What is IBS?
Irritable bowel syndrome (referred to as IBS) is a chronic digestive tract illness that causes bowel problems (diarrhea or constipation) and abdominal pain. These symptoms can come and go over time. IBS affects an estimated 10–15% of people in the U.S. and is more common in women and people younger than 50. The exact causes of IBS are unknown, but recent research has suggested that it may be related to problems with communication between your gut and the nervous system.
One common misconception is that IBS symptoms are due to anxiety. Although mental stressors can make IBS symptoms worse, IBS is a real disease for which the causes are still not completely understood. —Dr. Adam Pont
Four types of IBS
There are four types of IBS, which are based on the main type of bowel movement you have. The Bristol Stool Form Scale (BSFS) is a guideline used to categorize stool consistency. All types of IBS cause abdominal pain or discomfort at least once per week, and people with IBS have at least two of the following:
- Pain while having a bowel movement
- Change in frequency of bowel movements (either more or fewer per day)
- Change in consistency of stool (either loose, runny stool or hard, pebble-like stool)
Diarrhea-predominant IBS (IBS-D) is when you have diarrhea most of the time. Stool is mushy or fluffy with ragged edges, or all liquid with no solid pieces (BSFS 6 or 7) more than 25% of the time. And you do not have stool that has small hard pellets or is lumpy sausage-shaped (BSFS 1 or 2) more than 25% of the time.
- More frequent bowel movements when stool is soft or the sudden urge to have bowel movements
- Abdominal pain with the bowel movements
- Rifaximin (Xifaxan) —a gut-specific antibiotic
- Eluxadoline (Viberzi)—a controlled substance that acts on gut-specific opioid receptors.
- Alosetron (Lotronex)—affects serotonin but is only given to women with severe symptoms, and only after other therapies have proven ineffective.
Constipation-predominant IBS (IBS-D) is when you usually are constipated more often. You have small hard pellets or lumpy sausage-shaped stool more than 25% of the time. Your stool is not mushy or fluffy, or all liquid more than 25% of the time.
- Less frequent bowel movements when stool is harder
- You have the urge to have a bowel movement but can't pass stool.
- You have abdominal pain with harder stools.
- Linaclotide (Linzess) and plecanatide (Trulance)—increase fluid in intestines to make it easier to pass stool
- Lubiprostone (Amitiza)—only for adult women. Increases amount of fluid in intestines to ease stool passage
- Tegaserod (Zelnorm)—only for women younger than 65 who have one or no major cardiovascular risk factors and other treatment options didn’t work. It stimulates the gut to move things through quicker.
It helps if you keep a journal of your bowel movements and symptoms over a several week period and bring it to your doctor’s appointment. —Dr. Pont
Mixed IBS (IBS-M) is when more than 25% of your stools are small hard pellets or lumpy sausage-shaped and more than 25% of your stools are mushy or fluffy with ragged edges, or all liquid. Sometimes you can have both types of stool on the same day.
- Periods of more or less frequent bowel movement
- You may feel a sudden urge to have a bowel movement.
- You may feel the urge to have a bowel movement but can’t pass stool.
- Abdominal pain with some or all of these symptoms
Treatment: There is no specific treatment for IBS-M. Treatment will likely focus on which stool symptom (constipation or diarrhea) is most common or makes you most uncomfortable.
Complications: Sometimes treating diarrhea may make constipation symptoms worse (or vice versa), which can make treatment difficult and require trying different medications.
Undefined IBS (IBS-U) is when your symptoms meet the main criteria for IBS but you do not have either constipation or diarrhea for more than 25% of your bowel movements.
- You may have constipation, diarrhea, or both.
- Periods of more or less frequent bowel movements
- You may feel a sudden urge to have a bowel movement but can’t pass stool.
- Abdominal pain with some or all of these symptoms
Treatment: There is no specific treatment for IBS-U. Treatment will target the stool symptoms (constipation or diarrhea) that are most common or make you most uncomfortable.
Complications: Sometimes treating diarrhea may make constipation symptoms worse (or vice versa), which can make treatment difficult and require trials of different medications.
IBS does not increase your risk of colon cancer. —Dr. Pont
Can you have IBS-C and IBS-D?
Not technically. If you meet the criteria for both IBS-C and IBS-D then you have IBS-M.
How to treat IBS
In addition to the treatments for each type of IBS, there are several treatments that can be used for any type of IBS to help manage symptoms. These include:
- Trial of a specialized restrictive diet (called Low-FODMAP diet)
- Increasing intake of soluble fiber
- Peppermint oil supplement (Mentha piperita)
- Tricyclic antidepressants (TCAs) prescribed by your doctor
- Gut-directed psychotherapies (such as cognitive behavioral therapy or hypnotherapy)
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