Diabetes Mellitus USMLE Step 1 Practice Question
A 31-year-old woman with schizophrenia started olanzapine 3 months ago and now presents with galactorrhea, amenorrhea, and weight gain. Vital signs: BP 118/76, HR 82, RR 16, Temp 37°C, SpO2 98% on room air. Serum prolactin is elevated at 65 ng/mL (normal <25). Pregnancy test is negative. TSH and free T4 are normal. Which of the following best explains her endocrine dysfunction?
Answer choices
- AConstitutive activation of the RET receptor
- BBlockade of dopamine inhibition of lactotrophsCorrect answer
- CExcess ACTH production by the pituitary
- DExcess peripheral conversion of T4 to T3
- EDirect stimulation of prolactin release by thyroid hormone
- FHypothyroidism-induced hyperprolactinemia from TRH elevation
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