Small intestine conditions

Question 1

Define coeliac disease

Answer 1

Autoimmune disease triggered by dietary gluten peptides

Immune activation in the small intestine leads to:

• subtotal villous atrophy
• intestinal crypt hypertrophy
• lymphocytes infiltration of the epithelium and lamina propria

Question 2

In coeliac, what is the aeitiological component of gluten? WHat effect sodes this have in the body?

Answer 2

Due to sensitivity to the GLIADIN component of the cereal protein, gluten

Exposure to gliadin triggers an immunological reaction in the small intestine →

Crypt hyperplasia + villous atrophy →

lose ability to absorb →

diarrhoea and weight loss

If gluten is removed from diet, villi can return and patient is asymptomatic – the damage is REVERSIBLE

Question 3

What is a major factor in the genetic predisposition to coeliac disease?

Answer 3

Coeliacs carry one of two MHC class-II molecules

(HLA- DQ2 or -DQ8)

Required to present gluten peptides in a manner that activates an antigen-specific T cell response

Question 4

Explain the epidemiology of coeliac disease

Answer 4

• UK: 1/2000
• West Ireland: 1/300
• Rare in East-Asia
• Stable prevalence
• more common in women (2/3rds of patients)

Question 5

What are the risk factors for coeliac disease?

Answer 5

• Strong genetic component- 10% risk of first-degree relatives being affected
• Immunoglobulin A deficiency
• Other AI conditions- T1DM, autoimmune thyroid disease, IBD
• Genetic syndromes- Down’s, Sjoren’s

Question 6

What are the presenting symptoms of coeliac disease?

Answer 6

• Diarrhoea (chronic/intermittent)
• Bloating
• Abdominal pain, cramping, or distension
• Tiredness, malaise- iron deficiency anaemia is the most common clinical presentation in adults.
• Steatorrhoea (pale bulky stool, with offensive smell and difficult to flush away)
• Weight loss (despite normal diet)
• Failure to ‘thrive’ in children
• Amenorrhoea in young adults

Question 7

What are the signs of coeliac disease on physical examination?

Answer 7

Signs of anaemia:

• pallor

Signs of malnutrition:

• Short stature
• Abdominal distension
• Wasted buttocks in children

Signs of vitamin/mineral deficiencies:

• osteomalacia
• easy bruising

Dermatitis herpetiformis

• Intensely pruritic (itchy) papulovesicular lesions
• occur symmetrically over the extensor surfaces of the arms and legs, as well as on the buttocks, trunk, neck, and scalp

Question 8

List appropriate investigations for coeliac disease and state the positive result

Answer 8

NOTE- these tests only work if patient is not already on a gluten free diet- gluten challeneg test if not (6-8 weeks gluten)

Bloods

• FBC- low Hb
• Blood smear - microcytic hypochromic red cells

Serology

• IgA-tTG test
• IgG DGP (deamidated gliadin peptide)- for individuals with IgA deficiency.
• IgG anti-endomysial tranglutaminase antibodies(EMA)- more expensive

Invasive

• Small bowel endoscopy- atrophy and scalloping of mucosal folds- cuboidal pattern
• normal in up to 1/3rd of cases at diagnosis
• Small bowel histology- essential and the gold-standard test to confirm the diagnosis.
  
  • presence of intra-epithelial lymphocytes, villous atrophy, and crypt hyperplasia
• Skin biopsy- of any lesions suggestive of dermatitis herpetiformis- see granular deposits of IgA

Question 9

Generate a management plan for coeliac disease

Answer 9

The only accepted treatment of coeliac disease is a strict lifelong gluten-free diet.

Dietary counselling is important because the gluten-free diet has been associated with:

• low fibre
• vitamin and micronutrient deficiencies
• higher calories, sat fats, simple carbs

Patients should be checked for common deficiencies including iron, vitamin D, vitamin B12, and folate

If in coeliac crisis (<1%)- systemic glucocorticoid therapy

Question 10

Identify the possible complications of coeliac disease

Answer 10

• Iron, folate and B12 deficiency
• Osteomalacia
• Ulcerative jejunoileitis
• GI lymphoma (particularly T cell) – if untreated coeliac
• Increased risk of gastric/oesophageal/bladder/breast/brain malignancy
• Bacterial overgrowth
• Cerebellar ataxia (rarely)

Question 11

Summarise the prognosis for patients with coeliac disease

Answer 11

• FULL RECOVERY in most patients who strictly adhere to a gluten-free diet
• Symptoms usually resolve within weeks
• Histological changes may take longer
• Gluten-free diet must be followed for life