Few digestive diseases are as common and as difficult to live with as irritable bowel syndrome, also known as IBS. For patients seeking relief from disruptive digestive symptoms like cramping, pain, bloating, gas, diarrhea and constipation, their diagnosis can sometimes bring more questions than answers.

Understanding Irritable Bowel Syndrome

Although IBS is not dangerous, it can cause uncomfortable, annoying symptoms that affect your quality of life.

IBS is what doctors call a functional bowel disorder because it affects how your bowels work. IBS involves a change in bowel habits that lasts for more than three months but without symptoms, such as weight loss, rectal bleeding or bowel symptoms that wake you up at night, which would then suggest a more serious health issue.

IBS affects up to one-fifth of the U.S. population, although only a small fraction of those individuals seek treatment for their symptoms.

For some people, IBS may go away on its own. But for most people, IBS becomes a chronic condition.

IBS symptoms can appear for the first time in people of all ages, from children to older adults. However, most people first notice IBS symptoms in their 20s, 30s and 40s.

IBS can include a whole spectrum of symptoms. The three types of IBS are categorized by their main symptoms. They are:

  • IBS-C, which primarily involves constipation
  • IBS-D, which primarily involves diarrhea
  • IBS-M, for mixed symptoms including both diarrhea and constipation

People with IBS may also have abdominal pain, cramps, bloating and gas.

Yes, about two-thirds of people with IBS are women. Some women with IBS notice that their symptoms get worse around their menstrual cycle. Although hormone changes don’t actually cause IBS, they may aggravate symptoms.

Women with IBS may have pelvic pain. Some women with IBS also have fibromyalgia, a condition associated with widespread pain.

The cause of IBS is unknown, but there are many theories. One is that a change in the normal bacteria of the intestines may trigger IBS. Another theory is that a sensitivity to food additives may cause IBS in some people. Still another theory is that people may develop IBS if their intestines are hypersensitive to normal movements of the bowel, or what’s known as visceral hyperalgesia.

Most of us have been in stressful situations and felt the effects on our digestive system. So, it’s not surprising that in some people with IBS, stress can also aggravate symptoms.

We know that the digestive system has its own nervous system that is influenced by the brain. Some researchers call this the “mind-gut connection.”

Certain medications, including drugs that slow down activity in the intestines, can help people whose IBS symptoms get worse with stress. A few sessions with a GI psychologist may also be helpful.

No, IBS doesn’t raise your risk for colon cancer or IBD. But IBS can affect your quality of life. However, treatment can help.

Yes, some people with IBD may also have IBS symptoms at some point in their lives. Part of the reason is that IBS is quite common, and some people will have an overlap of both conditions.

Diagnosing Irritable Bowel Syndrome

If you have symptoms like diarrhea, constipation or both, a primary care physician or gastroenterologist (a specialist in digestive diseases) can rule out more serious conditions and help you find treatments that may improve your quality of life.

If you notice a change in your bowel habits, visiting your primary care physician or a gastroenterologist is often a good idea. That’s because you want to be certain that you actually have IBS and not a more serious condition, such as colon cancer. This is especially important if you are age 45 or older, which raises your cancer risks.

See a doctor right away if you have:

  • Rectal bleeding
  • Unexplained weight loss
  • Diarrhea that wakes you up at night

If you already know you have IBS but find that it affects your quality of life, seeing a doctor may help you find relief from your symptoms.

Gastroenterologists diagnose IBS by understanding your history and ordering tests to make sure that other problems, like inflammation, infection or cancer, aren’t causing your symptoms. For example, to rule out celiac disease, you may have a blood test. If you have a positive test, you may also have an endoscopy to get a biopsy of the small bowel to determine if you have celiac disease.

As doctors, we recognize that diagnosing IBS can be deeply frustrating for some patients, who sometimes undergo many tests and physical examinations, only to be told that there is “nothing wrong” with their intestines. But for many patients, knowing that their symptoms are only from IBS can be reassuring.

Your doctor may recommend getting tested for IBS if you have a change in your bowel habits that has bothered you at least once a week for the past three months.

No single test for IBS is available, so doctors make the diagnosis by ruling out more serious problems. In addition to doing an exam and taking your medical history, your doctor may order several tests to make the diagnosis, including:

  • Blood tests, which can help determine if you have food allergies that might cause your symptoms
  • Stool test, which can check for infections or other diseases
  • Hydrogen breath test, which can determine if you have lactose intolerance
  • Endoscopy, which examines your upper digestive tract and can rule out celiac disease
  • Colonoscopy, which examines your colon to check for more serious health issues like cancer or inflammatory bowel disease

No. In someone with IBS, the colon will look normal during a colonoscopy. However, having a colonoscopy can help rule out other problems like inflammatory bowel disease, also known as IBD, that can mimic IBS.

Although untreated IBS won’t lead to more serious conditions like IBD or cancer, it can affect your quality of life. If diarrhea, constipation or other digestive symptoms are disrupting your life, seeing an IBS expert may provide some relief.

Treating Irritable Bowel Syndrome

Not that long ago, a person with IBS might have struggled for decades without relief from their symptoms. Now, with more effective treatments available, many people with IBS can return to their normal, everyday lives.

Different drugs are approved to treat IBS-D (primarily diarrhea) and IBS-C (primarily constipation). Typically, for patients with IBS-M (mixed symptoms), doctors focus on treating the constipation, because it often triggers the diarrhea.

At UChicago Medicine, we select the most appropriate medicines as part of an individualized treatment plan based on your specific symptoms and goals.

Some prescription medications to treat IBS include:

  • Anti-spasm medications, which can slow down intestinal activity
  • Antidepressants, which may reduce pain
  • Antidiarrheal drugs
  • Antibiotics
  • Medications that increase intestinal lubrication to prevent constipation

Over-the-counter medications that include peppermint can help break down gas in the digestive system to ease symptoms.

Many probiotics are on the market, but most scientific studies have not shown them to be effective against IBS. Although probiotics are usually harmless, they can be expensive. So, if probiotics don’t seem to lessen your symptoms after a few weeks, you may want to stop taking them and save your money.

Dietary changes can make a difference in IBS, depending on what symptoms you have. For example, if you have IBS-D with a lot of gas and bloating, reducing fiber in your diet can ease symptoms. If you have IBS-D and are lactose intolerant, reducing milk products can be helpful.

A low-FODMAP diet, which reduces wheat, dairy and certain fruits and vegetables, also may help reduce gas in some people with IBS.

Eliminating products with high-fructose corn syrup may also help some people reduce their IBS symptoms.

We recommend examining what you eat using techniques like the elimination diet to better understand how certain foods affect with your symptoms.

No, there is no surgery for IBS. However, most people with IBS find relief with medications and other strategies.

Some people with IBS find that psychological support can help reduce their symptoms. This may include learning deep breathing and muscle relaxation techniques to improve the body’s relaxation response. At UChicago Medicine, we are among a select group of centers in the United States with expertise in GI psychology and clinicians who can offer these types of specialized resources.

Published March 2022

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Irritable Bowel Syndrome