The overlap between IBS and IBD: what is it and what does it mean?

The nature and clinical implications of irritable bowel syndrome (IBS)-type symptoms in patients with inflammatory bowel disease (IBD) who are in apparent remission have generated considerable debate. While, on the one hand, these symptoms satisfy Rome III criteria for IBS and their occurrence correlates highly with anxiety, a known trigger for IBS, on the other hand, recent studies have shown that many of these patients exhibit subtle inflammatory changes. Are these symptoms 'true' IBS superimposed on IBD, or an active but sub-clinical form of IBD? We propose a unifying model to explain and reconcile current knowledge on this topic, a model that could provide a conceptual framework for understanding the nature of these symptoms and point towards effective management strategies. We propose that IBS symptoms in IBD patients who are in remission be termed irritable inflammatory bowel syndrome in order to emphasize their unique presentation and etiology and to distinguish them from both IBS and IBD.