What is irritable bowel syndrome?

The term “irritable bowel syndrome” is commonly used by patients to describe any abdominal discomfort, nausea, bloating, constipation, or diarrhea. However, did you know that there is an actual definition and criteria for irritable bowel syndrome (IBS)? A group of physicians specializing in IBS have put together the Rome criteria, which is what gastroenterologists use to define and diagnose IBS. These criteria are as follows

  • Recurrent abdominal pain on average at least 1 day per week in the last three months, associated with >2 of the following:
    • Abdominal pain is related to defecation
    • Abdominal pain is associated with a change in stool frequency
    • Abdominal pain is associated with a change in stool form (appearance)

When should I see a doctor for irritable bowel syndrome?

If you are suffering from abdominal pain, constipation, or diarrhea (or all of the above!), then it is time to see a doctor for further discussion about your symptoms and to review your medical records.

What is the difference between irritable bowel syndrome with constipation, and irritable bowel syndrome with diarrhea?

Patients with IBS-constipation report that the majority (>25%) of their bowel movements are constipation, or very hard stools. Patients with IBS-diarrhea report that the majority of their abnormal bowel movements (>25%) are diarrhea.

But wait, what if patients have both diarrhea and constipation? If you have abdominal pain associated with your bowel movements, and those bowel movements alternate between constipation and diarrhea, then you have IBS-mixed (IBS-M).

Causes of irritable bowel syndrome

The cause of IBS is unknown. Researchers believe that IBS is a disorder of brain-gut interaction. Specifically, that there are disturbances in gut motility (how fast or slow the intestines move their contents), visceral hypersensitivity (the intestines are ultra-sensitive to their contents), altered mucosal and immune function, altered gut microbiota (bacteria lives in all of our intestines), and/or changes in the way our brain processes signals from the gut. It is thought that all or some of these changes may be present in a patient, leading to IBS.

How does a gastroenterologist diagnose irritable bowel syndrome?

A diagnosis of IBS starts with an office visit in order to discuss your abdominal pain and the relationship of your bowel movements to the abdominal pain. Although IBS is mainly a clinical diagnosis, further testing may be required in order to exclude other diseases such as Celiac’s disease, Crohn’s disease, gastritis, peptic ulcer disease, gastroparesis (slowly emptying stomach), ulcerative colitis, or other diseases that can cause abdominal pain, constipation, or diarrhea.

What are treatments for irritable bowel syndrome?

There is not a one size fits all treatment for irritable bowel syndrome. If, for instance, you have irritable bowel syndrome with constipation, then you would benefit most from the use of a medication to help increase your bowel frequency and the consistency of your stools. If, however, you have irritable bowel syndrome with diarrhea, then you would benefit the most from a medication that can decrease your bowel frequency and also improve the consistency of your stools. In addition to medications, I also often use dietary therapy such as the low FODMAPs diet. It is not uncommon to also use medications such as amitriptyline (or nortriptyline, or desipramine) if a patient also has untreated anxiety or depression that is contributing to their IBS symptoms.