Initial Management of Diarrhea with Negative Shiga Toxin Test

Assessment and Evaluation

The Infectious Diseases Society of America recommends evaluating patients with diarrhea for dehydration, which increases the risk of life-threatening illness and death, especially among young children and older adults 1, 2
Assess for fever, bloody or mucoid stools, severe abdominal cramping or tenderness, or signs of sepsis, which may indicate specific bacterial pathogens requiring targeted treatment 3
Consider clinical and epidemiological features that may suggest specific pathogens, such as recent travel history 2, food consumption patterns (raw/undercooked meat, seafood, unpasteurized dairy) 4, exposure to others with similar symptoms 1, and recent antibiotic use 1, 4

The Infectious Diseases Society of America recommends further stool testing for other common bacterial pathogens including Salmonella, Shigella, Campylobacter, Yersinia, and C. difficile in patients with a negative Shiga toxin test 3
Blood cultures should be obtained from infants <3 months of age 5, patients with signs of septicemia 1, immunocompromised individuals 1, and those with systemic manifestations of infection 3, 5
Consider specific testing based on clinical presentation, such as testing for Yersinia in patients with persistent abdominal pain 3 and testing for Vibrio species in patients with large-volume rice water stools or exposure to seafood/brackish waters 3

The American Academy of Pediatrics and the World Health Organization recommend fluid and electrolyte replacement as the cornerstone of management for patients with diarrhea 6, 7
For mild to moderate dehydration, use reduced osmolarity oral rehydration solution (ORS) 6
For severe dehydration, shock, altered mental status, or failure of oral rehydration therapy, administer isotonic intravenous fluids (lactated Ringer's or normal saline) 6, 7

If symptoms persist beyond 14 days, consider non-infectious conditions including inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) 5
Follow-up testing is not recommended in most people following resolution of diarrhea 5
For patients who do not respond to initial therapy, clinical and laboratory reevaluation may be indicated 5

Failing to distinguish between non-Shiga toxin E. coli and Shiga toxin-producing E. coli (STEC) when interpreting test results 6, 7
Inadequate fluid replacement, especially in high-risk populations like young children and elderly patients 2, 7