Electrolyte Disorders USMLE Step 1 Practice Question
A 48-year-old woman presents 2 days after thyroid surgery with perioral numbness and hand cramping. Vital signs show BP 128/82, HR 92, RR 16, temp 37.2°C, SpO2 98%. Physical examination reveals facial twitching upon tapping the facial nerve. Serum calcium is 6.8 mg/dL. ECG demonstrates prolonged QT interval. She denies recent neck pain or voice changes. Which electrolyte abnormality best explains her clinical presentation?
Answer choices
- AHypocalcemiaCorrect answer
- BHypercalcemia
- CHypophosphatemia
- DHypernatremia
- EHypermagnesemia
- FHypomagnesemia
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