Diagnosis of Post Infectious IBS by Mark Pimentel, MD

How does infection cause IBS & SIBO?
Recently we discovered that food poisoning is responsible for 60%-70% of diarrheal IBS cases, so the connection is quite significant. Bacteria that cause food poisoning release a toxin called CdtB. Your body responds by creating anti-CdtB antibodies to fight off the infection, but the CdtB toxin has some structural similarities to a protein called vinculin. Vinculin is naturally occurring and is important for proper gut function. Because of the similarities between vinculinand CdtB, the body becomes confused into thinking that it now needs to fight off vinculin. So the body starts to create anti-vinculin (autoimmunity), which damages your gut. These two antibodies, when elevated over a threshold, can indicate if a person has IBS caused by food poisoning, or what we call post-infectious IBS.

How common is post infectious IBS?
About 45 million people will get food poisoning this year in America. Studies show that about 11% or 1 in 9 of those people will develop IBS.

What is the treatment for post infectious IBS?

Studies have shown that FDA approved antibiotics and diet manipulation under the guidance of a dietitian can be effective treatments for post-infectious IBS. A recent review of treatment options can be found here.

How is post infectious IBS diagnosed?
Because we now have biomarkers for IBS, anti-cdtB and anti-vinculin, we can test a patients’ blood to see if these antibodies are elevated. If those antibodies are elevated, we can diagnose IBS with 96% - 100% certainty. The only licensed test specifically available for measuring these antibodies is ibs-smart™. You can find out how to get the test on the website, www.ibssmart.com.

Background of Dr Pimentel

Mark Pimentel, MD, FRCP(C) is Professor of Medicine at Geffen School of Medicine and Cedars-Sinai Medical Center in Los Angeles, California. Dr. Pimentel completed 3 years of an undergraduate degree in honors microbiology and biochemistry at the University of Manitoba, Canada. This was followed by his medical degree, and his BSc (Med) from the University of Manitoba Health Sciences Center in Winnipeg, Manitoba, Canada, where he also completed a residency in internal medicine. His medical training includes a fellowship in gastroenterology at the UCLA Affiliated Training Program. Active in research, Dr. Pimentel has served as a principal investigator or co-investigator for numerous basic science, translational and clinical studies in such areas as IBS, and the relationship between gut flora composition and human disease. His work has been published in the New England Journal of Medicine, Annals of Internal Medicine, American Journal of Physiology, American Journal of Medicine, American Journal of Gastroenterology and Digestive Diseases and Sciences, among others. Dr. Pimentel has been invited to present his work at meetings, grand rounds, and advisory boards in the United States and Internationally. He is a diplomate of the American Board of Internal Medicine (Gastroenterology) and a fellow of the Royal College of Physicians and Surgeons of Canada. Dr. Pimentel is also a member of several medical associations including the American Gastroenterological Association, the American College of Gastroenterology, and the American Neurogastroenterology and Motility Society.

A few of Dr. Pimentel’s most significant accomplishments include:

1. The discovery of rifaximin as a treatment for irritable bowel syndrome (IBS).

2. Developed the first blood test for IBS on the basis of IBS being derived from acute gastroenteritis.

3. Described the association between IBS and bacterial overgrowth which forms the basis for microbiome therapies in this condition.

4. Uncovered the methanogen (Methanobrevibacter smithii) as an agent for causing constipation in humans.

5. Discovered the use of lovastatin as a microbiome treatment for constipation on the basis of inhibiting methane production by methanogens.

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