For Clostridioides difficile, see GI: Diarrhea in Hospitalized Patients
Overview
- Most cases are self-limited bacterial or viral infections and will resolve <3 days in immunocompetent-hosts.
- Further evaluation is warranted for profuse diarrhea with dehydration, fever, bloody diarrhea, severe abdominal pain, recent antibiotic use, and patients who are elderly or immunocompromised.
Etiology / Risk Factors
Determine how illness started, duration, frequency and quality of stools (bloody/watery), signs and symptoms of hypovolemia, travel history, exposure history (see below), sick contacts, new medications (or recent antibiotics), and other associated symptoms (fever, etc.).
|
Bacteria |
Viruses |
|
Aeromonas hydrophila |
CMV (HIV, transplant recipients) |
|
*Bacillus cereus (beef, pork, fried rice), incubation 1-6 hours |
Norovirus (cruises, institutional outbreaks) |
|
Campylobacter (undercooked poultry, raw dairy) |
Rotavirus (daycares) |
|
Clostridioides difficile |
Protozoa |
|
Enterohemorrhagic E. coli, aka EHEC (beef esp. undercooked hamburger, pork, dairy, apple cider) |
Cryptosporidium (daycares, swimming pools, HIV, cows) |
|
Enteroinvasive E. coli (dairy) |
Cyclospora (raspberries) |
|
Enterotoxigenic E. coli (travelers) |
Entamoeba histolytica (Mexico, MSM) |
|
Mycobacterium avium complex |
Giardia (daycare, swimming pools, mountain streams) |
|
Salmonella (beef, pork, poultry, raw dairy, lizard exposure, travel) |
Isospora (HIV) |
|
Shigella (daycares, vegetables, homeless, HIV) |
Microsporidium (HIV) |
|
*Staph aureus (salads, meat, dairy), incubation 1-6 hours |
|
|
Vibrio cholera |
|
|
Vibrio parahaemolyticus (raw seafood, cirrhosis) |
|
|
Yersinia (beef, milk, cheese, iron overload states) |
Note: Blastocystis hominis (usually not a pathogen unless in the very immunosuppressed) |
*toxin mediated food poisoning
- Bloody diarrhea with fever (dysentery) is suggestive of bacterial pathogens (Enterohemorrhagic E. coli, non-typhoidal Salmonella, Shigella, Campylobacter) or amoebic colitis.
Acute Diarrhea in Resource Rich Settings
|
Watery Diarrhea |
Inflammatory Diarrhea (fever, mucoid or bloody stools) |
|
Norovirus |
Nontyphoidal Salmonella |
|
Clostridium perfringrens |
Campylobacter spp |
|
ETEC |
Shigella spp |
|
Other enteric viruses (rotavirus, adenovirus, astrovirus, sapovirus) |
EHEC |
|
Giardia lamblia |
Yersinia spp |
|
Cryptosporidium parvum |
Vibrio parahemolyticus |
|
Listeria monocytogenese |
Entamoeba histolytica |
|
Cyclospora cayetanensis |
|
Evaluation
- Traveler’s or community acquired diarrhea: if fevers or bloody stool, send stool gram stain and cultures for Salmonella, Shigella, Campylobacter. Diagnostic yield 1.5-5.6% for all patients, but higher in severe illness. Negligible yield if hospitalized > 3 days unless immunocompromised.
- At the VA and Moffitt, can send a stool PCR for common pathogens
- E coli O157:H7 culture and toxin assay: call lab if bloody or +risk factors (automatically done as part of the stool culture at UCSF - Moffitt).
- Rule out C diff if previous antibiotics, healthcare exposure or immunocompromised (note, rarely causes bloody diarrhea).
- Persistent diarrhea (>7 days): consider Giardia (stool antigen), acid-fast stains for Cryptosporidium, Cyclospora and Isospora. O&P x 3.
- If HIV+ add microsporidium assay and consider MAC (need colonoscopy for biopsy).
- Persistent abdominal pain and fever: culture for Yersinia entercolitica.
- Seafood exposure: culture for Vibrio spp.
- Consider sigmoidoscopy for proctitis in MSM or HIV (HSV, GC, Chlamydia, syphilis, Giardia, in addition to usual pathogens) with biopsy to rule out CMV.
- Fecal leukocytes (sensitivity 70%) can help document inflammation from invasive Salmonella, Shigella, Campylobacter, IBD, severe C diff.
- Fecal lactoferrin – has 90-100% sensitivity and specificity in distinguishing between inflammatory (bacterial + IBD) vs. non-inflammatory (viral, protozoal).
Management
(note that dosing is for immunocompetent hosts)
- Supportive care is the mainstay of treatment: IV Fluids and electrolyte repletion. Diet: bland, low fat, with limited dairy.
- Empiric antibiotics are not recommended in watery diarrhea.
- In inflammatory diarrhea in immunocompetent patients, empiric antibiotics are generally not recommended while waiting for diagnostic studies to return.
- Typical empiric regimen is fluoroquinolone or macrolide depending on local antibiogram and travel history.
- Avoid empiric antibiotics if EHEC is suspected given concern that antibiotics can lead to increased Shiga toxin production
- Giardia: metronidazole 250-500mg TID x 7-10 days.
- Isospora and Cyclospora: TMP-SMX DS BID x 7-10 days.
- Antimotility agents: contraindicated in bloody diarrhea with fever and with C. difficile. If just diarrhea, can start loperamide 4mg once, then 2mg after each unformed stool, not to exceed 16mg.
- Probiotics: may improve traveler’s diarrhea, but efficacy remains unclear. They may improve secondary lactase deficiency, a common sequela of diarrhea.
- Potential complications: HUS in enterohemorrhagic E. coli, Guillain-Barre in C. jejuni, malnutrition, and dehydration.
Key Points
- Most cases of infectious diarrhea are self-limited bacterial or viral infections.
- Dysentery suggests a bacterial infection or amoebic colitis.
IDSA Practice Guidelines for Acute Infectious Diarrhea:
https://www.idsociety.org/practice-guideline/infectious-diarrhea/
Barr W, Smith A. Acute diarrhea. Am Fam Physician. 2014;89(3):180‐189.
AU Guerrant RL, Van Gilder T, et al. Infectious Diseases Society of America, Practice guidelines for the management of infectious diarrhea. Clin Infect Dis. 2001;32(3):331.
Guerrant, RL et al. "Practice Guidelines for the Management of Infectious Diarrhea" Clinical Infectious Diseases 2001; 32:331–50
Mandell GL, Bennett JE, Dolin R. Principles and Practice of Infectious Diseases, Sixth Edition. Churchill Livingstone;2005.
Key words: Diarrhea, Travel, E coli