Inflammatory bowel disease (IBD)

Overview

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Digestive system

Digestive system

Crohn's disease and ulcerative colitis are both forms of inflammatory bowel disease. Crohn's disease most commonly affects the last part of the small intestine, called the ileum, and parts of the colon. Ulcerative colitis affects only the colon.

Inflammatory bowel disease, also called IBD, is an umbrella term for a group of conditions that cause swelling and inflammation of the tissues in the digestive tract.

The most common types of IBD include:

• Ulcerative colitis. This condition involves inflammation and sores, called ulcers, along the lining of the colon and rectum.
• Crohn's disease. In this type of IBD, the lining of the digestive tract is inflamed. The condition often involves the deeper layers of the digestive tract. Crohn's disease most commonly affects the small intestine. However, it also can affect the large intestine and, uncommonly, the upper gastrointestinal tract.

Symptoms of both ulcerative colitis and Crohn's disease usually include belly pain, diarrhea, rectal bleeding, extreme tiredness and weight loss.

For some people, IBD is only a mild illness. But for others, it's a condition that causes disability and can lead to life-threatening complications.

Symptoms

Inflammatory bowel disease symptoms vary depending on how bad the inflammation is and where it occurs. Symptoms may range from mild to severe. A person with IBD is likely to have periods of active illness followed by periods of remission.

Symptoms that are common to both Crohn's disease and ulcerative colitis include:

• Diarrhea.
• Belly pain and cramping.
• Blood in the stool.
• Loss of appetite.
• Losing weight without trying.
• Feeling extremely tired.

When to see a doctor

See a healthcare professional if you experience a lasting change in your bowel habits or if you have any of the symptoms of inflammatory bowel disease. Although inflammatory bowel disease usually isn't fatal, it's a serious disease that, in some people, may cause life-threatening complications.

Causes

The exact cause of inflammatory bowel disease remains unknown. Previously, diet and stress were suspected, but now, healthcare professionals know that these factors may aggravate IBD but aren't the cause of it. Several factors likely play a role in its development.

• Immune system. One possible cause is change in the function of the immune system. When the immune system tries to fight off an invading virus or bacterium, an immune response that is not typical causes the immune system to attack the cells in the digestive tract too.
• Genes. Several genetic markers have been associated with IBD. Traits passed down in families also seem to play a role in that IBD is more common in people who have family members with the disease. However, most people with IBD don't have this family history.
• Environmental triggers. Researchers believe environmental factors may play a role in getting IBD, especially factors that affect the gut microbiome. These may include:
  • Being raised in a sterile environment as a child, with limited exposure to germs.
  • Having a gastrointestinal infection early in life.
  • Taking antibiotics during the first year of life.
  • Being mostly bottle-fed.

Risk factors

Risk factors for inflammatory bowel disease include:

• Age. Most people who get IBD are diagnosed before they're 30 years old. But some people don't get the disease until their 50s or 60s.
• Race or ethnicity. IBD is more common in white people, but it can occur in anyone. The number of people with IBD also is increasing in other races and ethnicities.
• Family history. You're at higher risk if you have a blood relative — such as a parent, sibling or child — with the disease.

• Cigarette smoking. Cigarette smoking is the most important controllable risk factor for getting Crohn's disease.

  Smoking may help prevent ulcerative colitis. However, its harm to overall health outweighs any benefit, and quitting smoking can improve the general health of your digestive tract as well as provide many other health benefits.

• Nonsteroidal anti-inflammatory medicines. These include ibuprofen (Advil, Motrin IB, others), naproxen sodium (Aleve), diclofenac sodium and others. These medicines may increase the risk of getting IBD or worsen the disease in people who have IBD.

Complications

Ulcerative colitis and Crohn's disease have some complications in common and others that are specific to each condition. Complications found in both conditions may include:

• Colon cancer. Having ulcerative colitis or Crohn's disease that affects most of your colon can increase your risk of colon cancer. Screening for cancer with a colonoscopy at regular intervals begins usually about 8 to 10 years after the diagnosis is made. Ask a healthcare professional when and how often you need to have this test done.
• Skin, eye and joint inflammation. Certain conditions, including arthritis, skin lesions and eye inflammation, called uveitis, may occur during IBD flare-ups.
• Medicine side effects. Certain medicines for IBD are associated with a risk of infections. Some carry a small risk of developing certain cancers. Corticosteroids can be associated with a risk of osteoporosis, high blood pressure and other conditions.
• Primary sclerosing cholangitis. In this uncommon condition seen in people with IBD, inflammation causes scarring within the bile ducts. This scarring eventually narrows the ducts, restricting bile flow. This can eventually cause liver damage.
• Blood clots. IBD increases the risk of blood clots in veins and arteries.
• Severe dehydration. Too much diarrhea can result in dehydration.

Complications of Crohn's disease may include:

• Bowel obstruction. Crohn's disease affects the full thickness of the bowel wall. Over time, parts of the bowel can thicken and narrow, which may block the flow of digestive contents. Surgery may be needed to remove the diseased part of the bowel. Rarely, bowel or colon obstruction may be seen in ulcerative colitis and could be a sign of colon cancer.
• Malnutrition. Diarrhea, belly pain and cramping may make it difficult for you to eat or for your intestine to absorb enough nutrients to keep you nourished. It's also common to develop anemia due to low iron or vitamin B-12 caused by the disease.
• Fistulas. Sometimes inflammation can extend completely through the intestinal wall and create a fistula — a connection between different body parts that is not typical. Fistulas near or around the anal area are the most common kind. But fistulas also can occur internally or toward the wall of the abdominal area. In some cases, a fistula may become infected and form a pocket of pus known as an abscess.
• Anal fissure. This is a small tear in the tissue that lines the anus or in the skin around the anus where infections can occur. It's often associated with painful passing of stool and may lead to a fistula around the anus.

Complications of ulcerative colitis may include:

• Toxic megacolon. Ulcerative colitis may cause the colon to rapidly widen and swell, a serious condition known as toxic megacolon.
• A hole in the colon, called perforated colon. A perforated colon most commonly is caused by toxic megacolon, but it also may occur on its own.