Gastroenterology: Coeliac Disease Flashcards
What causes coeliac disease?
An enteropathy in which the gliadin fraction of gluten (and other related prolamines) in wheat, barley and rye provoke a damaging immunological response in the proximal small intestine mucosa
What does the damage provoke?
Progressive shortening of the villi and then absent, leaving a flat mucosa
Is it a relatively common disorder?
Yes, affects 1% of the population
What is the age of presentation partially influenced by?
The age of gluten introduction into diet
What is the classical presentation?
A profound malabsorptive syndrome at 8-24 months after introduction of wheat containing weaning foods
Faltering growth
Abdominal distension
Buttock wasting
Abnormal stools - diarrhoea, steatorrhoea
General irritability
The classical presentation is less common now. What is more common?
Children are more likely to present less acutely in later childhood
Variable features
Mild, non specific GI symptoms
Anaemia - iron and/ or folate deficiency
Growth faltering
Coeliac disease can be found on screening e.g
Of children at increased risk - they have DM, autoimmune thyroid disease, Down syndrome
First degree relatives of children with known coeliac disease
How is it diagnosed?
Strongly suggested by: positive serology
- raised IgA anti tissue transglutaminase (IgA-tTG) and endomysial antibodies (EMA)
Also measure total IgA - if deficient measure IgG anti-gliadin antibodies (not first line as anti-gliadin antibodies not always present)
Definitive: small intestine endoscopic biopsy showing mucosal changes, followed by the resolution of symptoms and catch up growth upon gluten withdrawal
What mucosal changes on biopsy indicate coeliac disease?
Increased intraepithelial lymphocytes
Various degree of villous atrophy and crypt hypertrophy
The overall wall thickness remains stable (the crypts get deeper)
What is the incidence?
Around 1 in 100
In terms of genetics, what is it associated with?
HLA-DQ2 (95%)
HLA-DQ10 (85%)
What part of the small intestine is usually affected?
Duodenum
What skin condition can it be associated with?
Dermatitis herpetiformis
- caused by circulating IgA in the blood - bind to the epidermal transglutaminase in dermis attracting neutrophils and causing inflammatory reaction
= itchy papules and vesicles on erythematous skin, often appearing in groups. Occur most commonly on scalp, shoulders, buttocks, elbows, knees
What are wheat, rye and barley collectively known as?
Prolamin
If a child has coeliac disease, what is the risk of the sibling having it?
30% risk
What other autoimmune diseases is it associated with?
T1DM
Autoimmune thyroid disease
Addison’s disease
What type of autoimmune disease is it?
T cell mediated
What is the enzyme responsible for gluten breakdown?
Tissue transglutaminase
Why does malabsorption occur?
The surface area for absorption becomes reduced (due to atrophy of villi)
What is the management?
All products containing wheat, rye, barley removed from diet
What can non adherence to the diet risk?
Micronutrient deficiency especially osteopenia
There is a small increased risk of bowel malignancy especially small bowel lymphoma
If the patient has been trialling a gluten free diet, will they be positive for anti-tGT?
No - they will need to eat at least 3g (a slice of bread) per day for at least 2 weeks to generate an inflammatory response and at least 4 weeks for a positive blood result
Why will some people have a false negative anti-tTG result?
3% of those with coeliac disease also have an IgA deficiency
On diagnosis, who should patients be referred to?
A dietician
