Mr. Smith is an alert patient in the ICU who was NPO for 2 weeks. He developed diarrhea shortly after enteral tube feedings were initiated. Classify the most likely type of diarrhea and the physiologic requirement for bowel continence that was altered.

Mr. Smith is an alert patient in the ICU who was NPO for 2 weeks. He developed diarrhea shortly after enteral tube feedings were initiated. Classify the most likely type of diarrhea and the physiologic requirement for bowel continence that was altered.

• A. Osmotic diarrhea due to antibiotic treatment
• B. Absorptive diarrhea due to atrophy of villi
• C. Mix diarrhea due to C. difficile
• D. Motility diarrhea due to increase motility

Answer: (B)

Prolonged disuse of the gut, such as two weeks of being NPO, leads to atrophy of the intestinal mucosa, especially the villi, which reduces the surface area available for absorption and the brush-border enzyme activity. When enteral feeding is started, this diminished absorptive capacity means more of the luminal contents remain unabsorbed, so water and electrolytes are not efficiently taken up. The result is a malabsorptive, or absorptive, type of diarrhea due to impaired absorption rather than excess secretion or an osmotic load. The key physiologic change here is the reduced absorptive surface area and function of the small intestine, which alters the bowel’s ability to form and contain stool properly. This is distinct from osmotic diarrhea (driven by nonabsorbable solutes in the lumen) or secretory diarrhea (driven by active secretion or infection such as C. difficile).

Prolonged disuse of the gut, such as two weeks of being NPO, leads to atrophy of the intestinal mucosa, especially the villi, which reduces the surface area available for absorption and the brush-border enzyme activity. When enteral feeding is started, this diminished absorptive capacity means more of the luminal contents remain unabsorbed, so water and electrolytes are not efficiently taken up. The result is a malabsorptive, or absorptive, type of diarrhea due to impaired absorption rather than excess secretion or an osmotic load. The key physiologic change here is the reduced absorptive surface area and function of the small intestine, which alters the bowel’s ability to form and contain stool properly. This is distinct from osmotic diarrhea (driven by nonabsorbable solutes in the lumen) or secretory diarrhea (driven by active secretion or infection such as C. difficile).