Calcium and Parathyroid USMLE Step 1 Practice Question
A 28-year-old woman with a 6-month history of chronic diarrhea and steatorrhea presents with muscle cramps and paresthesias. Vital signs are normal; SpO2 98% on room air. Laboratory studies reveal serum calcium 6.8 mg/dL, phosphate 5.2 mg/dL, PTH 245 pg/mL, and 25-hydroxyvitamin D 15 ng/mL. Chest X-ray shows normal cardiac silhouette without prolonged QT findings. She denies recent antibiotic use. Which nutritional deficiency is contributing to these biochemical abnormalities?
Answer choices
- AIron deficiency
- BCalcium supplementation excess
- CVitamin B12 deficiency
- DVitamin D deficiencyCorrect answer
- EZinc deficiency
- FVitamin A deficiency
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