Celiac disease, also called "sprue" and "gluten-sensitive enteropathy," is a chronic, lifelong condition in which certain cereal proteins in the diet lead to injury of the lining of the small intestine, or bowel. Gluten is an insoluble protein found in wheat, rye, and other grains. The cause of celiac disease is not clearly understood. A complex interaction between genetic and environmental factors causes celiac disease to develop in susceptible people who include wheat, rye, and barley cereals in their diet. An unknown third factor, possibly an infection or other triggering stimulus, may be required since many people with similar risk factors do not develop celiac disease.
Celiac disease affects all ethnic groups. Most frequently affected are Caucasians, then Blacks, and, only rarely, Orientals. Based on blood tests, about 1% of the European population has evidence of celiac disease, and preliminary data suggests the same is true in the United States. Most people with celiac disease have a certain genetic type, which can be detected by screening. Although present in about 35% of the general U.S. population, over 90% of patients with celiac disease have this genetic type. How this genetic type predisposes individuals to developing celiac disease is unclear. Groups at risk for celiac disease include those with:
Illness from celiac disease generally comes from two processes: injury to the intestine and from chronic inflammation. Upon biopsy (i.e., the removal of a small amount of tissue and/or fluid from a living body and its examination to confirm the presence of a disease), the small bowel injury has a typical appearance. White blood cells (lymphocytes) enter the lining of the small bowel. The usual ridges, like tall mountains and valleys, may become blunted, like small hills, or even flat, like the plains. The injured small bowel may lead to diarrhea and impaired absorption. Over time, nutritional deficiencies may develop, leading to poor growth; weight loss; short stature; delayed puberty; anemia; and a lack of "micronutrients," including vitamins A, E, and K; iron; zinc; and folic acid.
The second mechanism, chronic inflammation, may lead to a long-lasting ill feeling, with poor appetite, and possibly bone thinning and easy fractures, called osteoporosis. An eventual loss of regulation over the immune response has been thought to play a role in the increased risk for small bowel lymphoma noted in untreated celiac disease.
A similar inflammatory reaction may occur in the skin causing an itchy, scaly rash, called dermatitis herpetiformis, and is a non-intestinal indication of gluten sensitivity.
Celiac disease can be thought of as occurring in two forms: "symptomatic" and "silent." Both have positive blood tests for celiac disease-associated antibodies, and both have a typical injury on biopsy of the small intestine. In the symptomatic form, typical signs and symptoms are present. The most information about celiac disease is known from this type. Common findings include abdominal pain, chronic diarrhea with poor fat absorption (characterized as oily or greasy stools), vomiting, and nutritional deficiencies (iron deficiency anemia, bleeding due to vitamin K deficiency, and deficiencies of folic acid and zinc). Other findings include poor weight gain, weight loss, short stature, delayed puberty, abdominal distention and gas, and, in toddlers, irritability and edema (swelling of the feet, eyelids, and other soft tissues).
In contrast, affected individuals with the silent type feel fine, have mild or no symptoms, and do not know they have celiac disease. Less is known about silent celiac disease; although, it is about six times more common than symptomatic celiac disease. Whether silent celiac disease is a risk for the long-term complications seen in symptomatic celiac disease is unknown.
Most experts agree that if both the blood test and the small intestine biopsy are positive, then the diagnosis of celiac disease is made. The available blood tests include anti-endomyseal antibody, anti-gliadin antibody, and, the newest one, anti-transglutaminase antibody. These tests may be used separately or together, and are highly accurate in screening individuals for celiac disease. However, rarely, the antibody tests can be negative, especially in individuals with IgA deficiency and in young children.
A key in the proper diagnosis of celiac disease is improvement after starting a gluten-free diet. Symptoms should resolve, the antibody tests should become negative after 6 to 12 months of a strict gluten-free diet, and the small bowel injury should resolve completely. In difficult diagnostic cases, screening for DQ-2, the genetic marker of celiac disease, may be helpful. Previously, rechallenging the body with gluten to show a reappearance of the symptoms was required to diagnose celiac disease; but, now, it is rarely needed.
Treatment for celiac disease first involves replacing deficient nutrients and choosing a gluten-free diet. If patients-especially toddlers-are severely ill, a short course of prednisone improves symptoms quickly. A lifelong gluten-free diet is the treatment for celiac disease. A gluten-free diet means avoiding foods containing wheat, rye, and barley proteins. Pure oats is probably allowable. Following a gluten-free diet is quite challenging, as these products are widespread in Western diet. However, within one week of the diet, irritability resolves, and appetite and energy level improve. Many people with silent celiac disease report feeling healthy for the first time, even though they never before complained of symptoms. If a gluten-free diet is not followed, celiac disease will always recur; however, it may take weeks to months.
Currently, celiac disease cannot be prevented
Current research includes: identifying risk groups for celiac disease; understanding the genetic predisposition and environmental triggers for developing celiac disease; and determining how silent celiac disease is similar to and different from symptomatic celiac disease, especially regarding growth, osteoporosis, and intestinal malignancy.
About the Author
Dr. Hoffenberg is on staff at the Children's Hospital in Denver, the University of Colorado School of Medicine, and is the Director at the Center for Pediatric Inflammatory Bowel Diseases. His areas of specialty include Inflammatory Bowel Disease, Celiac Disease and Polyps.
Copyright 2012 Edward J. Hoffenberg, M.D., All Rights Reserved
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