How to avoid treating irritable bowel syndrome with biologic therapy for inflammatory bowel disease.

Some patients with an established diagnosis of Crohn's disease and symptoms compatible with a disease flare do not have evidence of active Crohn's disease by laboratory, endoscopic or radiographic criteria. In clinical trials, approximately 18% of patients with Crohn's disease and moderate to severe clinical symptoms have no evidence of ulceration at colonoscopy. There are multiple other causes of symptoms in patients with Crohn's disease, including the presence of disease complications (stricture, fistula and abscess), complications of surgical resection (bile salt diarrhea, steatorrhoea and small bowel bacterial overgrowth), concomitant irritable bowel syndrome, concomitant infections (Clostridium difficile, cytomegalovirus) and concomitant depression. In conclusion, the clinical impression of gastroenterologists based on the patient's history is frequently incorrect and is an insufficient basis for making therapeutic decisions. Colonoscopy and CT or MRI enterography should be employed routinely prior to any major changes in therapy: (1) before starting steroids, immunosuppressives or biologicals; (2) when patients fail to respond to steroids, immunosuppressives or biologicals; (3) when patients receiving maintenance therapy with immunosuppressives or biologicals relapse; (4) before surgery. Treatment of patients who have no evidence of active disease by imaging with steroids, immunosuppressives or biological agents will not address the cause of the symptoms and will expose the patient to risks that may be unnecessary. These patients should be systematically evaluated for bile acid diarrhoea, steatorrhoea, bacterial overgrowth, irritable bowel syndrome and depression.