Published: July 23, 2010
Updated: July 23, 2010
Many of the children I see in our clinics have abdominal pain. I do not know if it is due to stress or the effect of other environmental factors.
For patients that have persistent discomfort -- particularly those with accompanying weight loss -- I send them to our pediatric gastroenterologists.
Dr. Nancy McGreal, a pediatric gastroenterologist at Duke, explains how she diagnoses inflammatory bowel disease.
-- Dennis Clements MD, PhD, MPH
Inflammatory bowel disease (IBD) encompasses a group of chronic intestinal conditions including Crohn’s disease, ulcerative colitis, and indeterminate colitis.
IBD may occur at any age, affecting both children and adults. Making a diagnosis of IBD can sometimes be difficult, as there is no single test that alone determines if an individual has one of these conditions.
Rather, the diagnosis of IBD is a bit like a puzzle in which health care providers must piece together:
Listening carefully to a patient’s description of her symptoms is key to determining how to direct further testing towards a possible diagnosis of IBD.
IBD may present with a variety of different symptoms including: weight loss, abdominal pain, diarrhea, bloody stool, nausea, or vomiting, as well as growth failure and pubertal delay in children.
Signs or symptoms suggesting a diagnosis of IBD may guide a heath care provider to pursue additional tests discussed below.
When a diagnosis of IBD is suspected, most health care providers will draw blood to look for signs associated with inflammation and intestinal disease. Elevated levels of factors in the blood such as platelets (blood clotting cells), the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) indicate inflammation in the body.
Anemia (low red blood cell counts) may occur due to lack of absorption of iron in the intestine or from bleeding inside the gut. Because of poor absorption of nutrients, vitamin and mineral deficiencies including iron, vitamin D, vitamin B12, and zinc may also be clues toward a diagnosis of IBD.
Blood tests called “inflammatory bowel disease serologies” were created in recent years to identify markers in the blood that may be specific for IBD.
While these blood panels can be helpful in identifying patients who may have IBD, they do not preclude the need for performing endoscopy exams to confirm a diagnosis.
Many patients ask about the possibility of genetic testing for IBD. Although there have been great strides in our understanding of genetic factors underlying IBD, genetic testing is not currently recommended.
At present, there are approximately 40 genes associated with a genetic predisposition for Crohn’s disease. Many of these genes, however, are also found in individuals without IBD. Therefore, none of these genetic factors are felt to be diagnostic of IBD at this time.
The “gold standard” for making a diagnosis of IBD remains endoscopy with tissue sampling from the intestinal tract.
During an endoscopy, a patient is given sedation medication so that she is comfortable while a small camera attached to a flexible tube is inserted through the anus into the colon (large intestine) or through the mouth into the stomach and small intestine.
Forms of IBD have distinctive patterns of inflammation in the intestine. Tissue samples obtained during the procedure are examined under the microscope to confirm a diagnosis.
The small intestine, which averages 10 to 20 feet in length depending upon an individual’s age, may be affected by Crohn’s disease. Surveying the small bowel for evidence of IBD was previously limited by the length of available endoscopes.
A device called a video capsule endoscope (also known as a “pill cam”) has aided health care providers in visualizing the small intestine for evidence of IBD. About the size of a large vitamin tablet, the video capsule contains a camera. Once a video capsule is swallowed by a person, it travels through the intestinal tract over four to eight hours and transmits thousands of images to a recorder device.
The images obtained by the video capsule can help health care providers identify evidence of Crohn’s disease that may not have been seen on standard endoscopy exams.
Finally, radiographic exams such as x-rays, computed tomography (CT) scans, or magnetic resonance image (MRI) tests are additional tools employed to diagnose IBD.
Radiographic tests provide the ability to non-invasively examine the shape and diameter of the intestinal tract for signs of inflammation. These tests may also help identify complications of IBD such as abscesses, fistulas, and intestinal blockages.
Diagnosing a patient with IBD is not a simple task; rather, it involves assimilating information from a patient, laboratory tests, procedures, and radiology.
Of course, not all patients with the symptoms described above will have IBD. If you and your primary care provider are concerned about a possible diagnosis of IBD, a pediatric gastroenterologist is someone who can help find the right diagnosis and treatment for your condition.
-- Nancy M. McGreal, MD, is a gastroenterologist in Duke's Department of Medicine and Duke's Department of Pediatrics.
-- Dennis Clements, MD, PhD, MPH, is the chief of primary care pediatrics at Duke Children's Hospital.