Calcium and Parathyroid USMLE Step 1 Practice Question
A 72-year-old woman presents with progressive fatigue, polyuria, and constipation for 6 weeks. Vital signs: BP 138/82, HR 88, RR 16, Temp 37.2°C, SpO2 98%. Laboratory studies show serum calcium 12.8 mg/dL, phosphate 2.1 mg/dL, albumin 3.8 g/dL, and PTH 180 pg/mL. 24-hour urine calcium is elevated at 320 mg/day. Neck ultrasound reveals a solitary 1.2-cm hypoechoic mass at the inferior pole of the left thyroid gland. Thyroid function tests are normal. Which diagnosis best explains these findings?
Answer choices
- AFamilial hypocalciuric hypercalcemia
- BPrimary hyperparathyroidismCorrect answer
- CSecondary hyperparathyroidism
- DTertiary hyperparathyroidism
- EHypercalcemia of malignancy
- FThyroiditis with release of preformed thyroid hormone
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