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Overview of Inflammatory Bowel Disease (IBD)


Aaron E. Walfish

, MD, Mount Sinai Medical Center;

Rafael Antonio Ching Companioni

, MD, Digestive Diseases Center

Last full review/revision Sep 2020| Content last modified Sep 2020

In inflammatory bowel diseases, the intestine (bowel) becomes inflamed, often causing recurring abdominal pain and diarrhea.

The two primary types of inflammatory bowel disease (IBD) are

These two diseases have many similarities and sometimes are difficult to distinguish from each other. However, there are several differences. For example, Crohn disease can affect almost any part of the digestive tract, whereas ulcerative colitis almost always affects only the large intestine.

The cause of inflammatory bowel disease is not known, but evidence suggests that normal intestinal bacteria trigger an abnormal immune reaction in people with a genetic predisposition.

Inflammatory bowel disease affects people of all ages but usually begins before age 30, typically from age 14 to 24. A few people have their first attack between the ages of 50 and 70. IBD is most common among people of Northern European and Anglo-Saxon descent and is 2 to 4 times more common among Ashkenazi Jews than non-Jewish whites who live in the same region. Both sexes are equally affected. First-degree relatives (mother, father, sister, or brother) of people with IBD have a 4- to 20-fold increased risk of developing IBD. The tendency to run in families is much higher in Crohn disease than ulcerative colitis.

Symptoms of IBD

The symptoms of inflammatory bowel disease vary depending on which part of the intestine is affected and whether the person has Crohn disease or ulcerative colitis. People with Crohn disease usually have chronic diarrhea and abdominal pain. People with ulcerative colitis usually have intermittent episodes of abdominal pain and bloody diarrhea. In both diseases, people with longstanding diarrhea may lose weight and become undernourished.

Sometimes IBD can affect other parts of the body such as the joints, eyes, mouth, liver, gallbladder, and skin. IBD also increases the risk of cancer in areas of the intestine that are affected.

Diagnosis of IBD

  • Stool and blood tests

  • Endoscopy with tissue biopsy

To make a diagnosis of inflammatory bowel disease, a doctor must first exclude other possible causes of inflammation. For example, infection with parasites or bacteria may cause inflammation. Therefore, the doctor does several tests.

Stool samples are analyzed for evidence of a bacterial or parasitic infection (acquired during travel, for example), including a type of bacterial infection (Clostridioides difficile infection Clostridioides (formerly Clostridium) difficile-Induced Colitis Clostridioides difficile (C. difficile)–induced colitis is an inflammation of the large intestine (colon) that results in diarrhea. The inflammation is caused by toxin produced by C. difficile... read more [formerly Clostridium difficile]) that can result from antibiotic use.

Tissue samples may be taken from the lining of the digestive tract during endoscopy Endoscopy Endoscopy is an examination of internal structures using a flexible viewing tube (endoscope). Endoscopy can also be used to treat many disorders because doctors are able to pass instruments... read more (an examination of the digestive tract using a viewing tube) and examined microscopically for evidence of other causes of inflammation of the colon (colitis) or inflammation of the last part of the small intestine (ileum). This removal and examination of tissue is called a biopsy.

Doctors also consider other disorders that cause similar abdominal symptoms such as irritable bowel syndrome Irritable Bowel Syndrome (IBS) Irritable bowel syndrome is a disorder of the digestive tract that causes recurring abdominal pain and constipation or diarrhea. Symptoms vary but often include lower abdominal pain, bloating... read more , ischemic colitis Ischemic Colitis Ischemic colitis is injury of the large intestine that results from an interruption of blood flow. Abdominal pain and bloody stools are common. Computed tomography is usually done, and colonoscopy... read more Ischemic Colitis (which occurs more often in people older than 50), malabsorption syndromes Overview of Malabsorption Malabsorption syndrome refers to a number of disorders in which nutrients from food are not absorbed properly in the small intestine. Certain disorders, infections, and surgical procedures can... read more , including celiac disease Celiac Disease Celiac disease is a hereditary intolerance to gluten (a protein found in wheat, barley, and rye) that causes characteristic changes in the lining of the small intestine, resulting in malabsorption... read more Celiac Disease , and certain gynecologic disorders in women. The doctor may do imaging studies, such as x-rays X-Ray Studies of the Digestive Tract X-rays often are used to evaluate digestive problems. Standard x-rays (plain x-rays) do not require any special preparation (see Plain X-Rays). These x-rays usually can show a blockage or paralysis... read more , computed tomography Computed Tomography and Magnetic Resonance Imaging of the Digestive Tract Computed tomography (CT—see also Computed Tomography (CT)) and magnetic resonance imaging (MRI—see also Magnetic Resonance Imaging (MRI)) scans are good tools for assessing the size and location... read more (CT), or magnetic resonance imaging Magnetic Resonance Imaging (MRI) In magnetic resonance imaging (MRI), a strong magnetic field and very high frequency radio waves are used to produce highly detailed images. MRI does not use x-rays and is usually very safe... read more Magnetic Resonance Imaging (MRI) (MRI) of the abdomen to rule out other disorders. The doctor may do video capsule endoscopy Video Capsule Endoscopy Video capsule endoscopy (wireless video endoscopy) is a procedure in which the person swallows a battery-powered capsule. The capsule contains one or two small cameras, a light, and a transmitter... read more to evaluate the intestines of people who have Crohn disease.

