Intestine Path 2 Flashcards
What causes Crohn dz?
environmental, immunological and bacterial factors interact and result in chronic inflammatory disorder where immune system attacks GI tract in absence of any invader
What genetic factors may play a role in Crohn?
NOD2 gene
HLA-DQ4 and HLA-DR7
What cells may be implicated in the pathology of Crohn dz?
Th17 cells
What are symptoms of Crohn dz?
ab pain, diarrhea (maybe blood), malabsorption and weight loss, perianal itching, pain or bleeding
What are the complications of Crohn dz?
strictures, obstruction, fistulae, adhesions, abscesses
What are extraintestinal manifestations of Crohn dz and ulcerative colitis?
erythema nodosum and pyoderma gangrenosum uveitis, episcleritis inflammatory seronegative arthropathies hepatitis, PSC, coagulopathies hydronephrosis prothrombotic tendency in veins ostopenia in Crohns
What are characteristics of Crohn dz?
skip lesions, fat wrapping, cobblestoning, apthous ulcers, non-caseating granulomas, lymphoid beads, pyloric metaplasia, thickened fibrotic wall (look for sticks!), transmural inflammation and fissures
What is the treatment of Crohn dz?
antibiotics, 5-ASA, prednisone and immunomodulators
avoid surgical resection, not cured by surgery
What are the complications of ulcerative colitis?
iron deficiency anemia
blood loss requiring transfusion
toxic megacolon
dysplagia and adenocarcinoma
What are characteristics of ulcerative colitis?
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
What cell feature indicates high grade dysplasia in ulcerative colitis?
nuclei in upper half of cells
What are hyperplastic polyps?
small <5mm, non-neoplastic
rectosigmoid
smooth surfaced
What is the histology of hyperplastic polyps?
abundant crypts lined by mucinous goblet cells, star-like patterns to crypts, scant intervening lamina propria, no dysplasia
What are characteristics of adenomas (neoplastic polyps)?
sessile or pedunculated
tubular, tubulovillous, villous
What three features of adenomas correlate with risk of malignancy?
SIZE
architecture
degree of dysplasia
What do adenomas look like histologically?
bluer - mucin depletion/loss of goblet cells, nuclear hyperchromasia, piling of nuclei, mitoses
What is a sign that a high grade dysplasia is NOT at risk for being malignant?
doesn’t go past muscularis mucosa into submucosa - no lymphatic channels
What is FAP?
AD from APC gene ch 5q21, 100% risk of CRC
What are complications from the sheer number of polyps in FAP?
intussusception, obstruction, bleeding, rectal prolapse
What is HNPCC (Lynch syndrome)?
polyps - not as many as FAP
DNA mismatch repair gene mutation results in microsattelite instability
MMR mutation
What are the precursor lesions of Lynch?
sessile serrated adenomas, large right sided hyperplastic polyps, mucinous carcinomas (uterine/ovarian)
What diets are associated with CRC?
high in fat and low in fiber
What can have a protective effect against CRC?
aspirin and other NSAIDs
What are the two pathways for the dev of colon cancer?
APC/beta catenin pathway
DNA mismatch repair
What events constitute the APC/beta catenin pathway?
first - APC gene
remaining hits could be - K-ras mutations, p53 mutation, DPC4/DCC/SMAD4 mutation, EGFR, DCC
What are characteristics of right sided CRCs?
exophytic, obstruction is uncommon since ascending is wider –> iron deficiency anemia, SOB
What are characteristics of left sided CRCs?
outward into lumen, obstructs feces, napkin ring constriction or apple core lesion –> change in bowel habits, positive stool Guaiac test
What are microscopic features of CRC?
cribiforming (multiple lumens)
sometimes mucinous (colloid)
signet ring cells
geographic necrosis
What is the role of CEA in CRC?
not useful for screening
high rates correlate w adverse prognosis
serial measures can detect recurrence
good at detecting liver metastases from CRC
