What Happens to Your Gut When You Have IBS-C

Irritable bowel syndrome with constipation (IBS-C) is a disorder which is thought to be from dysfunctional communication between the gut and the brain. IBS-C is a different condition from occasional or functional constipation, and is diagnosed and treated differently.

Abdominal Pain and Bowel Movement Symptoms Define IBS-C

IBS is diagnosed using the Rome Criteria, a set of guidelines that focus on symptoms.

Abdominal pain is the key symptom used to diagnose IBS. This abdominal pain must occur at least one day a week for the last three months.

In addition to the abdominal pain, two of the following things must be true to get a diagnosis of IBS:

• The pain is related to having a bowel movement
• There is a change in the frequency of bowel movements
• There is a change in how the stool looks

There are different forms of IBS. To be diagnosed with constipation-predominant IBS, 25% of stools must be hard or lumpy, and 25% or fewer of stools must be loose or watery (diarrhea).

Other Gut Symptoms May Be Present

Aside from the symptoms laid out in the Rome Criteria needed for a diagnosis, people with IBS-C might also experience:

IBS-C Has No Gut Changes Seen With Endoscopy

Testing is not always needed to diagnose IBS. People with IBS will not have any changes in their colon that will show up on an endoscopy (such as a sigmoidoscopy or colonoscopy).

Blood tests, endoscopy, or imaging may be used if there’s any confusion about the diagnosis or if symptoms are clearly not from IBS-C. However, it is not always necessary to look for another source of the symptoms when the Rome Criteria are met.

Changes in Gut-Brain Communication in IBS-C

IBS used to be called a functional disorder. It is now called a disorder of gut-brain interaction. This doesn’t mean that IBS is “all in your head.” It means there’s miscommunication between the brain and the gut. Why this misfire between the central nervous system (the brain and spinal cord) and the enteric nervous system (nerves in the gut) begins is not well understood.

Researchers have theories about what might cause a person to develop IBS. People who live with IBS may have a digestive system that’s more sensitive to stimuli, such as food, stress, or bacteria/viruses.

It’s thought that IBS might start with one or more of these factors:

How IBS-C Differs from Functional Constipation

Most people have constipation from time to time, but that’s not the same as IBS-C. IBS-C is a consistent pattern of abdominal pain with hard and lumpy stools, making it different from other forms of constipation.

It can be difficult to diagnose various forms of constipation because symptoms are similar. Chronic idiopathic constipation (CIC), also called functional constipation, is a condition that also causes long-term digestive symptoms. One big difference is that CIC is not usually associated with abdominal pain, and IBS-C is only diagnosed when abdominal pain is present.

CIC might be caused by:

• Low motility (food and stool move slowly through the gut)
• Medications (such as antidepressants or opioid pain relievers)
• Pelvic floor dysfunction (the muscles used to have a bowel movement are not working well together)