Celiac Disease: New Guidelines
Celiac Disease: New Guidelines
In no preferential order, let me give you a list of 10 things that are important take-home messages from the ACG guidelines.
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1. Antigliadin antibody testing is out. This test is no longer part of the screening and should not be part of your diagnostic testing for celiac disease.
2. IgA TTG testing is in, but in patients who are IgA-deficient, this may be a real problem.
3. In patients who are IgA-deficient, you need to consider other testing, such as the DGP or the IgG TTG antibody. These test strategies are available in commercial laboratories.
4. Both serology and biopsy results can be misleading if the patient has been on a gluten-free diet. Don't rely universally on these, because serology and histology can normalize in the face of a gluten-free diet.
5. Genetic testing: HLA-DQ2 and -DQ8 are helpful in selected circumstances. If a patient has equivocal small-bowel biopsy findings, these tests would be very helpful. If the patient is HLA-DQ2 and -DQ8 negative, you can exclude the diagnosis of celiac disease. If you find a discrepancy between histology and serology, this is a useful test. In a refractory patient whom you think has celiac disease but is not responding to a gluten-free diet, HLA-DQ testing is helpful.
6. Celiac disease also has a high (10%) prevalence in Down syndrome. If a patient with Down syndrome is HLA-DQ2/8 negative, you can dismiss the diagnosis of celiac disease.
7. The next point is biopsies. The absolute number of biopsies is 4 from the postbulbar area and 1 or 2 from the bulbar area. Evidence suggests that between the 9- or 12-o'clock position on the bulb may increase the yield. The incremental yield is 9%-13% if you biopsied only the bulb and the distal biopsies were negative. Multiple biopsies again are the key.
8. Lymphocytic infiltration in the absence of small intestinal atrophy changes is not diagnostic of celiac disease. There are a number of differential diagnoses here, such as Crohn disease, graft-vs-host disease, giardiasis, autoimmune diseases and autoimmune enteropathy, and tuberculosis. A drug called olmesartan (Benicar®) [an angiotensin II receptor antagonist] can mimic celiac disease. Think about these other differential diagnoses when you find lymphocytic infiltration in the absence of villous atrophy.
9. Don't forget abnormal liver enzymes. In some patients, these may be the only manifestation of celiac disease apparent on routine testing. When you go through the diagnostic algorithm for elevated liver enzymes, don't forget celiac disease. These patients are typically very responsive to a gluten-free diet, and 95% will resolve. I have had 1 patient who did not resolve, and we had to ultimately treat him as having an autoimmune hepatitis. Another 5% of patients with celiac disease can have significant liver disease. It is something not to be missed.
10. The final issue is dietary involvement. Please involve the dietitian. This is very important. Think about the reintroduction of certain food products. In particular, oats need to be carefully monitored because they have a lot of cross-contamination. These patients need lifelong monitoring for vitamin deficiencies and a variety of micronutrient deficiencies. Think about iron; vitamin B12; vitamin D; folate; pyridoxine (vitamin B6); and a variety of other micronutrients, such as copper, zinc, and carnitine. Many nutrients can be malabsorbed, and these patients can be a metabolic nightmare if not recognized early.
Look at the ACG guidelines. They have given us evidence-based recommendations. Hopefully this will at least give you pause for thoughtful consideration the next time you talk to a patient. Beyond a little bloating and diarrhea, think outside the box. Celiac disease is grossly underdiagnosed, and we can all do better.
I'm Dr. David Johnson. Thanks again for listening. Hopefully this will serve you well, and I'll see you next time.
Top 10 Take-Home Messages for Celiac Disease
In no preferential order, let me give you a list of 10 things that are important take-home messages from the ACG guidelines.
[ CLOSE WINDOW ]
(Enlarge Slide)
1. Antigliadin antibody testing is out. This test is no longer part of the screening and should not be part of your diagnostic testing for celiac disease.
2. IgA TTG testing is in, but in patients who are IgA-deficient, this may be a real problem.
3. In patients who are IgA-deficient, you need to consider other testing, such as the DGP or the IgG TTG antibody. These test strategies are available in commercial laboratories.
4. Both serology and biopsy results can be misleading if the patient has been on a gluten-free diet. Don't rely universally on these, because serology and histology can normalize in the face of a gluten-free diet.
5. Genetic testing: HLA-DQ2 and -DQ8 are helpful in selected circumstances. If a patient has equivocal small-bowel biopsy findings, these tests would be very helpful. If the patient is HLA-DQ2 and -DQ8 negative, you can exclude the diagnosis of celiac disease. If you find a discrepancy between histology and serology, this is a useful test. In a refractory patient whom you think has celiac disease but is not responding to a gluten-free diet, HLA-DQ testing is helpful.
6. Celiac disease also has a high (10%) prevalence in Down syndrome. If a patient with Down syndrome is HLA-DQ2/8 negative, you can dismiss the diagnosis of celiac disease.
7. The next point is biopsies. The absolute number of biopsies is 4 from the postbulbar area and 1 or 2 from the bulbar area. Evidence suggests that between the 9- or 12-o'clock position on the bulb may increase the yield. The incremental yield is 9%-13% if you biopsied only the bulb and the distal biopsies were negative. Multiple biopsies again are the key.
8. Lymphocytic infiltration in the absence of small intestinal atrophy changes is not diagnostic of celiac disease. There are a number of differential diagnoses here, such as Crohn disease, graft-vs-host disease, giardiasis, autoimmune diseases and autoimmune enteropathy, and tuberculosis. A drug called olmesartan (Benicar®) [an angiotensin II receptor antagonist] can mimic celiac disease. Think about these other differential diagnoses when you find lymphocytic infiltration in the absence of villous atrophy.
9. Don't forget abnormal liver enzymes. In some patients, these may be the only manifestation of celiac disease apparent on routine testing. When you go through the diagnostic algorithm for elevated liver enzymes, don't forget celiac disease. These patients are typically very responsive to a gluten-free diet, and 95% will resolve. I have had 1 patient who did not resolve, and we had to ultimately treat him as having an autoimmune hepatitis. Another 5% of patients with celiac disease can have significant liver disease. It is something not to be missed.
10. The final issue is dietary involvement. Please involve the dietitian. This is very important. Think about the reintroduction of certain food products. In particular, oats need to be carefully monitored because they have a lot of cross-contamination. These patients need lifelong monitoring for vitamin deficiencies and a variety of micronutrient deficiencies. Think about iron; vitamin B12; vitamin D; folate; pyridoxine (vitamin B6); and a variety of other micronutrients, such as copper, zinc, and carnitine. Many nutrients can be malabsorbed, and these patients can be a metabolic nightmare if not recognized early.
Look at the ACG guidelines. They have given us evidence-based recommendations. Hopefully this will at least give you pause for thoughtful consideration the next time you talk to a patient. Beyond a little bloating and diarrhea, think outside the box. Celiac disease is grossly underdiagnosed, and we can all do better.
I'm Dr. David Johnson. Thanks again for listening. Hopefully this will serve you well, and I'll see you next time.
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