Be or Not to Be a Crohn’s Disease: CD and Its Numerous Differential Diagnosis

Abstract

Nowadays, there is still no gold standard test for Inflammatory Bowel Disease (IBD). Many etiologies are responsible of an inflammation of the gut. When a patient presents with signs suggestive of IBD (abdominal pain, diarrhea, and sometimes fever), the clinician had to establish whether the patient suffers from an IBD or from one of the numerous alternative diseases. The use of immunosuppressive agents and biotherapies in IBD treatment enforces the necessity to distinguish them from infectious diseases, particularly from tuberculosis. Clinical signs of IBD are not specific. This review will focus on the differential diagnosis of Crohn’s Disease (CD) and on the helpful tests for the diagnosis. Histopathological findings are sometimes insufficient to establish the diagnosis, granuloma is not specific and inconstant in CD (only in 15 to 60 % of cases). Serological assays (perinuclear antineutrophil antibodies pANCA and anti-Saccharomyces cerevisae antibodies ASCA) are contributing to the diagnosis, but their sensitivity and specificity are too weak for a gold standard. This review will be divided in 2 parts: first, a review of etiologies inducing granulomas in the gut (infections, systemic diseases, drug related disorder...), second, a review of controversies in the distinction between ulcerative colitis (UC) and CD. This review will contribute to provide to clinicians a strategy for differential diagnosis of CD (infection, systemic disease, neoplasm, drug related disorders, non specific inflammation...). Therefore, sensible and specific biomarkers are needed to facilitate the diagnosis of IBD in the future. Crohn’s disease is an Inflammatory Bowel Disease (IBD), able to affect all the gut mucosa. Crohn disease may induce lesion of epithelioid granuloma. However, this type of lesion may be associated with others affections, certain of these affections are infectious diseases, and contra-indicate formally the immunotherapy. Nowadays, there is no gold standard assay to make the etiological diagnosis of granuloma of the gastrointestinal (GI) tract.