Endoscopy in Crohn Disease

• Endoscopy in Crohn Disease Overview
• Endoscopy: What to expect
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Endoscopy in Crohn Disease Overview

Unfortunately, there is no simple lab test that allows a definitive diagnosis of Crohn disease. If you have symptoms suggesting inflammatory bowel disease, your primary care provider or gastroenterologist will probably recommend endoscopy (“scope”).

Endoscopy is a test in which a thin tube with a light and a tiny camera at the end is inserted into your digestive tract. The camera transmits pictures back to a video monitor, where they are magnified so your doctor can see exactly what the inside of your digestive tract looks like. The endoscope shows ulcers, bleeding, and other signs of Crohn disease and indicates the location and extent of the disease within the digestive tract.

With endoscopy, your doctor can tell whether you have Crohn disease or a similar condition called ulcerative colitis (or some other condition). Ulcerative colitis is, like Crohn disease, an inflammatory disease. Ulcerative colitis, like Crohn disease, affects one section of the large intestine (colon) only, while Crohn disease is more likely to affect the small intestine and often attacks different parts of the digestive tract with normal tissue in between (“skip lesions”).

Doctors have different names for endoscopy depending on which part of the digestive tract they are looking at.

• Esophagogastroduodenoscopy (EGD): Also called upper endoscopy, this test examines the lining of the esophagus (the tube between the mouth and stomach), the stomach, and the duodenum (the upper part of the small intestine).
  
  
• Colonoscopy: This test examines the lining of the colon, or large intestine, and sometimes the lower part of the ileum (the lowest part of the small intestine).
  
  
• Sigmoidoscopy: This test examines the lining of the lowest third of the colon, which includes the rectum. The name of the test derives from a bend called the sigmoid in this part of the colon.
  
  
• Endoscopic retrograde cholangiopancreatography (ERCP): This test combines endoscopy with x-rays to examine the ducts that open into the small intestine from the liver, gallbladder, and pancreas. In some people with Crohn disease, these ducts become inflamed and close up.
  
  
• Endoscopic ultrasound: This test combines endoscopy with ultrasound, a technology that uses sound waves to create images of organs deep within the body. (This is the same safe technology used to look at a fetus in its mother’s womb.) This technique is widely used in the United States to evaluate fistulas, a common complication of inflammatory bowel disease.

None of these tests allows the doctor to see the entire small intestine. Newer tests are being developed that will show more of the small intestine. For now, a combination of endoscopy and x-ray tests is used to diagnose Crohn disease. The x-rays may include an “upper GI series,” “small bowel follow-through,” and lower GI series, or barium enema.

Which of these tests your doctor chooses to do depends on the symptoms you have. Your symptoms suggest which part of your digestive tract is involved. For example, nausea and vomiting and dyspepsia suggest that the upper part of the tract is affected, and an EGD would probably be done. Rectal bleeding or pain with bowel movements, on the other hand, suggests that the lowest part of the tract is affected, and a sigmoidoscopy would probably be the first choice of test. Because colonoscopy allows examination of the lowest part of the small intestine, as well as the colon, this is the usual test of choice when Crohn disease is suspected.

Endoscopy allows the doctor to not only see the inside of the digestive tract, but also to take small samples (biopsies) of tissue for further examination under a microscope. This can help confirm the diagnosis and show the extent of the disease. In some cases, endoscopy can also be used for therapy. The doctor can use the endoscope to open a duct or remove a gallstone (ERCP).