Which of the following is an anatomical cause of chronic diarrhea in the small intestine?

• A. Intestinal obstruction
• B. Inflammatory bowel disease
• C. Cancer metastasis
• D. Bile acid malabsorption

Answer: (A)

Anatomical problems are physical changes or blocks in the gut that disrupt normal transit and absorption. An intestinal obstruction is a mechanical blockage that prevents contents from moving forward through the small bowel. When flow is impeded, the bowel still secretes fluids, and partially obstructed or intermittently blocked segments can allow ongoing secretions to reach the colon, while absorption is impaired, leading to chronic diarrhea or loose stools. Over time, this stasis can promote bacterial overgrowth and malabsorption, contributing to a persistent diarrheal picture.

Inflammatory bowel disease involves inflammation of the bowel lining rather than a structural blockage, so it causes diarrhea through mucosal injury and altered absorption rather than an anatomical obstruction. Cancer metastasis can affect the bowel and potentially cause obstruction or mucosal disease, but on its own it’s not the primary anatomical category described here. Bile acid malabsorption causes diarrhea through a biochemical mechanism—excess bile acids reaching the colon—rather than a fixed structural lesion.