A 22 year old man visits his physician for evaluation of new symptoms after the use of isoniazid treatment for TB. His skin is inflamed, had diarrhea and feeling like not himself. What is the vitamin deficiency responsible for this patient's new symptoms? A- Thiamine deficiency B- Riboflavin deficiency C- Niacin deficiency D- Folic acid deficiency E- Vitamin B12 deficiency Answer: http://medical-usmle.com/?p=1248
