Coeliac Disease

Question 1

What is coeliac disease?

Answer 1

Chronic immune-mediated systemic disorder in genetically predisposed people, triggered by exposure to dietary gluten (the major complex protein component of wheat, barley, and rye).

It is characterised by an inflammatory small bowel enteropathy with variable degrees of severity, a wide range of gastrointestinal and/or systemic symptoms, and the presence of coeliac-specific autoantibodies

Question 2

Briefly describe the pathophysiology of coeliac disease

Answer 2

Immune activation in the small intestine leads to villous atrophy, hypertrophy of the intestinal crypts, and increased numbers of lymphocytes in the epithelium and lamina propria. Locally these changes lead to gastrointestinal symptoms and malabsorption.

Question 3

What are the risk factors for coeliac disease?

Answer 3

• Family history
• Immunoglobulin A deficiency
• Type 1 diabetes
• Autoimmune thyroid disease

Question 4

What are the signs of coeliac disease?

Answer 4

• Dermatitis herpetiformis

Question 5

What are the symptoms of coeliac disease?

Answer 5

• Diarrhoea
• Bloating
• Abdominal pain and discomfort
• Anaemia
• Osteopenia and/or osteoporosis
• Fatigue
• Weight loss
• Failure to thrive

Question 6

Which type of anaemia is the most common in coeliac disease?

Answer 6

Iron deficiency anaemia

Question 7

What is dermatitis herpetiformis? And how does it appear?

Answer 7

A rare but persistent immunobullous disease. Characterised by intensely pruritic papulovesicular lesions that occur symmetrically over the extensor surfaces of the arms and legs, as well as on the buttocks, trunk, neck, and scalp. Biopsy-proven dermatitis herpetiformis almost universally occurs in association with coeliac disease.

Question 8

What investigations should be ordered for coeliac disease?

Answer 8

• FBC and blood smear
• IgA-tissue transglutaminase (IgA-tTG)
• IgG-tissue transglutamiase (IgG-tTG)
• Endomysial antibody (EMA)
• Skin biopsy
• Small bowel endoscopy
• Small bowel biopsy

Question 9

Why investigate FBC and blood smear? And what may this show?

Answer 9

• Iron deficiency anaemia is the most common clinical presentation in adults
• Low Hb and microcytic hypochromic red cells

Question 10

Why investigate IgA-tissue transglutaminase (Iga-tTG)? And what may this show?

Answer 10

• Order an IgA-tTG test in any patient with suspected coeliac disease
• Titre above normal range for laboratory

Question 11

Why investigate endomysial antibody (EMA)? And what may this show?

Answer 11

• EMA is a more expensive alternative to IgA-tTG with greater specificity but lower sensitivity
• Elevated titre

Question 12

Why investigate using skin biopsy? And what may this show?

Answer 12

• Order this test initially in any patient with skin lesions suggestive of dermatitis herpetiformis
• Granular deposits of IgA at the dermal papillae of lesional and perilesional skin by direct immunofluorescence

Question 13

Why investigate using small bowel endoscopy? And what may this show?

Answer 13

• The endoscopic appearance is not sensitive for diagnosis and may be normal in up to one third of cases at diagnosis
• Atrophy and scalloping of mucosal folds; nodularity and mosaic pattern of mucosa

Question 14

Why investigate using small bowel histology? And what may this show?

Answer 14

• Small-bowel histology is essential and the gold-standard test to confirm the diagnosis. Biopsies should be performed while on a gluten-containing diet. Patients with an elevated IgA-tTG level should be referred for duodenal biopsy.
• Presence of intra-epithelial lymphocytes, villous atrophy, and crypt hyperplasia

Question 15

What is shown this picture taken from an endoscopy from a patient with coeliacs?

Answer 15

Scalloping of the duodenal mucosa in a patient with coeliac disease

Question 16

Briefly describe the advice given to a patient with coeliac disease

Answer 16

Advise that the only effective treatment for coeliac disease is long-term adherence to a gluten-free diet.

Question 17

Patients should be checked for common deficiencies including iron, vitamin D, vitamin B12, and folate. How is this treated?

Answer 17

All patients with coeliac disease should take calcium and vitamin D supplements. Iron should only be given to individuals with iron deficiency.

Vitamin B12 (cyanocobalamin) and folate deficiencies should be corrected, especially since the gluten-free diet may be low in folate.

Bone mineral density should be evaluated after approximately 1 year on gluten-free diet to assess for osteopenia or osteoporosis.

Question 18

What compciations are associated with coeliac disease?

Answer 18

• Osteoporosis and osteopenia
• Dermatitis herpetiformis
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Question 19

What differentials should be considered in coeliac disease?

Answer 19

1. Peptic duodenitis
2. Crohn’s disease

Question 20

How does coeliac disease and peptic duodenitis differ?

Answer 20

• Differentiating signs and symptoms: patients present with chronic or recurrent abdominal pain or discomfort centred in the upper abdomen that is commonly related to eating. There may be a history of non-steroidal anti-inflammatory drug use and use of antacid medications to relieve the discomfort.
• Differentiating investigations: peptic duodenitis is associated with acid injury and leads to a spectrum of histological mucosal changes that may be difficult to distinguish from that seen in coeliac disease. For this reason, biopsies should be taken both in the duodenal bulb and in the second or third portion of the duodenum (relatively protected from peptic injury).

Question 21

How does coeliac disease and Crohn’s disease differ?

Answer 21

• Differentiating signs and symptoms: Crohn’s disease can affect any part of the gastrointestinal tract, and symptoms may be extremely variable.
• Differentiating investigations:
  
  • The classical findings on histological examination include granulomas, ulcerations, and acute and chronic inflammation often extending throughout all layers of the bowel wall
  • Tissue transglutaminase serology is usually negative and there should be no response to gluten withdrawal