Pituitary Disorders USMLE Step 1 Practice Question
A 35-year-old woman on chlorpromazine for schizophrenia presents with amenorrhea, infertility, and galactorrhea. Vital signs: BP 118/76, HR 82, RR 14, Temp 37°C, SpO2 98%. Prolactin is 180 ng/mL, free T4 is 1.2 ng/dL (low-normal), and TSH is 8.2 mIU/L. MRI of the pituitary shows no adenoma. Serum cortisol and LH are normal. Which of the following best explains the elevated prolactin?
Answer choices
- AOccult prolactinoma detected on sensitive assays
- BAutoimmune hypophysitis with pituitary inflammation
- CPregnancy-related physiologic hyperprolactinemia
- DPhenothiazine-induced dopamine antagonismCorrect answer
- EPrimary hypothyroidism causing TRH-mediated prolactin stimulation
- FEctopic prolactin production from a metastatic lung carcinoma
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