Which anatomical structure's resection can contribute to chronic small bowel diarrhea?

Which anatomical structure's resection can contribute to chronic small bowel diarrhea?

• A. Duodenum
• B. Pylorus
• C. Ileocolic junction
• D. Cecum

Answer: (C)

The key idea is that the ileocecal junction includes the ileocecal valve, which regulates flow from the ileum into the colon and prevents reflux of colonic contents back into the small bowel. If this junction is resected, the barrier is lost and small-bowel transit becomes faster while colonic bacteria can invade the ileum. This promotes small-bowel bacterial overgrowth, which impairs nutrient absorption and leads to chronic small-bowel-type diarrhea. While removing other regions can cause diarrhea through different mechanisms (for example, rapid gastric emptying after pylorus removal, or fat malabsorption after duodenal loss), none are as directly linked to chronic small-bowel diarrhea as losing the ileocecal valve.

The key idea is that the ileocecal junction includes the ileocecal valve, which regulates flow from the ileum into the colon and prevents reflux of colonic contents back into the small bowel. If this junction is resected, the barrier is lost and small-bowel transit becomes faster while colonic bacteria can invade the ileum. This promotes small-bowel bacterial overgrowth, which impairs nutrient absorption and leads to chronic small-bowel-type diarrhea. While removing other regions can cause diarrhea through different mechanisms (for example, rapid gastric emptying after pylorus removal, or fat malabsorption after duodenal loss), none are as directly linked to chronic small-bowel diarrhea as losing the ileocecal valve.