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WGO Handbook on Diet and the Gut_2016_Final

World Digestive Health Day WDHD – May 29, 2016 CELIAC DISEASE, continued toms and signs of malabsorption, very high tTG-IgA titer (>10 time upper limit of normal), and positive EMA in a second blood sample. When the country resources are low, CD diagnosis can rely on the sole presence of positive serology or even of a histology demonstrating intestinal damage, followed both by the good clinical response to GFD. Presumptive GFD followed by dramatic clinical improvement has been considered an indirect diagnostic tool for CD. However, this strategy (sometimes useful in underprivileged countries) must be strongly discouraged as the GFD will by time decrease the specific antibody levels and restore the damaged mucosa, not allowing a proper CD diagnosis. IMPORTANCE OF GENETICS FOR DIAGNOSIS OF CD AND POPULATION AT RISK First-degree and (to a lesser extent) second-degree relatives have an increased risk for CD. Because of the genetic predisposition, in HLA positive people the onset of the disease or symptoms, on a gluten-containing diet, may occur at any time in life. On the converse, a negative HLA test will exclude the possibility of CD. All first-degree relatives should be screened for celiac disease. Approximately 7% to 10% of first-degree relatives may develop CD; the risk varies considerably with their relationship with the index patient (the maximum risk in presence of the HLA haplotype DR3-DQ2, especially homozygotes, the minimum in presence of DR4-DQ8). Some other conditions (even if they may not be related pathogenically to CD) are considered at higher risk for CD. Therefore, there is the recommendation to test for CD the patients affected with type 1 diabetes mellitus, autoimmune thyroid disease, autoimmune liver disease, Down syndrome, Turner syndrome, Williams syndrome, and selective immunoglobulin A (IgA) deficiency. TREATMENT, THE GLUTEN-FREE DIET Patients with CD should not eat products containing wheat for the rest of their lives. Patients should consult a dietitian who is knowledgeable about gluten-free diets, especially during the first year after diagnosis. The safe limit of gluten intake varies across patients and has been considered to be 10-100 mg/day, although a subsequent study indicated that the upper limit should be closer to more like 50 mg/day. Celiac patients cannot eat the following cereals and flours: semolina, spelt, triticale, wheat germ, wheat starch, wheat bran, bulgur, couscous, durum flour, farro, gluten flour, Kamut, Einkorn, Emmer Graham flour, rye, or barley (including malt, malt extract, malt flavoring, and malt syrup). Gluten-free grains, flours, and starches that are allowed in a gluten-free diet include: amaranth, arrowroot, bean flours, buckwheat, corn, garbanzo beans, seeds, millet, Montina flour (Indian rice grass), nut flour, nut meals, oats (uncontaminated), potato flour, potato starch, quinoa, rice ( all forms), sorghum flour, soy flour, tapioca, and teff flour. A small subgroup of patients with CD may also be intolerant to pure oats. Oats must be pure and uncontaminated by gluten to be suitable per most CD patients. The majority of industrially produced foods may contain gluten. Any dietary deficiencies, starting from the correct fiber content, but also iron, folic acid, calcium, and (very rarely) vitamin B12, should be corrected. DIFFERENTIAL DIAGNOSIS In absence of a positive serology, the histological lesions suggestive of CD may suggest the presence of conditions other than CD. The differential diagnosis includes infective diseases (tropical sprue, giardiasis, cholera, H. pylori, HIV), immunodeficiency states, drug-induced enteropathy (olmesartan, mycophenolate, chemotherapy), allergy (eosinophilic gastroenteritis, in children enteropathy caused by food allergy), radiation damage, graft-versus-host disease, chronic ischemia, Crohn’s disease, and autoimmune enteropathy. EXTRAINTESTINAL MANIFESTATIONS AND COMPLICATIONS There are increased risks for unexplained infertility (12%), osteoporosis (30–40%), and bone fractures (35%) in classically symptomatic CD. Patients with (long-term untreated) CD have an elevated mortality risk due to an increased risk for malignancy. In particular, CD has been related to higher risk of malignant lymphomas, small-bowel adenocarcinoma, and oropharyngeal tumors. Likely, less than 1% of diagnosed patients may develop a severe complication called refractory CD, which is defined as persistence or recurrence of clinical symptoms and histopathological abnormalities despite excellent adherence to GFD for at least 12 months. Refractory CD must be considered, particularly in patients with CD diagnosed over the age of 50. This complication should be differentiated from the very common non-responsive CD, World Digestive Health Day WDHD May 29, 2016 WGO Handbook on DIET AND THE GUT 31


WGO Handbook on Diet and the Gut_2016_Final
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