coeliac and IBD

Question 1

How does gluten cause coeliac disease, a 6 step process

Answer 1

1) gluten + small intestine mucosa triggers release of
2) tissue transglutaminase which
3) diamidates glutamine in gliadin which triggers release
4) of IL-15 which trigfers release of
5) NK cells and intraepithelial T cells which causes
6) tissue destruction and villous atrophy

Question 2

what are 3 types of coeliac disease

Answer 2

asymptomatic, classical and atypical

Question 3

classical coeliac disease and atypical coeliac disease symptoms

Answer 3

classical: diarrhoea/ steatorrhea, flatulence, borborygmus, weight loss, weakness/fatigue, severe abdominal pain
atypical: anaemia in 10-15%, osteopenia and osteoporosis, muscle weakness, itchy skin conditions, lack of periods, bleeding disorders due to vit k defiency

Question 4

investigations for coeliac disease
general
serology - how does these work
surgical

Answer 4

general: U&Es, FBC, LFTs
serology: tissue transglutaminase IgA, endomysial IgA, deamidated gliadin peptide IgA and IgG. When small intestine exposed to gluten, there is overreaction of immune system to produce proteins involved in tissue damage, therefore we can monitor these for compliance to gluten free diet
surgical: duodenal biopsies

Question 5

how many biopsies needed from duodenum and why?

on microscopy, 4 changes you would see

Answer 5

4 biopsies as changes can be patchy

microscopic features:

• villous atrophy
• crypt hyperplasia
• inc lymphocytes in lamina propria (chronic inflam)
• inc intraepithelial lymphocytes (IEL)

gluten free diet = villous recovery

Question 6

5 coeliac disease complications

Answer 6

1) enteropathy associated T-cell lymphoma
2) dermatitis hepetiformis
3) refractory CD despite adherence to gluten free diet
4) infertility/miscarriage
5) high risk adenocarcinoma in intestines

Question 7

what is crohns?

said to be idiopathic but what are possible causes

Answer 7

an idiopathic chronic inflammatory bowel disease often complicated by fibrosis and obstructive symptoms

possible causes: genetic, infections, immunologic, environmental, dietary, vascular, NSAIDs, smoking (doubles risk)

Question 8

clinical feature of crohns (5 things)

Answer 8

> prolonged, non-bloody diarrhoea (blood if colon involved)
weight loss
low grade fever
abdo pain, relieved by opening bowels
chronic, indolent course with periods of remission/relapse

Question 9

morphological features of crohns

microscopic features of crohns

Answer 9

morphological:
> fat wrapping of serosa
> skip lesions (normal bowel separated by abnormal bowel)
> ulceration with cobblestone pattern
>strictures due to fibrosis

microscopic:
> full thickness inflammation bowel wall
>preserved crypt architecture
> mucosal ulceration
>fissuring ulcers
>granulomas

Question 10

5 complications of crohns

Answer 10

> deep ulcers lead to fistula
> intra-abdominal abcesses
> obstruction due to adhesions
> risk of adenocarcinoma
> obstruction due to strictures caused by inc fibrosis

Question 11

what is ulcerative colitis, what does it effect

one thing that protective, one thing that exacerbates UC

Answer 11

inflammatory bowel disease only effects large bowel from rectum to caecum. Unlike crohns, only affects mucosa and submucosa

smoking is protective, NSAIDs exacerbate

Question 12

5 clinical features of ulcerative colitis

Answer 12

• abdo pain
• low grade fever
• weight loss
• mucoid diarrhoea
• intermittent attacks of bloody diarrhoea

Question 13

microscopic features of UC

Answer 13

inflammation confined to mucosa
diffuse acute and chronic inflammation
crypt architecture distortion

Question 14

complications of UC

Answer 14

> toxic megacolon
> complications lead to surgery
> refractory to medical treatment
> refractory bleeding
> dysplasia/adenocarcinoma

Question 15

investigations of UC/ crohns

Answer 15

inflammatory markers eg CRP
endoscopy/biopsies
radiological imaging
FBC
LFTs
U&Es

Question 16

7 key differences between crohns and UC

Answer 16

Crohns bleeding is occassional, UC is very common

crohns obstruction common, UC uncommon

crohns fistula common, UC uncommon

crohns weight loss common, UC uncommon

crohns is entire GIT, contains skip lesions, whereas UC is large bowel only and continuous

crohns pathology is full thickness, crohns is mucosa/submucosa only

crohns smoking makes worse, UC smoking makes better