Clinical Features and Epidemiology of Celiac Disease

INTRODUCTION Celiac disease (CD) is an immune-mediated enteropathy caused by a permanent sensitivity to gluten in genetically susceptible individuals. It presents as symptomatic subjects with gastrointestinal and non-gastrointestinal symptoms, as well as subjects without specific CD symptoms that are affected by type I diabetes, Down syndrome, Turner syndrome, Williams syndrome, selective IgA deficiency, and first degree relatives of individuals with CD (1). Although the classic patient with malnutrition and a distended abdomen is readily diagnosed, it is becoming increasingly evident that symptomatic CD patients represent just the tip of the celiac iceberg (Figure 1). Affecting 1% of the general population in the United States, including children, untreated CD poses long-term adverse health consequences including osteoporosis, anemia, poor growth, increased risk of autoimmune conditions and intestinal lymphoma (2). This review describes the epidemiology, pathophysiology, associated conditions, and treatment of CD, with an emphasis on aspects specific to the pediatric population. CLINICAL FEATURES AND EPIDEMIOLOGY OF CELIAC DISEASE Once thought to be a rare childhood disorder characterized by malabsorption, abdominal distension, lethargy, and failure to thrive, celiac disease is a prevalent (~1/100) food hypersensitivity disorder caused by inflammation induced by ingestion of gluten, a protein found in wheat, barley, rye and other grains (3). This classic presentation makes for an easy diagnosis but in many patients the disease can be clinically silent or have predominant extra-intestinal manifestations (4). Clinical presentation depends on age, sensitivity to gluten, gluten load, and other undetermined factors. Increased awareness and widespread serologic evaluation has resulted in a shift in the presentation of celiac patients (5). A multitude of signs and symptoms have been ascribed to celiac disease (Table 1). Weight loss and diarrhea are not present in the majority of patients. A significant lag between onset of symptoms and diagnosis can exist because the overall onset of symptoms is gradual (6). Occasionally, a triggering event such as gastroenteritis, travel, stress or a change in diet can be identified. Frequently, non-specific, constitutional symptoms such as fatigue, lethargy, headache, poor appetite, and depression are concomitantly reported (7). Commonly, patients present with symptoms of bloating, abdominal pain, altered bowel habits and have been diagnosed with irritable bowel syndrome. Patients satisfying the Rome II criteria for irritable bowel syndrome have a 5% risk for having undiagnosed celiac disease as the cause of their symptoms (8). CELIAC DISEASE: A COMPREHENSIVE REVIEW AND UPDATE, SERIES #1