An Overview of Diarrhea Predominant IBS (IBS-D)

Diarrhea predominant irritable bowel syndrome (IBS-D) is a subtype of IBS in which a person experiences frequent episodes of diarrhea with accompanying abdominal pain. Like IBS, IBS-D is a functional gastrointestinal disorder (FGD) in that there is no visible disease, inflammation, or injury to account for its symptoms. It is estimated that approximately a third of people who have IBS experience the disorder with diarrhea as the predominant bowel habit.

Symptoms of IBS-D

As opposed to the other IBS sub-types, people who have IBS-D typically experience:

• Frequent bowel movements
• Loose stools
• Feelings of urgency

In addition, people who have IBS-D also experience some or all of the following symptoms of IBS:

• Abdominal pain
• Gas and bloating
• A feeling of incomplete evacuation
• Mucus in the stool

According to the Rome III criteria for FGDs, other health disorders must be ruled out and symptoms must be experienced for at least three days per month over the past three months for a diagnosis of IBS-D to be made.

Some people who have IBS may find that they switch from times of having IBS-D to times of experiencing constipation-predominant IBS (IBS-C). Others alternate between constipation and diarrhea on a regular basis, a condition known as irritable bowel syndrome - alternating type (IBS-A).

Causes

Although the exact reason why a person would develop IBS-D may not necessarily be pinpointed, researchers are investigating several different areas of inquiry. These include:

• A dysfunction in the brain-gut connection, with possible neurotransmitter involvement
• Food sensitivities
• Gut dysbiosis
• Idiopathic bile acid malabsorption (I-BAM)
• Microscopic inflammation of the lining of the gut
• Small intestinal bacterial overgrowth (SIBO)

Treatment 

If you think that you might have IBS-D, please make an appointment with your doctor. There are other serious health conditions that share many of the same symptoms with IBS-D. It is essential that these be ruled out.

If your doctor concludes that you have IBS-D, they will work with you on a treatment plan. They may recommend or prescribe you a medication. Options include:

• An anti-diarrheal medication, such as Imodium
• An antidepressant to slow down motility and ease the pain
• An antispasmodic to reduce gut cramping and pain
• Xifaxan, a targeted antibiotic
• A bile acid binder such as cholestyramine
• A targeted opioid medication such as Viberzi

IBS-D symptoms may also benefit from dietary changes. Eating smaller meals and avoiding large fatty meals may be of help. Keeping a food diary may identify possible food sensitivity. In addition, the low-FODMAP diet has research support for easing the symptoms of IBS-D.

Last, IBS-D symptoms may be reduced through mind/body approaches, with cognitive-behavioral therapy (CBT) and hypnotherapy having the most research backing their effectiveness for IBS.