Treatment of IBD

  • Drugs

  • Sometimes surgery

  • Diet and stress management

People with very severe disease sometimes need surgery.

Diet and stress management

Most people and their families are interested in diet and stress management. Although some people claim that certain diets have helped improve their IBD, including one with rigid carbohydrate restrictions, diets have not been shown to be effective in clinical trials What Participants Need to Know About Clinical Trials People expect doctors to use treatments that work well and to stop using those that do not. However, it is often difficult for doctors and other scientists to tell which treatments work. Making... read more . Doctors sometimes recommend stress management techniques to help people deal with the stress of having a chronic disease.

Health maintenance

IBD puts people at increased risk of developing certain infections and disorders because of their underlying disease, poor nutrition, or use of immunomodulating drugs. Vaccinations and diagnostic tests and screenings can help lessen the risk.

The influenza vaccine Influenza Vaccine The influenza virus vaccine helps protect against influenza. Two types of influenza virus, type A and type B, regularly cause seasonal epidemics of influenza in the United States. There are... read more is needed every year to help protect against the flu. The pneumococcal vaccine Pneumococcal Vaccine Pneumococcal vaccines help protect against bacterial infections caused by Streptococcus pneumoniae (pneumococci). Pneumococcal infections include ear infections, sinusitis, pneumonia, bloodstream... read more helps protect against bacterial infections caused by Streptococcus pneumoniae. People who are over age 50 who are not taking high doses of drugs that suppress the immune system (such as the corticosteroid prednisone or biologic or related agents) should consider receiving the herpes zoster vaccine Herpes Zoster Vaccine There are two herpes zoster vaccines. The newer herpes zoster vaccine is preferred over the older herpes zoster vaccine because it provides better and longer-lasting protection. The newer vaccine... read more (to help protect against shingles Shingles Shingles is a painful skin rash caused by a viral infection that results from reactivation of the varicella-zoster virus, the virus that causes chickenpox. What causes the virus to reactive... read more Shingles ). People who are going to start taking immunomodulating drugs and who have not been exposed to the varicella virus should receive the varicella vaccine Varicella Vaccine The varicella vaccine helps protect against chickenpox (varicella), a very contagious infection caused by the varicella-zoster virus. It causes an itchy rash that looks like small blisters with... read more (to protect against chickenpox) before starting immunomodulating drugs. People should also receive routine tetanus-diphtheria Tetanus-Diphtheria Vaccine The tetanus-diphtheria (Td) vaccine protects against toxins produced by the tetanus and diphtheria bacteria, not against the bacteria themselves. There is also a combination vaccine that adds... read more , hepatitis A Hepatitis A Vaccine The hepatitis A vaccine helps protect against hepatitis A. Typically, hepatitis A is less serious than hepatitis B. Hepatitis A often causes no symptoms, although it can cause fever, nausea... read more , hepatitis B Hepatitis B Vaccine The hepatitis B vaccine helps protect against hepatitis B and its complications (chronic hepatitis, cirrhosis, and liver cancer). Generally, hepatitis B is more serious than hepatitis A and... read more , and human papillomavirus Human Papillomavirus (HPV) Vaccine The human papillomavirus (HPV) vaccine helps protect against infection by the strains of HPV that are most likely to cause the following: Cervical cancer, vaginal cancer, and vulvar cancer in... read more vaccines if appropriate.

Women who have IBD and who are not taking immunomodulating drugs should have cervical cancer screening with a Papanicolaou (Pap) test Screening for Cervical Cancer Sometimes doctors recommend screening tests, which are tests that are done to look for disorders in people who have no symptoms. If women have symptoms related to the reproductive system (gynecologic... read more Screening for Cervical Cancer every 3 years. Women who have IBD and who are taking immunomodulating drugs should have a Pap test every year.

More Information about IBD

The following are some English-language resources that may be useful. Please note that THE MANUAL is not responsible for the content of these resources.

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Eosinophilic esophagitis is an inflammatory disorder in which the wall of the esophagus, the tube leading from the throat to the stomach, becomes filled with a type of white blood cells called eosinophils. Which of the following is believed to be the cause of this disorder?
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