3- pathology of IBD Flashcards
what are the 2 main types of idiopathic inflammatory bowel disease (IBD)?
crohn’s disease & ulcerative colitis
what is aetiology of IBD?
unknown cause hence the name idiopathic inflammatory bowel disease
what is crohn’s disease?
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)
what is the most common area of crohn’s disease?
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
who is crohn’s most common for?
young people (mostly 20-30) and more common in males
what is symptoms for crohn’s disease?
- abdominal pain
- small bowel obstruction
- diarrhoea
- bleeding PR
- anaemia
- weight loss
what is characteristic feature of crohn’s disease (seen both macroscopically & microscopically)?
occurs in patchy, segmental distribution throughout GI tract
what is seen microscopically for crohn’s disease?
- increased chronic inflammatory cells in lamina propria and crypt branching with granulomas
- shattered colonic crypts leading to ulcers, fibrosis
do patients always respond to treatment for crohn’s?
no, some patients don’t respond well to treatment (steroids) →so they lead to fibrosis to structures to bowel obstruction to surgery
what does crohn’s look like macroscopically?
→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
what is hallmark inflammation of crohn’s?
transmural inflammation = inflammation involves all layers of bowel wall (leading to bleeding in bowel)
- deep knife like fissuring ulcers
what type of granuloma for crohn’s?
non-caseating granuloma
what are complications of crohn’s?
- 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
what is the abnormal immune response in crohn’s?
- Persistent activation of T-cells and macrophages (failure to switch off)
- Excess proinflammatory cytokine production
- Maybe alterable by changing intestinal microflora…”Probiotics”
what is ulcerative colitis?
- Chronic inflammatory disorder confined to colon and rectum
- Mucosal and submucosal inflammation
- Unknown aetiology
who is more likely to have ulcerative colitis?
- young people but less for children than crohns
- more in females
where is ulcerative colitis?
starts from recctum and goes up to where it stops
- disease confined to colon & rectum
- continuous and confluent extending proximallly for carrying lengths
what is clinical symptoms of ulcerative colitis?
Diarrhoea, mucus and blood PR
= chronic course of exacerbation & remission
what happens to colon in ulcerative colitis?
red & inflamed
what is histological appearance of ulcerative colitis?
- 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
do all patients respond to ulcerative colitis treatment?
- no, can need life saving therapy
what is characteristic type of inflammation for ulcerative colitis?
superficial inflammation = confined to mucosa & submucosa (except in toxic megacolon)
what granulomas are in ulcerative colitis?
none
what are complications of ulcerative colitis?
- 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
what is toxic megacolon?
= complication of ulcerative colitis
- colon swells up to massive size and will rupture if not removed = emergency colectomy is required
what are similarities between crohn’s and ulcerative colitis?
- Chronic diseases
- Unknown aetiology
- Ulceration
- Inflammation
- Relapsing and remitting course
- Bloody diarrhoea
- Both increase risk of cancer
what are 2 key differences between crohn’s and ulcerative colitis?
- 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
