Campylobacter Infection is the Most Likely Diagnosis
Your patient's positive Gastro PCR for Campylobacter, combined with the clinical presentation of yellow foul-smelling diarrhea, indigestion/reflux symptoms, and initial dark stools, confirms Campylobacter jejuni/coli infection as the cause. 1, 2
Why This Diagnosis Fits
- Campylobacter classically presents with bloody or dark diarrhea initially (seen in 21-97% of cases), followed by watery to loose yellow stools as the infection evolves 3, 2
- The yellow, foul-smelling diarrhea with varying Bristol types 4-6 is consistent with the enterocolitis pattern of Campylobacter, which affects both small intestine and colon 4
- Abdominal discomfort, nausea, and acid reflux-like symptoms are common manifestations of Campylobacter infection, as the organism causes significant gastrointestinal inflammation 5, 2
- The normal CBC is expected in uncomplicated Campylobacter infection, as systemic involvement is rare in immunocompetent patients 6
Immediate Treatment Recommendation
Start azithromycin immediately—1000 mg single dose OR 500 mg daily for 3 days—as this is the first-line treatment with 96% clinical cure rate and reduces symptom duration from 50-93 hours to 16-30 hours when given within 72 hours of onset. 1, 2
Why Azithromycin Over Other Options
- Fluoroquinolones (like ciprofloxacin) have resistance rates exceeding 90% in many regions, with 33% clinical failure rates when the isolate is resistant 1, 7
- Macrolide resistance remains low at approximately 4%, making azithromycin far superior to fluoroquinolones in the current resistance landscape 1
- Early treatment (within 72 hours) provides maximum benefit; delaying beyond this window reduces antibiotic effectiveness 1, 2
Expected Clinical Course
- Most patients experience symptom resolution within 3-5 days without treatment, but azithromycin shortens this to 1-2 days when given early 3
- Bloody stools typically resolve within the first few days, transitioning to the yellow watery pattern you're observing 3
- If diarrhea persists beyond 10-14 days, further evaluation is warranted to rule out complications or alternative diagnoses 3, 2
Critical Monitoring Points
- Watch for severe complications including toxic megacolon, intestinal perforation, or bacteremia, particularly if fever worsens or severe abdominal pain develops 2
- Avoid antimotility agents (loperamide, opiates) as they may prolong bacterial shedding and worsen outcomes in invasive diarrhea 5, 1
- Monitor for post-infectious complications over the following weeks to months: Guillain-Barré syndrome (typically 1-3 weeks post-infection), reactive arthritis, or irritable bowel syndrome 5, 3, 6
Supportive Care Essentials
- Maintain adequate hydration with oral rehydration solutions, especially given the ongoing diarrhea 3
- Continue normal diet as tolerated; there's no need for dietary restrictions beyond avoiding foods that worsen symptoms 1
When to Reassess
If symptoms worsen or fail to improve after 48 hours of azithromycin treatment, consider alternative diagnoses or complications such as post-infectious IBS, which can develop in 10-14% of patients following Campylobacter infection. 5, 1
The dark stools at onset were likely blood-tinged from the initial inflammatory colitis phase, while the current yellow stools represent the ongoing enteritis with bile malabsorption and rapid transit 3, 2. This evolution is typical for Campylobacter infection and does not suggest a separate pathology.