3- pathology of IBD

Question 1

what are the 2 main types of idiopathic inflammatory bowel disease (IBD)?

Answer 1

crohn’s disease & ulcerative colitis

Question 2

what is aetiology of IBD?

Answer 2

unknown cause hence the name idiopathic inflammatory bowel disease

Question 3

what is crohn’s disease?

Answer 3

granulomatous condition
- chronic inflammatory & ulcerating condition of GI tract that can affect anywhere from mouth to anus
- it is characterised by exacerbations & remissions (has unpredictable response to therapy)

Question 4

what is the most common area of crohn’s disease?

Answer 4

can occur anywhere from mouth to anus but common in terminal ileum & colon

• 2/3 have small bowel disease (mostly terminal ileum)
• 1/6 have colonic/anal
• 1/6 both

Question 5

who is crohn’s most common for?

Answer 5

young people (mostly 20-30) and more common in males

Question 6

what is symptoms for crohn’s disease?

Answer 6

• abdominal pain
• small bowel obstruction
• diarrhoea
• bleeding PR
• anaemia
• weight loss

Question 7

what is characteristic feature of crohn’s disease (seen both macroscopically & microscopically)?

Answer 7

occurs in patchy, segmental distribution throughout GI tract

Question 8

what is seen microscopically for crohn’s disease?

Answer 8

• increased chronic inflammatory cells in lamina propria and crypt branching with granulomas
• shattered colonic crypts leading to ulcers, fibrosis

Question 9

do patients always respond to treatment for crohn’s?

Answer 9

no, some patients don’t respond well to treatment (steroids) →so they lead to fibrosis to structures to bowel obstruction to surgery

Question 10

what does crohn’s look like macroscopically?

Answer 10

→looks like cobbled street, stricturing of terminal ileum with thickening of the bowel wall & fat trapping →leads to bowel obstruction

• also produces intermittent long serpiginous ulcers that destroy mucosa
• pseudopolyps can also be seen but less common

Question 11

what is hallmark inflammation of crohn’s?

Answer 11

transmural inflammation = inflammation involves all layers of bowel wall (leading to bleeding in bowel)
- deep knife like fissuring ulcers

Question 12

what type of granuloma for crohn’s?

Answer 12

non-caseating granuloma

Question 13

what are complications of crohn’s?

Answer 13

• malabsorption
• fistulas
• anal disease (sinuses, fissures, skin tags, abscesses)
• intractable disease = often needs surgery & leads to no bowel left
• Perforation
• Malignancy
• Amyloidosis
• Others (extraintestinal assoc.)
• Rarely Toxic megacolon

Question 14

what is the abnormal immune response in crohn’s?

Answer 14

• Persistent activation of T-cells and macrophages (failure to switch off)
• Excess proinflammatory cytokine production
• Maybe alterable by changing intestinal microflora…”Probiotics”

Question 15

what is ulcerative colitis?

Answer 15

• Chronic inflammatory disorder confined to colon and rectum
• Mucosal and submucosal inflammation
• Unknown aetiology

Question 16

who is more likely to have ulcerative colitis?

Answer 16

• young people but less for children than crohns
• more in females

Question 17

where is ulcerative colitis?

Answer 17

starts from recctum and goes up to where it stops

• disease confined to colon & rectum
• continuous and confluent extending proximallly for carrying lengths

Question 18

what is clinical symptoms of ulcerative colitis?

Answer 18

Diarrhoea, mucus and blood PR
= chronic course of exacerbation & remission

Question 19

what happens to colon in ulcerative colitis?

Answer 19

red & inflamed

Question 20

what is histological appearance of ulcerative colitis?

Answer 20

• diffuse mucosal chronic active colitis, massive influx of inflammatory cells
• The crypts appear shortened and separate from the muscularis mucosae
• inflammatory cells filling mucosa and extending to submucosa
• basal lymphoplasmacytic infiltrate with irregular shaped branching crypts
• neutrophils invade the epithelium & abscesses in crypt lumina

Question 21

do all patients respond to ulcerative colitis treatment?

Answer 21

• no, can need life saving therapy

Question 22

what is characteristic type of inflammation for ulcerative colitis?

Answer 22

superficial inflammation = confined to mucosa & submucosa (except in toxic megacolon)

Question 23

what granulomas are in ulcerative colitis?

Answer 23

none

Question 24

what are complications of ulcerative colitis?

Answer 24

• intractable disease
• toxic megacolon
• colorectal carcinoma (longer you have disease, increased chance of cancer)
• blood loss
• electrolyte disturbance (hypokalaemia)
• extra GI manifestations like eyes, liver, joints, skin

Question 25

what is toxic megacolon?

Answer 25

= complication of ulcerative colitis
- colon swells up to massive size and will rupture if not removed = emergency colectomy is required

Question 26

what are similarities between crohn’s and ulcerative colitis?

Answer 26

• Chronic diseases
• Unknown aetiology
• Ulceration
• Inflammation
• Relapsing and remitting course
• Bloody diarrhoea
• Both increase risk of cancer

Question 27

what are 2 key differences between crohn’s and ulcerative colitis?

Answer 27

• crohn’s has patchy segmental disease and ulcerative colitis is diffuse, continuous disease
• crohn’s inflammation is transmural inflammation and ulcerative colitis is superficial inflammation