Can Enteritis Present with Bloody Diarrhea?
Yes, enteritis can present with bloody diarrhea, but this specifically indicates invasive bacterial colitis or amoebic dysentery rather than simple enteritis. 1
Understanding the Clinical Distinction
The presence of visible blood and mucus in stool is a critical diagnostic marker that distinguishes inflammatory bacterial enterocolitis from non-inflammatory enteritis:
- Bacterial hemorrhagic enterocolitis is characterized by bloody, purulent, and mucoid stools, often accompanied by fever, tenesmus, and severe abdominal pain 2, 3
- Viral enteritis (rotavirus, norovirus) causes watery, non-bloody diarrhea and does not produce visible blood in stool 1
- The pathologic changes in inflammatory diarrhea range from superficial exudative enterocolitis to transmural enterocolitis with overt ulceration 2
Primary Bacterial Pathogens Causing Bloody Diarrhea
The most common bacterial causes of bloody enteritis include:
- Shigella, Salmonella, Campylobacter, and enteroinvasive E. coli are the primary bacterial pathogens that produce visible blood in stool 1
- Shiga toxin-producing E. coli (STEC) causes severe abdominal pain with grossly bloody stools, though patients are typically afebrile at presentation 1
- Yersinia enterocolitica causes persistent abdominal pain and fever, particularly in school-aged children, mimicking appendicitis 1
- Campylobacter jejuni/coli presents with highly variable stool patterns ranging from watery diarrhea to bloody, mucoid stools 4
- Noncholera Vibrio species can cause bloody diarrhea, especially with seafood exposure 1
Parasitic Causes
Entamoeba histolytica (amoebic colitis) causes bloody diarrhea with a more indolent onset compared to bacterial causes 1. A wet preparation of recently passed stool looking for amoebic trophozoites aids diagnosis 1.
When to Suspect Bacterial vs. Viral Etiology
Key clinical indicators for bacterial inflammatory enteritis:
- Bloody or mucoid stools indicate invasive bacterial pathogens rather than viral gastroenteritis 1
- Fever combined with bloody diarrhea suggests bacterial etiology, though STEC is an important exception (typically afebrile) 1
- Fecal leukocytes detected on stool examination suggest inflammatory bacterial colitis 5
- The total white blood cell count and neutrophil count are often increased with invasive bacterial pathogens 5
Critical Diagnostic Approach
When bloody diarrhea is present:
- Stool culture for bacterial pathogens is warranted when fever and bloody or mucoid stools are present 1
- Test specifically for STEC O157 when right-sided abdominal pain occurs with bloody diarrhea 1
- Consider amoebic serology and stool examination for trophozoites if travel to endemic areas 1
- Endoscopy or proctoscopic examination should be considered in persons with persistent, unexplained diarrhea, acute diarrhea with clinical colitis, or in immunocompromised patients 5
Important Clinical Pitfall
Never assume all bloody diarrhea requires antibiotics. The IDSA provides a strong recommendation against empiric antimicrobial therapy for bloody diarrhea in immunocompetent children and adults while waiting for test results 6. This is because antibiotics for STEC O157 and other STEC producing Shiga toxin 2 increase the risk of hemolytic uremic syndrome 6. Always consider STEC even when fever is present, as antibiotics can precipitate life-threatening complications 6.