Diagnosis and Treatment of Post-Camping Diarrhea with Greasy, Watery Stools
Most Likely Diagnosis
This clinical presentation is highly suggestive of giardiasis (Giardia lamblia infection), given the three-week duration, greasy/fatty stools (steatorrhea), flatulence, crampy abdominal pain, and recent wilderness camping exposure with likely contaminated water exposure. 1, 2
Diagnostic Approach
Stool testing for parasites is strongly recommended for travelers with diarrhea lasting ≥14 days, specifically testing for Giardia, Cryptosporidium, Cyclospora, and other intestinal parasites. 1, 2
Key diagnostic steps:
- Obtain stool specimens for ova and parasite examination, with molecular testing (multiplex PCR panels) preferred when available for rapid and accurate diagnosis 1
- The greasy, watery character of stools (steatorrhea) is particularly characteristic of Giardia, which causes malabsorption 3
- Three-week duration classifies this as persistent diarrhea (>14 days), which has higher frequency of protozoal pathogens and justifies parasitic evaluation 1
Important differential considerations:
- Post-infectious irritable bowel syndrome (PI-IBS) should be considered if parasitic testing is negative, as up to 10-17% of travelers develop IBS after infectious diarrhea 1, 4
- Blastocystis hominis and Dientamoeba fragilis are also common in returning travelers with persistent symptoms (found in 26.6% and 18.7% respectively), though their pathogenic role remains debated 3
- Lactose intolerance may develop secondary to intestinal infection and should be reassessed if symptoms persist 1
Treatment Recommendations
Empiric Treatment While Awaiting Results
For persistent watery diarrhea lasting ≥14 days, empiric antimicrobial treatment should generally be avoided until diagnostic testing is completed. 1 However, given the high clinical suspicion for giardiasis based on the greasy stool character and camping exposure:
- Consider empiric treatment with metronidazole or tinidazole for presumed giardiasis if the patient is significantly symptomatic and testing will be delayed
- Metronidazole 250-500 mg three times daily for 5-7 days is standard therapy for giardiasis
- Tinidazole 2 grams as a single dose is an alternative with better compliance
Symptomatic Management
Loperamide is NOT recommended for persistent diarrhea of unknown etiology, particularly when parasitic infection is suspected, as inhibition of peristalsis may worsen outcomes. 5
- Fluid and electrolyte replacement is essential, as dehydration is a frequently identified risk factor for diarrhea-related complications 2, 5
- Oral rehydration solutions are preferred over plain water 1
Critical Pitfalls to Avoid
- Do not use loperamide for persistent diarrhea >14 days or when parasitic infection is suspected, as it may prolong infection and cause complications including toxic megacolon 5
- Do not assume simple self-limited travelers' diarrhea when symptoms persist beyond 14 days - this duration mandates parasitic evaluation 1
- Reassess for non-infectious conditions including inflammatory bowel disease and post-infectious IBS if symptoms persist despite appropriate antimicrobial therapy 1
- Among backpackers on wilderness trails, diarrhea incidence ranges from 11-56%, with water contamination being a primary source despite filtration practices 6
Follow-Up Considerations
If symptoms persist despite treatment or testing is negative, consider:
- Post-infectious functional bowel disease or IBS, which occurs in approximately 10-11% of patients after infectious diarrhea in travelers 1, 4
- Repeat stool testing with molecular methods if initial testing was culture-based only 1
- Evaluation for small intestinal bacterial overgrowth (SIBO) or other malabsorptive conditions if steatorrhea persists 3