Calcium and Parathyroid USMLE Step 1 Practice Question
A 58-year-old woman presents with recurrent nephrolithiasis and progressive diffuse bone pain. Vital signs: BP 138/82, HR 88, RR 16, Temp 37.2°C, SpO2 98%. Laboratory studies reveal serum calcium 11.2 mg/dL (normal 8.5-10.5), phosphate 2.1 mg/dL (normal 2.5-4.5), and PTH 145 pg/mL (normal 15-65). Urine calcium is elevated. Recent DEXA scan shows decreased bone mineral density. She denies recent thiazide diuretic use. Which of the following is the most likely diagnosis?
Answer choices
- APrimary hyperparathyroidismCorrect answer
- BSecondary hyperparathyroidism due to chronic kidney disease
- CVitamin D deficiency
- DHypoparathyroidism after thyroid surgery
- EPseudohypoparathyroidism
- FHumoral hypercalcemia of malignancy from PTHrP secretion
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