Electrolyte Disorders USMLE Step 1 Practice Question
A 68-year-old man with nephrolithiasis history presents with progressive bone pain, constipation, and depression. Vital signs: BP 138/82 mmHg, HR 88/min, RR 16/min, temp 37.2°C. Laboratory studies reveal serum calcium 12.2 mg/dL, phosphate 2.0 mg/dL, PTH 180 pg/mL, and alkaline phosphatase 92 U/L. Urinalysis shows no hematuria. He denies recent immobilization or thiazide use. Which diagnosis best explains these findings?
Answer choices
- AVitamin D intoxication
- BRhabdomyolysis
- CPrimary hyperparathyroidismCorrect answer
- DChronic hypoparathyroidism
- ETumor lysis syndrome
- FPTHrP-mediated hypercalcemia with suppressed intact PTH
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