Calcium and Parathyroid USMLE Step 1 Practice Question
A 49-year-old woman with end-stage kidney disease underwent successful renal transplantation two years ago. She now presents with fatigue and polyuria. Vital signs: BP 148/92, HR 88, RR 16, Temp 37°C. Laboratory studies reveal calcium 11.2 mg/dL, phosphate 3.1 mg/dL, and markedly elevated PTH at 892 pg/mL. Serum creatinine is normal. Parathyroid ultrasound shows gland enlargement. She denies medication non-adherence. Which of the following best explains her persistent hypercalcemia and elevated PTH?
Answer choices
- AAutonomous parathyroid hyperplasia after chronic stimulationCorrect answer
- BParathyroid hormone related peptide secretion by a malignancy
- CResistance of target tissues to parathyroid hormone
- DAccidental removal of the parathyroid glands during surgery
- EVitamin D intoxication
- FTertiary hyperparathyroidism with development of a parathyroid adenoma
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