Bacterial Gastroenteritis and Risk Factors for Irritable Bowel Syndrome

ABSTRACT & COMMENTARY
Source: Neal KR, et al. BMJ 1997;314:779-782.

The authors set out to evaluate the prevalence of gastrointestinal symptoms six months after bacterial gastroenteritis and to determine factors and associations with post-dysenteric symptoms. They mailed a questionnaire to 544 individuals who had bacterial gastroenteritis confirmed by microbiological methods over a six-month period. A quarter of the subjects reported persistence of altered bowel habit six months after an episode of infective gastroenteritis. One in 14 developed the irritable bowel syndrome, with an increase seen in women (relative risk, 3.4) and with the duration of the initial diarrheal episode (relative risk, 6.5 for a diarrheal episode that lasted from 15-21 days). The authors conclude that altered bowel habit persists for at least six months following bacterial gastroenteritis in one-fourth of infected people and that about one in 14 cases go on to develop the classical irritable bowel syndrome. The severity of the initial illness and female gender predict the likelihood of prolonged bowel disturbance.

COMMENT BY EAMONN M.M. QUIGLEY, MD, FRCP

Clinicians have long been familiar with patients with the irritable bowel syndrome or other functional gastrointestinal disorders who give a history of the sudden onset of their now chronic symptoms in relation to a "flu-like illness" or a "gastric upset." Experimental studies of immune-motility interactions in the gastrointestinal tract provide a pathophysiologic basis for this phenomenon, but until recently, there were few data to support this somewhat anecdotal observation. This important study from England, together with other studies from the United Kingdom and the United States, now provide a firm basis for a relationship between the irritable bowel syndrome and prior infective gastroenteritis. The study reported here provides perhaps the best evidence for a direct progression from an acute gastroenteritis to a chronic irritable bowel syndrome. This study does not, of course, tell us about the pathophysiology and does not define whether the development of the irritable bowel syndrome represents its clinical expression in individuals who are already predisposed, or the de novo induction of dysmotility or other altered physiology in individuals who previously had a normal gastrointestinal tract. This study should encourage physicians to pay particular attention to the mode of onset of functional disorders, as there is a suggestion that those with a relatively acute, perhaps infectious-related onset, have a better prognosis.

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