Celiac disease

Celiac disease is a permanent intolerance to gluten, and causes damage to the small intestinal mucosa by an autoimmune mechanism in genetically susceptible individuals. Celiac disease is one of the most common gastrointestinal disorders in the world. It is estimated that celiac disease affects 1% of the population but 90% of these individuals remain undiagnosed.

Celiac disease was thought to be a rare malabsorptive disorder of infancy and childhood. However, it is now considered to be a common, chronic, multisystem autoimmune disorder that can present at any age when gluten is present in the diet. Awareness of celiac disease among health professionals remains poor.[1,2] The mean delay in diag­nosis of celiac disease in Canadian adults is 11.7 years. Early diagnosis of celiac disease will prevent nutritional deficiencies and may also re­duce the risk of developing certain cancers and other autoimmune disorders.

Typical symptoms of celiac disease include abdominal pain, diarrhea, and weight loss. However, many individuals present with atypical symptoms including anemia (iron or folate deficiency), extreme weakness, constipation, mouth ulcers, short stature, osteo­porosis, menstrual irregularities, and infertility. Additional symptoms in children include delayed growth and puberty, vomiting, irritability, and dental enamel defects.

Celiac disease is a hereditary disorder. Both first- and second-degree relatives of the person with celiac disease are at risk of developing the disease. Other high-risk groups include patients with autoimmune disorders and Down syndrome. Screening is recom­mended for all high-risk individuals.

Serological screening by primary care physicians of all individuals with relatives of patient with celiac disease or presenting with the following symptoms led to a 42-fold increase in the diagnoses of celiac disease:[3]
• Abdominal pain
• Diarrhea
• Bloating
• Constipation
• Irritable bowel syndrome
• Fatigue
• Anemia
• Abnormal liver function tests
• Infertility
• Epilepsy
• Ataxia
• Thyroid disease
• Type 1 diabetes

Dermatitis herpetiformis (DH) is “celiac disease” of the skin. If a chronic, severely itchy, blistering rash does not respond to conventional therapy, DH should be considered. A skin biopsy will help make the diagnosis of DH and a gluten-free diet will help alleviate the symptoms.

Highly sensitive and specific serological tests are available to screen for celiac disease. The currently recommended test is the IgA-tissue transglutaminase antibody (TTG). IgA deficiency is common in celiac disease and total serum IgA level must also be measured. Patients with a positive TTG test should be referred for endoscopic small intestinal biopsy for confirmation of the diagnosis.

Celiac disease can be effectively treated by a strict, lifelong adherence to a gluten-free diet. A gluten-free diet should not be started before a biopsy is done, as it will affect the interpretation of the biopsy and make confirmation of the diagnosis difficult.

—Mohsin Rashid, MBBS, FRCPC, 
Dalhousie University, Halifax

References

1. Cranney A, Zarkadas M, Graham ID, et al. The Canadian Celiac Health Survey. Dig Dis Sci. 2007;52:1087-1095.
2. Rashid M, Cranney A, Zarkadas M, et al. Celiac disease: Evaluation of the diag­nosis and dietary compliance in Canadian children. Pediatrics 2005;116:e754-e759.
3. Catassi C, Cryszak D, Louis-Jacques D, et al. Detection of celiac disease in primary care: A multicenter case-finding study in North America. Am J Gastroenterol 2007;102:1461-1463.