Celiac Disease Flashcards
What is Coeliac Disease?
Systemic autoimmune disorder that affects the small intestine
What is Coeliac disease triggered by?
The ingestion of gluten peptides found in wheat, barley, rye and other related grains.
Malaborption is the hallmark of coeliac disease
What is the most pathogenic component of gluten called?
Gliadin
What deamidates gliadin once it is absorbed?
tissue transglutaminase (tTG)
What is the pathophysiology of coeliac disease?
Deamidated peptides are presented by antigen-presenting cells via HLA molecules DQ2 or DQ8 to T helper cells which then trigger an immune response
What does immune activation in Coeliac disease result in?
Villous atrophy, lymphocyte accumulation, intestinal crypt hyperplasia, resulting in malabsorption.
There are also numerous extraintestinal manifestations
What are the risk factors for coeliac disease?
Family history of coeliac disease
HLA-DQ2 and HLA-DQ8
Other Autoimmunity - type 1 diabetes, autoimmune thyroid disease and autoimmune hepatitis
IgA deficiency - allows increased gluten peptides to circulate in the submucosa
Down’s syndrome
Turner’s Syndrome
Serological testing should be offered to people with what symptoms and signs?
Persistent abdominal symptoms:
- indigestion
- Diarrhoea (watery) or steatorrhoea (pale, floating stools)
- Abdominal bloating or discomfort
- Constipation
Prolonged fatigue
Unexpected weight loss
Faltering growth in children
Severe or persistent mouth ulcers
Serological testing should be offered to people with what other features?
Unexplained iron, vitamin B12 or folate deficiency
Type 1 diabetes mellitus
Autoimmune thyroid disease
Irritable bowel syndrome in adults
A first-degree relative with coeliac disease (e.g. parents, siblings or children)
What is the name of the itchy vesicular skin eruption associated with coeliac disease?
Dermatitis Herpetiformis
Also known as Duhring’s disease
What should patients ideally be on 6 weeks prior to investigations?
A gluten-containing diet
What is the first line investigation for coeliac disease?
Tissue transglutaminase antibodies (tTG; IgA) and total IgA
Serological test is for IgA antibodies against tTG
Total IgA must also be measured as a small portion of patients are IgA deficient, which would give a false negative anti-tTG measurement
What is the second line investigation for coeliac disease?
Endomysial antibodies (IgA)
Serological test and performed if anti-tTG is weakly positive
If a patient with suspected coeliac disease is IgA deficient what investigation could be carried out?
Anti-tTG, endomysial, or gliadin (IgG) antibodies
What other type of antibodies are also found in some patients with coeliac disease?
Anti-casein
What is the gold-standard diagnostic test for coeliac disease?
Duodenal biopsy
- All patients with positive serology should be referred for biopsy
- A jejunal biopsy is occasionally performed
- The Marsh histological classification is used
What are the classic findings on small bowel histology for a patient with coeliac disease?
1) Villous Atrophy
2) Crypt Hyperplasia
3) An increase in intraepithelial lymphocytes
4) lamina propria infiltration with lymphocytes
What other investigations could be considered for someone with suspected coeliac disease?
FBC: typically a microcytic anaemia. Alternatively, folate or vitamin B12 deficiency can result in macrocytic anaemia
Nutritional status: 25-hydroxy vitamin D, calcium, iron studies, Vitamin B12, folate
Skin biopsy: if there is evidence of possible dermatitis herpetiformis
HLA testing: DQ2 or DQ8 testing is only performed in a specialist setting
How is key way coeliac disease managed?
Gluten-free diet: this involves the avoidance of the following:
Wheat: bread, pastry and pasta
Rye
Barley: beer (whisky is made using malted barley but is safe to drink as gluten is removed in the distillation process)
Oats: this remains controversial but may be required in some patients
What are the other managements that can help coeliac diease?
supplements:
Patients should receive calcium, vitamin D and iron supplementation if the patient’s diet is insufficient
Dietician input:
Patients may be offered input regarding their diet and risks associated with non-compliance with dietary measures
Vaccinations:
Due to functional hyposplenism, coeliac patients are at risk of pneumococcal infection so should all be offered vaccination, with a booster every 5 years [9]; influenza vaccination is offered on an individual basis
Refer to a specialist:
If symptoms persist despite a gluten-free diet or significant extra-intestinal manifestations, the patient may require referral to a gastroenterologist
What are the complications of coeliac disease?
Dermatitis herpetiformis: usually occurs in active disease and if persistent may require treatment with dapsone
Malignancy: increased risk of small bowel adenocarcinoma and enteropathy-associated T-cell lymphoma
Malabsorption-related:
Increased risk of osteoporosis
Calcium and vitamin D deficiency: may lead to secondary hyperparathyroidism and osteomalacia
Anaemia: microcytic anaemia (iron deficiency) or macrocytic anaemia (vitamin B12 / folate deficiency); folate deficiency is more common than vitamin B12 deficiency in coeliac disease
Peripheral neuropathy (B12/folate)
Infection: hyposplenism is associated with coeliac disease and increases the risk of pneumococcal infection
Lactose intolerance
Subfertility and recurrent miscarriages
Extra-intestinal malignancies: non-Hodgkin’s and Hodgkin’s lymphoma, and oesophageal cancer (all are rare)
Coeliac crisis
What is a coeliac crisis?
A rare, life-threatening syndrome associated with significant metabolic derangements, presenting with severe diarrhoea and electrolyte disturbances
When is bone mineral density checked in those with coeliac disease?
After 1 year of gluten-free diet in those who have other risk factors for osteoporosis
