What is Post infectious IBS (PI-IBS)?

What is post infectious IBS ( PI-IBS)?

Stomach Bug is a familiar term to most of us. Common symptoms of stomach bug are abdominal pain, diarrhea, vomiting, fever. These symptoms usually clear up in few days in a common stomach bug. However, in some people, the symptoms linger on and develop into Irritable bowel Syndrome (IBS).

The development of irritable bowel syndrome following acute infection of stomach or intestines is called post infectious IBS. PI-IBS was first recognized during World War II in soldiers returning to the United Kingdom. They developed IBS-type symptoms after suffering bacterial dysentery.

More recently, PI-IBS has been described following infections from a range of bacteria including Campylobacter, Salmonella, and Shigella.

Bacterial infections are usually spread by consuming contaminated food or water, or by contact with infected people or animals.

The increased risk of post infectious IBS is mostly associated with bacterial infections but can also happen with viral and parasitic infections.

What are the risk factors for post infectious IBS:

Several risk factors have been studied that can cause PI-IBS. These include prolonged fever, longer duration of initial infection, young age, gender(women>men), anxiety/depression.

Individuals who experience anxiety and depression in the first few months following the initial infection are more prone to develop IBS-PI.

Why does PI-IBS happen?

The cause of bowel symptoms following acute infection is uncertain, although many theories have been proposed.

- One theory says that there is a bile acid malabsorption following the stomach infection. This leads to diarrhea and hence IBS.
- Another thought is a possibility in an increase in inflammatory cells in the lining of the intestines.
- The use of antibiotics use for gastrointestinal infections was also observed to be a risk factor for developing PI-IBS.

What are the Symptoms of IBS-PI?

- Abdominal pain
- Changes in bowel habits. Most people with PI-IBS develop diarrhea (IBS-D) or a mix of diarrhea and constipation (IBS-M).
Its rare to see constipation in post infectious IBS.
- Other symptoms include bloating, gas and belching.


How is it Diagnosed?

There is no specific test to make a diagnosis of PI-IBS. However, a good medical history, physical examination, and some specific tests can help rule out other medical conditions from IBS.

Your physician might also suggest a newer test for PI-IBS called IBS Smart test. It tests specific biomarkers of IBS in the blood and helps to distinguish between IBS-D/IBS-M with IBS.
Reasearch has shown that two antibodies, anti-CdtB and anti-vinculin, are elevated in the blood of patients with Predominant and Mixed-Type Irritable Bowel Syndrome (IBS-D and IBS-M).
IBS-smart test measures the levels of these antibodies in your blood and determines your likelihood of having IBS-D or IBS-M.

Other tests that your physician might order are more invasive like colonoscopy/sigmoidoscopy.

How is PI-IBS Treated?

- Diet Changes: Try eliminating foods that trigger your IBS symptoms. Keeping a diary to track your diet and bowel symptoms can be very helpful. Many physicians recommend eliminating milk products temporarily since lactose intolerance is common and can aggravate IBS. The low FODMAP diet can help.

- Increase dietary fiber intake. Bulk forming fiber supplement such as psyllium can help increase fiber intake. Fiber supplements should be started at a low dose and increased slowly over several weeks to avoid gas.

- Psychosocial Therapies: Stress and anxiety can worsen IBS symptoms. Talk to your clinician to figure out a way to reduce the stress/anxiety/depression. This includes counseling or may be prescription medications.

- Medications: Although many drugs are available to treat symptoms of PI-IBS, these drugs do not cure the condition. Some options include the use of anti-diarrheal agents such as Imodium, probiotics.

What Is the Prognosis for IBS-PI?

Although IBS can cause substantial physical discomfort and emotional distress, most people are able to control their symptoms and live a normal life without getting serious health issues.
Patients whose IBS is post-infectious have a more favorable prognosis than those for whom the origin of the IBS is unknown.

Meenakshi Aggarwal MD
Family Medicine
Hillsboro, Oregon

Dr. Aggarwal, MD is a board-certified family physician and Ob/Gyn. Her areas of special interests include Women’s Health and Preventive Medicine. She believes that the human body is a reflection of its soul. With proper diet, exercise, and medications when indicated, the body can achieve a good quality of life.

References: uptodate