Coeliac disease (GI) Flashcards

1
Q

What is coeliac disease?

A

Systemic autoimmune disease triggered by dietary gluten peptides found in wheat, rye, barley and related grains causing chronic intestinal malabsorption

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2
Q

What is the immune reaction in coeliac disease triggered by?

A

Gliadin - a component of gluten that patients with coeliac disease become intolerant to

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3
Q

What does immune activation in coeliac disease lead to? (3)

A
  • villous atrophy
  • hypertrophy of the intestinal crypts
  • increased numbers of lymphocytes in epithelium and lamina propria
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4
Q

What conditions is coeliac disease associated with? (4)

A
  • autoimmune thyroid disease
  • dermatitis herpetiformis
  • IBS/IBD
  • T1DM
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5
Q

What is dermatitis herpetiformis, and how do we investigate and manage it? (4)

A
  • itchy vesicular skin lesions on extensor surfaces (elbows, knees, buttocks)
  • Ix - skin biopsy under direct immunofluorescence showing IgA deposition in granular pattern in upper dermis
  • Rx - gluten-free diet
  • Rx - dapsone
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6
Q

What markers is coeliac disease associated with? (2)

A
  • HLA-DQ2
  • HLA-DQ8
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7
Q
A
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8
Q

Describe the aetiology of coeliac disease?

A
  • gluten peptides stimulate IL-15 production –> immune activation and epithelial damage
  • gluten peptides are deaminated by tissue transglutaminase and bind to coeliac-associated HLA peptides (DQ2 or DQ8) which activates Th cells
  • Th cells promote plasma cell maturation –> anti-tissue transglutaminase antibodies which attack villi, causing villous atrophy, hypertrophy of intestinal crypts and increased lymphocytes within epithelium and lamina propria
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8
Q

What deficiencies are patients with coeliac disease likely to have? (4)

A
  • iron
  • folate
  • B12
  • vitamin D
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9
Q

What are the clinical features of coeliac disease? (12)

A
  • diarrhoea (osmotic) - chronic or intermittent, might also get steatorrhoea (pale, greasy, offensive-smelling stool due to malabsorption)
  • bloating
  • abdominal pain
  • anaemia (signs of IDA)
  • dermatitis herpetiformis (intensely itchy papulovesicular lesions on extensor surfaces)
  • osteopenia/osteoporosis (vitamin D deficiency + hypocalcaemia)
  • fatigue
  • weight loss
  • failure to thrive / faltering growth in children
  • easy bruising (vitamin K deficiency)
  • peripheral neuropathy
  • ataxia
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10
Q

What are the features of a coeliac crisis? (5)

A
  • hypovolaemia
  • severe watery diarrhoea
  • acidosis
  • hypocalcaemia
  • hypoalbuminaemia
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11
Q

What are some risk factors for coeliac disease? (6)

A
  • Fx coeliac disease
  • IgA deficiency
  • autoimmune risk - T1DM, autoimmune thyroid disease, IBD
  • HLA-DQ2/8 - although most never develop coeliac disease
  • infancy or 4th/5th decade
  • female
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12
Q

What are the first-line investigations for coeliac disease? (4)

A
  • IgA-tTG antibodies
  • FBC
  • endomysial IgA
  • small bowel endoscopy and histology (biopsy)
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13
Q

What is the first investigation we do for coeliac disease?

A

IgA-tTG = raised

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14
Q

When might you get a IgA-tTG false negative (coeliac disease)?

A
  • might get a false negative if patient has IgA deficiency
  • account for this via endomysial antibody (EMA) test to look for selective IgA deficiency = elevated
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15
Q

What other (less relevant) serology tests are there for coeliac disease? (2)

A
  • anti-gliadin antibodies elevated - not recommended
  • anti-casein antibodies in some patients
16
Q

What is the gold standard test for coeliac disease diagnosis?

