Crohn Disease (cont.)
How Is Crohn's Disease Diagnosed?
Crohn's disease can be difficult to diagnose because the symptoms are nonspecific, meaning that they occur with many different gastrointestinal disorders. Your health-care professional conduct a detailed medical interview to try to pinpoint the diagnosis. The patient will be asked questions about their symptoms, medical problems they have had in the past, previous surgeries, medications currently taking, family history, diet, habits, and lifestyle. The patient will be examined carefully to look for physical signs that might reveal the diagnosis.
Blood tests may be ordered to test for Crohn's disease. The purpose of these is to detect inflammation or nutritional deficiencies.
- Blood cell counts: Complete blood count (CBC) blood test may show abnormalities and may indicate anemia or inflammation.
- Electrolytes: Low levels may be an indication of problems in absorbing nutrients from foods in the intestine.
- Protein (albumin): Again, a low level may indicate absorption problems in the digestive tract.
- C-reactive protein and orosomucoid: These are markers of inflammation, and their levels correlate with how active the disease is.
- Erythrocyte sedimentation rate: This is another marker of inflammation and disease activity.
- Perinuclear antineutrophil cytoplasmic antibody (p-ANCA) antigen and anti-S cerevisiae antibodies [ASCA]): These tests are useful in distinguishing Crohn's disease from ulcerative colitis. A test result positive for p-ANCA antigen and negative for ASCA suggests the diagnosis of ulcerative colitis; a test result positive for ASCA and negative for p-ANCA antigen suggests Crohn's disease.
A stool sample may be collected to check for blood and signs of inflammation or infection, including parasites that could cause similar symptoms.
A person may undergo imaging studies X-ray films) to detect the extent of Crohn's disease and any complications that may have developed.
- Barium contrast studies is a series of X-ray films taken after you drink a contrast material containing a chalky substance called barium. The barium allows the intestine to show up better than on a plain X-ray film. Barium studies are very useful in defining the nature, distribution, and severity of the disease. The barium studies may include an upper GI series or barium swallow (X-ray films of the upper part of the digestive system) and a small bowel follow-through (X-ray films of the small intestine).
- Barium enema works on the same principal as the barium contrast studies of the upper digestive system, but the barium is introduced into the lower digestive tract through the rectum. This test is done to see whether the patient's colon and rectum are involved, and to what extent.
- CT scan called CT enterography or MRI called MR enterography is useful for assessing the extent of involvement of small intestine in Crohn's.
- Ultrasound is helpful in assessing complications outside of the intestine, such as fistulas, an abscess, or abnormalities of the liver, bile duct, or kidneys. MRI may be used instead.
Endoscopy is used to examine the lining of the stomach, upper intestine, or colon; and often provides the best information about the extent of involvement due to Crohn's.
- Endoscopy involves inserting a thin tube with a light and a tiny camera on the end into a body cavity or organ. The camera transmits pictures of the inside of the organ so that the doctor can see inflammation or bleeding or other signs of problems.
- Both the upper and the lower parts of the digestive tract can be examined endoscopically. Endoscopy of the lower part of the digestive tract is called colonoscopy. Endoscopy of the upper digestive tract is usually called simply upper endoscopy (EGD, esophagogastroduodenoscopy).
- In both cases, the doctor can use the endoscope to take a biopsy. A biopsy is a tiny sample of tissue taken from the mucosal lining of the digestive tract. These tissues are examined under a microscope by a pathologist (a doctor who specializes in diagnosing diseases by examining tissues and cells in this way).
- Endoscopic retrograde cholangiopancreatography (ERCP) is another endoscopic procedure that is helpful for both diagnosis and treatment in people who have Crohn's disease in their pancreas or bile duct, called sclerosing cholangitis.
Medically Reviewed by a Doctor on 9/11/2017
Senthil Nachimuthu, MD, BS
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