Stool Cultures
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Pull up a stool and let’s talk about it…
Last week one of our fellows gave a great talk on Chronic Diarrhea (or “Dirrhorea”) – if you missed that, check it out here!
For review, diarrhea is defined as the passage of 3+ unformed stools per day and is further defined by chronicity:
Acute: symptoms < 14 days
Subacute: symptoms 14-30 days
Chronic: symptoms > 30 days
Diarrhea is then further defined as inflammatory or non-inflammatory.
Noninflammatory diarrhea:
Watery, non-bloody, associated with periumbilical cramps, bloating, nausea/ vomiting
Disrupts normal absorption/secretory process in small bowel, no tissue invasion so no fecal leukocytes
Usually self-limited
Inflammatory diarrhea:
Blood or pus, fever
Usually caused by invasive or toxin-producing bacterium
Diagnostic eval requires routine stool cultures, and testing as indicated for C. diff, and O&P
Fecal leukocytes or lactoferrin usually are present
A stool culture is useful in infectious etiologies of diarrhea to guide treatment. So when would you consider getting one? As most infectious diarrhea is acute and self-limiting illness, there needs to be good cause to obtain a culture. I ask myself: when would I need to treat a diarrheal illness? I start thinking about treating based on severity and vulnerability.
There are 4 main indications for obtaining a stool culture:
Severity: severe diarrhea (total disability due to diarrhea; significant dehydration, sepsis)
Inflammation: Blood or Fever (≥38.5)
Chronicity: persistent diarrhea (≥14 days)
Significant risk factors: immunocompromised, people employed as food handlers, confined to nursing home or work in day-care center.
Additional review:
The Clinical Problem Solvers team has a neat Schema they’ve created for thinking about Chronic Diarrhea:
