Flashcards in Coeliac Disease Deck (10):
What is coeliac disease?
- = a gluten enteropathy; T cell mediated reaction to gliadin
Pathophys of coeliac disease
- Gluten peptides, e.g. gliadin, are deamidated by free tissue transglutaminase (tTG)
- These deamidated peptides bind to HLA DQ2 or DQ8, present in most CD patients (80-90%)
- This activates cytotoxic T cells -> Abs produced -> epithelial damage
Histopath features of coeliac disease
- villous atrophy and crypt hyperplasia
- increased number of plasma cells and lymphocytes in lamina propria
- increased intraepithelial lymphocytes
- Most severe in proximal bowel
What is the relationship between HLA DQ2/DQ8 and coeliac disease?
- 30-40% caucasians carry DQ2/DQ8, but <3% of these develop CD (so there must be an interplay for pathophys)
What other conditions can coeliac disease be associated with?
○ Dermatitis herpetiformis
○ Bone fractures /metabolic bone disease
- Thyroid disease
What vitamin deficiencies can you develop with coeliac disease?
iron, Ca, folic acid > vitamin B12 (bc of proximal bowel)
- Usually have small bowel (duodenal) biopsy for Dx:
• 1st biopsy - evidence of villous atrophy with gluten diet
• Follow up biopsy - evidence of villous improvement without gluten
- Adequate gluten needed for 6 weeks
Aside from the GS Dx Ix, what other Ix could you do for coeliac?
- FBE and blood smear: microcytic anaemia (rare to have folate and vitamin B12 deficiencies leading to macrocytic anaemia)
- IgA-tTG and anti-gliadin Abs
○ High specificity and sensitivity
- EMA (endomysial antibody)
- IgA deficient pts have false negative - so measure serum IgA concomitantly (via serum protein electrophoresis)
Future risk with coeliac disease of...?
• Intestinal lymphoma
• Carcinoma e.g. small bowel and colon