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Overview of Inflammatory Bowel Disease (IBD)


Aaron E. Walfish

, MD, Mount Sinai Medical Center;

Rafael Antonio Ching Companioni

, MD, HCA Florida Gulf Coast Hospital

Reviewed/Revised Nov 2023

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

The 2 primary types of inflammatory bowel disease (IBD) are

These 2 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 IBD is not known, but evidence suggests that normal intestinal bacteria inappropriately trigger an immune reaction in people with a genetic predisposition.

IBD 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. It is 2 to 4 times more common among people of Ashkenazi Jewish ancestry (those from Central or Eastern Europe) than non-Jewish White people from 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 Inflammatory Bowel Disease

The symptoms of IBD 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.

Did You Know...

  • Inflammatory bowel disease increases the risk of cancer in affected areas of the intestine.

Diagnosis of Inflammatory Bowel Disease

  • Stool and blood tests

  • Endoscopy with tissue biopsy

To make a diagnosis of IBD, 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... 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). In addition to examinations, doctors can use endoscopy to do biopsies and give treatment. Endoscopes... 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) can show some blockages or paralysis of the digestive tract, or abnormal air patterns in the abdominal cavity... read more , computed tomography Computed Tomography and Magnetic Resonance Imaging of the Digestive Tract Computed tomography (CT) and magnetic resonance imaging (MRI) scans are good tests for assessing the size and location of abdominal organs. Additionally, cancerous (malignant) or noncancerous... read more (CT), or magnetic resonance imaging Magnetic Resonance Imaging (MRI) Magnetic resonance imaging (MRI) is a type of medical imaging that uses a strong magnetic field and very high frequency radio waves to produce highly detailed images. During an MRI, a computer... 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 symptoms that suggest Crohn disease.

Treatment of Inflammatory Bowel Disease

  • Medications

  • Sometimes surgery

  • Diet and stress management

Although there is no cure for IBD, many medications (see table and table ), including aminosalicylates, corticosteroids, immunomodulating medications, biologic agents, small-molecule agents and antibiotics, can help reduce inflammation and relieve the symptoms of IBD.

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. 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 medications. 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... read more helps protect against bacterial infections caused by Streptococcus pneumoniae. People who are age 19 and older should receive the shingles vaccine Shingles Vaccine The herpes zoster virus that causes shingles is the same virus that causes chickenpox. After chickenpox resolves, the virus remains in the body. It can be reactivated years later and cause shingles... read more . The shingles vaccine should be given before people start taking immunomodulating medications whenever possible. 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. COVID-19 vaccines COVID-19 Vaccine Coronavirus disease 2019 (COVID-19) vaccines provide protection against COVID-19. COVID-19 is the disease caused by infection with the SARS-CoV-2 virus. There are multiple COVID-19 vaccines... read more that use mRNA are recommended for people who have IBD, including those who are taking immunomodulating medications.

Women who have IBD and who are taking immunomodulating medications should be screened for cervical cancer Cervical Cancer Screening and Prevention Cervical cancer develops in the cervix (the lower part of the uterus). Most cervical cancers are caused by human papillomavirus (HPV) infection. Having regular cervical cancer screening tests... read more every year. Women who have IBD and who are not taking immunomodulating medications should have cervical cancer screening every 3 years.

More Information

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

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