Irritable bowel syndrome (IBS): are gastrointestinal infections to blame?

IBS is a chronic, episodic medical condition that is associated with abdominal pain or discomfort and altered bowel habits. The underlying causes of most cases of IBS remain obscure, although clinical studies have found low levels of inflammation markers in biopsies and other tissues from many IBS patients.

Post-infectious IBS is diagnosed on the basis of the acute onset of IBS symptoms following an episode of acute infectious gastroenteritis accompanied by fever, vomiting and diarrhoea. Typically, the acute infectious symptoms of vomiting and fever resolve over several days, however, abdominal discomfort, bloating and diarrhoea persist.

Epidemiology of post-infectious IBS

Studies in which large numbers of patients have been followed up after experiencing bacterial, viral or parasitic GI infections have reported that between 5% and 30% of all affected individuals will remain symptomatic.¹ Some report having symptoms for 10 years and beyond.² Prevalence rates appear to be higher after epidemic infections than after sporadic ones although this, says Prof. Enck, may be an artefact of over-reporting associated with major outbreaks. The search for predictors of who will remain symptomatic and who will develop post-infectious IBS goes on.

“So far, we know that women, younger people, and those who have a more severe initial infection are more prone to developing post-infectious IBS³,” explains Prof. Enck. “We also think that an individual’s psychological make-up may affect how well they recover from the initial infection and its symptoms.⁴ Of course, a genetic trait is also likely, but this has not yet been confirmed.”

Treatment options

According to Prof. Enck, the management of post-infectious IBS should not only focus on treating the acute IBS symptoms but also on how to prevent the persistence of symptoms during and immediately after a GI infection. He thinks possibilities for the latter include more aggressive initial medical management of the intestinal infection, re-establishment of the normal intestinal milieu (using probiotics, for example⁵) or the development of better coping strategies that might include nutritional or psychological support. “All of these approaches have the possibility of improving the long-term outcomes after an acute GI infection and reducing the incidence of post-infectious IBS, however, the benefits will need to be shown in future clinical trials,” says Prof. Enck.

UEG attempts to unravel the problem

UEG is taking an active role in trying to understand the epidemiology and risk factors associated with post-infectious IBS and has set up a Working Team under the chairmanship of Prof. Robin Spiller from the University of Nottingham in the UK and Prof. Enck. A worldwide survey involving more than 6,000 IBS cases has been initiated that already suggests a higher incidence of post-infectious IBS in northern Europe compared with southern Europe. The importance of living conditions and travelling has also been highlighted.⁶ It is hoped that follow-up of these patients will show who will recover over time and who will not, and highlight factors that might predict a poor or good recovery.