Coeliac disease

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Coeliac disease (also termed non-tropical sprue, celiac disease and gluten intolerance) is an autoimmune disease characterised by chronic inflammation of the proximal portion of the small intestine caused by exposure to certain dietary gluten proteins. Pathologic changes to the structure and function of the small bowel's mucosa impair the body's ability to digest or absorb nutrients from food. It is estimated that 1 in every 133 to 250 persons (up to 3 million) in the United States and 1% of people in the world are affected by coeliac disease.

The principal cause of the disorder is an immunologic reaction to components of certain dietary glutens. This is a cell-mediated reaction, not a typical IgE type allergy. The targets of the immunologic response are gliadin, hordein, and secalin, proteins contained in the gluten component of wheat, barley, and rye. Traditionally, oats have been included in the list as well, but some recent studies have brought into question whether this is necessary [1]. Corn (maize), sorghum, and rice are considered safe for a patient to consume. They contain types of gluten that do not trigger the disease.

In most patients, a strict wheat and gluten-free diet will relieve the symptoms. Some patients suffer from refractory sprue. Many cases of refractory sprue are in patients exquisitely sensitive to even trace amount of the problematic glutens; thus, dietary restriction fails due to trace contamination of products with wheat proteins. In other patients, a sprue-like condition may be due to intolerance to other dietary proteins such as those found in egg, milk, or soy.

Signs and symptoms

• Loss of villi lining of the small bowel
• Reduced surface area available for absorption
• Coeliac disease improves dramatically when gluten (a protein found in wheat products) is removed from the diet
• Causes diarrhea (with bulky pale offensive stools which may float) due to malabsorption in 50% of patients. In some patients, coeliac disease is first suspected after finding a combination of lactose intolerance and fructose malabsorption in standardized tests.
• Weight loss
• Selective dietary deficiencies such as dietary iron deficiency, Vitamin B12 deficiency, osteoporosis (due to Vitamin D malabsorption), or other secondary dietary deficiencies may be the sole symptom or found in addition to diarrhea
• There is an increased risk of intestinal T-cell lymphoma in untreated cases
• Runs in families
• Predominates in Northern European populations

Tests

Characteristic appearance on bowel biopsy.

The gold standard test is a jejunal biopsy taken with a crosby capsule . However nowadays a distal duodenal biopsy is taken at upper GI endoscopy (OGD). The standard changes seen under dissecting microscope are loss of villous height and hypertrophy of the crytps. There is often some degree of inflammation with inflammatory cells (plasma cells and lymphocytes) seen in the lamina propria.

Patients have gliadin antibodies. There are also blood tests for anti-gliadin antibodies and IgA antibodies to endomysium. note that in IgA deficiency, in which celiac disease is common, this test will not be significant.

Anti-endomysial antibody testing is useful to screen high risk populations

Causes

Unknown but probably:

• Partly a genetic susceptibility to the illness (identical twins do not have 100% concordance however).
• together with an environmental agent, probably a virus or other infection
• It is associated with other autoimmune disease (these diseases are also probably a combination of susceptibility + infection).

Religious controversy

The Catholic Church teaches that Communion hosts must contain some unleavened wheat, as it believes that the bread served at the Last Supper did. Sufferers of celiac disease who are Catholic cannot safely consume wheat gluten, and this causes conflict if the attendee's church refuses to make an exception. Several bishops and parishoners have also petitioned for a change in church teaching.

See also: Gluten-free, casein-free diet, Gastroenterology, Dermatitis herpetiformis

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