If your symptoms suggest that you may have IBD, your doctor will suggest an endoscopic evaluation (or “scope”). The endoscopy will aid in determining whether you have ulcerative colitis or Crohn’s disease and which part of your bowel is affected. Ulcerative colitis and Crohn’s disease have different potential complications and individual medical and surgical treatments. Their distinction may be important, particularly prior to considering surgery, which can be curative in ulcerative colitis, but not Crohn’s disease. Inflammation in Crohn’s disease typically occurs in patches, or “skip areas” in the bowel — that is, normal-looking colonic tissue appears in between areas of inflammation (Figure 1b). Also, the ulcers are deeper (see Figure 4). Ulcerative colitis, on the other hand, has continuous inflammation that starts at the rectum and extends up throughout part or most of the colon (see Figures 2 and 5) . Only Crohn’s disease may coincidentally involve the small bowel (Figure 1).
A gastroenterologist may suggest one or more endoscopy procedures, or different types of “scopes”, to evaluate an individual for possible IBD. They generally use a thin, flexible tube with a lighted camera inside the tip, which allows your doctor to look directly at the lining of the gastrointestinal (GI) tract. The image is magnified and appears on a television screen used by your doctor to perform the exam. The part of the GI tract examined gives each procedure its name:
- Sigmoidoscopy: examines the lining of the lower third of the large intestine (the rectum and sigmoid colon).
- Colonoscopy: examines the lining of the entire large intestine (colon), and usually provide a glance into the very end of the small intestine (or ileum).
- EGD (Esophagogastroduodenoscopy): examines the lining of the esophagus, stomach (gastro), and duodenum (first part of the small intestine).
- ERCP (Endoscopic retrograde cholangiopancreatography): examines the bile ducts in the liver and the pancreatic duct.
- Wireless capsule endoscopy: has the unique capacity to examine the entire 5 meters of small bowel. This ultramodern technology employs a pill camera (see Figure 7) that after swallowed takes thousands of images while moving along the small bowel. The images are transmitted to a receiver without needing any wire connection, providing the physician with detailed images of the small bowel lining. (see Figure 8 below).
Figure 8: Capsule endoscopy videos. Left: normal; Right: Crohn’s disease