coeliac disease and inflammatory bowel disease Flashcards
1
Q
what is coeliac disease? 4
A
- Gluten sensitive enteropathy or coeliac sprue
- An auto-immune mediated disease of the small intestine triggered by the ingestion of gluten in genetically predisposed individuals leading to malabsorption with cessation of symptoms on a gluten free diet
- Gluten is a protein compound of wheat, rye and barley which is left behind after washing off the starch
- Gluten consists of gliadin and glutenin’s
2
Q
what are the genetic abnormalities of coeliac disease? 4
A
- Associated with HLA-DQ-2 in 95% of patients and HLA-DQ8 in 5%
- The genes are located on chromosome 6p21
- Other coeliac disease genes are under investigation
- Coeliac disease has strong hereditary predisposition affecting 10% of first-degree relatives
3
Q
who gets coeliac disease? 6
A
- Most prevalent in western Europe and USA especially patients with Irish or Scandinavian descent
- Increasing incidence in Africa and Asia
- A lot of patients in the community have undiagnosed coeliac disease- it requires a high index of suspicion
- High prevalence in patients with down’s syndrome, type 1 diabetes mellitus, auto immune hepatitis and thyroid gland abnormalities
- Bimodal presentation in childhood and late thirties
- 20% of patients with coeliac disease are older than 60
4
Q
how does gluten cause coeliac disease? 7
A
- gluten in wheat + small bowel mucosa
- tissue transglutaminase
- diamidates glutamine in gliadin
- negatively charged protein
- IL-15
- natural killer cells + intraepithelial T lymphocytes
- tissue destruction + villous atrophy
5
Q
what happens to the bowel lining when people with coeliac disease eat gluten?
A
Normal small bowel lining has finger-like villi which are destroyed when people with coeliac disease eat gluten
6
Q
What are the symptoms of coeliac disease? 4
A
- Flat mucosa does not absorb nutrients and leads to the symptoms of coeliac disease
- Asymptomatic coeliac disease- detected by a blood test
- Classic coeliac disease
- Atypical coeliac disease
7
Q
Classic coeliac disease with gastrointestinal symptoms? 8
A
- Diarrhoea (smelly, pale and bulky stool but rich in fat- steatorrhea) 45-85%
- Flatulence 28%
- Borborygmus 35-72%
- Weight loss 45% of patients
- In children- failure to thrive
- Weakness and fatigue 78-80%
- Severe abdominal pain 34-64%
- Irritable bowel syndrome
8
Q
Atypical coeliac disease due to extra-interstitial symptoms? 10
A
- Anaemia 10-15%
- Osteopenia and osteoporosis
- Muscle weakness, pins and needles, loss of balance 8-14%
- Itchy skin conditions such as dermatitis hepeitformis 10-20%
- Lack of periods, delayed periods in teenagers, infertility in women and impotence and infertility in men
- Bleeding disorders due to vitamin K deficiency
- Emaciation (being abnormally thin or weak)
- Pot belly due to gaseous distention
- Muscle wasting
- Osteoporosis
9
Q
What are the investigations for coeliac disease? 4
A
- General investigations: FBC U&E, LFTs
- Serology for diagnosis of coeliac disease: tissue transglutaminase IgA, endomysial IgA (connective tissue covering the smooth muscle fibres), deamidated gliadin peptide IgA and IgG, for monitoring compliance to gluten free diet, sero-negative coeliac disease reported in 9% of patients
- HLA-DQ2 and HLA-DQ8 in children with positive TTGA and symptoms to avoid biopsies
- Duodenal biopsies
10
Q
How do routine coeliac disease tests work? 3
A
- They assess tissue damage
- When the small bowel is exposed to gluten there is an over production of the immune system to produce antibodies to the proteins involved in tissue damage
- Antibodies to tissue transglutaminase, endomysium and deamidated gliadin peptide
11
Q
What are the microscopic features of coeliac disease? 7
A
- At least 4 biopsies should be sampled from the duodenum at the upper GIT endoscopy as changes can be patchy
- On microscopy there is:
- Villous atrophy
- Crypt hyperplasia
- Increase in lymphocytes in the lamina propria/ chronic inflammation
- Increase in intraepithelial lymphocytes (IEL)
- Recovery of villous atrophy on gluten free diet
12
Q
What are the complications of coeliac disease? 6
A
- Enteropathy associated T cell lymphoma
- High risk of adenocarcinoma of small bowel and other organs- large bowel, oesophagus, pancreas
- May be associated with dermatitis hepetiformis- very itchy skin condition
- Infertility and miscarriage
- Refractory coeliac disease despite strict adherence to gluten free diet
- Gluten free diet may reduce risk of complications
13
Q
What constitutes inflammatory bowel disease? 8
A
- Chron’s disease
- Ulcerative colitis
- Diverticular disease
- Ischaemic colitis
- Drug induced colitis NSAIDS
infective colitis - CD and UC= collectively known as idiopathic inflammatory disease
- Some overlap in aetiology, clinical presentation, morphological features and treatment
- important to distinguish CD from UC because of different complications and different surgical procedures
14
Q
what is Crohn’s disease? 4
A
- an idiopathic chronic inflammatory bowel disease often caused by fibrosis and obstructive symptoms
- can affect any part of the GIT from mouth to anus
- high prevalence in the western world, increased incidence in patients with Jewish origin
- bimodal presentation with peaks in the teens-20s and 60–70-year-olds
15
Q
what causes CD? 3
A
- Exact cause is unknown
- Genetic, infectious, immunologic, environmental, dietary, vascular, smoking, NSAIDs and psychological factors are all implicated
- Defects in mucosal barriers which allow pathogens and other antigens to induce an unregulated inflammatory reaction
