What is the most likely cause of watery diarrhea and bloating in the enterally fed adult patient?

• A. Lactose content of the enteral formula
• B. Sorbitol content of liquid medications
• C. Sorbitol content of the enteral formula
• D. Lactose content of liquid medications

Answer: (B)

The key idea is that osmotic diarrhea and bloating in an enterally fed patient are often driven by non-absorbable sugars in what is given with the feeding, especially sorbitol in liquid medications. Sorbitol is a sugar alcohol that isn’t fully absorbed in the small intestine; the unabsorbed sorbitol pulls water into the intestinal lumen, producing watery stools. In the colon, it can also be fermented by gut bacteria, resulting in gas and bloating. This medication-related osmotic effect is a common, dose-dependent cause of diarrhea in patients receiving enteral nutrition, because many liquid meds contain sorbitol as a sweetener or laxative.

Lactose in formulas or in liquid meds can cause diarrhea mainly in people with lactose intolerance or low lactase activity, but many adult formulas are lactose-free or tolerated, and lactase deficiency would not universally explain new diarrhea in every enterally fed patient. Therefore, the sorbitol content of liquid medications best explains the watery diarrhea and bloating in this scenario. If symptoms persist, reviewing and possibly substituting sorbitol-containing meds with sorbitol-free alternatives is a reasonable next step.