What Is Post-Infectious IBS?

Frequently Asked Questions About Post Infectious IBS

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Have you ever had a bad “stomach bug?” If so, you know that typically the symptoms of fever, vomiting and diarrhea clear up within a matter of days. Unfortunately, for some people, that return to health does not always happen as expected. In some cases, a person finds that symptoms linger and develop into a case of irritable bowel syndrome, or IBS. When this occurs, the condition is classified as post-infectious irritable bowel syndrome (IBS-PI).

What Are the Risk Factors for IBS-PI?

Research has identified several factors that may increase the risk that IBS-PI will develop following a GI infection:

  • Severity of the Initial Infection: For the most part, IBS-PI is the result of bacterial infection, such as food poisoning, rather than that of a virus. The toxicity of the particular bacteria, the length of time of the illness and the severity of initial symptoms all affect the likelihood of developing IBS-PI.
  • Gender: Females are at higher risk than males.
  • Anxiety and Stress: IBS-PI appears to be more likely to develop in individuals who experienced higher levels of anxiety and/or stressful life events in the three months leading up to the initial infection.
  • Activity Level: One research study found that individuals who remained active in spite of initial gastrointestinal symptoms were more likely to develop IBS-PI.

Research points to two protective factors:

  • Age: Individuals over the age of 60 face a lesser risk.
  • Vomiting; Research indicates that vomiting during the initial illness cuts the risk of IBS-PI by as much as 50 percent.

What’s Going On in There?

It is thought that during a GI infection, there is an increase in inflammatory cells in the lining of the intestines.

Under typical circumstances, these cells decrease with time. Preliminary research into the matter suggests that this inflammatory response takes longer to dissipate in cases of IBS-PI and that higher numbers of these cells continue to be seen well after the initial infection.

How Is IBS-PI Treated?

As with all cases of IBS, treatment is generally focused on relief of specific symptoms. Options include the use of anti-diarrheal agents such as Imodium, probiotics, and the recommendation of a low-fiber diet.

What Is the Prognosis for IBS-PI?

The good news is that patients whose IBS is post-infectious have a more favorable prognosis than those for whom the origin of the IBS is unknown, as it is estimated that approximately half of all IBS-PI patients will return to a state of healthy digestive functioning. The bad news is that it may take years. Recovery is less likely to happen if there is co-existing anxiety or depression, thus treatment of these emotional symptoms becomes an important health priority.


Dupont, A. “Post-infectious irritable bowel syndrome.” Current Gastroenterology Reports 2007 378:384.

Quigley, E. “Gut Bacteria and Irritable Bowel Syndrome” International Foundation for Functional Gastrointestinal Disorders Fact Sheet.

Spence, M. & Moss-Morris, R. “ The cognitive behavioural model of irritable bowel syndrome: a prospective investigation of patients with gastroenteritis Gut 2007 56:1066-1071.

Spiller, R. “ Postinfectious irritable bowel syndromeGastroenterology 2003 124:1662-1671.

Spiller, R. “Post-infectious Irritable Bowel Syndrome: A Sub-Type of Irritable Bowel Syndrome” International Foundation for Functional Gastrointestinal Disorders Fact Sheet.

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