Criteria for the diagnosis of postinfectious IBS:
(1) acute onset of signs and symptoms consistent with IBS (see below)
(2) preceded by an episode of acute infectious gastroenteritis with >= 2 of the following:
(2a) fever
(2b) vomiting
(2c) diarrhea
(2d) positive stool culture for bacterial pathogen (or other laboratory evidence)
(3) exclusion of other explanations (parasite, persistent infection, reinfection, IBD, etc)
Rome III criteria for IBS:
(1) recurrent episodes of abdominal pain/discomfort (including bloating)
(2) >= 3 days per month for the previous 3 months
(3) >= 2 of the following:
(3a) improvement of symptoms following defecation
(3b) onset associated with a change in frequency of defecation
(3c) onset associated with a change in stool appearance.
In postinfectious IBS the patient usually has persistent diarrhea as opposed to constipation.
