Inflammatory Bowel Disease

Diagnosis

The diagnosis of IBD is based on a combination of exams: endoscopic, X-rays, and blood and tissue tests. Upon diagnosis, IBD patients may need additional tests to monitor the disease and diagnose possible complications or side effects of medications. Mayo specialists are very experienced at conducting and interpreting these tests.

Laboratory Tests

A CBC (complete blood count) test can detect infection and anemia, as well as monitor for side effects of certain IBD medications. Liver function tests help screen for liver and bile duct abnormalities seen in some IBD patients. Stool studies determine whether patients have treatable bacterial infections that can trigger a flare-up of IBD. Antibody tests can help clarify the situation for "indeterminate colitis" patients without a definite diagnosis.

Endoscopy

Several types of endoscopy are used to determine if the patient has ulcerative colitis or Crohn's disease and how much bowel is affected. All use a thin, flexible tube with a lighted camera inside the tip, which allows doctors to look at the lining of the gastrointestinal (GI) tract. The image is magnified and appears on a television screen. Each procedure is named for the part of the GI tract examined:

• Sigmoidoscopy — Examines the lining of the lower third of the large intestine (the sigmoid colon).
• Colonoscopy — Examines the lining of the large intestine (colon), and sometimes can peek 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.
• Endoscopic ultrasound: Uses an ultrasound probe attached to an endoscope to obtain deep images of the gut. In IBD, this is most often used to look at fistulas in the rectal area.
• Capsule endoscopy — Patients swallow computerized cameras in vitamin-sized capsules to produce images of sections of the small intestine that are beyond the reach of an EGD. Read more on capsule endoscopy.

Radiology Tests

Radiologic tests provide information that endoscopy cannot. EGD and colonoscopy can visualize only the stomach, the very upper small intestine (EGD) and the colon and very lower small intestine (colonoscopy). Most of the small intestine cannot be imaged by endoscopy, although Mayo is currently evaluating capsule endoscopy for this purpose. Radiographic tests can image the small intestine.

Plain X-rays

Plain X-rays without contrast detect blockage in the small or large intestine.

X-rays with Contrast

Contrast X-rays are used with endoscopy in monitoring and treating IBD. These X-rays track special liquid contrast, usually barium, as it passes through the intestine, highlighting specific conditions.

CT Scan

A CT scanner takes simultaneous X-rays from different angles to reconstruct images of the internal organs.

MRI

Magnetic Resonance Imaging (MRI) is used to evaluate perianal fistulas and abscesses in patients with IBD. Other potential uses are being investigated.

White Blood Cell Scan

Inflammation of the GI tract is characteristic of ulcerative colitis and Crohn's disease. Leukocyte scintigraphy (tagged white blood cell scan) detects white blood cell accumulation in inflamed tissue.

Ultrasound

In general, ultrasound technology is not useful for examining the bowel, although sometimes it is used in combination with other radiological tests.