Metabolism USMLE Step 1 Practice Question
A 7-year-old boy with cystic fibrosis and chronic steatorrhea presents with progressive balance difficulty and decreased vibration sense in his lower extremities. Vitals: BP 105/68, HR 92, RR 22, Temp 37°C, SpO2 98% on room air. Deep tendon reflexes are diminished. Serum prothrombin time is elevated. He denies recent respiratory infections. Which vitamin deficiency best explains these neurological findings?
Answer choices
- AVitamin A
- BVitamin K
- CVitamin C
- DVitamin D
- EVitamin ECorrect answer
- FVitamin B12
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