A friend who just returned from a missionary trip in a third world country complains of severe large volume diarrhea. She is most likely experiencing which of the following types of diarrhea?

A friend who just returned from a missionary trip in a third world country complains of severe large volume diarrhea. She is most likely experiencing which of the following types of diarrhea?

• A. Secretory
• B. Absorptive
• C. Motility
• D. Mixed

Answer: (A)

Diarrhea is classified by how water is lost in the gut, and this pattern helps explain a traveler’s severe, large-volume watery stools. Secretory diarrhea is driven by toxins that stimulate active secretion of electrolytes and water into the intestinal lumen, producing very large volumes of watery stool that persist even with fasting. This mechanism fits infections like cholera, which are a classic travel risk in some settings. The stool remains copious and watery because the body is actively secreting fluid, not because there’s a failure to absorb nutrients. In contrast, absorptive (osmotic) diarrhea comes from substances that aren’t absorbed, pulling water into the gut, and it typically decreases with fasting as the osmotic load is reduced. Motility diarrhea results from rapid intestinal transit and isn’t usually characterized by such huge volumes. Mixed diarrhea has features of more than one mechanism but the presentation described—severe, large-volume watery diarrhea after travel—best aligns with a secretory process.

Diarrhea is classified by how water is lost in the gut, and this pattern helps explain a traveler’s severe, large-volume watery stools. Secretory diarrhea is driven by toxins that stimulate active secretion of electrolytes and water into the intestinal lumen, producing very large volumes of watery stool that persist even with fasting. This mechanism fits infections like cholera, which are a classic travel risk in some settings. The stool remains copious and watery because the body is actively secreting fluid, not because there’s a failure to absorb nutrients.

In contrast, absorptive (osmotic) diarrhea comes from substances that aren’t absorbed, pulling water into the gut, and it typically decreases with fasting as the osmotic load is reduced. Motility diarrhea results from rapid intestinal transit and isn’t usually characterized by such huge volumes. Mixed diarrhea has features of more than one mechanism but the presentation described—severe, large-volume watery diarrhea after travel—best aligns with a secretory process.