Vitamins and Nutrition USMLE Step 1 Practice Question
A 6-year-old boy with cystic fibrosis presents with difficulty seeing in dim light and night blindness over the past 2 months. Vital signs: BP 95/60, HR 98, RR 22, Temp 37°C, SpO2 98% on room air. Examination reveals dry conjunctivae with foamy Bitot's spots on the temporal sclera. Serum retinol level is 15 µg/dL (normal >20 µg/dL). No signs of corneal scarring are noted. Which vitamin deficiency most likely explains these findings?
Answer choices
- AVitamin E
- BVitamin C
- CNiacin
- DVitamin D
- EVitamin ACorrect answer
- FVitamin K
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