A

Endoscopic intestinal biopsy - done on all suspected patients to confirm/exclude diagnosis, needed to confirm diagnosis

17
Q

Which part of small bowel is endoscopic biopsy done for coeliac disease?

A

Traditionally duodenum, but sometimes jejunum

18
Q

What findings on small bowel endoscopy and biopsy indicate coeliac disease? (5)

A
  • villous atrophy
  • crypt hyperplasia/hypertrophy
  • scalloping of mucosal folds with increase in intra-epithelial lymphocytes
  • lamina propria infiltration with lymphocytes
  • mosaic pattern of mucosa
19
Q

What might you see in FBC in coeliac disease? (2)

A
  • microcytic hypochromic RBCs (anaemia)
  • IDA or folate/B12 deficiency
20
Q

Which patients should be screened for coeliac disease?

A

Patients with unexplained iron-deficiency anaemia

21
Q

What would a blood smear show for coeliac disease? (3)

A
  • target cells & Howell-Jolly bodies due to functional hyposplenism
  • microcytic hypochromic RBCs
22
Q

When would a skin biopsy be done for coeliac disease?

A

If any lesions suggest dermatitis herpetiformis

23
Q

What is important for coeliac disease investigations in terms of patients’ gluten intake?

A

Patients must have eaten gluten for at least 6 weeks before they are tested for antibodies or biopsy, or else they may be negative

24
Q

What are some differential diagnoses for coeliac disease? (11)

A
  • peptic duodenitis (chronic/recurrent abdo pain related to eating)
  • Crohn’s disease
  • giardiasis (diarrhoeal illness)
  • small-intestinal bacterial overgrowth
  • post-gastroenteritis
  • tropical sprue
  • immunodeficiency states
  • Graft-vs-Host disease
  • autoimmune enteropathy
  • drug-induced enteropathy
  • non-coeliac gluten sensitivity (no villous atrophy)
25
Q

What is needed for diagnosis of coeliac disease? (2)

A
  • positive IgA-tTG
  • positive small bowel endoscopy/biopsy changes
26
Q

What is the first-line management of coeliac disease?

A

Gluten-free diet + vitamin and mineral supplementation (+pneumococcal/influenza vaccines)

27
Q

What foods can patients with coeliac disease not tolerate? (4)

A

BROW

  • Barley (beer)
  • Rye
  • Oats (only some with coeliac cannot tolerate)
  • Wheat - bread, pasta, pastry
28
Q

What are some notable gluten-free foods? (3)

A
  • rice
  • potatoes
  • corn (maize)
29
Q

What vitamin/mineral supplements are given for those with coeliac disease?

A
  • all patients should take calcium and vitamin D (ergocalciferol + calcium carbonate)
  • iron to those with IDA (ferrous sulfate)
  • vitamin B12 (cyanocobalamin) and folate (folic acid) deficiencies should be corrected
30
Q

What immunisation is offered to coeliac disease patients and why?

A
  • patients offered pneumococcal vaccine (with booster every 5 years recommended) and also influenza vaccine regularly
  • because they often have a degree of functional hyposplenism
31
Q

What do we do if a coeliac patient fails to respond to therapy/refractory coeliac disease?

A

Referral to dietician or gastroenterologist

32
Q

How do we manage a coeliac crisis? (3)

A
  • rehydrate
  • correct electrolyte abnormalities
  • consider short-course corticosteroid (anti-inflammatory)
33
Q

What are some complications of coeliac disease? (9)

A
  • anaemia - iron, folate and vitB12 deficiency
  • osteoporosis/osteopenia/osteomalacia (reduced BMD due to low vitD/calcium)
  • hyposplenism –> infection
  • dermatitis herpetiformis
  • lactose intolerance
  • subfertility
  • recurrent acute pancreatitis
  • enteropathy-associated T cell lymphoma of small intestine
  • rare - oesophageal cancer etc
34
Q

Describe the prognosis of coeliac disease.

A
  • majority have resolution upon starting gluten-free diet
  • <1% develop refractory coeliac disease