Pituitary Disorders USMLE Step 1 Practice Question
A 28-year-old woman presents to clinic 6 months after an uncomplicated vaginal delivery with complaints of progressive fatigue, persistent amenorrhea, and inability to breastfeed despite attempting lactation. She reports sleeping 10-12 hours per night but continues to feel exhausted during the day. During her delivery, she experienced massive postpartum hemorrhage requiring emergency blood transfusions and an estimated blood loss of 2.5 liters. On examination: temperature 36.5°C, blood pressure 98/60 mmHg, heart rate 54/min, respiratory rate 13/min. Skin appears pale and slightly cool. Laboratory studies show:
- Hemoglobin 9.8 g/dL (normal: 12-16)
- TSH 0.8 mIU/L (normal: 0.5-5.0)
- Free T4 8.2 pmol/L (normal: 10-20)
- Prolactin 2.2 ng/mL (normal postpartum: >20 ng/mL)
- LH <1 mIU/L (normal follicular: 2-10) Which of the following is the most likely diagnosis?
Answer choices
- APostpartum thyroiditis with secondary hypothyroidism
- BSheehan syndrome with panhypopituitarismCorrect answer
- CSevere postpartum anemia with superimposed depression
- DPeripartum cardiomyopathy with reduced cardiac output
- EPrimary adrenal insufficiency from autoimmune destruction
- FPostpartum psychosis with catatonic features
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