Symptoms of Crohn's Disease
Crohn's disease typically presents with bloody diarrhea, fever, weight loss, and abdominal pain, with characteristic endoscopic findings of aphthous ulceration, skip lesions, and granulomas on biopsy. 1
Core Clinical Manifestations
The hallmark symptoms of Crohn's disease include:
- Bloody diarrhea is a cardinal feature that distinguishes Crohn's disease from many other enteropathies 1
- Fever occurs as part of the systemic inflammatory response 1
- Weight loss results from malabsorption, reduced intake, and inflammatory catabolism 1
- Abdominal pain is frequently reported and can be severe 1
- Chronic diarrhea with increased stool frequency is common, particularly during active disease 2
Additional Gastrointestinal Symptoms
Beyond the classic presentation, patients may experience:
- Fatigue as a prominent systemic symptom 3
- Malnutrition due to impaired absorption and chronic inflammation 3
- Perianal disease including fistulae and abscesses 1
Important Diagnostic Considerations in Patients with SIBO History
In patients with a history of SIBO, distinguishing between Crohn's disease flare and SIBO recurrence is clinically challenging because symptoms overlap substantially. 2
- SIBO occurs in 45.2% of Crohn's disease patients and can mimic acute flare 4, 2
- Both conditions present with increased stool frequency, abdominal pain, meteorism, flatulence, and weight loss 2
- SIBO patients with Crohn's disease report higher stool frequency (5.9 vs 3.7 bowel movements/day) and lower body weight compared to those without SIBO 2
- SIBO is significantly more frequent in Crohn's patients with prior intestinal surgeries, ileocecal resection, or colonic involvement 2
Key Differentiating Features
Elevated inflammatory markers (ESR, CRP) and elevated fecal calprotectin strongly suggest active Crohn's disease rather than isolated SIBO. 1, 5, 6
- Normal inflammatory markers are expected in SIBO, and elevated levels should prompt investigation for Crohn's disease or other inflammatory conditions 5, 6
- Fecal calprotectin has 81% sensitivity and 87% specificity for detecting organic inflammation in IBD 6
- SIBO does not cause elevated calprotectin or inflammatory markers 5, 6
Clinical Pitfalls to Avoid
- Do not assume symptoms are solely from SIBO in patients with known Crohn's disease—SIBO represents a frequently ignored complication that often mimics acute flare 2
- Targeted work-up with hydrogen-methane breath testing is recommended when SIBO is suspected in Crohn's patients with corresponding clinical signs 2
- SIBO is independently associated with clinical relapse in quiescent Crohn's disease (hazard ratio 2.79), making detection clinically relevant for prognostic assessment 7
- Patients with penetrating disease behavior have 3.66-fold increased risk of relapse 7
Extraintestinal Manifestations
Crohn's disease may present with:
- Arthritis or arthralgia as musculoskeletal manifestations 1
- Pyoderma gangrenosum as a cutaneous manifestation 1
- Primary sclerosing cholangitis as a hepatobiliary complication 1
When to Suspect Crohn's Disease Over SIBO Alone
Consider Crohn's disease when patients present with: