Coeliac disease Flashcards
What is Coeliac disease
Immune mediated inflammatory condition provoked by gluten
Clinical presentation of Coeliac disease
Range of possible symptoms, with onset at any age (two peaks; infancy and 5th decade). Persistent GI symptoms. Faltering growth. Prolonged fatigue. Unexplained weight loss. Severe mouth ulcers. Iron, B12 or folate deficiency (anaemia). IBS. Family Hx of Coeliac.
Examination of Coeliac disease - what does DQ stand for
Dietary Query
Pathophysiology of Coeliac disease
α-Gliadin is the toxic portion of gluten.
It is resistant to proteases in GI tract, and passes epithelial barrier of the small intestine
-> Deamination by tissue transglutaminase (increasing immunogenicity)
-> interacts with antigen presenting cells (macrophages) in the lamina propria via HLA DQ2 and DQ8 and deaminated gliadin is expressed on MHC2.
This activates gluten sensitive T cells
-> Inflammatory cascade and release of mediators
-> Cell damage (villous atrophy and crypt hyperplasia)
Aetiology of Coeliac disease
Strong genetic association with HLA DQ2 and DQ8. Attacks caused by the presence of gluten in the diet.
Epidemiology of Coeliac disease
1/100 in UK
common in Irish
Diagnosis of Coeliac disease
Serology: IgA tissue transglutaminase antibodies (IgA-tTG blood test) have a very high sensitivity and specificity for Coeliacs. Also endomysial antibodies.
Then, Distal Duodenal Biopsy: Histological changes.
Treatment fo Coeliac disease
Gluten free diet
Nutritional supplement as required
Complications of Coeliac disease
Increased incidence of malignancy, reduced by gluten free e.g. GI t-cell lymphoma
When would you suspect Coeliac disease
Diarrhoea + weight loss or anaemia
FBC Coeliac disease
low Hb high RCDW (Red blood Cell Distribution Width) low B12 low ferritin IgA levels
Examples of gluten free food
Rice Maize Soya Potatoes Sugar
Prescribe-able gluten free food
Gluten-free... Biscuits Flour Bread Pasta
How does coeliac disease cause damage to the gut
Gliadin binds to secretory IgA in the mucosal membrane
The gliadin-IgA is transcytosed to the lamina propia
Gliadin binds to tTG and is deaminated
Deaminated gliadin is taken up by macrophages and expressed on MHC2
T helper cells release inflammatory cytokines and stimulate B cells
This causes gut damage.
Symptoms
Bloating, failure to thrive, diarrhoea
Dermatitis Herpetiformis