Colonoscopy and Irritable Bowel Syndrome (IBS): What to Know
A colonoscopy is a procedure used to diagnose and treat some digestive conditions but is not routinely performed to diagnose irritable bowel syndrome (IBS).
IBS causes digestive system symptoms such as abdominal pain, diarrhea, and/or constipation, and sometimes bloating. It is a complex condition that involves the connection between the gut and the brain. The checklist healthcare providers consult to diagnose IBS is called the Rome IV criteria.
Tests such as a colonoscopy might be helpful to determine other causes of symptoms. This article will look into using a colonoscopy in diagnosing IBS and how testing might be used to determine the cause of signs and symptoms in the digestive system.
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Can a Colonoscopy Detect IBS?
A colonoscopy does not help diagnose IBS. With IBS, there are no changes inside the colon that could be detected by a colonoscopy.
The American College of Gastroenterology (AGA) has published guidelines on managing IBS. This guide for healthcare providers outlines the evidence for diagnosing and treating IBS.
The AGA recommends against using a colonoscopy for the diagnosis or management of IBS for most people. A colonoscopy might be performed if a person is over 45 or some symptoms might be from a condition other than IBS.
Red Flag Digestive Symptoms
When IBS is thought to be the reason for digestive symptoms, a colonoscopy is not usually performed as part of the diagnostic process. A colonoscopy might be performed if a person has the following signs, symptoms, or risk factors, to screen for disease processes other than IBS:
Family history of digestive disease, such as colon cancer or inflammatory bowel disease (IBD)
Older age when symptoms start, such as 45 years or older
Unintended weight loss
What Conditions Can an Endoscopy Diagnose?
Endoscopy procedures are done with the use of special tools that look inside the digestive system. A thin scope with a light and a camera on the end is passed through the mouth to see the upper digestive system or through the anus to see the large intestine (as with a colonoscopy).
A colonoscopy looks inside the colon. By seeing the lining of the colon, certain conditions can be detected and/or diagnosed. A biopsy of the large intestine (taking small pieces of tissue for examination in a lab) can be done while a colonoscopy is being performed.
Biopsies can be tested to look for changes caused by disorders such as celiac disease, IBD (which includes Crohn’s disease and ulcerative colitis), or to find microscopic changes in the tissue. Growths called polyps that are the precursor to cancer can also be seen and removed for testing.
An upper endoscopy might be performed if symptoms are experienced in the esophagus, stomach, or first part of the small intestine (the duodenum). This test might look for conditions affecting the upper digestive system, such as gastroesophageal reflux disease (GERD).
How IBS Is Diagnosed
IBS is diagnosed through a set of questions called the Rome IV criteria. This system was developed by experts in IBS and other conditions that are affected by the gut-brain axis (the two-way communication between the digestive system and the brain).
According to the Rome IV criteria, in order to diagnose IBS, a person must have abdominal pain at least one day a week for the last three months. Two of the following three symptoms also must be present:
Pain associated with a bowel movement
A change in stool frequency (going to the bathroom more or less often)
A change in how the stool looks
Some lab tests might also be performed to rule out other common conditions that cause digestive problems. This includes a blood test that can be used to diagnose celiac disease. It may also include a stool test (to look for a substance called fecal calprotectin) and a blood test (C-reactive protein) to rule out IBD.
Tests to examine the anus and rectum may be able to detect conditions affecting the pelvic floor. Tests to diagnose food allergies are not recommended unless other symptoms are associated with allergies.
Part of the path to a diagnosis of IBS could include a change to diet. A trial of a low fermentable oligosaccharides, disaccharides, monosaccharides, polyols (FODMAP) diet might be recommended to see if it helps with symptoms.
Medications and/or specialized types of psychotherapy (talk therapy) may also be recommended to treat the symptoms.
Related: How Irritable Bowel Syndrome (IBS) Is Diagnosed
Colonoscopy for IBS: What to Expect
For some people, there may be a reason to order a colonoscopy if symptoms are suspected to be caused by something other than IBS. In that case, the procedure will be similar to a colonoscopy performed for screening for colon cancer or other conditions. Colonoscopies are conducted in healthcare facilities.
You will prepare in the weeks and days before the test by adjusting your diet as instructed by your healthcare provider and clearing the colon of stool. The colon needs to be as clear of waste as possible so that the interior walls of the large intestine can be seen clearly.
The day before the procedure, you will take recommended laxatives and other bowel prep medications. Look to your healthcare provider for instructions and ask questions as necessary. It’s important to understand the instructions fully, to start the preparation on time, and to finish it.
The colon is clear when there is no more stool being passed out of the anus. Bowel movements that are mostly water and appear clear may continue.
A colonoscopy is normally conducted while the patient is under sedation so you don't feel anything and/or are asleep. Because of this, you will need someone to drive you home after the test. Recovery is normally to rest for the remainder of the day and return to work, school, or other activities the next day.
Colon Polyps
Polyps in the colon are the precursor to colon cancer. If found during a colonoscopy, they will be removed. Most people who have colon polyps do not have any symptoms.
There could be some overlap between the symptoms of IBS and colon polyps, especially if a large polyp is blocking the intestine, causing constipation and/or diarrhea.
However, polyps may bleed, and bleeding in the digestive system is never a symptom of IBS. This is why it is important to seek care for any new symptoms in the digestive system and to describe the symptoms well to a healthcare provider.
Related: Colonoscopy: Overview
Can a Colonoscopy Aggravate IBS?
A colonoscopy is not performed routinely to diagnose IBS in people who have symptoms typical for IBS. There may be a need for a colonoscopy to look for other reasons for symptoms or to screen for colon cancer.
There is little data on how bowel movements might change after a colonoscopy. It’s not known how many people may have IBS symptoms after having a colonoscopy.
Anecdotal evidence, which refers to the experiences of people outside of formal medical studies, shows that some people with IBS experience changes in their symptoms after having a colonoscopy. This can mean either an improvement or a worsening of symptoms.
Some people find that IBS symptoms are worse during periods of stress. Having a colonoscopy might be stressful for a number of reasons. The disruption of your routine, scheduling, possible costs, and preparation can be emotional and stressful. This stress could mean that IBS symptoms crop up before or after a colonoscopy.
One study showed that some people who were prescribed quinolone antibiotics before a colonoscopy had more IBS symptoms after the test.
As with any medical test, including a colonoscopy, there should be a good reason for having one. You and your healthcare providers will work together to determine when a colonoscopy clearly is needed.
Related: Potential Risks of a Colonoscopy
How Often Should People With IBS Get a Colonoscopy?
A colonoscopy is not used for routine monitoring of IBS. A colonoscopy might be recommended if there are changes to the severity or frequency of symptoms or if there are new symptoms, such as blood in the stool.
A colonoscopy might also be recommended for colorectal cancer screening when a person meets the guidelines for screening. People with IBS are not at an increased risk for colon cancer.
One study found an increase in the rate of colon cancer in people with IBS during the first year of diagnosis of IBS. The study authors think that this is not because IBS causes colon cancer but that colon cancer may be misdiagnosed as IBS.
Summary
A colonoscopy is a tool used to diagnose and treat some digestive conditions. It is not routinely performed to diagnose IBS, however. IBS used to be diagnosed once other conditions were excluded. But now, it is diagnosed when the symptoms a person experiences meet the Rome IV criteria.
It’s not clear if a colonoscopy could affect the symptoms of IBS because there is little data on the subject. However, people with IBS will want to manage their stress levels before having a colonoscopy.
Read the original article on Verywell Health.
