Inflammatory bowel disease (IBD) is a gastrointestinal condition with symptoms that range from mild to life-changing. It is not the same as irritable bowel syndrome (IBS), which can be challenging to live with but is generally not as serious.
Research is ongoing into the causes of IBD. There is a known genetic component, and some environmental factors may contribute to its development. There is also good evidence IBD is an autoimmune disorder.
In this article, we’ll talk about what IBD is, how it presents, what triggers IBD flares, and how IBD is diagnosed and treated.
What Is Inflammatory Bowel Disease?
Inflammatory bowel disease includes two disorders that cause chronic inflammation of the digestive tract: ulcerative colitis and Crohn's disease. These very different conditions are usually easy to tell apart, but if a firm diagnosis can’t be made a person might be said to have indeterminate colitis.
Ulcerative colitis is a condition characterized by chronic inflammation of the colon and rectum, together known as the large intestine, with ulcers (open sores) forming along its inner lining. (Source)
Crohn’s disease can affect any part of the gastrointestinal (GI) tract from the mouth to the anus, and is divided into types depending on which part or parts are affected. Inflammation from Crohn’s can penetrate the entire thickness of the intestinal wall. (Source)
A third diagnosis, indeterminate colitis, can be given if it isn’t possible to tell whether a patient has ulcerative colitis or Crohn’s disease. However, this diagnosis is not common.
Signs and Symptoms
Signs and symptoms of IBD vary depending on the specific condition, the severity of inflammation, and the parts of the GI tract affected. Some features that are common to both ulcerative colitis and Crohn's disease include:
- abdominal pain and cramping
- rectal bleeding or bloody stool
- reduced appetite
- weight loss
IBD vs. IBS
Inflammatory bowel disease and IBS may have similar symptoms, but are two distinct conditions that require different treatments.
Irritable bowel syndrome is considered a functional GI disorder, meaning it disrupts bowel function without damaging the GI tract. It affects approximately 10% to 15% of adults in the United States, impacts women more often than men, and is one of the most frequently diagnosed GI conditions.
Symptoms of IBS
Signs and symptoms of IBS vary in severity but may include:
- chronic and persistent abdominal pain
- mucus in the stool
- abdominal bloating or feeling full
- being unable to have a bowel movement despite feeling the need
Differences Between IBD and IBS
There are several key differences between IBD and IBS:
- IBD is classified as a disease, and IBS is classified as a syndrome, or group of symptoms.
- IBD can cause harmful gut inflammation, but IBS does not.
- IBD can cause visible damage to the colon, but with IBS a colon exam is normal.
- IBD incurs an increased risk for colon cancer, but IBS does not.
It is possible to have both IBD and IBS. There is no evidence that having IBS increases the risk of developing IBD. (Source, Source)
Causes and Triggers of IBD
The exact cause of IBD is unknown, but it is likely due to an abnormal relationship between the gut microbiome and the immune system. Normally, the immune system attacks foreign invaders, such as viruses and bacteria. However, in IBD, the immune system may attack healthy cells in the digestive tract, giving rise to the characteristic inflammation of that region. (Source)
It isn’t entirely clear why this happens, but it seems to be a combination of intestinal microbes causing inflammation of the gut lining and a tendency of the immune system to respond inappropriately to microbes that are harmless or even beneficial. (Source)
There is also a genetic component to IBD, and if you have family members with the condition you may be more likely to have it. However, most people with IBD do not have this family history. (Source)
It was once thought IBD was caused by diet and stress. Research has shown, however, that while diet and stress can make IBD symptoms worse, they don’t cause the condition. (Source, Source)
A flare is a resurgence or worsening of IBD symptoms. Common symptoms of ulcerative colitis or Crohn’s disease flares are:
- frequent and/or urgent bowel movements
- bloody stool
- abdominal pain
- weight loss
- loss of appetite
- nausea and vomiting
IBD Flare Triggers
- Missing, skipping, or taking the incorrect dose of medication: Not taking, or taking an incorrect dose of, prescribed IBD medication can trigger a flare-up.
- Antibiotics: Antibiotics used to treat bacterial infections can alter the bacteria in the gut, causing diarrhea or inflammation.
- Stress: Physical or emotional stress can exacerbate IBD symptoms.
- Foods that irritate the digestive tract: Certain foods, such as those that are fried or greasy, can trigger IBD symptoms.
