Monday, August 13, 2007
Pill camera to diagnose celiac disease gaining acceptance
Technology for diagnosing digestive has progressed to the point that we now have a video camera pill (wireless video capsule endoscopy) that you can swallow. As the food doc and a gastroenterologist keenly interested in celiac disease and Crohn’s disease, I perform capsule endoscopy regularly on my patients and have now for several years. The pill camera is increasingly being used to evaluate celiac disease especially since it is covered by more insurance plans now for this indication. Rondonatti et al. report a multicenter study in the August 2007 issue of the American Journal of Gastroenterology that confirms video capsule endoscopy has good sensitivity and excellent specificity for the detection of villous atrophy in patients with suspected celiac disease. Capsule endoscopy offers the ability to see the entire length of the small intestine, far beyond the reach of the standard endoscope. Unfortunately, though capsule endoscopy is ideal for evaluating celiac disease, until just recently, most insurance companies have not been covering the test for this indication alone.
ADVANTAGES OF PILL CAMERA IN CELIAC DISEASE DIAGNOSIS
The advantages of capsule endoscopy are several. They include the avoidance of standard endoscopy, too invasive for many patients because it requires an intravenous line, sedation and swallowing a long flexible tube compared to simply swallowing a pill camera. The ability to visualize the entire small bowel where areas of villous mucosal injury as well as other complications of longstanding celiac disease can be seen that may be missed on standard endoscopy is also a distinct advantage. Those with longstanding undiagnosed and untreated celiac disease may also benefit from the reassurance that lymphoma or small bowel cancer is not present beyond the reach of the standard scope.
DISADVANTAGES OF PILL CAMERA IN DIAGNOSIS OF CELIAC DISEASE
However, the lack of ability to sample the intestine by biopsy with the pill camera and concerns about the reliability of visual appearance to correlate with biopsy results has prevented it from being widely accepted as an alternative to standard endoscopy. Studies like this recent one however continue to show that capsule endoscopy may be an acceptable alternative to standard endoscopy and biopsy in patients with characteristic symptoms and blood tests.
EXPERIENCE WITH PILL CAMERA IN DIAGNOSIS OF CELIAC DISEASE
In my own experience, several patients with suspected celiac disease but “normal” upper endoscopy and/or biopsies have had characteristic villous atrophy in a patchy manner, sometimes further down the small bowel. A few of these patients went on to have a repeat upper endoscopy with a longer scope and biopsies directed at known areas of abnormality seen on capsule endoscopy that confirmed their diagnosis. In others who have positive blood tests we mutually agreed to accept their diagnosis of celiac disease.
FUTURE OF PILL CAMERA IN DIAGNOSIS OF CELIAC DISEASE
In the future the diagnosis of celiac disease may consist of testing for the presence of HLA DQ2 and DQ8, endomysial and/or tissue transglutaminase antibody blood tests and the pill camera. It is possible that perfection of stool or saliva tests for celiac specific antibodies along with a mouth swab for genetics will be combined with the pill camera will be the standard. Currently, only Enterolab offers stool antibody tests for gluten related antibodies and the tests are not standardized or validated for diagnosis of celiac disease though appear to be very sensitive for the earliest stages of gluten sensitivity.
Despite slowness of insurance carriers to approve capsule endoscopy for evaluation of suspected celiac disease, interest in this technology is high in the research setting. The number of studies reporting the utility of this approach as a non-invasive evaluation of the small intestine combined with blood tests to diagnose celiac disease is gathering increased support. Stay tuned as we follow the progress of the role of capsule endoscopy (or pill camera) for the diagnosis of celiac disease as well as the non-invasive evaluation of numerous digestive tract disorders.
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Rondonatti E et al. “Video capsule endoscopy in the diagnosis of celiac disease: A multicenter study. Am J Gastroenterol 2007;102:1624-1631.