GI: Coeliac Disease Flashcards
What is coeliac disease?
A condition in which there is inflammation of the mucosa of the upper small bowel that improves when gluten is withdrawn from the diet and relapses when gluten is reintroduced
What is gluten?
Entire protein content of the cereals wheat, barley and rye. Prolamins (gliadin from wheat, hordeins from barley, secalins from rye) are damaging factors.
These proteins are resistant to digestion by pepsin and chymotrypsin because of their high glutamine and proline content and remain in the intestinal lumen triggering immune responses.
How does Gluten cause an immune response?
- Gliadin pass through the epithelium -> deaminated by TTG
- Gliadin binds to antigen-presenting cells -> interact with CD4+ T cells in the lamina propria via HLA-DQ2 or DQ8
- T cells produce pro-inflammatory cytokines
- CD4+ T cells interact with B cells -> anti-endomysial and tissue transglutaminase antibodies
- Inflammatory cascade releases metalloproteinases and other mediators -> villous atrophy and crypt hyperplasia (increased no of lymphocutes in epithelium and lamina propria)
What proportion of coeliacs have mutations of HLA DQ2?
95%
The rest are HLA DQ8
What is the prevalence of coeliac disease?
1:100
Risk factors for developing coeliac
+ve in fam history
Type 1 diabetes
Downs syndrome (increased risk 20 fold)
IgA deficiency
What are symptoms of coeliac disease?
- Features of anaemia - tiredness, malaise
- Weight loss
- Diarrhoea/Steatorrhoea
- Abdominal pain
- Bloating
- Nausea + vomiting
- Weakness
What are signs of coeliac disease?
- Signs of anaemia - Conjunctival pallor, angular stomatitis, Pale palmar creases
- Apthous ulcers
- Weight loss
- Clubbing
- Osteomalacia
- Dermatitis herpatiformis
What investigations would you consider doing in someone presenting with symptoms suggestive of coeliac disease?
-
Bloods - FBC, LFTs, U+E’s Iron studies, B12, folate, Blood film, albumin, calcium
- IgA-TTG,
- IgA levels,
- Endomysial antibodies,
- HLA typing,
- Antigliadin antibodies
- Imaging - Upper GI endoscopy, DEXA bone scan
Why would you check IgA levels when testing IgA-TTG?
Exclude subclass deficiency of IgA which may have lead to flase negative
What might you see on FBC in someone with coeliac disease?
- Microcytic anaemia
- Can be macrocytic - if B12 deficient
If someone had a positive Anti-TTG/endomysial antibody, what investigation would you consider doing?
Upper GI endoscopy - make sure they continue to eat at least 1 gluten meal per day until this investigation
–> Distal Duodenal Endoscopy + BIopsy (confirmation)
What macroscopic features might you see on endoscopy in someone with coeliac disease?
- Paucity of mucosal folds
- Scalloping
- Mosaic pattern of mucosa
What are the major histological features of coeliac disease?
- Presence of intra-epithelial lymphocytes
- Villous atrophy
- Crypt hyperplasia
How would you manage someone with coeliac disease?
- Lifelong gluten-free diet
- Consider Calcium + Vit D supplement +/-iron
- Consider pneumococcal vaccine
- Consider DEXA scan
What are causes of steatorrhoea?
- Liver disease
- Cholestatic jaundice
- Pancreatic disease
- Small bowel disease - Coeliac, bacterial overgrowth, parasites, drugs
- Intestinal resection
- Ileal disease - Crohn’s
What is the Following?
Dermatitis herpatiformis - blistering subepidermal eruption of the skin associated with a gluten-sensitive enteropathy
