Calcium and Parathyroid USMLE Step 1 Practice Question
A 63-year-old man with stage 4 chronic kidney disease presents with diffuse bone pain and severe pruritus. Vital signs: BP 158/92 mmHg, HR 88/min, RR 16/min, Temp 37°C. Laboratory studies reveal calcium 7.2 mg/dL, phosphate 6.8 mg/dL, PTH 487 pg/mL, and calcitriol 18 pg/mL. Serum creatinine is 3.2 mg/dL. He denies recent fractures. Which of the following is the most likely diagnosis?
Answer choices
- ATertiary hyperparathyroidism
- BHumoral hypercalcemia of malignancy
- CFamilial hypocalciuric hypercalcemia
- DSecondary hyperparathyroidism due to chronic kidney diseaseCorrect answer
- EPrimary hyperparathyroidism
- FHypoparathyroidism with low PTH and hyperphosphatemia
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