Symptoms of Clostridioides difficile Infection
The hallmark symptom of C. difficile infection is diarrhea, defined as three or more unformed stools within 24 hours, but clinicians must recognize that severe CDI can present paradoxically without diarrhea, manifesting instead as abdominal distention, ileus, or toxic megacolon 1, 2.
Classic Presentation
The typical symptom profile includes:
- Diarrhea: ≥3 loose or watery bowel movements in 24 hours (Bristol Stool Chart types 6-7) 1
- Abdominal pain or cramping 1
- Fever 3
These symptoms must occur in the absence of laxative use within the preceding 48 hours to warrant testing 1.
Atypical and Severe Presentations
A critical pitfall is missing CDI in patients without diarrhea. Recent evidence demonstrates that up to 19.5% of CDI cases present atypically with gastrointestinal dysmotility symptoms appearing before diarrheal onset 4. These atypical presentations include:
- Rapid abdominal distention 2
- Constipation or minimal bowel movements 2
- Paralytic ileus 3, 5
- Vague abdominal complaints with change in bowel function 2
In severe disease, patients may develop:
The absence of diarrhea in severe CDI correlates with significantly increased mortality 4. In one case series, 5 of 9 patients presenting without diarrhea developed toxic megacolon requiring total colectomy, with 2 deaths 2. Atypical presentations are associated with delayed diagnosis (median 4 versus 2 days) and 2.6-fold increased 90-day mortality compared to typical presentations 4.
Post-Infectious Symptoms
After successful treatment, clinicians should distinguish between:
- Asymptomatic colonization: Up to 56% of treated patients shed spores for 6 weeks without symptoms 8
- Post-infectious functional bowel disorder: Occurs in up to 35% within 2 weeks of resolution, but only 4.3% have symptoms beyond 3 months 8
- CDI-associated functional bowel disorder: Affects 27.7% of patients referred for recurrent symptoms, more common in younger females with anxiety/depression 9
Never order a "test of cure" as asymptomatic shedding is common and does not require treatment 8.
Diagnostic Approach
Testing should only be performed when:
- Patient has ≥3 unformed stools in 24 hours AND
- Symptoms are not clearly attributable to other causes (laxatives, tube feeding, chemotherapy) AND
- No laxative use in preceding 48 hours 1
However, maintain high suspicion for CDI even in the absence of diarrhea if patients develop rapid abdominal distention, especially with multi-organ dysfunction 2. Small-bowel involvement occurs in 16.3% of cases and contributes to atypical presentations 4.