Irritable bowel syndrome (IBS) is a disorder that affects the large intestine. Common signs and symptoms include cramping, abdominal pain, bloating, gas, diarrhea, and constipation.

There is no single cause for IBS, but long-term management is often prescribed based on signs and symptoms. IBS can also be treated with medication and counseling in severe cases.

Causes

- Muscle contractions in the intestine. The layers of muscle in the intestine contract as they move food through your digestive tract. However, gas, bloating, and diarrhea can occur when contractions are stronger and last longer than normal. Weak intestinal contractions can slow food passage and lead to hard, dry stools.
- Inflammation in the intestines. IBS increases the number of immune cells in the intestines. This immune response can cause pain and diarrhea.
- Abnormalities in the nervous system. Abnormalities in nerves can cause greater than normal discomfort when passing gas or stool. These abnormalities can result in pain, diarrhea or constipation.
- Changes in bacteria in the gut. Gut bacteria (microflora) reside in the intestines and help maintain health. However, microflora in patients with IBS is different from microflora in healthy people.
- Severe infection. IBS may develop after severe diarrhea caused by bacteria or a virus.

Common Signs and Symptoms

- Abdominal pain
- Excess gas
- Cramping and/or bloating
- Diarrhea and/or constipation
- Mucus in the stool

Risk Factors that Increase the Likelihood of IBS

- Young age: Studies show that IBS occurs more frequently in people under age 50.
- Female: IBS is more common among women. Estrogen therapy before or after menopause is a risk factor.
- Family history of IBS
- Mental health issues: anxiety, depression, sexual, physical or emotional abuse.

IBS Aggravators

- Food: including wheat, dairy products, milk, beans, cabbage, citrus fruits, and carbonated drinks.
- Stress
- Hormones: Signs and symptoms worsen during or around menstrual periods.

Complications Over Time

- Poor quality of life: Patients suffering from IBS miss three times as many work days.
- Mood disorders: IBS can lead to depression and/or anxiety.