Coeliac disease Flashcards
Define coeliac disease
Complex immune mediated disorder triggered by gluten ingestion in genetically predisposed individuals, affecting the small intestine
Involves the innate and adaptive immune response.
What is the key epidemiology of coeliac disease?
Less common than IBS, but more common that IBD (crohns)
Peak in 30-40years, equal in males and females
What HLA antigens are most frequently associated with coeliac disease?
HLA-DQ2 - 95%
HLA-DQ8 -5%
Note only a small percentage of people with these haplotypes will develop coeliacs disease
What factors contribute to the aetiology of coeliacs disease?
Genetic predisposition - HLA-DQ2 and HLA-DQ8.
Gluten exposure - wheat, barley etc -> environmental trigger, particularly gliadin.
Other environmental factors such as early life gluten, infections (viral), changes in gut microbiota and other lifestyle factors may also contribute to coeliacs disease
What is the relevant pathophysiology of coeliacs disease?
- In digestion gluten is partially digested to gliadin peptides.
- Gliadin cross the intestinal epithelium and is deamidated by tissue transglutaminase (enzyme in mucosa) -> now has high affinity for HLA antigens on APCs.
- APC with deaminated gliadin, activates CD4+ cells -> pro-inflam cytokines, IELs, and B cells (with anti-tTG autoantibodies)
- The innate immune response such as NKc receptors on IELs are activated.
- Results in villous atrophy, crypt hyperplasia, increase IELS in mucosa and epithelial cell destruction.
What is the key antibody involved in coeliacs disease?
anti-tTG
Anti-tissue transglutaminase
What are the gastrointestinal symptoms of coeliacs disease?
Diarrhoea - losse, watery or bulky stools
Crampy abdominal pain and bloating - due to malabsorption and gas production
Steatorrhea - fatty, foul-smelling stools (impaired fat absorption)
Nausea and vomiting - more severe disease
What are the extra-intestinal manifestations?
Dermatitis herpetiform - pruritic, vesicular rash - elbow, knee, bum
Fatigue - iron deficiency anaemia and malabsorb.
Weight loss
Bone pain and fractures - malabsoprtion of calcium and vitamin D
Peripheral neuropathy - numbness, tingling or burning of extremities
What serological testing should be done for Coeliac disease?
IgA anti-tTG -> initial screen (note can be false negative in IgA deficiency)
Anti-endomysial antibodies (EMA) -> more specific
Total serum IgA - prevents false negatives
What is the gold standard test for diagnosing coeliacs disease?
What will it show?
Duodenal biopsy - multiple samples.
Show - villous atrophy (flat top), crypt hyperplasia, increase intraepithelial lymphocytes
What is non-coeliac gluten sensitivity?
Presents with bloating, abdo pain and irregular bowel movement after gluten ingestion
However, no damage to the small intestine. No genetic HLA link
NGCs symptom onset if quicker -? typically within hours or days of gluten ingestion.
What are the key management principles for coeliac disease?
Strict gluten free diet
Address associated nutritional deficiencies
Monitor for complications and associated conditions
Provide long-term follow up and support
How might you help a coeliac patient achieve a gluten free diet?
Refer to dietician
Avoid all gluten sources including wheat, barley and rye.
Advise on risk of cross-contamination and checking of food labels
Encourage coeliac support groups
How are nutritional deficiences typically treated in coeliacs disease?
Common - iron, calcium, VitD, VitB12, folic acid and zinc
Consider - DEXA scan in those at risk of osteoporosis
What monitoring and follow up is required for coeliac disease?
Repeat serological testing after 6-12months to ensure antibody levels are decreasing -> indicates dietary adhrenace
Monitor for symptom resolution and potential complications
Refer to gastro if persistent symptoms, complications, refractory or suspected malignancy.
