Answer: A. Paul was treated with vitamin A 100,000 units orally for 3 days, followed by 50,000 units daily for 2 weeks, then 20,000 units orally daily for an additional 2 months. His vitamin A level at 6 weeks after the start of treatment was 24.6 mcg/dL, and at 3 months after treatment it was 33.4 mcg/dL. He was able to discontinue the large-dose vitamin A supplementation at that time. However, he was instructed that he must not stop his strict vitamin regimen again. Patients who have undergone biliopancreatic diversion with duodenal switch have a greater risk of developing vitamin deficiencies. They must be on lifelong daily multivitamins, calcium, and vitamin B12 (at least once monthly if injected or daily sublingual). The amounts of these vitamins that the patients require are individualized, and sometimes additional supplements such as vitamin D and iron are also needed. Regular surveillance should be conducted to ensure that these patients do not have vitamin deficiencies.

Julia Jurgensen APRN, CNP, practices at the Mayo Clinic in Rochester, Minnesota, in the department of endocrinology, specializing in diabetes management and obesity.

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