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G18 Gastroenterology
Small and Large Bowel Toronto Notes 2019 Celiac Disease (Gluten Enteropathy/Sprue)
Definition
• abnormalsmallintestinemucosaduetointestinalreactiontogluten,aproteinfoundinwheat,barley, rye, and possibly oats (certified gluten-free oats may be acceptable in a subgroup of patients)
Etiology
• theonlyautoimmunediseaseinwhichautoantigen(variousgliadinpeptides)isrecognized
• associatedwithotherautoimmunediseases,especiallySjögren’s,thyroiddisease,DMType1
• glutenisbrokendowntogliadin,whichisthetoxicfactor
• HLA-DQ2(chromosome6)foundin80-90%ofpatientscomparedwith20%ingeneralpopulation;
celiac also associated with HLA-DQ8 (note: up to 40% of Caucasians carry the HLA alleles, but will never develop celiac disease)
Epidemiology
• morecommoninwomen
• familyhistory:10-15%offirst-degreerelatives
• maypresentanytimefrominfancy(whencerealsintroduced)toelderly • peakpresentationininfancy
Clinical Features
• classicpresentation:diarrhea,weightloss,anemia,symptomsofvitamin/mineraldeficiency,failureto thrive; more common current presentation: bloating, gas, iron deficiency
• improveswithgluten-freediet,deteriorateswhenglutenreintroduced
• diseaseisusuallymostsevereinproximalbowel
■ iron, calcium, and folic acid deficiency (proximal absorption) more common than vitamin B12 deficiency (absorbed in ileum)
• glutenenteropathymaybeassociatedwithdermatitisherpetiformisskineruption,epilepsy,myopathy, depression, paranoia, infertility, bone fractures/metabolic bone disease
Investigations
• serologicaltests
■ serum anti-tTG antibody, IgA, is 90-98% sensitive, 94-97% specific ■ IgA deficient patients have false-negative anti-tTG
◆ therefore, measure serum IgA concomitantly (via serum immunoglobulin quantitation)
• incorporateserumtestingtTGand/orDGPIgGinIgAdeficiencies
• smallbowelmucosalbiopsy(usuallyduodenum)isdiagnosticwithincreasedintraepithelial
lymphocytes (earliest pathologic finding)
■ crypt hyperplasia
■ villous atrophy
■ note: villous atrophy also seen in small bowel overgrowth, Crohn’s, lymphoma, Giardia, HIV
• improvementwithagluten-freediet,butshouldnotbestartedbeforeserologicaltestsandbiopsy
• considerCTenterographytovisualizesmallboweltoruleoutlymphoma
• evidenceofmalabsorption(localizedorgeneralized)
■ steatorrhea
■ low levels of ferritin/iron saturation, Ca2+, Fe, albumin, cholesterol, carotene, B12 absorption
• quantitativefecalfat>7%
Treatment
• dietarycounselling
■ gluten free diet; avoid barley, rye, wheat (as these grains are related and also have toxic factor, similar
to gliadin)
■ oats allowed if not contaminated by other grains (grown in soil without cross-contamination) ■ rice and corn flour are acceptable
■ iron, folate supplementation (with supplementation of other vitamins as needed)
• ifpoorresponsetodietchange,consider
■ alternate diagnosis
■ non-adherence to gluten-free diet
■ concurrent disease (e.g. microscopic colitis, pancreatic insufficiency)
■ development of intestinal (enteropathy-associated T-cell) lymphoma (abdominal pain, weight loss,
palpable mass)
■ development of diffuse intestinal ulceration, characterized by aberrant intraepithelial T-cell
population (precursor to lymphoma)
Prognosis
• associatedwithincreasedriskoflymphoma,carcinoma(e.g.smallbowelandcolon;slightincrease compared with general population), autoimmune diseases
• riskoflymphomamaybeloweredbydietaryglutenrestriction
Gluten Found in BROW Barley
Rye
Oats (controversial) Wheat