Repeated USMLE Questions Step 1- 312

A 62-year-old man complains of fatigue, progressive weakness and numbness of his arms and legs. Complete blood count shows decreased numbers of erythrocytes and increase in the mean cell volume.

Removal of which of these structures requires lifelong administration of the vitamin involved in this case?

A-Ascending colon

B-Gall bladder


D-Left kidney



This is a case of megaloblastic anemia due to vitamin B12 deficiency. Vitamin B12 is absorbed in the ileum after combining with intrinsic factor secreted in the stomach. Removal of the stomach or the ileum results in lifelong administration of vitamin B12 to protect the patient against megaloblastic anemia.

The correct answer is C

2 thoughts on “Repeated USMLE Questions Step 1- 312”

  1. its very helpful for medical students.

  2. Hello sir
    Dr. Ray makar

    Case history of Girl
    Girl age around 16 years old and she sufferings from last two years to inregular menstrual cycle.
    After examination of ultrasound her uterus is anteverted and ovaries are not visualised.
    Doctor prescribed medroxyprogestrone acetate 10mg tablet.
    After taking that tablet menstrual cycle occur regular for two months, but again same problem repeated.
    Finally doctor suggested for surgery.
    So now according to you Dr. Ray what is the procedure for her treatment.

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