Pathology of Inflammatory Bowel Disease

Question 1

What is the definition of Inflammatory Bowel Disease (IBD)

Answer 1

Spectrum of chronic intestinal inflammation with episodic symptoms and exacerbation

spectrumL
CD - Indeterminate colitis - UC

Question 2

Where is IBD most more common?

Answer 2

well-developed areas
urban areas
higher socioeconomic classes

Question 3

What pathology is NOD2/CARD-15 associated with?

Answer 3

Crohn’s

gene product binds to bacterial peptidoglycans

Question 4

What pathology is IL23R gene associated with?

Answer 4

IL-23 receptor

inc risk for both CD and US

Question 5

What pathology is HNFA gene associated with? What other gene is it associated with?

Answer 5

reduce barrier function (tight junction defects)
Crohn’s
associated with MODY (maturity onset diabetes of the young)

Question 6

What characteristic of the gut flora is associated with IBD?

Answer 6

anti-flagellin antibodies - Crohn’s

Question 7

What are the mucosal immune responses in CD and UC?

Answer 7

1. CD: TH1 cells that produce INF-gamma (chronic delayed type sensitivity rxn)
2. US: excessive activation of TH2 cells

Question 8

What are characteristics of Crohn’s Disease?

Answer 8

1. Mouth to anus (skip lesions) - spares rectum
2. cobblestoning, creeping fat
3. Radiology: STRING SIGN
4. NONCASEATING GRANULOMAS W MULTINUCLEATED GIANT CELLS (pathognomonic)
5. Transmural inflammation
6. Paneth cell metaplasia (left colon)
7. mucosal aphthous ulcers (ulcers run parallel to length of bowel

Question 9

What are histological features of Crohn’s?

Answer 9

Noncaseating Granulomas
Multinucleated Giant Cells
Paneth Cell metaplasia

Question 10

What are characteristics of Ulcerative Colitis?

Answer 10

1. Continuous lesions (starts at rectum, extends prox)
2. Mucosa + submucosa (not full thickness)
3. Friable + hemorrhagic
4. Flattened mucosa = radiography = lead pipe
5. chronic = inflammatory pseudopolyps
6. crypt abscesses

Question 11

What are pseudopolyps comprised of? what do they look like?

Answer 11

mononuclear inflammation
polypoid appearance (rug like)

Question 12

How does smoking affect risk of UC and CD?

Answer 12

CD: increased risk
UC: decreased risk

Question 13

What is the clinical presentation, extranintestinal features, and complications of Crohn’s?

Answer 13

clinical presentation: RLQ colicky pain, aphthous ulcers

Extraintestinal features: Erythema nodosum, iritis/uveitis, pyodermagrangrenosum, spondyloarthropathy, nephrolithiasis

Complications: Fistulas, calcium oxalate stones

Question 14

What is the clinical presentation, extranintestinal features, and complications of Ulcerative Colitis?

Answer 14

presentation: Left sided pain, bloody/mucus diarrhea

Extraintestinal features: PSC, pyoderma grangrenosum, spondyloarthropathy

Complications: Epithelial dysplasia, adenocarcinoma, toxic megacolon

Question 15

What are the two types of Microscopic colitis what are shared features of the two?

Answer 15

1. Colagenous colitis
2. Lymphocytic colitis

Idiopathic, chronic, watery diarrhea w/o blood or weight loss
radiographically: normal bowel

Question 16

How are Collagenous colitis and lymphocytic colitis different?

Answer 16

Collagenous colitis: F>M, Dense subepithelial collagen layer; intraepithelial lymphs, mixed inflammation in Lamina Propria

Lymphocytic colitis: normal appearing basement membrane area, more dense thant collagenous colitis,
associated with celiac disease

Question 17

What is Dysplasia associated lesion or mass (DALM)? what are risk factors?

Answer 17

Long term complication of IBC
risk:
1. duration of ibd (>8-10 years)
2. extent of ibd (pancolitis > left sided disease)
3. Severity (more common = more risk)