IBD Flare Treatments
- Corticosteroids: Corticosteroids have anti-inflammatory properties and can be used to achieve short-term IBD remission, but long-term steroid use may have side effects.
- Check drug levels: It is possible to become resistant to IBD medication. If your usual medication is not preventing IBD flares, you may have actually developed antibodies against it.
- Change medication: Switching medication dosage, trying a new medication, or adjusting your medication regimen may alleviate flares.
IBD Risk Factors
- Genetic predisposition: Research has pinpointed a number of genes that may be involved in susceptibility to IBD. Risk may increase if a close blood relative, such as a parent or sibling, has Crohn’s or ulcerative colitis. (Source)
- Early antibiotic exposure. In the US, an association has been found between receiving an antibiotic in the first year of life and later development of IBD, presumably because of disruption in the normal gut microbiome. In other countries where infants are exposed to more pathogens, however, early antibiotic exposure may have a protective effect. (Source)
- Race and ethnicity: IBD affects people of all races and ethnicities, but in the US the incidence is significantly higher among white people. Studies have shown increasing incidence in recent years among both white and non-white people. (Source)
- Age: Most people are diagnosed between the ages of 15 to 29, although they may have symptoms for years before they receive a diagnosis. (Source)
- Smoking: Cigarette smoking increases your risk of developing Crohn's disease, although we aren’t sure why. Oddly, some studies have found a lower incidence of ulcerative colitis among smokers. (Source)
- Non-steroidal anti-inflammatory medications: Medications such as ibuprofen (Advil and Motrin), naproxen sodium (Aleve), and diclofenac sodium (Voltaren), may increase risk of developing IBD or worsen the condition. (Source)
How Is IBD Diagnosed?
Your health care provider will likely only diagnose IBD once other causes for your symptoms are ruled out. Specific diagnostic tests and procedures are conducted to confirm the condition.
IBD Lab Tests
Lab tests are used both to make sure symptoms are not due to infection or another medical problem, and to confirm the suspicion that symptoms are due to IBD.
- Blood tests: Blood tests are often ordered to check for anemia, which may be caused by intestinal bleeding, and for evidence of infection or inflammation. If an IBD diagnosis appears likely, antibody tests may be done to confirm it. (Source)
- Stool tests: Stool may be tested for the presence of bacteria, parasites, or other disease-causing pathogens. It may also be tested for blood and for certain proteins that reveal the presence of gut inflammation. (Source)
IBD Endoscopic Procedures
These procedures are more invasive than blood and stool tests, but they allow visual inspection of the GI tract.
- Colonoscopy: Under current U.S. guidelines, colonoscopies to check for colon cancer are recommended for everyone aged 45 and over. Colonoscopy, which allows visualization of the entire colon by way of a thin, flexible, lighted tube with a camera on its end, is also used to diagnose IBD. Tissue samples for biopsy may be taken during the colonoscopy.
- Flexible sigmoidoscopy: A sigmoidoscopy also involves a thin, flexible, lighted tube with a camera, but is only inserted as far as the last part of the colon, known as the sigmoid. Ulcerative colitis usually begins in the rectum, and this much less invasive procedure may be more appropriate than colonoscopy if ulcerative colitis is suspected. (Source)
- Upper endoscopy: Like other procedures, an upper endoscopy involves a flexible, lighted tube with a camera, but it is inserted through the mouth rather than the rectum and visualizes the upper GI tract including the esophagus, stomach, and beginning of the small intestine. It may be used to diagnose Crohn’s disease, which can affect any part of the GI tract, and to look for other causes of symptoms such as nausea, vomiting, and abdominal pain.
- Capsule endoscopy: A capsule endoscopy allows visualization of the small intestine, which is out of reach of most other methods. A wireless camera encased in a capsule about the size of a large vitamin is swallowed, and as it moves through the GI tract it transmits images to a recorder worn on a belt. Painless and less stressful than more invasive procedures, a capsule endoscopy does not allow tissue sampling for biopsy. (Source)
- Balloon-assisted enteroscopy: The small intestine is narrow but very long (between 20 and 25 feet!) and is twisted and packed into a small space, making it hard to advance an endoscope through it. This kind of endoscope has one or two balloons attached to it, which can be inflated to open the intestine and clear a passage for the endoscope. It is sometimes used in conjunction with capsule endoscopy. (Source)