Post infectious IBS (PI-IBS) refers to the cluster of IBS symptoms that occur after an episode of acute intestinal enteritis (IE).
IE refers to inflammation within the intestines. The condition is most often caused by eating or drinking things that are contaminated with bacteria, viruses or parasites (i.e. food poisoning).These germs settle in the intestine, causing inflammation and swelling. Foodborne IE is extremely common, with estimates from the US suggesting that the condition affects 1 in 6 individuals annually. IE also commonly develops when Westerners who travel to developing countries (traveller’s diarrhoea), in military personnel during a period of deployment, and in people taking certain medications, undergoing radiotherapy or suffering inflammatory conditions such as Crohn’s disease.
While IE is usually self-limiting (symptoms usually last <5 days), in a proportion of people, IE can lead to lasting symptoms and what’s known as PI-IBS.
It is estimated that PI-IBS develops in 4-36% of individual following an episode of IE[2, 3]. This wide variation in estimates of prevalence may reflect:
A recent meta-analysis looked at the prevalence, risk factors and outcomes of PI-IBS. The study included data from over 20000 individuals from 45 studies, all of whom had suffered IE, then been followed for between 3 months and 10 years. The study revealed a few interesting findings:
Similar to typical IBS, PI-IBS is characterised by abdominal pain and alternating bowel habits, although diarrhoea (as opposed to constipation) tends to be the predominant bowel habit in PI-IBS
Unlike typical IBS which is considered a chronic condition (characterised by intermittent symptom flares), symptoms typically improve and resolve over time in PI-IBS. However, complete symptom resolution may take several years, with some studies showing that complete symptom resolution occurs in approximately half of all cases within 6-8 years[3, 4].
There are no widely accepted treatments for PI-IBS, so the condition is often treated empirically, with treatment choice guided by symptom severity and predominant symptoms (often abdominal pain and diarrhoea). Treatment options your doctor or dietitian may recommend include:
Whatever treatment you choose, it is important to have realistic expectations regarding symptom response. While symptoms should improve with treatment, they often persist to some degree for many years. A trial and error approach should be used, but try one therapy at a time to get the clearest picture about which treatments are working and which are not.