Calcium and Parathyroid USMLE Step 1 Practice Question
A 45-year-old man with hypertension and type 2 diabetes presents with muscle cramps and paresthesias. Vital signs: BP 148/92 mmHg, HR 88/min, RR 16/min, temp 37°C. Labs show serum calcium 6.8 mg/dL, phosphate 5.8 mg/dL, PTH 780 pg/mL, 25-hydroxyvitamin D 8 ng/mL, and GFR 32 mL/min/1.73m². He denies recent chemotherapy. Which intervention would most directly address the underlying pathophysiology?
Answer choices
- AVitamin D2 supplementation at 50,000 units weekly
- BUrgent parathyroidectomy to remove hyperplastic tissue
- CHigh-dose calcium supplementation to normalize serum calcium
- DPhosphate restriction and phosphate binders to reduce hyperphosphatemiaCorrect answer
- ELoop diuretics to increase urinary phosphate excretion
- FCinacalcet allosterically sensitizing calcium-sensing receptor
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