Celiac disease is an autoimmune disorder of the small intestine that occurs in genetically predisposed people of all ages from middle infancy on up. Symptoms include chronic fatigue and diarrhea. A growing portion of diagnoses are being made in asymptomatic persons as a result of increased screening.
Celiac disease is caused by a reaction to gliadin, a gluten protein found in wheat. Upon exposure to gliadin, the enzyme tissue transglutaminase modifies the protein, and the immune system cross-reacts with the bowel tissue, causing an inflammatory reaction. That leads to flattening of the lining of the small intestine. This interferes with the absorption of nutrients because the intestinal villi are responsible for absorption.
Celiac disease has been linked with a number of conditions. In many cases it is unclear whether the gluten-induced bowel disease is a causative factor or whether these conditions share a common predisposition. Immunoglobulin (Ig) A deficiency is present in two percent of patients with celiac disease, and in turn this condition features a tenfold increased risk of celiac disease. Other features of this condition are an increased risk of infections and autoimmune disease. Other autoimmune disorders such diabetes mellitus type q, autoimmune thyroiditis and primary biliary cirrhosis.
Serological blood tests are the first-line investigation required to make a diagnosis of celiac disease. Serology for anti-tTG antibodies has superseded older serological tests and has a high sensitivity and specificity for identifying coeliac disease. Modern anti-tTG assays rely on a human recombinant protein as an antigen. Guidelines recommend that a total serum IgA level is checked in parallel, as celiac patients with IgA deficiency may be unable to produce the antibodies on which hese tests depend. Blood HLA test have similar accuracies for celiac disease test.
At present, the only effective treatment is a life-long gluten free diet. No medication exists that will prevent damage, or prevent the body from attacking the gut when gluten is present. A tiny minority of patients suffer from refractory disease, which means they do not improve on a gluten free diet. This may be because the disease has been present for so long that the intestines are no longer able to heal on diet alone, or because the patient is not adhering to the diet, or because the patient is consuming foods that are inadvertently contaminated with gluten. If alternative causes have been eliminated, steroids or immunosuppresants may be considered in this condition.
