Post-infectious irritable bowel syndrome.

Irritable bowel syndrome (IBS) affects 8% to 22% of the general population. Although patients describe an insidious onset of symptoms, including abdominal pain relieved with bowel movements, excessive intestinal gas, variable bowel habits, and abdominal bloating, a subgroup of individuals describe the onset of IBS symptoms following an episode of acute gastroenteritis, known as post-infectious IBS (PI-IBS). Several studies have demonstrated the development of IBS following infection. Risk factors for the development of PI-IBS are female sex and longer duration of initial illness. Although the underlying mechanism of PI-IBS is unclear, ongoing inflammation is clearly a factor in the pathogenesis. The underlying inflammatory process results in increased enterochromaffin cells, T-lymphocytes, intestinal permeability, colonic transit time, and a variety of immunologic abnormalities. PI-IBS patients tend to have a better prognosis than do those with idiopathic IBS, with resolution of symptoms within 5 to 6 years. Treatment is similar to that of idiopathic IBS.