CELIAC DISEASE (Nontropical Sprue; Gluten Enteropathy; Celiac Sprue) - A chronic intestinal malabsorption disorder caused by intolerance to gluten.
Etiology and Prevalence - This hereditary disorder is caused by sensitivity to the gliadin fraction of gluten, a cereal protein found in wheat and rye and less so in barley and oats. Gliadin acts as an antigen and forms an immune complex in the intestinal mucosa, promoting aggregation of killer lymphocytes. These lymphocytes cause mucosal damage with loss of villi and proliferation of crypt cells. The prevalence of celiac disease varies from about 1:300 in southwest Ireland to > 1:5000 in North America. No single genetic marker exists.
Celiac disease may be asymptomatic. Most patients have steatorrhea that can range from mild to massive (7 to 50 g [20 to 150 mEq] fatty acid/day). Celiac disease may cause short stature, infertility, or recurrent aphthous stomatitis or be associated with dermatitis herpetiformis, sometimes without diarrhea. There is no typical presentation. Many symptoms (eg, anemia, weight loss, bone pain, paresthesia, edema, skin disorders) are secondary to deficiency states. If overt alimentary symptoms (eg, diarrhea, abdominal discomfort, distention) also occur, the diagnosis is unlikely to be missed. Without these direct clues, celiac disease may not be suspected.
Symptoms are absent in children until they eat food containing gluten. The child fails to thrive; begins to pass pale, malodorous, bulky stools; and suffers painful abdominal bloating. Iron-deficiency anemia develops, and if hypoproteinemia is severe enough, edema appears. Celiac disease is strongly suspected in a pale, querulous child, with wasting of the buttocks and a potbelly, who has an adequate diet (thus ruling out protein-calorie malnutrition or kwashiorkor).
Presentation in women occurs 10 to 15 yr earlier than in men because amenorrhea or anemia in pregnancy may heighten clinical suspicion. Family incidence is a valuable clue. Also, an adult patient may not recollect childhood disease, although GI disease may have led to smaller stature compared with siblings and mild bowing deformities of the long bones. The disease may be unmasked after partial gastrectomy.
Iron-deficiency anemia tends to occur in children, and folate-deficiency anemia in adults. Depending on severity and duration, there can be any combination of low albumin, Ca, K, and Na and elevated alkaline phosphatase (resulting from bone involvement) and prothrombin time.
Diagnosis - Diagnosis is suspected on the basis of the symptoms and signs, enhanced by laboratory and x-ray studies, and confirmed by biopsy showing a flat mucosa and by subsequent clinical and histologic improvement on a gluten-free diet. Jejunal biopsy can be performed even in small infants, but to obviate the risk of bowel perforation, only an experienced investigator should perform the test. If a biopsy cannot be performed, the diagnosis may depend on the clinical and laboratory response (including D-xylose absorption) to a gluten-free diet. Endomysial antibody (EMA) titers show high sensitivity and specificity and are thus a proposed screening test for celiac disease. Typical mucosal abnormalities appear in apparently healthy siblings of affected patients.
The 5-g D-xylose test is usually abnormal. Untreated patients have low C3 and C4, which rise with gluten withdrawal, and normal or increased serum IgA; in 33% to 50%, IgM is reduced.
|
|
|
