BLOODY DIARRHEAA good discussion on the differential diagnosis of bloody and none bloody diarrhea of acute onset occurred today.
As always, a good history (as always) goes a long way in helping to focus the picture. In addition to a travel/sick contacts/dietary/medication history, sexual history is also important.
It is recommended that all patients with acute bloody diarrhea (including on history and FOB +) undergo stool culture.
DIFFERENTIAL DIAGNOSIS
Infection:
cytoxic - E. coli (EHEC) O157:H7 (often present with no fever), C. Difficile
invasive - E. coli (EIEC), Salmonella, Shigella, Yersinia, Campylobacter
Inflammatory: Inflammatory Bowel disease, radiation proctitis/colitis
Ischemic Colitis
Non diarrheal causes of Lower GI bleed should also be considered (diverticular disease, etc.)
Other considerations are rarer and depend on immunosuppression (CMV colitis) and exposure (GI anthrax, Intestinal TB, intestinal amebiasis, HSV procitis etc.)
A study of infectious etiologies (determined by stool culture) of acute bloody diarrhea in patients presenting to the ER in the US is posted here. If found enteropathogens in 12.5% of cases that were cultured despite the physician's presumptive diagnosis of a noninfectious cause.
A second study of the clinical and epi factors of diarrhea in the U.S. is posted here.
For an excellent blog on Infectious Disease issues see: http://www.idologist.com/Blog/
