Overlap between functional abdominal pain disorders and organic diseases in children

Functional abdominal pain disorders are highly prevalent in children. These disorders can be present in isolation or combined with organic diseases, such as celiac disease and inflammatory bowel diseases. Intestinal inflammation (infectious and non-infectious) predisposes children to the development of visceral hypersensitivity that can manifest as functional abdominal pain disorders, including irritable bowel syndrome. The new onset of irritable bowel syndrome symptoms in a patient with an underlying organic disease, such as inflammatory bowel disease, is clinically challenging, given that the same symptomatology may represent a flare-up of the inflammatory bowel disease or an overlapping functional abdominal pain disorder. Similarly, irritable bowel syndrome symptoms in a child previously diagnosed with celiac disease may occur due to poorly controlled celiac disease or the overlap with a functional abdominal pain disorder. There is little research on the overlap of functional abdominal disorders with organic diseases in children. Studies suggest that the overlap between functional abdominal pain disorders and inflammatory bowel disease is more common in adults than in children. The causes for these differences in prevalence are unknown. Only a handful of studies have been published on the overlap between celiac disease and functional abdominal pain disorders in children. The present article provides a review of the literature on the overlap between celiac disease, inflammatory bowel disease, and functional abdominal pain disorders in children and establish comparisons with studies conducted on adults.