Syspath - Gi - Small And Large Bowel

Front 1

Name four viral enteropathogens

Back 1

* Norwalk
* Rotavirus
* Adenovirus
* Poliovirus

Front 2

Name 5 common bacterial enteropathogens

Back 2

Campylobacter Jejuni
Clostridium difficile
E. coli
Salmonella
Shigella
Yersinia
Mycobacterium

Front 3

What are the four mechanisms by which bacterial enteropathogens function?

Back 3

1) Ingestion of a Preformed Toxin (staph enterotoxin)
2) Colonization, then Toxin Production (E. coli, Samonella, Shigella, Vibrio)
3) Locally-acting Cytotoxin (Shigella, Campylobacter)
4) Local Tissue Invasion

Front 4

What's the difference between a Diarrheal Syndrome and a Dysenteric Syndrome?

Back 4

Diarrhea caused by toxins, Dysentery caused by local tissue invasion and destruction

Front 5

Why are Celiac patients so responsive to wheat?

Back 5

Celiac Sprue involves a T-Cell mediated immune response against gluten, a component of wheat.

Front 6

"Volcano Lesions" are associated with which enteric pathology?

Back 6

Pseudomembranous Colitis

Front 7

What parasitic infection mimics Crohn's Disease?

Back 7

Amoebiasis

Front 8

In what syndrome does maldigestion due to ineffective enzymes mimic pancreatic insufficiency?

Back 8

Zollinger-Ellison. Low duodenal pH makes pancreatic enzymes ineffective.

Front 9

Histologically, how does Celiac Sprue appear?

Back 9

** Note that these findings are NON-SPECIFIC to celiac sprue!

* Flat, blunted mucosal villae
* Increased leukocytes in the lamina propria
* Intraepithelial lymphocytosis

Front 10

What's the pathology? (bowel mucosa)

Back 10

Celiac Sprue

Front 11

What are the pathologic characteristics of Ulcerative Colitis?

Back 11

* Typically limited to the distal colon
* Ulcerating inflammation of MUCOSA ONLY
* Continuous (no skip lesions)
* Cancer risk is 20-30x baseline

Front 12

What's the mechanism behind both Crohn's and Ulcerative Colitis?

Back 12

Autoimmunity of a CD-4 T-Cells gainst normal epithelium.

Front 13

What are the pathologic characteristics of Crohn's Disease?

Back 13

* May occur throughout the GI tract
* Often "patchy" involvement
* Transmural Inflammation
* Often forms Fistulae

Front 14

How do diverticula form? Where do they form?

Back 14

Bowel diverticula typically form in the descending and sigmoid colon, through all layers of the bowel. The typically appear where arteries perforate through to the submucosa, forming a weak spot in the gut wall.

Front 15

What's the difference between diverticulosis and diverticulitis?

Back 15

Diverticulitis is an acute infection, diverticulosis is the presence of divertucula in the bowel wall.

Front 16

What are the features of a hyperplastic colonic polyp?

Back 16

Hyperplastic polyps signify a benign overgrowth of epithelial glands. They are not considered precursor lesions.

Front 17

What are the features of a colonic adenoma?

Back 17

Colon adenomas are true intraepithelial neoplasia. They are commonly asymptomatic, and may develop into cancer. They come in three types: Tubular, Tubulovillous, and Villous, in increasing order of both rarity and malignancy.

Front 18

What are the features of a Hamartoma?

Back 18

Hamartomas are benign malformations of glands and stroma. There are two forms in the colon:
1) Juvenile Polyps
2) Peutz-Jeghers Polyps (part of the Peutz-Jeghers Syndrome)

Front 19

What are Lymphoid Polyps?

Back 19

Lymphoid Polyps are benign inflammatory structures consisting of granulation tissue and remnants of mucosa, caused by chronic IBD.

Front 20

What's the most common neoplasm of the colon?

Back 20

Adenomatous polyps are found in 30-40% of people over age 50. They are small, pendunculated, and contain a malignant foci. APs are a precursor to colonic adenocarcinoma.

Front 21

Describe Peutz-Jeghers in the colon.

Back 21

PJ polyps are themselves benign hamartomas, but are associated with a propensity for colonic carcinoma.

Front 22

Describe the pathology of APC.

Back 22

Adenomatous Polyposis of the Colon is an autosomal dominant (often spontaneous) mutation of a tumor suppressor gene in teh Wnt pathway. Most have colon cancer by age 40.

Front 23

Describe the pathology of HNPCC

Back 23

HNPCC is typically a defect in the mismatch repair gene MLH-1 or MLH-2. Tendency is to develop an early (<40 years) right-sided colon cancer.

Front 24

What dietary factors are considered risks for colon cancer?

Back 24

* High caloric content
* Low fiber content
* High refined carbs
* Increased red meat intake
* Decreased intake of protective micronutrients

Front 25

How does a low-fiber diet contribute to the development of colon cancer?

Back 25

Decreased stool bulk slows transit time – prolongs contact of bowel contents

Front 26

What is the single-most important prognostic factor in colon cancer?

Back 26

The presence of lymph node metastasis is the single-most important prognostic factor in colon cancer.

Front 27

What's the pathology? (Colon)

Back 27

Tubular Adenoma. Epithelial cells show nuclear elongation, stratification and crowding, most pronounced at surface, with tubular arrangement of crypts and glands.