From the Guidelines
Yes, it is still possible for this patient to have Crohn's disease despite negative serology and minimal colonoscopy findings. The chronic prednisone (5 mg daily) and Orencia (abatacept) could potentially mask symptoms and alter test results.
Recommendation:
- Perform a small bowel capsule endoscopy to further evaluate the small intestine, as CT enterography showed suspicious findings.
- Consider temporarily discontinuing prednisone and Orencia (if medically feasible) for 4-6 weeks before repeating IBD serology and colonoscopy with biopsies.
- Measure fecal calprotectin to assess intestinal inflammation.
Justification:
Crohn's disease can affect any part of the gastrointestinal tract, and the small bowel findings on CT are concerning, as noted in the British Society of Gastroenterology consensus guidelines on the management of inflammatory bowel disease in adults 1. Chronic immunosuppression can alter the typical presentation and test results of inflammatory bowel disease. Negative serology does not rule out Crohn's, especially in an older patient on immunosuppressive therapy, and the focal active colitis on biopsy, while non-specific, could be consistent with early or partially treated Crohn's disease.
Additional considerations:
- Monitor for worsening of rheumatoid arthritis symptoms if medications are adjusted.
- Consider consulting with a gastroenterologist specializing in inflammatory bowel diseases for further evaluation and management, as suggested by the ACR Appropriateness Criteria for Crohn disease 1. The combination of CT enterography and ileocolonoscopy has been advocated as the diagnostic algorithm of choice at initial presentation, and CT enterography allows for assessment of the entire small bowel, including the distal ileum, which is helpful in establishing a CD diagnosis in cases in which the terminal ileum and colon are not involved or when intramural disease is predominant 1.
From the Research
Diagnosis of Crohn's Disease
- Crohn's disease (CD) is a chronic inflammatory condition that can affect any part of the gastrointestinal tract, characterized by transmural inflammation, and can be diagnosed using a combination of radiographic, endoscopic, and pathological findings 2.
- The diagnosis of CD is based on the Montreal classification, which takes into account the age at diagnosis, disease location, and disease behavior 2.
- Abdominal Computed Tomography (CT) enterography is a preferred first-line radiologic study for assessing small bowel CD, while magnetic resonance enterography/enteroclysis has similar diagnostic accuracy and prevents exposure to ionizing radiation 2, 3.
Inflammatory Bowel Disease (IBD) Serology
- IBD serology, including anti-Saccharomyces cerevisiae antibody (ASCA), anti-Chlamydia trachomatis antibody (ACCA), anti-laminaribioside carbohydrate antibody (ALCA), anti-mannobioside carbohydrate antibody (AMCA), and perinuclear anti-neutrophil cytoplasmic antibody (pANCA), can be used to support the diagnosis of CD, but negative results do not rule out the disease 2, 4.
- The presence of chronic abdominal pain, diarrhea, and focal mild active colitis on colonoscopy biopsies, as well as small bowel inflammation on CT enterography, can still be consistent with CD despite negative IBD serology 2, 3, 5.
Treatment and Management
- The management of CD involves a comprehensive care team and tailored therapeutic interventions to address symptomatic response and subsequent tolerance of the intervention 2, 5.
- Medications such as steroids, immunomodulators, and biologic therapies, including Tumor Necrosis Factor (TNF) inhibitors, can be effective in inducing and maintaining remission in CD patients 2, 5, 6.
- The use of chronic low-dose prednisone and Orencia (abatacept) for rheumatoid arthritis does not necessarily preclude the diagnosis of CD, and the presence of CD should be considered in patients with persistent gastrointestinal symptoms despite treatment for other conditions 2, 5.