patient?

Fluoxetine
Hydrocortisone
Levothyroxine
Propylthiouracil
Radioactive iodine treatment

Correct answer
Levothyroxine
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correct answer: C

This woman complains of symptoms of hypothyroidism with an elevated TSH. Levothyroxine, a synthetic form of thyroid hormone, is the most appropriate choice.
Fluoxetine is an SSRI could be used for depression. Serum TSH would be normal in depression.

Hydrocortisone is a steroid that could be used for Addison’s Disease (chronic adrenal insufficiency). Serum TSH should be normal in Addison’s.

Propylthiouracil and (E) radioactive iodine treatment are used in hyperthyroidism. Serum TSH would be low in hyperthyroidism. Propylthiouracil inhibits the enzyme thyroperoxidase, thus resulting in decreased thyroxine production. It also inhibits the peripheral deiodination of T4 to T3 (T3 is more active). In radioactive iodine treatment, there is thyroid uptake of the radioactive isotope iodine-131, which results in cytotoxic radiation delivered to some thyroid cells.