“Acute” here is defined as diarrhea persisting less than 2 weeks, or longer if it has begun to get better. We always assume it’s due to some germ in the bowels (see Differences Among Germs for broad basic summary) (see Acute Gastroenteritis for specific germs that cause it).
Covid-19 may rarely cause diarrhea without fever or cough in the first 1-2 days of illness. Some offices, clinics, etc. might insist on a Covid test first, & not let them inside until results are back.
Diagnosis for most acute diarrhea: Acute Gastroenteritis due to Viruses (not Covid)
- Gets better on its own; treatment doesn’t help
- Begins to improve within a week
- May take 1-2 months for stools to become fully normal again
The Clinician’s Approach to Acute Diarrhea
During 1st Week of Illness: We assume the germ is a Virus
We call this Acute Gastroenteritis
1. Prevent Dehydration / Treat it if present (see Symptoms of Dehydration)
- If bad enough to need IV fluids, patient needs close follow-up every day
2. Order Stool Cultures for Bacteria only if any of the following:
- Bloody diarrhea
- High Fever
- Significant abdominal pain
- White blood cells in stool (not often checked)
- Persistent, profuse diarrhea
- Maybe food-handlers (if required by job)
3. While awaiting Culture results, we only give antibiotics if bloody diarrhea with fever. For example:
- Azithromycin or Levofloxacin, 500 mg once daily for 3 days
- Also for travelers from poor countries in the last 2 weeks (Azithromycin if to Asia)
- Also for diarrhea in pregnancy (other drugs, to also treat Listeria bacteria)
4. Bloody diarrhea: Special Tests we may consider:
- C. difficile toxin
- O157:H7 Shiga toxin
5. If recent antibiotic use or hospitalization, plus significant diarrhea, test for C. difficile toxin
If not even the least bit better after 1 week = it’s probably not a virus.
- Stool Cultures for Bacteria
- Stool for Giardia antigen
- Maybe tests for Parasites (“Ova & Parasites“)
If 2 -3 weeks go by and there’s no change at all >> see Chronic Diarrhea
See Acute Diarrhea — Full Text for more in-depth explanations and discussions.