IBD Histopathology Flashcards

1
Q

What are the main causes of infective diarrhoea?

A

gastroenteritis/enterocolitis
- bacterial (shigella)
- viral (rotavirus)
-protozoan (giardiasis)
atypical infective agents can cause diarrhoea in immunosuppressed individuals
pseudomembranous colitis can be a complication of C. diff

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2
Q

What are the main hallmark causes of diarrhoea?

A

inflammation
neoplasia
vascular disease

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3
Q

What are the main inflammatory causes of diarrhoea?

A
  • infective
  • Coeliac
  • IBD
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4
Q

What vascular diseases can precipitate diarrhoea?

A

vasculitis
ischaemic enteritis/colitis
radiation enteritis/colitis
(these all damage small blood vessels)

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5
Q

What types of neoplasia may cause diarrhoea?

A

lymphoma (malabsorption)
distal colon carcinoma (overflow diarrhoea)
neuroendocrine tumour (secretes peptides such as 5-HT/serotonin. These can result in episodic palpitations, flushing and diarrhoea)

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6
Q

What are the main histological features of ulcerative colitis?

A
  • wide, shallow intestinal crypts
  • inflammation is limited to mucosa
  • mixed acute and chronic inflammation in mucosa
  • crypt branching
  • crypt abcesses
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7
Q

What intestinal complications may present with ulcerative colitis?

A
  • backwash ileitis (in those with pan-colitis)
  • appendix involvement (66%)
  • ulceration starts in rectum and spreads proximally
  • increased incidence sclerosing cholangitis
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8
Q

What histological features are common to both ulcerative colitis and Crohns?

A
  • mixed acute and chronic inflammation in mucosa
  • crypt branching
  • crypt abcesses
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9
Q

Where the gross features that distinguish ULCERATIVE COLITIS from Crohn’s?

A
  • only affects colon
  • begins distally in rectum, spreads proximally
  • may involve entire colon (pancolitis)
  • geographical ulcers
  • confluent/continuous involvement
  • strictures are unusual
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10
Q

What intestinal complications may present with Crohn’s disease?

A
  • patchy involvement of upper GI tract
  • skip lesions
  • fistula formation which links bowel to other viscera
  • appendix involvement (33%)
  • fat wrapping: mesenteric fat coats bowel surface
  • rectal sparing
  • perianal skin tags and fistulas
  • cobblestone mucosa
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11
Q

Where the gross features that distinguish CROHN’S from UC?

A
  • ileum involvement (66%) - hosepipe thickening of terminal ileum
  • colon involvement (33%), mainly right sided
  • usually spares rectum but anus often involved (75%)
  • skip lesions
  • fat wrapping (on serosal surface)
  • strictures
  • thickened wall
  • fistulae
  • cobblestone mucosa
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12
Q

What are the main histological features of Crohn’s?

A
  • deep, fissuring ulcers through entire wall
  • lymphoid inflammation (throughout wall)
  • granulomas often found in bowel and lymph nodes
  • Crohn’s rosary: bead-like lymphoid aggregates in mucosal propria
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13
Q

Describe the nature of the inflammation in Crohn’s

A
transmural inflammation
skip lesions
can occur anywhere along GI tract
strictures
linear ulcers
fissures
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14
Q

Describe the nature of the intestinal inflammation in ulcerative colitis

A
continuous colonic involvement 
begins in rectum, progression proximally through colon
active disease: superficial ulceration
inactive disease: atrophy 
pseudopolyps
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15
Q

What are the different types of ulcerative colitis?

A

proctitis: only rectum
proctosigmoiditis: rectum and sigmoid colon
distal colitis: only left side of colon
pancolitis: entire colon
backwash ileitis: distal/terminal ileum

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16
Q

What are the main clinical features of UC?

A

typical: diarrhoea with blood and mucus

may present with toxic megacolon

17
Q

What is toxic megacolon?

A

acute form of colonic distension
megacolon = dilated colon
Sx: abdo pain, bloating, fever, tachycardia, dehydration
Tx: colectomy if severe, otherwise conservative management using steroids and fluid resuscitation, antibiotics for sepsis

18
Q

What are the clinical features of Crohn’s disease?

A

typical: abdo pain, diarrhoea, abdo mass, weight loss

19
Q

What extra-intestine features are present in UC?

A
Anaemia
fever
PSC
uveitis
ankylosis spondylitis and sacro-iletis
pyoderma gangrenousum
20
Q

What are the extra-intestinal features in Crohn’s disease?

A
anaemia
fever
anterior uveitis 
aphthous ulcers
seronegative arthritis
erythema nodosum 
anal skin tags
perianal fistulae
21
Q

What are the short and long term risk of UC?

A

short: anaemia, toxic megacolon, perforation, peritonitis
long: colonic adenocarcinoma

22
Q

What is the risk of colonic adenocarcinoma in UC?

A

risk is proportional to length of inflamed colon

history and duration of disease

23
Q

What are the short and long term risk of Crohn’s?

A

short: intestinal obstruction, fistulae, pericolic abscess
long: colonic adenocarcinoma, small bowel lymphoma

24
Q

What is an aphthous ulcer?

A

recurrent round or oval sore/ulcer
inside the mouth or where skin is not tightly attached to the bone
similar to canker score
in Crohn’s patients, they may appear concomitantly with intestinal inflammation flare ups

25
What is the complication of an aphthous ulcer?
It can deteriorate into a granuloma sloughing of intestinal mucosal debris scar tissue
26
What is the hallmark histological appearance found in Crohn's disease?
cobblestone mucosa = irregular nodular appearance of mucosa with hyperaemia and focal superficial ulceration
27
What is hyperaemia?
increase of blood flow to a given tissue clinically hyperaemia presents as erythema Occurs physiologically through vasodilation
28
What investigations are performed to Dx IBD?
``` Blood tests Stool tests Endoscopy Radiography Biopsy ```
29
What lab results are indicated in the Dx of IBD?
- haemogram - CRP increased - ESR increased - platelets increased - Hb decreased - faecal calprotectin levels correlate with histological inflammation
30
How can faecal calprotectin help in IBD monitoring?
levels will correlate with histological changes Can also predict relapses and detect pouchitis
31
What is pouchitis?
inflammation of the ileal pouch (artificial rectum surgically created out of ileal tissue in patients who have had a colectomy) Some evidence t suggest link between FODMAP diet and risk of pouchitis
32
What is the histology characteristic of UC?
- mucosal inflammation (superficial ulceration) - distorted architecture - superficial ulcers - granuloma are absent or affecting mucosa only
33
What is the histology characteristic of Crohn's?
- transmural inflammation - patchy inflammatory architecture with skip lesions - deep ulcerative fissures - mucosal and transmural granulomas
34
What are genetic factors are there for IBD?
UC: more common with HLA-DR2 alleles Crohn's: more common in DR5/DQ1 alleles 3-20x higher incidence in 1st degree relatives
35
What colonic complications are present with UC?
``` bleeding cancer strictures perforations toxic megacolon pseudopolyps haemorrhoids ```
36
What are the intestinal complications in Crohn's?
``` cancer fistula abscess perforation stricture ```
37
What surgical treatment options are available for Crohn's disease?
``` iliocaecal resection segmental resection colectomy and ileorectal anastomosis temporary loop ileostomy proctocolectomy stricturoplasty ```
38
What are the other forms of IBD, other than UC and Crohn's?
collagenous colitis/lymphocytic colitis ischaemic colitis infective colitis indeterminate colitis