Coeliac disease is a permanent inability to tolerate gluten.
1 in 2000.
Can present at any age.
F > M in adult diagnosed disease.
Common in Europe, (1 in 300 in Ireland) rare in Black Africans.
Thought to be an autoimmune disease with genetic and environmental components.
· Genetic: 90% of patients have the HLA A1,B8,DR3, DR7,DQW2 haplotype. 70% concordance of monozygotic twins.
· Environmental: There is amino acid sequence homology between gliadin and adenovirus 12, increased childhood incidence in those exposed to gluten containing foods from a young age.
Gluten ingestion results in mucosal damage causing a flattening of villi (subtotal villous atrophy) which in turn leads to a more generalised malabsorption.
Patients may present with irritability and failure to thrive in childhood, delayed puberty, short stature, or vomiting, diarrhoea, anorexia or abdominal distension at any age.
There is an association with development of small bowel lymphoma and a small increased risk in the development of small bowel adenocarcinoma. There is also an association with dermatitis herpetiformis (HLA B8 linkage is shared) and other organ specific autoimmune conditions, e.g. primary biliary cirrhosis.
There is lymphocytic infiltration of the lamina propria, and an increase in intraepithelial lymphocytes (which bear the γδ eceptor). Loss of normal villous architecture ranges from blunting (partial villous atrophy) to complete loss (total villous atrophy) with crypt hyperplasia in an attempt to compensate.
· Serology: Screening by IgG gliadin and IgG anti-reticulin antibodies is sensitive but not specific. Screening by IgA gliadin and IgA anti-reticulin an-tibodies is specific but not sensitive. Antiendomysial antibodies (IgA) are found in the serum of most patients (sensitivity 98% specificity 93–99%), but total IgA must also be measured as coexistent IgA deficiency is not uncommon. ELISA for transglutaminase anti-body has been shown to be sensitive and specific.
· Small bowel biopsy is diagnostic when taken at diagnosis, later when on a gluten free diet showing recovery of architecture and after gluten challenge showing villous loss again.
A gluten free diet leads to a restoration of normal villous structure and resolution of dermatitis herpetiformis. Haemoglobin and antiendomysial antibodies may be checked at routine follow-up to look for inadvertent gluten intake.