Small bowel vs colon as source of diarrhea

Q: All of the following are sources of diarrhea from the colon except? (select one)

A) Vibrio cholerae

B) Shigella

C) Clostridioides difficile

D) Yersinia

E) Enteroinvasive E. coli

Answer: A

The objective of this question is to highlight the importance of proper history during clinical exams. Subsequently, it may guide towards the appropriate diagnosis. The probable bugs in diarrhea are usually either in the small bowel or colon, which may have different characteristics of diarrhea. Diarrhea of small bowel origin is usually large volume, watery, and results in cramps, gas, and bloating. Fever is unlikely. In contrast, diarrhea from colon is small volume and associated with painful bowel movements. Fever and blood/mucoid in stool are common. Inflammatory cells are seen on stool microscopy, which is unlikely in small bowel diarrhea.

Salmonella, Escherichia coli, Clostridium perfringens, Staphylococcus aureus, Bacillus cereus, and Vibrio cholerae usually originate in the small bowel.

Shigella, Clostridioides difficile, Yersinia, and Enteroinvasive E. coli are mostly found in the colon.

#GI

#ID

References: 

1. Lam C, Chaddock G, Marciani Laurea L, Costigan C, Cox E, Hoad C, Pritchard S, Gowland P, Spiller R. Distinct Abnormalities of Small Bowel and Regional Colonic Volumes in Subtypes of Irritable Bowel Syndrome Revealed by MRI. Am J Gastroenterol. 2017 Feb;112(2):346-355. doi: 10.1038/ajg.2016.538. Epub 2016 Dec 13. PMID: 27958282; PMCID: PMC5318666.

2. Sweetser S. Evaluating the patient with diarrhea: a case-based approach. Mayo Clin Proc. 2012;87(6):596-602. doi:10.1016/j.mayocp.2012.02.015

3. Murray JA, Rubio-Tapia A. Diarrhoea due to small bowel diseases. Best Pract Res Clin Gastroenterol. 2012;26(5):581-600. doi:10.1016/j.bpg.2012.11.013