IBS, IBD and SIBO;

Diagnosing and deciphering the differences


It’s easy to mix up irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) because the names sound very similar, and some people with IBD can also have IBS. It gets even more complicated when Small Intestinal Bacterial Overgrowth (SIBO) gets added to the mix.

While all three can have some similar symptoms, these gastrointestinal disorders are vastly different medical conditions. Due to the similarities and sometimes overlap of these disease states, understanding the characteristics of each is critical to determine the best diagnosis and treatment plan.

Read on to understand the differences between IBS, IBD and SIBO. Plus, discover hidden culprits of the conditions and how to accurately diagnose.

Breakdown of IBS, IBD and SIBO:

Irritable Bowel Syndrome, or IBS, is a common disorder that affects the large intestine, according to the Mayo Clinic. Many patients experience symptoms that include cramping, abdominal pain, bloating, gas, diarrhea, constipation, or both.

Inflammatory Bowel Disease, or IBD, is a term for both Crohn’s Disease and Ulcerative Colitis (UC). Each condition is characterized by chronic inflammation of the gastrointestinal (GI) tract, per the Centers for Disease Control and Prevention.

Small Intestinal Bacterial Overgrowth, also known as SIBO, occurs when there is an abnormal increase in the overall bacterial population in the small intestine. The particular bacteria is not commonly found in that part of the digestive tract, as cited by the Mayo Clinic.

Similarities and Differences:

Providers have found that many SIBO, IBS and IBD symptoms are similar. Common symptoms include abdominal pain, constipation, distention, diarrhea and bloating. Recent research has discovered that SIBO could actually be the root cause of IBS. In addition, researchers found SIBO is often present in people with IBD.

Meanwhile, IBS is characterized by a recurrent abdominal pain plus a combination of associated symptoms as defined by the Rome IV criteria. IBD is a pathological disease and is different in that it causes inflammation either on the mucosa (Ulcerative Colitis), or throughout the entire digestive system (Crohn’s Disease). SIBO occurs when there is an excessive amount of bacteria build-up in the small intestine, which gives off gases that cause symptoms to occur.

How to Diagnose:

Proper diagnosis is critical to determining the most successful treatment plan for patients. Affected patients are oftentimes living with two or more of the disorders, due to the nature of each disease.

In order to achieve the most accurate diagnosis of SIBO, a hydrogen and methane breath test must be performed, per the North American Consensus of Breath Testing.

For IBS, typical diagnosis includes exclusion of other diseases and use of the Rome Criteria. The Rome Criteria is a set of guidelines used by clinicians to classify the diagnosis of a patient with an FGID (disorder of gut-brain interaction). This also helps to identify what type of IBS a person may have. If additional testing is required providers may have to perform a Colonoscopy, which is an invasive procedure where a small flexible tube is used to examine the length of the colon.

In order to diagnose IBD, invasive procedures are typically performed. This includes colonoscopy, upper endoscopy, sigmoidoscopy, and capsule endoscopy. Each procedure provides a clear view of the gastrointestinal tract to determine if a patient has UC or Crohn’s Disease based on where the inflammation is located.

IBSchek® is the first clinically validated blood test for Irritable Bowel Syndrome with predominant diarrhea (IBS-D) and mixed symptoms (IBS-M). IBSchek is a non-invasive test that can be administered in the comfort of the home with a simple finger stick. The combination of IBSchek and a hydrogen & methane breath test could determine the diagnosis of IBS and SIBO, alleviating the stress and safety concerns associated with an invasive procedure.

Despite available at-home testing, an invasive procedure may still be necessary for proper diagnosis. It is critical for doctors and patients to consider all options before deciding on the best plan for diagnosis and treatment.