What is postinfectious IBS (PI-IBS)?
IBS symptoms develop in approximately 10% of healthy individuals after an infectious gastroenteritis. PI-IBS is most commonly reported after a bacterial infection such as Campylobacter, Salmonella, and Shigella, but has also been reported after viral, bacterial, protozoa, and nematode infections. Even after clearing the infection, there remains an increase in inflammatory (including CD3 lymphocytes, CD8 intraepithelial lymphocytes, and calprotectin-positive macrophages) and neuroendocrine cells that can release cytokines, serotonin, and other molecules that are capable of stimulating motor and sensory neurons in the GI tract. Risk factors for developing PI-IBS in persons who have had gastroenteritis are (1) female gender, (2) age younger than 60 years, (3) absence of vomiting, and (4) prolonged diarrhea with the infection. Additionally, anxiety, neurosis, somatization, and stressful life events before or during the infection also appear to be risk factors for determining who will develop IBS.