Intestine Path 2

Question 1

What causes Crohn dz?

Answer 1

environmental, immunological and bacterial factors interact and result in chronic inflammatory disorder where immune system attacks GI tract in absence of any invader

Question 2

What genetic factors may play a role in Crohn?

Answer 2

NOD2 gene

HLA-DQ4 and HLA-DR7

Question 3

What cells may be implicated in the pathology of Crohn dz?

Answer 3

Th17 cells

Question 4

What are symptoms of Crohn dz?

Answer 4

ab pain, diarrhea (maybe blood), malabsorption and weight loss, perianal itching, pain or bleeding

Question 5

What are the complications of Crohn dz?

Answer 5

strictures, obstruction, fistulae, adhesions, abscesses

Question 6

What are extraintestinal manifestations of Crohn dz and ulcerative colitis?

Answer 6

erythema nodosum and pyoderma gangrenosum
uveitis, episcleritis
inflammatory seronegative arthropathies
hepatitis, PSC, coagulopathies
hydronephrosis
prothrombotic tendency in veins
ostopenia in Crohns

Question 7

What are characteristics of Crohn dz?

Answer 7

skip lesions, fat wrapping, cobblestoning, apthous ulcers, non-caseating granulomas, lymphoid beads, pyloric metaplasia, thickened fibrotic wall (look for sticks!), transmural inflammation and fissures

Question 8

What is the treatment of Crohn dz?

Answer 8

antibiotics, 5-ASA, prednisone and immunomodulators

avoid surgical resection, not cured by surgery

Question 9

What are the complications of ulcerative colitis?

Answer 9

iron deficiency anemia
blood loss requiring transfusion
toxic megacolon
dysplagia and adenocarcinoma

Question 10

What are characteristics of ulcerative colitis?

Answer 10

friability and bleeding, pseudopolyps, loss of haustral folds, continuous distribution, shortening of colon, chronic inflammation of MUCOSA, no fibrosis or granulomas, collar button ulcers, gland dropout

Question 11

What cell feature indicates high grade dysplasia in ulcerative colitis?

Answer 11

nuclei in upper half of cells

Question 12

What are hyperplastic polyps?

Answer 12

small <5mm, non-neoplastic
rectosigmoid
smooth surfaced

Question 13

What is the histology of hyperplastic polyps?

Answer 13

abundant crypts lined by mucinous goblet cells, star-like patterns to crypts, scant intervening lamina propria, no dysplasia

Question 14

What are characteristics of adenomas (neoplastic polyps)?

Answer 14

sessile or pedunculated

tubular, tubulovillous, villous

Question 15

What three features of adenomas correlate with risk of malignancy?

Answer 15

SIZE
architecture
degree of dysplasia

Question 16

What do adenomas look like histologically?

Answer 16

bluer - mucin depletion/loss of goblet cells, nuclear hyperchromasia, piling of nuclei, mitoses

Question 17

What is a sign that a high grade dysplasia is NOT at risk for being malignant?

Answer 17

doesn’t go past muscularis mucosa into submucosa - no lymphatic channels

Question 18

What is FAP?

Answer 18

AD from APC gene ch 5q21, 100% risk of CRC

Question 19

What are complications from the sheer number of polyps in FAP?

Answer 19

intussusception, obstruction, bleeding, rectal prolapse

Question 20

What is HNPCC (Lynch syndrome)?

Answer 20

polyps - not as many as FAP
DNA mismatch repair gene mutation results in microsattelite instability
MMR mutation

Question 21

What are the precursor lesions of Lynch?

Answer 21

sessile serrated adenomas, large right sided hyperplastic polyps, mucinous carcinomas (uterine/ovarian)

Question 22

What diets are associated with CRC?

Answer 22

high in fat and low in fiber

Question 23

What can have a protective effect against CRC?

Answer 23

aspirin and other NSAIDs

Question 24

What are the two pathways for the dev of colon cancer?

Answer 24

APC/beta catenin pathway

DNA mismatch repair

Question 25

What events constitute the APC/beta catenin pathway?

Answer 25

first - APC gene

remaining hits could be - K-ras mutations, p53 mutation, DPC4/DCC/SMAD4 mutation, EGFR, DCC

Question 26

What are characteristics of right sided CRCs?

Answer 26

exophytic, obstruction is uncommon since ascending is wider –> iron deficiency anemia, SOB

Question 27

What are characteristics of left sided CRCs?

Answer 27

outward into lumen, obstructs feces, napkin ring constriction or apple core lesion –> change in bowel habits, positive stool Guaiac test

Question 28

What are microscopic features of CRC?

Answer 28

cribiforming (multiple lumens)
sometimes mucinous (colloid)
signet ring cells
geographic necrosis

Question 29

What is the role of CEA in CRC?

Answer 29

not useful for screening
high rates correlate w adverse prognosis
serial measures can detect recurrence
good at detecting liver metastases from CRC