Current understanding of pathogenesis of functional dyspepsia.

Functional dyspepsia (FD) is a disorder in which upper abdominal symptoms occur in the absence of organic disease that explains them. Many pathogenic factors have been proposed for FD, including motility abnormalities, visceral hypersensitivity, psychosocial factors, excessive gastric acid secretion, Helicobacter pylori, genetics, environment, diet, lifestyle, and post-infectious FD. Many of those pathogenic factors are also common to irritable bowel syndrome and other functional gastrointestinal disorders, so understanding FD offers a glimpse into the nature of functional gastrointestinal disorders in general. Motility abnormalities and visceral hypersensitivity are thought to be important in the manifestation of FD symptoms, but the other factors are also thought to contribute by interacting and modifying motility and visceral hypersensitivity.