This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Iron deficiency anemia, Subject name: Pathology
[{'content': 'A 62-year-old man presents with pallor, fatigue, and dyspnea on exeion. A complete blood count reveals microcytic hypochromic anemia. The likely cause of this hematological finding is? \nSelect and explain. \nA. Increased iron requirement, B. Gastrointestinal bleeding, C. Hypersplenism, D. Hemolytic anemia', 'role': 'user'}, {'content': 'Answer: B \nExplanation: - Iron deficiency anemia is the most common cause of hypochromic microcytic anemia - In men and postmenopausal women, the usual cause of IDA is occult gastrointestinal blood loss (due to helminthic infestations, GI malignancies, etc). warrants a complete workup, including GI endoscopy to detect the source of the bleeding. - In young women, the cause is most often related to menstrual blood loss (increased iron requirement), compounded by deficient dietary intake.', 'role': 'assistant'}]