Before attributing chronic diarrhea to IBD, which conditions should be ruled out?

• A. Infectious, neoplastic, SIBO, abnormal anatomy, and extra-intestinal disease
• B. Infectious and neoplastic diseases only
• C. SIBO and abnormal anatomy only
• D. Extra-intestinal disease only

Answer: (A)

Before attributing chronic diarrhea to inflammatory bowel disease, clinicians must rule out a broad differential diagnosis. Infections can cause ongoing diarrhea and inflammation-like symptoms, so stool testing and targeted evaluations are essential to exclude chronic infectious causes. Neoplastic processes, such as colorectal cancer or gastrointestinal lymphomas, can present with persistent diarrhea and weight loss, making careful endoscopic evaluation with biopsies important. Small intestinal bacterial overgrowth can mimic IBD with bloating and diarrhea, so assessing for SIBO helps avoid misdiagnosis. Abnormal anatomy, including structural problems from surgery, strictures, or diverticular disease, can produce chronic diarrhea independently of mucosal inflammation and needs appropriate imaging or endoscopic assessment. Finally, extra-intestinal diseases—systemic conditions outside the gut that can present with GI symptoms or confound the picture—should be considered. Because each category can imitate or accompany IBD, ruling out all of them provides a safer, more accurate diagnostic path.