coeliac disease Flashcards
Coeliac Disease: Definition
- Autoimmune condition
- genetic
- causes villus atrophy and crypt hypertrophy when gluten (gliadin) is ingested
- bc autoantibodies are created in response
name the differences which occurs to the small intestine
villous atrophy
crypt hypertrophy
genotypes
HLA-DQ2
HLA-DQ8
autoantibodies
Anti-tissue transglutaminase antibodies (anti-TTG)
Anti-endomysial antibodies (anti-EMA)
Anti-deamidated gliadin peptide antibodies (anti-DGP)
Coeliac Disease: Complications
dermatitis herpeiformis
- IgA mediated
- blistering, itchy disease of skin
enteropathy-associated T cell lymphoma
- should be suspected in patients with unresponsive coeliac disease
coeliac crisis
Coeliac Disease: Aetiology
Caused due to an intolerance to proteins called prolamins
Genetic:
Strong association with human leukocyte antigens
HLA-DQ2 - present in 95% of cases
HLA-DQ8 present in 5%
Genetic testing has a high negative predictive value - those without the gene are unlikely to have the disease
coeliac crisis presentation and treatment
- presentation: unexplained diahrrhea, severe malabsorption and electrolyte imbalances
- treatment - rehydration with electrolytes and corticosteroids to reduce inflammation
Coeliac Disease: DDx
cow milk, food sensitive enteropathies
chrones disease
colitis
GIT lymphoma
whipples disease
IBS
Coeliac Disease: Epidemiology
Common in northern Europeans
Coeliac Disease: Investigations
To get a diagnosis - gluten challenge: 10g gluten day for 4-6 weeks:
- IgA anti-tissue transglutaminase - high while eating gluten
gold standard:
endoscopy with duodenal biopsy before and after eating gluten:
Raised intraepithelial lymphocytes
Coeliac Disease: Management
gluten free diet
bone density:
- dexa scan
- frax score
immunisations - more suseptable to infections
calcium and vitamin D suppliments
Coeliac Disease: Key Presentations
Diarrhoea, Weightless and Anaemia
Coeliac Disease: Pathophysiology
- gluten converted to gliadin
- binds to IgA forming complex
- binds to transferrin which allows the complex to cross from lumen to lamina propria
- reacts with tissue transglutaminase which removes an amide from gliadin
- this is then presented to the Thelper cells via HLA molecule DQ2/DQ8 - phagocytosed
- Thelper then secrete pro-inflammatory cytokines
- causes mass inflammation
- damage to enterocytes
lead to formation of:
- anti-gliadin
- anti-TGi
- anti-endomysim antibody
pathology - damage to enterocytes causes which 3 features
- villus atrophy
- crypt hyperplasia
- inflammatory infiltration
Coeliac Disease: Risk Factors
Fx History
Type 1 diabetes
Genetic (HLA)
Autoimmune thyroid disease
IgA defiency
Inflammatory Bowel Disease
Coeliac Disease: Signs
- mouth ulcering
- muscle wasting
- anaemia - malabsorption or iron and folate
- osteoporosis - malabsorption of Ca and vitD
- dermatitis herpetiformis
- failure to thrive
Coeliac Disease: Symptoms
- malabsoption - anaemia
- iron deficiency
- weight loss
- tired all the time
- abdominal bloating
- diarrhoea
- dermatitis herpesformis
Coeliac Disease: What is gluten made up of?
Complex mix of: gliadin and glutenin
Conditions associated with coeliac disease?
“I Don’t Take Apples, I Take Oranges”
*IgA deficiency
*Down’s syndrome
*Turner’s syndrome
*Autoimmune thyroid disease and autoimmune hepatitis
*IgA nephropathy
*Type 1 diabetes mellitus
*Other autoimmune conditions (e.g. Sjögren’s, myasthenia gravis, Addison’s disease)
How do you get a diagnosis?
To get a diagnosis - gluten challenge: 10g gluten day for 4-6 weeks
The first-line blood tests are:
- Total immunoglobulin A levels (to exclude IgA deficiency)
- Anti-tissue transglutaminase antibodies (anti-TTG)
second line:
anti-EMA
Why do people with coeliac disease recieve the pneumococcal vaccine?
Due to Hyposplenism
Dermatitis herpetiformis
- itchy, blistering skin rash
- typically affecting the knees, elbows and natal cleft
what might be seen on blood slide
- howell-jolly bodies
- hypersegmented anaemia
(megaloblastic anaemia)
most sensitive test overall
duodenal biopsy bc it shows the differences in the muscosa even in those with mild disease
where is coeliac
small intestine
commonly duodenum and jejunum
what to use to treat dermatitis herpiformis
dapsone (antibacterial and anti-inflammatory)
if IgA deficient what test shoud you then carry out
- anti-TTG
- anti-EMA
in what cases do coeliac patients need a serology
new diagnosis of autoimmune thyroid disease or type 1 diabetes
pruritic vesicles
dermatitis herpiformis
first - first line investigation
total IgA and IgA TtG
anisocytosis
RBC of different sizes
if igA auto anti neg, what test then
igG anti-antibody
biobsy is usually done after a positive result
tenderness and bowel sounds
tenderness - no
bowel sounds - yes
types of anaemia
- iron deficiency
- megalobastic - B12 + folate deficiency
