Understanding Crohn's Disease (CD)
What is CD?
CD is one of a group of disorders collectively referred to as inflammatory bowel disease (IBD). CD causes painful inflammation in your digestive tract and usually occurs in the lower part of the small intestine or colon.
What causes CD?
While the direct cause of CD is unknown, here's what we do know: First, you may be more likely to experience CD if it's part of your family's medical history. Second, CD symptoms begin when your immune system attacks healthy cells in your body , for reasons we do not yet understand.
Normally, the immune system (the body's natural defense system), protects your body from bacteria, viruses and other foreign agents. When you have CD, your immune system incorrectly targets your gastrointestinal tract. This causes inflammation—leading to the symptoms and flares usually experienced with CD.
Who gets CD?
Approximately 500,000 Americans have CD, which affects men and women equally.
What's more, CD:
- Seems to run in families—20-25% of people with CD have a close relative with some form of IBD
- Most often appears in people between the ages of 15 and 30, although it may occur at any age
- People of Caucasian and Jewish origins have a higher risk of developing IBD compared with other racial and ethnic subgroups
Hear from these actual patients with moderately to severely active CD who didn't respond well to other therapies and were treated with REMICADE®. Individual results may vary.
Symptoms may range from mild to severe. They tend to show up after meals, with pain usually centered at or below the navel, often in the lower right section of the abdomen.
People with CD have periodic disease flares (when the disease is active) followed by periods of remission (times when there are few or no symptoms).
The most common symptoms of CD include:
- Abdominal pain
- Frequent diarrhea
- Rectal bleeding
Other symptoms may include:
- Loss of appetite
- Weight loss
Fistulas are another common symptom. Fistulas occur when the inflammation and ulcers caused by CD break through the intestinal wall and form an abscess (or a tunnel) outside of it.
How is CD diagnosed?
Although there is no cure for CD, the sooner CD is diagnosed, the sooner you may be able to gain control of your symptoms  and possibly induce remission.
To confirm a diagnosis—and to rule out other conditions that can cause similar symptoms—your physician will probably perform a complete physical exam and order medical tests. There is no single test that can confirm the diagnosis of CD.
Diagnostic tests may include:
- Blood tests: These tests can provide your gastroenterologist with information that will help assess your overall condition
Examinations: These exams help your gastroenterologist see inside your body to determine whether you have CD. Different types of tests include:
- Barium enema: This test helps gastroenterologists examine the colon and rectum
- Upper GI and small bowel follow-through: In this test, X-rays help doctors examine the esophagus, stomach, duodenum, and small intestine
- Enteroclysis: This test is used to reveal abnormalities in the small intestine
- Computerized tomography (CT) scan: This detailed scan is used to detect abnormalities
- Ultrasound: By using sound waves, this test examines organs of the pelvis and abdomen without exposure to radiation and is often used in combination with other radiologic tests
- Magnetic resonance imaging (MRI): By using radio waves and superconducting magnets, this test can help detect fistulas and abscesses
- Stool tests: These noninvasive tests examine stool samples to determine the possibility of bacterial, viral, or parasitic causes of diarrhea
- Urine tests: Also called urinalysis, these tests are used to detect the presence of bacteria, red blood cells, and white blood cells in your urine
- Endoscopic examinations: These tests use a tool called an endoscope to get a detailed view of the intestinal tract. Different endoscopic exams may include: sigmoidoscopy, colonoscopy, and upper endoscopy
It's important to discuss all your symptoms with your doctor to determine the appropriate tests.
CD and ulcerative colitis 
CD and ulcerative colitis (UC) are classified as types of IBD, a term used to describe inflammatory conditions affecting the digestive (or gastrointestinal [GI]) tract.
While CD and UC are both IBDs and have similar symptoms, there are a few distinct differences between the 2 conditions:
Despite these differences, in approximately 10% of cases, doctors are unable to confirm a diagnosis of either CD or UC. These cases are called indeterminate colitis.