Celiac Disease: Misdiagnosed and Misunderstood
Celiac disease (also known as celiac sprue) is an autoimmune intestinal disorder that affects millions of Americans, but is often misdiagnosed and misunderstood. I interviewed Revolution Health’s gastroenterologist, Dr. Brian Fennerty, to help set the record straight. I highly recommend that you listen in to the entire conversation here, but I’ve captured the highlights in written form below.
Dr. Val: What is celiac disease?
Celiac disease is a genetically determined sensitivity to gluten, which is a protein component of wheat and other cereal grains. Some people think of it as an allergy to gluten, but it’s not a true allergy because it causes symptoms through a different biological pathway. Allergies respond to anti-histamines (and involve IgE antibodies released by eosinophils and mast cells) whereas gluten sensitivity involves IgA and IgG antibodies (released by different types of cells called lymphocytes) and do not respond to anti-histamine treatments. So the treatment for celiac disease is largely avoidance of gluten containing foods rather than directly treating the immune response.
Dr. Val: Is celiac disease under-recognized by physicians?
About 1-2% of adult Americans actually have a gene for celiac disease. However, many people with the gene don’t have symptoms. And there are others who don’t have the gene who do have celiac disease. This makes celiac disease both common, and commonly misdiagnosed.
Dr. Val: Why do some people with celiac disease have symptoms and others don’t?
That’s the million dollar question. It’s probably due to the relative vigorousness of their immunological response to gluten, and how much of their bowel is involved. Symptoms of celiac disease can range from a severe gluten intolerance in a child who stops eating (due to pain and bloating) and ceases to grow due to malnourishment, to an elderly person who has no intestinal symptoms whatsoever but is found to be iron-deficient on a screening exam – which leads eventually to the diagnosis of celiac disease.
Dr. Val: How do you diagnose celiac disease?
Doctors often misunderstand how best to diagnose this disease, and because of that patients are often misled. Nowadays we screen for celiac disease with a blood test called “tissue trans-glutaminase” (TTG) to determine whether or not this enzyme is present in an abnormal form (which is the case in patients with celiac disease). However the test has an 80% sensitivity, which means that 80% of the people who have celiac disease test positive with the TTG test, but 20% of the people who test positive do NOT have celiac disease. When only 1 or 2% of the population has the disease, a positive test is given so frequently that most people who test positive don’t actually have the disease. A negative test, on the other hand, is more helpful to exclude the diagnosis of celiac disease. So anyone with a positive celiac blood test should assume that they don’t have celiac disease until it has been confirmed with a duodenal biopsy.
Dr. Val: How invasive is a biopsy for celiac disease? Are there risks involved?
The biopsy involves an upper endoscopy (NOT a colonoscopy) so there is no bowel prep requirement so it’s much more comfortable. The biopsy itself is very shallow, so there’s no risk for bleeding. The only risks are those associated with a regular endoscopy. It is a sedated exam, so you may lose time from work, but it’s not painful or as involved as a colonoscopy.
Dr. Val: Could you still miss celiac disease on a biopsy?
It’s possible though quite unlikely. The test is very accurate, but there are some mild cases of celiac disease where the part of the bowel that we biopsy is not involved in the disease process and may not be visible under the microscope. If the disease is still strongly suspected in someone with a negative biopsy, a second biopsy can be done with a longer scope (called an enteroscope) to get a sample of tissue from farther down in the small intestine. A second option would be for the patient to swallow a camera capsule so that we can take photos of the bowel wall to see if there are changes in the lining of the intestine suggestive of celiac disease. A third option is to try a gluten-free diet and see if the patient’s symptoms improve.
Dr. Val: Is there any new research or potential therapies for celiac disease?
Because this is an immunologic disorder (where the intestine’s immune system is reacting abnormally to a normal dietary constituent and causing inflammation) we can try to control the inflammatory response. In the past we tried very potent immunomodulators like chemotherapy, or anti-inflammatories used in other auto-immune diseases like rheumatoid arthritis or Crohn’s disease. However, these are very strong medications with many unwanted side-effects. There are targeted therapies being developed that will help to block the gluten response without exposing the patient to the potent general anti-inflammatory properties of chemotherapy-type agents, but we don’t know yet if this approach will be successful.
Dr. Val: What’s your advice for patients with celiac disease?
I have three pieces of advice that I generally give my patients with celiac disease:
1. Become as informed as possible about your disease. Websites such as the Celiac Sprue Association and NFCA are excellent sources of trustworthy information. At the same time, the Internet is an extremely dangerous place for celiac patients because there are a lot of websites that are not science-based, but driven by marketers who are trying to sell products to patients. So the patient has to learn to filter the information they’re getting off the Internet.
2. Consult with a dietician or nutritionist who understands celiac disease. Not all dieticians are skilled at counseling people with gluten sensitivity, so be sure to find one who has expertise in this area. A good dietician or nutritionist is the most important part of the healthcare team for a patient with celiac disease.
3. Make sure your diagnosis is accurate. There are many tens of thousands of people walking around with a diagnosis of celiac disease who do not have it. If you’ve been diagnosed on the basis of a blood test alone, and your symptoms don’t correlate perfectly with gluten sensitivity, you need to question that diagnosis.
Dr. Val: Do people with celiac disease have higher risks for other gastrointestinal disorders?
Yes. Celiac disease is associated with diabetes, so people with celiac disease should be screened for diabetes. Some people believe that patients with celiac disease are at higher risk for irritable bowel syndrome, though it’s unclear if that’s because of overlapping symptoms and not an actual increase in IBS. Patients with celiac disease are at higher risk for iron and calcium deficiencies (due to absorption problems in the intestinal lining) which can lead to anemia and osteoporosis. There is also a higher risk of small bowel lymphoma, which is a very rare form of cancer. A celiac patient’s risk (like anyone’s risk) of breast cancer or prostate cancer, of course, are far higher than the very small (but increased) risk of intestinal lymphoma.
So there you have it folks, all you ever needed to know about celiac disease. I’m going to be participating Washington DC’s Gluten Free Cooking Spree this Friday, April 11th. I’m teamed up with the chef from Cafe Atlantico to create a gluten free meal that’s going to be out-of-this world delicious. If you’re local, I hope I see you there!This post originally appeared on Dr. Val’s blog at RevolutionHealth.com.
