Celiac Disease

Celiac disease, also called gluten-induced enteropathy or nontropical sprue, is a disorder of impaired nutrient absorption in which intolerance to the protein gluten causes damage to the small intestine, leading to malnutrition and growth failure. Antibodies against gluten, a protein found mainly in wheat, rye, oats, and barley, destroy the lining or epithelium of the small intestine, which is normally responsible for nutrient absorption as digested food passes through the gastrointestinal tract. The clinical manifestations and degree of symptoms among celiac patients are believed to correlate with the extent of damage to the small intestinal lining. Classic symptoms include diarrhea, bloating, vomiting, loss of appetite, fatigue, and even irritability. In many cases, short stature or growth failure can precede these other signs of malnutrition or gastrointestinal disease. Removal of gluten-contain-ing food products from the diet, within a few weeks to months, can dramatically improve a patient's well-be-ing by eliminating symptoms and protecting against further destruction to the small intestinal epithelium. If left untreated, however, celiac disease can have severe and even life-threatening complications, including osteoporosis, central and peripheral nerve disorders, lack of dental enamel formation, infertility, and intestinal lymphoma.

It is estimated that anywhere from one in 150 to one in 250 people worldwide has celiac disease. Although celiac disease can affect an individual of any age or gender, women are three times as likely to be affected as men. However, the variable clinical presentations among those affected—ranging from no symptoms to severe disease and growth failure—suggest a higher incidence than reported, with many cases remaining [Page 358]undiagnosed. Most cases appear primarily in whites of northern European ancestry; however, there appears to be increasing incidence among African and Asian populations in recent years. Presentation and diagnosis of celiac disease appears to peak in two age groups—that is, between the ages of 1 and 4, and again after 50 years of age.

Healthy epithelium of the small intestine is characterized by small hair-like projections, or villi, that are responsible for nutrient absorption. The specific damage in celiac disease occurs to the villi, which become partially or completed flattened. This flattening interferes with nutrient absorption, which can lead to malnutrition and growth failure. Classically, celiac disease is characterized by the presence of villous atrophy—which leads to malabsorption manifest by symptoms such as weight loss and nutrient or vitamin deficiency—and the resolution of epithelial lesions and amelioration of symptoms upon removal of gluten-containing foods.

People can be screened for celiac disease with blood testing for antibodies specific to the disease. Antibodies to endomysium, a component of smooth muscle connective tissue, and to tissue transglutaminase, a protein within endomysium, are highly sensitive and specific for celiac disease. These antibodies are present in high levels in more than 90 percent of people with untreated celiac disease and are rarely found in those without celiac disease. While levels, or titers, of these antibodies can provide a presumptive diagnosis of celiac disease, a tissue sample, or biopsy, of the small intestine remains essential for definite diagnosis. The antibody titers may also be useful in monitoring clinical response to a gluten-free diet. As patients completely remove gluten from their diet, there is a reduction in the amount of antibodies present, and this response to treatment can be followed over time. Blood levels of endomysial and tissue trans-glutaminase antibodies may even become negative in patients strictly adhering to a gluten-free diet.

...