A Q & A with Anthony Lembo, MD

Irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) are two conditions that affect the gastrointestinal (GI) tract, which includes the esophagus, stomach, small and large intestine. IBS is often confused with IBD, but the two conditions are distinctively different.

IBS is a chronic, non-inflammatory condition that is classified as a syndrome — it consists of a group of symptoms. IBD, on the other hand, refers to inflammation or chronic swelling of the intestines.


Getting an accurate diagnosis and treatment is essential in managing both IBS and IBD. Dr. Anthony Lembo, a gastroenterologist in the Digestive Disease Center at Beth Israel Deaconess Medical Center and an expert on IBS, shares an overview of both conditions.

Q. Who gets IBS or IBD, and is it possible to have both?

IBS affects between 25 and 45 million people in the United States, which is about 10 to 15 percent of the entire population. It is more commonly found in women — about two out of three IBS sufferers are females. IBS affects people of all ages, including children.

Meanwhile, there are about 1.6 million Americans who suffer from IBD. This chronic disease tends to run in families and it affects both genders equally. Ethnically, IBD is more common among Caucasians, but it affects people in other racial groups as well. In addition, smokers are at higher risk of getting IBD than non-smokers.

There is a certain possibility that some IBD patients have IBS symptoms simultaneously.

Q. What are the symptoms of IBS and IBD?


IBS has multiple symptoms, including chronic abdominal pain, discomfort, gas, bloating, cramping, diarrhea and constipation, or alternating between the two. Some people experience IBS-C, which means IBS with constipation that causes abdominal pain and difficult or infrequent bowel movements, while others experience IBS-D, which is IBS with diarrhea followed by frequent loose stools or an urgent need to move the bowels. There are some who experience both constipation and diarrhea.

IBS does not develop into IBD or cause permanent harm in the intestines, such as intestinal bleeding, other intestinal diseases or cancer. However, IBS can significantly impact patients’ daily lives. According to a recent survey, the symptoms can be so burdensome that some IBS patients would give up their essential pleasures — caffeine, use of cell phone and the internet and even sex — to be free of the symptoms.

On the other hand, there are two main forms of IBD, Crohn’s disease and ulcerative colitis. Both conditions are immune-mediated disorders characterized by chronic inflammation of the GI tract. These conditions have many similar symptoms, but they affect different areas of the GI tract.

Ulcerative colitis is confined to the colon, causing inflammation, and sometimes ulceration, of the inner layer of the lining of the colon. Crohn’s disease can appear anywhere along the GI tract, where it typically affects the ileum, the third portion of the small intestine and the beginning of the colon, cecum. Both conditions present with rectal bleeding and diarrhea, bloating, abdominal cramping, pain, reduced appetite, unintended weight loss and fatigue.

Q. What are the causes of IBS and IBD?

There has been an ongoing debate among researchers that miscommunications between the brain and the intestinal tract trigger IBS. However, the exact cause of IBS is not fully understood yet, but hypersensitivity of the intestines, dysmotility (when the strength or coordination of the esophagus, stomach or intestines muscles do not work as they should) and alterations in the intestinal flora have been associated with IBS. In addition, psychological factors, such as stress, can exacerbate the condition.

Just like IBS, the exact cause of IBD is unknown. Diet and stress may worsen the condition. Studies have suggested that a combination of things, including genes, immune system and environmental factors, play a role in causing IBD. Unlike the immune systems of most people, patients who have IBD have an immune system that attacks harmless body substances, which causes inflammation in the GI tract

Q. How do you diagnose IBS or IBD?

Diagnosing IBS usually starts by excluding other gastrointestinal disorders. Doctors usually check for medical history and a physical exam is done. If a patient does not respond to a treatment or shows more serious symptoms, additional tests — blood tests, stool samples, endoscopic or external imaging procedures — may be done.

There are different ways of diagnosing IBD, which include blood tests, stool tests, endoscopic and external imaging procedures.

Q. How are IBS and IBD treated?

There are limited treatment options for IBS at this time. Currently, the drugs approved by the Food and Drug Administration (FDA) for IBS are linaclotide and amitiza for IBS-C, and rifaximin, eluxadoline and alosetron for IBS-D. There still is a long way to go, but a lot of avenues are being looked at. There is no guaranteed cure in the near future, but better treatments will be found. There are a lot of promising drugs under study as well. One important thing physicians would like to highlight is for patients to be more communicative to their doctors about these types of issues.

Unfortunately, there is no complete cure for IBD at the moment, but the initial goal of IBD treatment is managing and preventing the inflammation in the GI tract. There are two approaches, depending on the severity of a patient’s condition: medications or surgery.

Surgery may be necessary when medications no longer control the symptoms of IBD. Surgical treatment removes the affected portion of the bowel, but occasionally a complete removal of the colon or rectum is considered.


For medication treatment, there are multiple drugs used to help patients, including biologics, which are medication therapies made from living organisms that work by blocking the action of specific proteins or receptors of inflammation. They are designed to help restore the body’s ability to fight the disease. There are currently six biologic therapies approved for the treatment, which have huge impact on IBD and other immune-mediated disease treatment. The overall key to success with all these medications is taking them as prescribed. Non-adherence with the medication regimen is associated with an increased risk of a flare of the disease.

Although there are limited treatment options available for both IBS and IBD, paying attention to diet can help reduce the symptoms and improve patients’ health. Having a balanced diet that includes a variety of foods from all food groups is significant. Recently, a diet low in fermentable carbohydrates has been shown to improve symptoms in some patients. Additionally, exercising regularly and getting proper sleep is highly recommended.

April 2016

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Above content provided by Beth Israel Deaconess Medical Center. For advice about your medical care, consult your doctor.